Tuesday, 23 December 2014

Blown Gearbox?

Ok so now this is starting to wear a little thin but guess what yup I done blew it again!
Basically I have been driving the car no more than 2 weeks since picking it up after its new brushes and bearing were fitted and the day before yesterday I was driving home from a short visit to the mother in laws and POP WHIIIIRRRR! The sound of grinding teeth coming from the gearbox, initially I assumed that the motor has simply popped out of its collar but after speaking with Brent it seems that I may well have blown the gearbox (as my assumptions are simply impossible there is no room for movement in the collar and the motor is clamped tightly to the gearbox)
And now I think of it my worst fears are unfortunately coming true I had initially worried about the fact that I was potentially putting 3 times the torque through this little gearbox and my initial plans were to lose the gearbox completely, however due to the transverse gearbox arrangement it was decided (to my annoyance) that it would be simpler to keep the existing gearbox, I am now regretting that decision.
What I should have done, and will now probably have to do is dump the expensive coupling plate and collar and all the motor mounts again expensively constructed and source a differential that is capable of taking some serious torque and get this and its matching rear wheel hubs fitted under the beat, dump the whole Beat gearbox, axels and wheel hubs and fit the motor inline as I had originally planned.
Alternatively I find out what has broken and replace it like for like with parts sourced on line from somewhere! (this could be difficult or impossible) 

Wednesday, 3 December 2014

Replacing the LVC/HVC loom

I have been meaning to get around to replacing the LVC/HVC loom with decent ODBC II cables to allow for the removal of the Traction Pack without the need to unwrap and separate 18 spade terminal connections (6 per box) and then re wrap them on reconnect with insulating tape.
Seeing as this would require the complete removal of the entire Traction Pack and cracking the lids (Silicone sealed against damp) I had been putting it off until I had another reason to do it, Well here it came, I was around the mother in laws the other day and when I went to leave the car switched on as normal but when I put my foot on the pedal “nothing” not a dickybird no movement what so ever from the motor, suspected low 12V at first but a laptop conformed the problem was not with the controller at all as far as it was concerned it was all systems go! So this left only one possible explanation, The LVC/HVC loom was preventing throttle.
So I either had another dead cell or there was a fault on the loom and considering the recent damp spell I was suspecting damp in the loom.
Taking a little risk I removed the loom and connected the throttle directly to enable me to drive home (which worked) and the next day (which was a Sunday luckily) I set about the complete removal of the traction pack.
I had previously purchased the required ODBC II cables (4 of them, Three short 1 meter and one long 3 meter) to allow the complete LVC/HVC replacement loom, The huge advantage of the ODBC II cables is the waterproof plugs and sockets that are designed for automotive use and so do not suffer from damp or dirt getting into the connections and causing failures.
After removing all the lids I found that yet again despite my efforts with silicone the front Battery box has been compromised with a little water nothing major but not good all the same, So I took a heat gun to it on low to dry it our properly and after fitting the ODBC LVC/HVC loom cable did a full silicone seal to try once more to protect against water, However I think the under tray is vital now to see if that will stop water getting into this front box.
Strangely and despite there being no rubber grommets at all on the rear boxes they were both dry as a bone so obviously the front is where the water issues are causing problems, let’s hope the new waterproof LVC/HVC cable loom does the trick (Plus the imminent front under tray) 

The Beat goes in for brush and bearing replacement

I finally got the Beat booked in for brush and bearing replacement and I also asked Brent to fit a protective aluminium tray on the underside of the car to protect against water and dirt ingress into the motor area (I had previously thought that water and dirt were the primary cause of the early brush and bearing failure but on second thoughts I feel that the most likely cause is the lack if RPM monitoring/limiting)
And after getting the Beat back from Brent with its new brushes and bearings and a shiny new aluminium under tray (1.2mm) Brent informed me that he had taken most of the time cleaning up the dirt and grit from the motor so that he could fit the new bearing so I now feel that the tray is money well spent.
However Brent did not get time to do the front tray to protect the front battery box from water ingress in the same way and I now feel that this is also a requirement (I will book it in soon for the front tray).

250 Cells tested nearly half way there!

Testing continued over the next couple of weeks until I reached the half way mark and the fog began to close in.
Now I live in a low lying area prone to flooding and we get some awesome fog this time of year, Coupled with the fact that I have just had the roof of my workshop replaced and part of this job meant the old fascia boards being removed and not replaced has resulted in the workshop getting a little more condensation that it used to.
No biggie I thought and began to plan for some replacement plastic fascia boards, However the Antec 480P PSU I had been using to power my BC168 was and old reused ex PC PSU and had a fair amount of dust in it, The addition of a little condensate soaked into this dust meant that one Saturday morning when I went out to begin another productive days cell testing I switched on the PSU to hear a crackling sound, Rapidly switched off checked the connections and tried again, as soon as I switched back on BANG! Shit there goes another PSU and after disassembling and looking for the fault I decided it was simpler to replace.
So I put in an order for as brand new 450W Antec which arrived the other day, speaking of arrivals I have a box of silicone cell separators sitting in my hallway that arrived a few weeks ago now and I will be using these soon to start constructing the Traction Pack proper.

Silicone sheet delivery imminent!

I had also ordered the silicone separators from a company called Silex they have cut them to size for me for very little extra cost, let’s hope it is all good when it arrives, I went for plain white 1.5mm 40shore (the shore rating I have discovered is the hardness of the silicone sheet) I checked with a sales rep that 40 shore was approximately the same as a standard baking sheet and was assured that it was, I also checked with them that it was 100% insulating with no impurities that would compromise it’s electrical insulating capability again I was assured it was, I only checked this as I discovered on their website that they sell conductive silicone! Which in my mind was like being able to by insulating copper or dry liquid!
So fingers crossed I may be in a position to start laying out the blocks of cells for a sizing for the Ali battery boxes I need to get made, I am planning on keeping them all under the bonnet this time as there is plenty of room and the weight should nicely compensate for the lack of engine and gearbox and laying the cells out so that they are lying flat in blocks of 30 top to bottom (so 30 high) the space under the bonnet appears to give room for 5 blocks of 30 wide so that would be 150 cells and seeing as I need to get 350 under the bonnet with possible room to upgrade to 400 cells (to give me a 300v nominal rather than 260v nominal as advised by Steve, So room for an additional 50 cells), That would be 2 full rows (of 150 cells) and a row with 100 cells at either the front or back, Each of these rows will be separate boxes of cells bolted to a frame exactly as the previous EV but all in one place, The boxes will be linked in series as before and as before I will need to run cables for LVC/HVC and balance leads although this time I am going to use ODBII Cables as they are much better in the damp that JST connectors (which are shit for EV use!) I may also have an issue sourcing more of the methods LVC/HVC boards as Steve tells me that he has stopped making them and Steve has no stock AFAIK bummer, these are really good boards.
Still I have just started collaborating on a BMS with Simon Rafferty who UI met at the BMMF this year and is famed in DIY EV circles for being the inspiration behind the EMW high voltage charger design, so maybe this will fit the bill, watch this space ;-)

Brushes and bearing arrived in double quick time!

Despite my partner moaning about the cost of shipping from Bulgaria I was astonished to find the brushes and bearings arrived in double quick time on Friday 7th in fact I had only just sent an email to Kostov asking for a tracking number and they arrived! Which is odd because Kostov had given me the impression that the brushes would need preparing and that they may have them ready for sending by the 5th or 6th, So I had sent an email asking (politely) what sort of preparation brushes required to which I got a big fat silence! Followed by the parts arrival on my doorstep on the 7th! I wonder if this may be a “lost in translation” issue. Anyway due to me not knowing exactly when the parts would be here and assuming they would be sent over land (not air freight) I mistakenly assumed they would be a while and did not book my mechanic to get the Honda in for fitting of said brushes and bearings, the upshot of this is that he 18th is the earliest he can do it much to my partners dismay!

Testing, Testing 1,2 – 350 Cells!

I have been testing EIG’s constantly every spare minute (outside of my normal working day and working around my kids and partner) and what with the Halloween and Guy Fawkes Night celebrations and a dose of flu. I think I have managed pretty well to get to around 95 cells by the third weekend however this weekend I could just not bring myself to drag my sorry ass out of bed early enough to get stuck in so by the time I had managed to get to it I was already way behind schedule to achieve my “Required” 30 cells in one weekend target. So to quicken things up I decided to try the 40 amp 2S discharge and graph again (WHAAAAAT! I hear you cry) yes I know the last time I tried this I blew up the Powerlab 8 but it is well within the power rating of the Powerlab 8 and seeing as I have just tested over 90 cells without a single hitch with this new Powerlab 8 I am confident that the problem must have been with the previous one being faulty. So with everything crossed and my nose twitching for the first sign of any unusual smells I cautiously setup the 2S test and to my relief it all worked perfectly I carried on testing 2S all day to catch up to my 30 cell target and now have around 125 EIG’s tested and awaiting assembly into a sweet traction pack.

Tuesday, 28 October 2014

EIG Cell Testing continued

So seeing as the EV was out of action and my mechanic had pushed back the start of the RX8 build due to his business partner upping sticks and declaring he wanted to sell up and move on, I got busy with the testing of the new EIG cells, and this time I was going to make sure that there was no chance of failure.
So I bought a brand new 12V battery to compliment the better of my two existing 12v lead acid batteries and dumped the older/weaker one just in case this had anything to do with the failure (although Steve assures me that the Powerlab will compensate for any weakness in the Pb cells and simply fail the test rather than going bang so I still feel the last power lab must have been faulty) and I also replaced all the 12v battery terminal connections with brand new bright and shiny connectors again just in case a bad connection had caused any sort of spiking.
Voltage spikes are the most likely cause of electrolytic failure so I am taking no chances, also I reduced my test cell to a single 20Ah EIG cell rather than 2 in series even though the powerlab should be well able to handle 2S of these cells (we had already done the power calculations to check we were not pushing it beyond the 1344W limit and again if we did try to it should just fail the test not explode!) I was not willing to take any chances this time and am going to stick to single cell tests despite the huge amount of time this will eat.
So to get the ball rolling proper I configured my BC168 balance charger to charge at 6S (8A) so I could top up 6 EIG’s at once and once I had the first six charged the ball really started to roll, it turns out that a single cell test takes around 28 minutes @ 40A to discharge and it takes the BC168 around 3 hours to charge 6 cells so all in all a pretty good balance I can charge 6 whilst I am discharging 6 (albeit one at a time) and then rotate.
So pushing hard to keep this turnaround going I managed to get 30 cells done in 1 weekend that is 1/10th of the entire pack so assuming I only get weekends to do it (I will be doing some in evenings) it would take me 10 weekends to complete the job.

Brush/Bearing wear on the Kostov K9!

Ok so here comes another tale of woe due to my own inexperience of EV related matters, I was driving to work the other day with my daughter to drop her at school, on the short divergence to do the school drop I have to pass a lane with a large regular flood puddle and being an EV driver I always take it slow through this puddle, it is not enough to swamp the motor thankfully but if I hit it with any speed it would give it a damn good wash, Still on this particular day as soon as I had passed the puddle a new and very disconcerting noise appeared and sounded distinctly like brush failure!
So I limped it home and took the fat fryer to work, Guessing that there was more than a clean going to be required here I dropped it down to my mechanic and waited for him to have the time to investigate, a few days later I had the bad news “new brushes required” and the following day a call to say that one of the bearings was also failing (the one outside nearest the wheel).
After thinking over the issue for a day or two and during a chat with a friend the penny dropped, RPM Sensor! I Still have no RPM sensor “WHAAAT” I hear all you EV experts shout, Yes I am a fool and have been driving the little Honda Beat EV for over a year with no RPM sensor and no sensor means no RPM limiting, So now the penny has dropped it seems almost obvious that if you don’t limit the revs somehow then at some point you will be over-speeding the motor, And on a similar note I also have no motor temperature monitoring either.
So I guess the key words here are MONITORING and LIMITING!
So a new set of brushes and bearings are on order and my EV sits looking sorry for itself waiting for the parts to arrive from Bulgaria!

Testing the EIG cells

I began testing the EIG cells by balancing them to 3.8v and then balance charging them up to the 4.15v max Voltage (slightly lower than the normal 4.2v of standard LIPO if there is such a thing as standard LIPO!) shown on the DataSheet.

Then using my newly purchased Powerlab 8 I did a discharge and graph test at 20A and everything looked great a nice looking graph formed over the course of around an hour at which point the Laptops power saving mode kicked in and put the PC to sleep ruining the test!
Bugger! So I began again and at this point things started to go wrong, firstly I could not repeat the test without the Powerlab stating that I had disconnected the battery and then quitting, after much dicking around suspecting bad voltage sensing leads and trying other batteries (the original Turnigy’s I had laying around) I eventually discovered that the hibernation mode kicking in whist the previous test was running had corrupted the AppData in the profile on the laptop and this was preventing me from running another test! (Talk about tenuous links) thankfully I am an IT engineer otherwise I might have gone mad with that one.
So finally I had gotten back to where I was and thought I would attempt a higher power discharge using 2 Lead Acid batteries in series providing a 40A current dumping capability (BAD IDEA)
Now according to Steve my local expert (and the instruction manual) the Powerlab 8 is perfectly able to do a 40A discharge and Steve tells me he has done many hundreds of 40A tests using his own Powerlab 8,And although he did warn me that seeing as I was intending to test the whole 20+KW pack using this unit and that they are not really designed for such extensive repetitive use I would need to watch the connections carefully for any signs of localised heating around the connections, especially the banana plugs.
Fine I thought as I began my very first 40A discharge and graph, first of all everything seemed fine and the 40A discharge graph began to appear as expected on the laptop screen, then within a second or two of starting the test a bad burning smell appeared and I frantically searched the connections for the tell-tale signs of heating but in less than a second there was a loud hissing and steam began gushing out of the rear fan of the Powerlab, power was disconnected less than 1 second later, I did not wait for the bang!
On closer examination I could see the blown electrolytic capacitor from the rear of the Powerlab 8 its tin can blown up like a balloon!
So bugger again another failed bit of kit, I know I am pushing the boundaries here but a 40A discharge is what this Powerlab device is rated at and so should have easily managed this test without failing, after speaking with Steve he feels that the unit must have been faulty and advised me to send it back for a complete replacement!
I know from my electronics experience if an electronic product is going to fail it will fail in the first 3 months of regular use and in my line of work (IT support) you see it time and time again around 3 in a hundred new computers will have a component fail in the first 3 months, some are critical and kill the PC most of the time though they go unnoticed until the faulty component is next used it might be a CD drive or the hard disk, audio or video but guaranteed you will find fault if you dig deep enough!
So today much to my annoyance I have packed up the Revolectrix Powerlab 8 a second time (They sent me a Powerlab 6 by mistake the first time I ordered! Still Anthea from Revolectrix UK called me to apologise personally and had the correct one out within a day or two so I can’t complain about the service it was second to none, Thanks Anthea)
So I wait for my replacement Powerlab and I am now fearful of doing 40A discharges despite Steve’s reassurance I don’t fancy blowing up another Powerlab for any reason even if they are supposed to do a 40A discharge.
I may not have any choice however so I may just get Steve in to double check that I am not doing anything daft before I attempt another 40A test, The one and only 20A test of the EIG cells I did manage showed extreme promise however as it took a whole hour to drop down to 3.8V from 4.15v and the low voltage discharge cut off for these cells is 3V (although I may set my cut off a little higher than this 3.3v for example) so it should take around 2 hours to do a 20A discharge.
Hence the need for the 40A discharge as I have 350 of these cells to test and at 2 hours for 2 cells (I am testing these in a 2S1P configuration) we are talking about 175 hours of test time never mind the battery swapping and connecting etc.

Monday, 8 September 2014

Brighton Mini Maker Fair (BMMF) 2014

Phew that was one hell of a busy day on Saturday, I spent the whole day from around 9:00AM till 6:00PM jabbering like a crazy man about the wonders of Electric Vehicles had a lot of interest and some serious contacts to so well worth the effort, I also showed the 3D printers again this year but was unable to run them as we were outside and the printers don’t like draughts.

We were so busy I did not even go inside the fair once and below is the only photo we managed to take.

It was absolutely heaving inside, thankfully we were outside and enjoying the good weather at least, also someone mentioned that the Brighton Marina Drive speed trials were on the same day! Whose idea was it to do these events on the same day, Bummer I would love to have done the trials in the EV, maybe next year.

Cycle Analyst finally fitted!

So seeing as the BMMF is drawing in very close now my maker genes are kicking into overdrive and last night I finally stole the time from my family to fit the Cycle Analyst into the “ElectroBeat”
I had previously prepared for the fitting by threading three wires through the bulkhead behind the seats and routing them into the central trunk where the brake cable electric windows & gear stick are located, Once I had it all apart and had a look where I left off it was a fairly simple matter of connecting one of the three wires to the –ve side of the shunt (already fitted), The –ve side of the shunt is connected to the Traction Packs –ve terminal the +ve side of the shunt is connected to the –ve that goes to the Soliton Jr controller, The Shunt goes inline between the controllers –ve terminal and the batterys –ve terminal, The only other connection (the third one) goes to the +ve side of the Traction Pack, I connected it to the controller side of the HV contactor so that it is switched off when the ignition is turned off.

A Shunt is just a very accurate high current resistor that allows for exact measurement of current flow through it by the Cycle Analyst or another current (Amp) counter.

Even though this was a fairly simple fit it still took me 2 ½ hours to fit what with the fiddling with crimps (making sure the crimps were good) carefully routing the cables protecting the 300v +ve signal that is routed to the dashboard (an obvious safety concern) and redoing the shunt connections when I realised I had routed them the wrong way out of the heat shrink sleeve that I slid back to expose the shunt (I have not shrunk this as yet as I was awaiting the fitting of this Cycle Analyst thereby completing the shunt connections) also whilst I was redoing the shunt connections the right way I broke the screw that connects the signal wire to one side of the shunt and I note that they seem to be deliberately placed as close to the resistive junction as possible, Seeing as I broke the screw off in the hole that is placed close to the junction I had no choice but to put that sides signal wire onto the 50A battery connection, I may have to redo this again and remove the shunt for drilling out so I can fit the signal wire where it is supposed to be mounted closest to the resistive junction.

Still once it was all back together and safely zip tied in place (yes the meter is held in with zip ties at the moment I am currently 3D printing a dashboard mount for it.)  And all the cables were safely zip tied to the (immovable parts of the) brake cables and electric window cables I put the covers back on just in time as darkness fell at around 8:30 (Winter is on its way!) fired up the ignition and was greeted with the lovely site of the Cycle Analyst V2.23 message (I had previously tried to fit the V3 Cycle Analyst but as it turned out the design had changed so much that they had connected the –ve Battery terminal to the Chassis! A big NO-NO in High Voltage EV’s but then this Cycle analyst is designed for e-bikes that don’t generally require 200+ volts!  

BMMF 2014 is nearly here!

I have been trying to concentrate on a second 3D Printer build so that I have something new to show at the BMMF but it looks like I will not be able to complete this before next Saturday now so I will probably just concentrate on the EV and just see how it pans out with the printer, reason being as it depends on whether I have to leave the car outside as if so I won’t be able to have a stall inside and 3D printers don’t like draughts so the printer may well have to be just static this year, Bummer ;-(
Still it should be fun and that is really what it is all about, also I had planned to concentrate on the car this year anyhow so I will probably just do that.

Planning the RX8 build

The first Monday of my hols I visited the Mechanics to find out when they could get the RX8 in for its strip down and motor fitting, it is booked for mid-September so I paid Steve for the Kostov 11 inch and Soliton 1 controller and advised Brent of the need to get Steve’s MX5 in for the motor & controller removal, Steve has assured me that he will cover any additional “removal” costs although I might well take some other parts from his MX5 EV for my RX8 EV.

So it’s chocks away for the start of the RX8 build and I am seriously looking forward to it, The battery is bought and paid for as is the motor & controller, I have been planning the battery compartment layout it will be laid out in rows of 5 (5S) and blocks of 5 (5P) I will arrange the 70S in 14 rows of 5 starting in one corner of the battery box and going to the other side up or down a row and back again, continuing on until I reach the other corner, The reason for this configuration is to simplify the buss bar manufacture as it will mean that all I will need to do to fabricate the buss bars is cut (or get cut) some 3 mm copper plate into squares and rectangles in order to join all the +ve’s and –ve’s correctly no special shaping will be required as I can modify the plastic cassettes by removing some small plastic tabs that currently separate the cells +ve’s and –ve’s bridge them with a plate that joins 5 +ve’s together in parallel same with the –ve’s and then make the bar wide enough to reach over to the next 5 +ve’s in that row, when I reach the end of a row of 5 I will make a buss bar that reached up or down to the next row and orientate that row in the other direction so I can continue the series arrangement of the 70S string.

I will knock up a diagram to explain this, I will also be modifying the cassettes in another way as Steve suggests that the latest advice from the manufacturers themselves is to hold the battery pouches in compression, not to actually compress them but to avoid any potential swelling from separating the layers in the cell pouches, Steve suggested putting balloons at each end to put them under a little pressure but I think I may just go for a tight fit in the boxes as in the Honda.

Steve has also suggested I should lose the aluminium separators on the cassettes and replace them with a sheet of silicone between every cell, I would be inclined to agree with this good advice as the cell pouches are made from Mylar which is itself a conductor and aluminium is also a conductor so the whole battery bank is only very slightly protected from shorting by the small air gaps between cell pouches, a sheet of silicone as a separator would provide both an insulator between cells and also a method of holding the whole cell block in compression.

The only issue I have wit this current layout plan is that the cassettes seem to support the pouches vertically and the blocks of cells are arranged with the tabs at the top so other than the supporting plastic cassette the cell pouches would be hanging from there tabs.

I was planning on cutting off the cassette frame completely just retaining the top piece that provides support for the screw terminals and allows the top tab parts to be bolted in blocks and separate the cells using silicone sheet, however this would appear to mean that the cells would literally be hanging by their tabs (not good) so the obvious answer would be to arrange the battery pack so that the pouches lay flat rather than tabs at the top, this will complicate the wiring arrangement but should not cause a major problem, I will try and get photos and drawings of the proposed arrangement uploaded soon.

Dead Cell & Powerlab 8 Purchase

So after removing the safety LVC on Wednesday, I drove the car apparently normally on Thursday and Friday and then took the car off road for a couple of weeks whilst I had a break from work and investigated the issue, when I did finally find the time to investigate I reinstated the LVC and separated just the front battery box and sure enough after another test drive my suspicions were confirmed the fault was either in the LVC loom or a faulty LVC/HVC board or a dead cell, either way I would need to get the box out and investigate.

So a while later I had the box on the bench with the lid off and the issue was immediately apparent one of the cells in the offending parallel block had a severe burn mark on the balance lead plug, so as it turned out it was a dead cell after all and the LVC was just doing its job as it should do.
Just before I had taken my holiday I had ordered a Revolectrix Powerlab 8 battery tester and so I was able to test the apparently dead cell on this doing a discharge and graph, Now I have done over a hundred of these tests and they normally take around 15 minutes to do a 20A discharge and graph test, this faulty cell crapped out in around thirty seconds, it began and looked normal but as soon as the load was applied and the discharge began proper cell 4 bombed and dropped straight below 3.0V activating the cut out.

So lesson learned I now know that if the EV’s throttle appears to cut out intermittently under load this is most probably a dead cell rearing its head and at least I have the option of laying off the throttle and limping home to investigate the fault rather than breaking down on the road side as I did before the safeties were implemented.

Once the faulty 5S cell pack was replaced with one of the ones I had opted not to use before (The best of the worst from my last battery rebuild which Steve had said looked fine anyhow) I rebalanced the cars whole Traction Pack to 3.8v (Probably unnecessary) and then charged using the EMW on-board charger and top balanced to 4.2v since then I have been driving the EV without any issues all the LVC/HVC is reinstated and things are back to normal, unfortunately due to other demands I did not get any of the “Treats” I had planned even started!

Still there is always tomorrow.

Purchase of Battery pack for the RX8

I recently had a stroke of luck in sourcing 350 x EIG C020 LIPO cells on the web, I came across a guy trying to sell a small number of them and after enquiring it turned out he had sold them all and that was that, or so I thought, about a month or two later he re-contacted me saying that he had a friend who had hundreds more available if I was interested, I said I was and to cut a long story short I cashed up for 350 of them which are now sitting proudly in my workshop awaiting construction into the RX8’s Traction Pack.
Although these cells are second hand they are in very good condition and I have been assured that they have done very few full cycles and so are almost new, Another big advantage with them is that they already have connection tabs with screw holes and are mounted in cassettes that clip together in blocks of around 30 cells, they guy who sold them to me also had buss-bars but these were in a 3P configuration and so are not appropriate for my needs.
I am hoping to use them in a 5P 70S configuration to give me a nominal voltage of around 260v, Steve recommended that I get closer to 300V but I think I will go with the 5P configuration and add more in series later if I can afford to. 

Thursday, 31 July 2014

Power loss Issue & A lesson in logging trip data from your Soliton!

I drove to work on Tuesday (29th July) of this week and as I left immediately began to lose power in an intermittent fashion, not total power loss, The contactor did not cut out but it seemed as if the throttle was cutting back, Slight panic ensued as I began to think that a dead cell might be rearing its head but after pulling over and checking all voltages everything seemed normal.
I cast my mind back to the previous day and remembered that I had left my headlights on after arriving at work only for an hour though before a colleague told me so and I rushed back up to the car park to switch them off, Also I had driven home fine with no power loss issue that evening and so although it seemed unlikely I stuck the 12v lead acid (only around 3 months old, so essentially brand new) on a 2A trickle charge and left for work in the Deep Fat Fryer (The Diesel) that eve I tested again, same issue, power cutting out intermittently jerking the car around as it tries to “fly stop fly stop” etc.
A little more thought on the previous days and I remembered that we had just had a lot of rain and my car sits outside in it after it’s nightly 2-3 hour charge, so my mind got to thinking that some water had got in somewhere and was causing this issue, A few emails to Steve and he ran me though the “pre-flight” checks to try and track the problem down, Although I had already sort of ruled out the 12v I was still not entirely convinced so I left the 12v disconnected from car and charged overnight.
Next day (Wednesday eve) I checked the 12v all seemed fine and during my emails with Steve he asked me to check the logs, Logs? I asked and he seemed surprised that I was not already logging data, a little more reading and sure enough I have completely missed out on a very simple way to log your trips using a laptop and an Ethernet cable and running the Solition’s Datalogger a very simple command line data logging app that pushes the data coming out of the Soliton to a laptop via Ethernet and stores it in a simple text file, a brief search on this and I found an app called EV Trip viewer by “bhayman AKA Bryan” that imports these files and displays them in a human readable format (save all the dicking about in excel you would need to do otherwise), Cheers Bryan.
I had already looked into another Android based app called “EV Dash” by “Evlowrider AKA Pete” which involves setting up a WIFI router in the car and using an android phone or tablet to connect to the router and then capture data that way, however I could not get my dumb old android pad to connect to a router on the 169.254 range so I dropped the attempt for later pickup.
So using this newly found data logging capability I ran a test up the road and sure enough on reading the data in EV Logger it appeared that the throttle was cutting out intermittently, So seeing as I had only recently (since the rebuild) implemented the LVC I assumed that it might be the cause and went about removing the LVC loop from the throttle, and sure enough things returned to normal, well minus and Low Voltage cut-out safety for protecting the cells!
I have a couple of weeks holiday booked starting next Monday so I hope to get a few more treats implemented, such as, reinstating the LVC once the fault is found and fixed, finally fitting the Charge Analyst as my fuel gauge, removing the charger and trying to isolate it from the car chassis to avoid those electrifying moments when I forget the car is plugged and charging, maybe if I get time I will update the firmware on the charger as well.
But in the meantime and basking in the warm glow of another problem solved for now, I leave you with this juicy screenshot of my trip to work this morning, I particularly like the section when I am not necessarily sticking to the speed limits on an open stretch of clear road with no other cars in sight, where you can see the amps drop off as despite my “leadfoot” the power required to push the car at full pelt drops back as I attain top speed ;-) Sweet!

Thursday, 12 June 2014

Finally fit the front pads and flush the whole brake fluid chamber

Ok so I finally found the time last night to fit the front brake pads and bleed the whole brake fluid system through completely with brand new fluid, Although it feels a little better this morning I won’t be able to test the brakes properly until the front pads have bedded in properly (a week of my short commutes)

I am hopeful that now I have new discs on the rear and new pads all round that I will notice a significant difference, However I still think I am going to need to add an additional vacuum chamber to make the vacuum brake system work properly (already bought one) and I may well need to wire a bounce-less switch setup to the relay controlling it possibly with a capacitor resistor arrangement to provide an adjustable pulse of vacuum pump time.

The current 2 relay setup (one to provide current to the vac pump, the other to protect the vacuum sensor/switch from having too much current drawn through it) is just not working reliably enough to say the brakes are “working” satisfactorily.

Wednesday, 4 June 2014

Brake Disc’s and Pads arrived

Disc’s and Pads turned up on Tuesday 27th May 2014 when I arrived home I immediately grabbed them and began fitting.

The brake performance has been s#!t to say the least ever since I have had the car I am hoping this is going to help significantly, did both rear discs and pads on Tuesday evening.

Will try and do the front pads this weekend in between digging a pond (the work just never ends!) after speaking to a friend at work who knows his cars (fossil fuel cars anyhow) I described the colour of my brake fluid and he has suggested it is shot and needs replacing completely so I may well drain the lot and replace that as well at the same time, plus I am beginning to think that I will probably need an additional vacuum chamber as well as I think the pump is just not enough with such a small brake vac chamber as the Honda Beat has, I have seen Mike on diyelectriccar’s RX8 and he is using a nice looking 3 spheres chamber that seems to work well, will probably try and source something similar.

Ordered new rear brake discs and pads all round

Well it was about time for the 5-6 months I have been driving the EV the brakes have been more than a little wanting.

I have already dismantled and serviced any jammed callipers and when I did this the pads did not seem overly worn, however since then it has become apparent (now the rear brake pads are at least applying pressure to the disc) that the rear discs are shot.

I could get them skimmed but in an effort to get the job done quickly and easily I have elected to just buy new as the rear ones are nearly half the price of the fronts and the fronts are still in fairly good condition.

I also bought new Ultimax pads for the whole car at the same time, I may keep the knackered discs just to see if I could setup my newly acquired CNC to skim the disc’s as this skill could come in very handy.

Thursday, 22 May 2014

Brighton Mini Maker Fair comes around again!

Heck that was another year already! Well not quite but the BMMF have contacted me again to submit an application to exhibit at the BMMF 2014 in September.
I really enjoyed it last year (despite nearly losing my voice) so it was a no brainer to apply again, Plus this year I have the car finished and running so I will actually be able to show the car itself as well as my 3D printer, last year despite my efforts the car was just shy of being ready.
And in fact this year it is in a much better place with all the safety’s in place and the charger fitted and working with the J1772 plug adaptor fitted in the “ex” petrol filler cap and all 4 new alloy wheels with better sized (smaller) tyres fitted, it looks the nuts :-)
Photos coming very soon.

Fitting some smaller tyres

This weekend (17th May 2014) I finally got around to fitting some smaller tyres on the two front alloys and got them back on the car (they have been sitting in the barn since I bought them and realised that although the rears were fine I would need smaller tyres to avoid the rubbing.
I have replaced the stock 13 & 14 inch alloys with larger 15 inch BBS style deep dish alloys, they were needed urgently after I first got the car on the road as I had a major lack of grip due to the massive torque now available!
I had put the original 13 inch wheels back in place after I realised my first tyre choice was just too large for the front wheel arches and have been driving the car like this for several months waiting for my local part worn tyre fitter to come up with the goods.
The car looks fantastic now with its set of 4 matching BBS style deep dish 15 inch wheels, photos coming very soon (always best to get the photos done in summer)
Even with these smaller tyres there is still a very small amount of rubbing on full lock when turning right, full lock left seems not to have the issue so I will investigate where exactly the rubbing is and see if I can do anything more about it later, but for day to day use it is now fine with the matching BBS alloys.

LVC-HVC Wiring

Ok so the LVC/HVC cut off boards have two white plugs at the top of each board (one board for each parallel bank in the traction pack)

They are labelled as shown in the image below

Online manual for these boards below


Only found this manual recently (thanks again Steve)

I “just” need to connect all the HVC/LVC board connections in a chain connect the HVC part to the charger and connect the 6 solder connections at the top (can’t quite see them in the photo above) in line with the throttle cable, between the Throttle Position Sensor (TPS) and the Soliton Jr’s Throttle input.

So this bank holiday weekend 3rd/4th/5th May 2014 I spent several hours joining all the 3 packs HVC/LVC loom cables together, I have soldered them all up as I have not got any inline 6 way connectors handy although if I need to remove the pack again (I sincerely hope not any time soon) I would have to cut these cables, so I do need to buy some inline 6 way connectors for this purpose.
As the front 3rd of the Traction Pack is a good 2 meters further forward than the other two boxes I had to run a long 6 way cable under the car to join the front battery box HVC/LVC loom, I threaded this 6 way through another second hand inner tube and fastened this under the car using many zip-ties.

Once the HVC/LVC loom was complete I wired the Throttle and Controller as shown in the picture above (to the solder terminals hidden behind the white plugs at the top) this is so the LVC cut off can cut the throttle.

It is very difficult to test the LVC in the real world without running the pack to near flat, I did test the board on the bench with a variable PSU attached to fake a cell voltage and sure enough when the cell voltage drops to 3.00v the Throttle signal line drops to 0v (cutting the throttle)

I then set about connecting the HVC to the chargers BMS pin, I ran 4 wires out of the charger box, 5v, Gnd, BMS & EOC. After much fiddling about testing this I discovered that it only seems to work if I leave the BMS & EOC pins connected together (otherwise the charger never starts at all) and then connect the HVC “sig” line to these via a low value resistor (I was advised to add a resistor inline to avoid the Methtek boards drawing to much current) I am not sure the resistor is even necessary but I put one in just in case I ended up having to use two 51 Ohm resistors wired in parallel as that was all I had to hand that worked it seemed if the resistor was even 100 Ohms the signal would just not get through or was not detected on the far side of the current limiting resistor.

So to summarise:-

1) Connected 5v from the control board in the EMW charger and fed this directly into the HVC 5v pin.
2) Connected Gnd from the control board in the EMW charger and fed this directly into the HVC Gnd pin.
3) Connected the BMS/EOC pins from the control board in the EMW charger together.
4) Connected the HVC “Sig” line on the Methtek board (HVC/LVC chain) to the BMS/EOC via two 51 Ohm resistors in parallel.
5) Connected the “Throttle” 3 Pin soldered connections to the throttle.
6) Connected the “Controller” 3 Pin soldered connections to the controller.

I have just realised after writing this up (This is why it is a very good idea to write things up) that I have not fed the LVC part of the HVC.LVC chain with 5V or Gnd!  As this would be active when the car is running (unlike the HVC part which is only active when the car is charging) I would need to source this 5V & Gnd from the Soliton controller! (Update After speaking with Steve the + 5v & Gnd

Shit I had better check this when I get home tonight as I may very well not have a functional LVC!
Anyway I did test the HVC side of the HVC/LVC cut out extensively in the car by using a variable resistor to work out what value of current limiting resistor I would need, and testing it by starting a charge and then shorting the HVC “Sig” line to ground to see if the charger stopped and sure enough if I connected it directly it worked.

My initial guess of a 1K resistor did not work so I put in the variable and dropped the resistance until it started working, checked the resistance and it was way low I eventually settled on the two 51 Ohms in parallel which should give around 25 Ohms resistance and burn around ½ watt power (2 x ¼ watt resistors) I could be completely wrong here as my electronics is still decidedly rusty!

Back on the road at last.

It has been a long couple of months but at last my EV is back up and running, this time with and HVC/LVC harness in place!
LVC is already wired in line with the throttle albeit to only the 2 rear battery boxes I will be wiring the 3rd and final (for now) battery box in tonight which will give me a proper low voltage cut out at 3.0v on the nose on any of the cells in any of the 3 battery boxes, basically if any of the cells hits 3.0v the throttle is cut, I have not tested this in place as yet but I have tested the board on the bench with a variable PSU as a test cell and sure enough the LVC “Sig” line drops to 0v when the cell pin goes below 3.0v.
Once the HVC/LVC loom is complete (Tonight) I will be wiring the HVC side of it into the BMS pin on the charger in an attempt to get the HVC working as well although this would only cut out as a last ditch safety measure as it cuts at 4.4v not 4.2v.
So I still need to upgrade the firmware on my charger to allow a CV cut out of 4.2v (currently limited to 3.99v) and also to put in some physical isolation of the chargers case from the chassis of the car, this is because when the charger is plugged in and running the chassis has some voltage on it, I would not call it live but I think the stray voltage might be either leakage from the bridge rectifier, or possibly inducted from the large toroid.
I also need to investigate a low voltage safety in the charger software as according to Steve the charger should error if it detects an abnormally low voltage and cause you to check to see if any dead cells are present, charging dead cells could result in a thermal runaway event (Yeah don’t I know it!)
And to top this lot I still need to implement the fuel gauge and the heater/demister.

BC168 balance charger wigs out!

In order for me to test and balance all of the 108+ cell packs that I have discharged, graphed, charged and balanced over the last 2 months I needed to buy a good LIPO charger and Steve recommended the BC168 LIPO Fast charger/balancer for around £90, I looked it up online and sure enough it appeared to be the bees knees of LIPO chargers (and I still think it is) after running around 80 cell packs through it (not many according to Steve he has put several thousand through his) the ground connection wire to the breakout board was showing a significant browning of the plastic suggesting it was getting hotter than it should have, I did not consider this a major issue and carried on testing the remaining cell packs whilst angling the output fan over the breakout board to keep it from getting worse, however after only a few more cells the device began playing up and would not show a reading on and cell pack on S1 line, I initially suspected the breakout board but after testing this it turned out to be the device itself and now it won’t charge properly at all the voltage sensing seems to have gone out the window as it jumps wildly about trying to sense the correct voltage, basically it’s fried. Shit!

Not convinced I did anything wrong to damage the unit so we are going to try and get an RMA on it however as it is a fairly cheap device and they come from Hong Kong it may take more time than it is worth, for now Steve has lent me his so I can at least finish the remaining packs to get my car back on the road.

Collected 42 new (used) batteries

I collected my new batteries, They are used identical Turnigy LIPO’s 5S1P’s from Steve’s Electric MX5 which he is sadly breaking (house purchase forces cashing in of assets me thinks) still I intend to purchase the Motor and Controller from it to convert my RX8 so it is not all bad news.
Carried on testing the new cells same as before
1) Charge to 4.2v
2) Discharge and graph
3) Check graphs and discard any bad one’s (Steve assured me there should be none)
4) Balance good cell packs to 3.8v and fit them in 3rd and last battery box

Unfortunately when we pulled the batteries from Steve’s car we noticed an imbalance on some of the cells in a parallel block so all of them were showing cell 2 as being down at 1.5v and after testing and graphing these cells 8 of them showed an imbalance after a single charge and discharge and graph, and the failed one was done at 0.8v on cell 2.
I pulled these 8 to one side and collected another 6 from Steve to cover any possible bad ones (only needed 6 as Steve had given me 2 extra to cover the potential bad one in the first place, And as I completely forgot to take the bad ones back to him when I collected I now have all of these extra ones to find 6 good cells from to fill the last 6 slots in my last battery box (getting close now)
Last night (24th April) I fitted all the cells in the last 3rd battery box and packed them ready for wiring, just need to charge/graph and balance 6 more of the 14 cell packs I have and fit them before I can wire up the last box and close the lid.
As soon as this is done I will drop the remaining 8 iffy cells back to Steve, There is really only 1 definite bad cell in this 8 but I want to make sure the 6 I fit are all good and well balanced cell packs, after all I have just spent 2 months testing every single cell and balancing them perfectly.

Battery rebuild begins (12th April 2014)

Started by taking all the good batteries and stuffing them back in the boxes completed one box I am 6 cells short to complete the second (although these 6 failed cell packs are no good for an EV battery they are still useable for other projects) advised Steve of the additional battery requirements (he already knew about the 36 incinerated + 1 swollen cell pack, so 5 more required.)

As I could do no more battery stuffing I moved on to fitting the buss bars back in and realised I was going to need more (new) neoprene so I put in a web order for another roll.

At this point I decided to call it a day (weekend) and spend the rest of my spare time with the partner & kids (mowing and strimming the lawn more like!)

Battery Testing Finally Completed (12th April 2014)

And by completed I mean:-

1) Ran every one of 72 x 5S1P cell packs through a discharge (to 3.5v) and graph test using the Powerlab8 Battery Workstation
2) Checked all the graphs to see if any cell packs were out of balance, made a note of the ones that were for additional test
3) Bottom balanced all Cell packs to 3.8v (Storage charge)
4) Checked all cell packs physically for any signs of swelling, (Weirdly every single one looked fine until the very last discharge test on the very last cell pack which swelled up like a balloon)
5) Ran all cell packs that failed first test through a balance charge (to 4.2v) using a BC 108 balance charger
6) Ran all cell packs that failed first test through a second discharge (to 3.5v) and graph test using Powerlab 8
7) Checked all graphs to see if any cell packs were still out of balance, Discarded any cell packs that were (5 were!)
All that lot basically took me 6 weeks of spare evenings to complete!

Battery Testing Continued

I spent several evenings this week (17th-23rd March 2014) testing batteries and have completed the first battery box 36 cell packs and the first few cell packs in the second (last remaining) battery box, so I probably have about 30 left to test, once this is done I can get onto the balancing, so far I have only had one cell pack show any signs of swelling and strangely this one seemed perfectly balanced, however Steve has recommended that I discard any that show signs of swelling, So I guess I will repurpose this one for another small battery powered project such as a 3D printed quad copter or the inverted pendulum balancing bot I am planning to build.

Let’s hope I don’t have many more that I will need to discard, I should be able to complete all this testing this weekend coming.

Battery testing begins

I began by removing the 2 remaining battery boxes that survived and getting them into my workshop, removed the lid from the first and removed all the buss-bars, LVC/HVC boards and all additional cabling until I had just the cells, attempted to pull one out, not budging, panicking a little as I was assuming they had all swollen due to the over charge I contacted Steve and asked how much force I could use on the banana leads after all I don’t want to start another fire in this box whilst I am trying to disassemble!

Steve was also assuming the batteries were probably swollen beyond use and this is the main reason I needed to get the whole lot apart to check for swelling and discard any swollen cells, after Steve’s reassurance that I could safely give them a good yank without puling the banana leads out of the cell packs, I went back for another try, this time I turned the whole box upside down and gave the end/edge of it a good whack on the bench in my workshop, flipped it back over and almost in despair grabbed a couple of banana leads and yanked!

To my surprise it popped out sweet as a nut, and of course once one was out the rest came easily, and to my great surprise and relief there was not a jot of swelling to be seen on any of them in fact they all looked good as new!

Borrowed a Powerlab8 from Steve and began testing batteries this weekend just gone 15th March. The powerlab8 is a cool little unit and does a lot of stuff but I was basically just using it to do a discharge from the overcharged state to an “Empty” state 3.5v whilst graphing the discharge on a PC that way you can see if any of the cells are out of balance or damaged in any way.

To achieve this is a little tricky though, the powerlab8 is best run from a 12v or 24v lead acid battery this allows you to do a fast charge/discharge at 20A, simulating actual usage discharge speeds, as I was not versed in the use of the powerlab8 Steve ran me through the basics via email, and after doing 4 discharges my 12V Lead acid battery hit its fully charged state (denoted by the voltage popping up to 14v, peukert effect!

As Steve explained) despite me attaching (what I thought were headlight) bulbs to the 12v to drain excess current, so after a little more fiddling around finding 12v devices that I could attach to drain the 12v and provide a load, I finally settled on the 4 bulbs I had initially, plus a 12v cooler box, plus a 12v car tyre pump, plus a single true headlight bulb wired so that it was on full beam i.e. both filaments lit, And at last this seemed to be enough, I was now able to continue testing and to my surprise at 4 x the speed as before for the first 4 tests I had only been dumping 5A rather than the 20A I had set because the 12v battery could not take any more.

So this greatly increased the speed at which I could test and by Sunday evening I had tested almost all of a single box worth of 5S1P cell packs, I think around 6 will need rebalancing for sure but I may just balance the whole lot and retest the ones that were out of balance to check there is no intrinsic issues.

This Still leaves me short the 36 cell pack’s I incinerated and 4 new LVC.HVC cut-off boards with extender boards (I had better make sure I use them this time eh! You f##!ng TWAT!)
And I am going to need to do some reworking of the buss-bars as well!

Lessons Learnt!

OK so why did I incinerate 1/3rd of my traction pack, well several reasons but basically the main (FIRST) one it is I AM A TIT! and did not wire the Low Voltage cut-off boards into the Soliton, in fact I was putting it off (here come the excuses!) due to the fact that we have been having such shit weather (rain, I AM TALKING NOAHS FLOOD!) and our house is in a flood plain and so I had spent the last few months (literally months) dealing with the flooding every weekend without fail, I was out with a spade walking fields and digging trenches to alleviate the flooding and prevent our house from flooding this went on for several months before we finally got the EA to visit with a big digger and dig us a new drainage ditch to take the massive excess of water away.

OK excuses over, the other (SECOND) reasons were that I did not wire the High Voltage cutt-off to the charger I had just recently fitted, this will be complicated by the fact that in order to test this I will probably have to remove the charger again along with do a lot more reading and testing to get this working.

Other (THIRD) reasons could include the fact that I had not fitted any sort of fuel/charge gauge in fact I had only just picked it up and was trying to wing it to some good weather (which is now finally here TO LATE! To save me from my own stupidity!)

However after speaking to Steve he feels that the EMW charger was partly to blame because it should have picked up the fact that the total voltage was below a safe limit to begin charging (which was almost certainly true, even though I did not check this and cannot prove it!) he has advised that I check that the charger does include a below minimum voltage check and won’t run (Errors!) if the total pack voltage is below the expected “empty” value. I am not even sure if the charger checks for this.

Also as I already know I am lying to the charger as it won’t allow me to set a CV of above 3.99v I need to set 4.2v

So all in all I have a heck of a lot of work to get the EV back on the road but I am determined to do it and ASAP.

“Dooms Day” EV Style (or how to incinerate 1/3 of your traction pack)

Tuesday 25th February, Left for work as normal in the EV after a normal charge the night before, got to my daughter school and dropped her off as I was leaving I got a call from my partner “you have my car keys!) Shit I thought, now I will be pushing my range to get home and back to work and home again, my EV only has 40 mile range and my round trip to work is 22 miles, my daughter school is around 2/3rds the way to my work and I and I had not pushed the charge to the max the night before as I was not anticipating any extra journeys.

Oh well I thought, better get the keys back to the missus and worry about this later (BIG MISTAKE NUMBER ONE), drove home and back to work no probs, left for home that evening and got nearly home before the car began to judder and slow, shit I thought, oh well it’s another tow (third time I have run a cell flat or the low voltage cut-off in the Soliton has kicked in I am not really sure) anyway towed the car home (only a few hundred yards) and put it on charge as normal (BIG MISTAKE NUMBER TWO, Steve has already advised me that following a run flat you should always check your cells for problems!)

Came out a couple of hours later expecting the car to be nearly charged (after all I had done extra mileage and was expecting a longer charge time this evening, possibly double my normal 2 hour charge) it was still far from charged, strange I thought Oh well I will give it more time (BIG MISTAKE NUMBER THREE) and went back in for another hour or two, I was not unduly worried as the charger throttles back the duty cycle when it nears the max voltage for the entire pack.

When I came out to switch off I realised that I was in BIG TROUBLE, there was an all pervading smell that told me something was not right, I checked the voltage in the charger and it was still far from max and still at around 70% duty, SHIT! SHIT! SHIT! Cut the power and checked the front battery box as this is the only one I can get easy access to by flipping the bonnet up.

Extremely strong chemical smell coming from under the bonnet obviously from the LIPO batteries, got my widget and checked voltages on this third of the pack and to my horror 2 banks were not reporting anything DEAD and the other two were severely overcharged at 4.4v per cell! FUCK! FUCK! FUCK! MAJOR PROBLEM, called Steve for rapid advice, he told me to watch it closely and whilst I was on the phone to him doing exactly that the smoke began! Just a whiff at first “It’s smoking Steve what the fuck do I do” Steve advised tipping a shitload of water on it.

As I was fetching the first watering can (luckily we have a load of water butts around our garden with thousands of litres) the venting began!

I am talking Lithium steam train at full tilt! I spent the next 2 hours tipping water on the burning battery until it finally gave up venting around 1:00 AM in the morning.

Went to bed with doom and gloom in my heart (oddly satisfied that I had at least prevented the whole car going up in flames!)

Spent the next weekend decontaminating the car and the area of my garden it had vented in.
Spent the weekend after that stripping the burned battery box out of the car and recovering whatever I could (not a lot) all 36 5S cells in this box were torched, the fire had ripped through the box end to end taking everything with it bar the Ali box which survived remarkably intact and the buss-bars however these will need servicing with new banana plugs (sockets seem ok) the plugs are supposed to spin freely some do not anymore and therefore will need replacing.

Also all the batteries in the rest of the car (the other 2/3rds) were also all severely overcharged to around 4.4v per cell, and after speaking with Steve it appears I will have to breakdown the entire pack test everything, rebalance all cells that are good, discard any bad cells and reassemble.

Basically a shit load of work!

Monday, 24 February 2014

Now it’s done, Do it all again! :-(

So 3 days in from finally getting the charger onboard the EV and I learned to my cost that the Soliton does indeed damage the charger if it is permanently connected to the live traction pack terminals, I got home and went to charge as usual (a little more excited than usual in fact due to the new improved and much simpler charging regime) except this time as I turned off the car and stepped out to unlock the workshop where I charge from I noticed a fan whirring from the boot, Damn! Opened boot to be presented with the charger running whilst seemingly not plugged in! Damn Damn! Check output diode with DVM, its blown! Dead short across 1 of the diodes in the package! Damn Damn Damn!

However luckily I was planning on building another of these cool chargers and had already bought a second identical output diode from Digikey so after another evening of rapid strip down part replacement and reconstruction I was ready to charge once more, however I would be unable to fit the charger into the car again until I had sourced another HV contactor, an email to Steve and a swift meeting a few days later and I had 2 HV contactors in hand (Thanks again Steve)  the second is for the ceramic heater I am intending to fit soon for rapid demisting of the windscreen.

So after a minor rewire of the charge +ve cable via an HV contactor that is activated from the 12v line of the charger (so it switches on and connects the output of the charger to the +ve line of the traction pack) the charger is now back in the car and working as expected. Sweet!

Monday, 27 January 2014

Fitting the EMW Charger into the “ElectroBeat”

So finally this weekend I found the time (Stole the time from my family more like!) to get the charger fitted into my EV.

I began by using a MiniCraft drill (Dremel in the US) with several cutting discs to cut the holes for the two fans, as I began I intended to cut circles and bolt the fans to the car but it soon became apparent that it would be much simpler to cut a single large rectangular hole and leave the fans bolted to the charger case.

After this I moved onto re-orientating the J1772 socket so that the plug would point down and not up (my mechanic had fitted it this way round to avoid the socket cap fouling the ex-petrol filler cap), I discovered that a little minor bending of the ex-petrol filler cap’s closure clip was all that was required to fix this. Checked it all fitted by plugging the J1772 plug into the socket it looks so sweet, massive EV grin :-)

Once this was done I ripped the lid of the charger disconnected the control board and attempted to fit the charger case into the mini boot, it again became apparent that in order to do this I would have to strip the fans off the case and refit them once the charger case was fitted, all in all this was a complete bitch to fit partly due to the addition of a couple of M8 bolts to hole the massive capacitor bracket in place, this needed another hole to be drilled in the cars boot to accommodate the extra bolt length.

Once this was all done I discovered that access to the Bolt holes that I had drilled to hold the charger firmly fixed into the car boot was severely limited by the fact that the bolt hole on the underside of the boot was behind a bulkhead pressed panel, luckily there was a hole in it just large enough for me to get my fingers into and hold the bolt in place whilst I did a little contortion-ism to get the nut on the other end, damn I hate working on cars but heck at least with EV’s there is no bloody oil and s#!t to get covered in, road dirt is about the worst you will encounter (which reminds me I must get my water-pump fixed so I can use my jet-washer again!)

Once the charger was securely bolted into the car I refitted the controller (just 4 nuts as it only needs moving about an inch to the left to allow the charger to be squeezed in place) and drove the car back into the barn as the light was beginning to fade at this point (damn I hate British winters! Oh and if you are wondering why my tone has changed to the decidedly miserable I have just given up smoking again! Whoopeee!)
Once back in the barn lights on (short break for  a cup of tea) and continued onto wiring in the J1772 socket wires to the charger.
When this was done I reworked the charge cables so that they would connect with the new charger permanently (no crappy Anderson connectors here) unfortunately the 50A cable I had was too short so I have had to temporarily extend it with a lower 16A cable for the time being (fused of course, 30A fuse).

I had previously checked to see if it was safe to have the charger permanently connected without the controller damaging the charger when driving and according to Steve (Jozztek) this should be fine (well at least according to his experience of doing this several times before) but he did mention that someone on the diyelectriccar forum had suggested that the charger may be damaged by the Soliton over a long period of time, we shall see as I would rather not fit yet another HV contactor, and I feel that the output diode should be beefy enough to handle it as this charger is seriously over specked for what I actually need in this EV.

So for now I will have to stick to 16A charges (better than 12A which was the max I could do up till now) until I can get a longer 50A welders cable fitted (I do actually have a bit of cable that would extend the existing cable but it needs two crimps to be fitted and I don’t have a crimp tools that is up to the job (borrowed this from Steve when I was wiring up my EV) I will have to get a longer cable from Steve or crimp the bit I have next time I am round his way.

Once this was all done I refitted the fans I had previously stripped and wired them up (a total bitch as I needed to pull the wires through a hole that was fairly inaccessible, but got there in the end.

After this I decided that it was about time I extended all the wires from my driver board to the control board (on the lid of the charger case) so that I can remove the lid without disconnecting all the cables (which has been a pain in the arse since I first put the charger inside its case) this took a fair while as there is around 11 wires to extend each one needed to be Cut/Stripped/Tinned & Hooked, then the extension wires also needed the same at both ends so this was 44 x Cut/Strip/Tin/Hook/Solder/Heat-shrink!

Whilst doing this job I realized that I was talking to myself and was starting to sound like the geek kid out of “Cloudy with a chance of meatballs”, “CUT/STRIP/TIN/HOOK/SOLDER/SHRINK”, man I really need a break from the EV!

Anyway 44 renditions of that mantra later and voila I had a lid that could be removed without breaking the charger.

As I was seriously running out of time (it was pushing 11:00PM at this point) and my partner was threatening to leave me forever (again) unless I left that other bitch alone and came in for some dinner!
I thought it best to stop for another cup of tea and then get back wire up the J1772 ASAP (basically because I have to use this as my commuter car I have no choice but to get the EV charged every weekday night and Sundays ready for the following Monday)

So refreshed (well sort of) I got back to wiring up the 8 meter J1772 cable and plug up to a fuse box I have spare in the workshop, the only disadvantage of this setup is that I have to charge the car outside (in the rain!) The big advantage is faster charging.

So about another 30 minutes or so later the J1772 was wired and ready to go.

Plugged it in and bam (no it did not blow up!) the charger whirred into life, stepped through the motions and began charging the car, MASSIVE EV GRIN! :-))

Finished charging the car at around 1:00AM (16A charge) and it pissed down so I call that a successful full weather test.

And the Beat does look sweet with a proper charge cable hanging out the ex-petrol filler cap.
Might need to earth the car to the mains earth though as I do get a nice tingle off the chassis now :-$ 

Getting used to using the EMW charger

I ran a test a the weekend with the intention of filming the whole charge sequence, it all went well until firstly my camera ran out of space on its SD Card, offloaded the contents and continued filming at which point the DC current clam I had borrowed ran out of battery, closely followed by the AC Current clam I was borrowing from work timing out (odd that it would time out whilst readings are changing but I get is is a cheap one designed for single current readings.
All of this put the kibosh on me getting a complete charge cycle recorded and due to the need to have the car running for Monday (For my work commute) I resorted to just finishing the charge and seeing how I got on with a week’s worth of actual use of this charger to charge my car.
I am charging from approximately a half charged pack to a fully charged pack every week day evening and so far so good I have had to limit the charge current to 12 Amps to avoid melting anything (again!) and this means that it takes approximately 3 hours to complete the charge (Half Charge) I am visiting regularly during the charge cycle to check on things and other than a slightly melted Anderson connector it is all going well.
I intend (if I have time) this weekend to try and get the charger fitted into the car and wire up the J1772 socket so that I can use the heavy duty J1772 cable I have purchased, this will allow a much greater current to be drawn and therefore a faster charge.
However there are a number of constraints more to do with the location in which I am charging the car, currently I have it parked in the entrance of my barn which has a standard domestic 32A 3 pin UK socket supply, as I have already melted several 3 Pin plugs and sockets this is not ideal, the supply for the barn comes from my workshop where the electricity meter is located, this would be the ideal place to connect the J1772 lead and plug for charging but it means that the car would have to be charged outside in the atrocious weather we are currently experiencing ,a good test of the waterproof-ness of my cars electrics you might think.
I have several concerns over this fact and the amount of work required to fit the charge into my car, I still have several things to complete to get the charger fitted:-
1) Drill some fan holes in the car, trivial but time consuming
2) Reworking the fans so that they fit in the car rather than being jerry rigged on the outside of the charger box as they are currently, and wiring them up 
3) Securing the charger box inside the car, already have the holes drilled for this just a matter of bolting it in
4) Securing the heat-sink inside the charger case, I have a problem here as the heat-sink appears to have some voltage on it and the last time I used metal machine screws to secure the heat-sink I got a shook from the case (not good) might 3d print some screws and tap/die them off to fit (not sure if ABS will be strong enough to handle the vibration though)
5) Wiring the output connections in permanently with bigger wires (already have these made up) to avoid the need for Anderson connectors (from my limited experience Anderson connectors are not really up to the job)
6) Wiring in the J1772 socket to the chargers AC inputs, this should be fairly trivial the cable is already in the car, however
7) I need to change the orientation of the J1772 socket so that when the plug is inserted it points down, my mechanic fitted it so the socket points up to avoid the socket cap fouling the ex-petrol filler hinge, I will probably have to mod the socket lid by hack sawing of the tab that is fouling the hinge, as if I intend to run this in foul weather I need the plug pointing down so any water runs down and drips off the cable not down into the plug!
8) Insulating the chargers case from the cars chassis, although this is not required it would be another level of safety if I have a short inside the charger for any reason.
9) I have also been advised that to resolve the voltage on the heat sink issue I might be able to use mica sheet to electrically isolate the bridge/IGBT/Output diode from the heat sink (I need to check this with Valery first though)

Monday, 6 January 2014

Collected Fuel/Charge Gauge.

At last I visited Steve this weekend for just a couple of hours (he is as busy as me) and collected a few bits and bobs, mainly I swapped the V3 Charge Analyst for his V2 as it turns out the guy who makes these has made a big change to the design which means that I would have had to make the Car’s chassis common with the Traction Packs –ve terminal, BAD IDEA! This would mean that if I had the covers off or boot open and was working on the car whist leaning on the chassis I would only need to touch a live terminal an bamm! Instant perm!
The V2 Charge analyst does not have this problem as it does not require a common ground, Steve can’t understand why the guy that makes these has done this as it has essentially blown this product for HV use post V2!
Also picked up the extra cell cables I need for the LVC/HVC circuit and borrowed a DC current clamp to run some tests on the charger.
Steve finally got to take it for a spin and I think he was impressed, although it is not as powerful as his it sure shifts when you boot it, his primary concern was the shit brakes which although I have serviced them still don’t work that much better, I know that 1 Disc on the rear is shot and needs skimming/replacing but even though they are tiny discs and pads so I think I will look at getting bigger callipers and disc’s fitted if I can find some that will fit.

Voltage sensing fixed & Chargers Final Assembly nears completion

Found the problem with my voltage sensing circuit, I have accidentally used a 0.1uf ceramic capacitor for C32 instead of the correct 1uf, swapped it out for the correct 1uf value and tried calibration again, 10 volts better on the first sensing during calibration, and once you punch in the correct value it then senses voltage bang on correct, Sweet!
Wired up some fans I had ripped off a bunch of old CPU coolers I had laying around and bolted them to the outside of the case to suck air through the Ali box I have the charger fitted into now, wired the into the 12V circuit and fitted an AC mains cable for now whilst I continue testing.
I got a belt (Electric Shock) off the case the first time I fitted it into the case and discovered that the heat sink appears to have some voltage on it, proved this by removing the metal machine screws holding the heat sink to the case and the problem disappeared, not sure if this is right but I noticed a post from Arber on the EV forum (diyelectriccar) who has the same non PFC charger and he is also getting around 30v AC on his case, I posted a reply stating I had the same problem and promised him I would check mine to see what the voltage was i.e. AC/DC and how much, but I have not had the chance to test this as yet. However I know it is AC as I know what AC electrocution feels like having put my hands in the wrong place to many times before (use to be an apprentice TV engineer/Tea boy in the days of CRT TV’s) but it would be good to get a reading anyhow.
Continued testing the charger over the next few days and melted a few more AC power plugs :-$, I think it is time to move onto getting my J1772 Lead wired in and working as this would solve all the overheating AC plug issues and allow greater currents to be drawn and therefore faster charging.
I am not really interested in fast charging at home but on the go it would be a very handy feature, I noticed today that my most local EV meet is in Portsmouth around 60 miles from me, my car has 40 mile range so I could stop in to the Little chef at Fontwell and charge whilst getting a spot of lunch get to the meet have a short spin and get back to the little chef for the next charge to bring me home again, it’s that or take the Diesel or maybe I should organise a more local meet.
Damn it is getting exiting I can’t believe I am nearly able to travel in this little electric beauty, talk about Electric Dreams!
Heck maybe I will fit an additional battery box in the front there is plenty of room for it and I could use the extra weight for grip  whilst racing ,but I think I would be better off waiting till I replace my battery completely and by them 3-5 years from now (probably 3) I will hopefully be getting a much better energy density for my cash, this year 170kwh batts are available if expensive and I hear of 200kwh also being available this year, bring it on!