Monday, 11 November 2013

Charger repair begins

Sunday I was still feeling unwell but decided to try and pickup from where I left off about a month ago with my charger build, Solved the display refresh issue by downloading the latest firmware release (V11) after reading the last few entries on the diyelectricar charger thread last night, luckily this latest post included the TimerOne & LCD libraries, after downloading installing libraries compiling and flashing the display issue has vanished!

Horrah, I just hope when I get to the HV tests I don’t blow another IGBT/Driver/Isolator as this charger is starting to look expensive already.

However my envy of seeing other people using these chargers successfully should keep me going ;-)
Can’t wait to charge on the go, I am currently running my EV (for around a month now) to and from work via School for my daughter I do around 25 miles round trip and use approximately half of my 10kw traction pack, I only specified 40 mile range so currently it is all looking pretty good.

I am borrowing a couple of Zivan chargers from a friend who’s EV is off the road at the moment, charging takes me around 2 to 2 and a half hours total although I have to revisit half way through to switch off one charger as I am using one charger to charge two (paired) of my three battery boxes, the other to charge the third.

I hope to get my HV cut off boards (installed in the batt boxes) to control the charger so I can simply plug and go rather than timing everything.

Test1                                                       Test2
Calibration Sequence

New alloys & tyres for better grip in the wet and brake servicing

Came down with the flu on Wednesday and took a couple of days off work as I was coughing and contagious, so I did not get to touch the car for a couple of days.

On Saturday I was still feeling s#!t but managed to drag myself to the local tyre place and get some 195/50 R15’s on the new rims I had bought last weekend, whilst I was fitting them I serviced the whole braking system by removing the piston side of the callipers and freeing up the slightly seized rams(just needed a tweak with a pipe wrench to free up the ram) the car had been sitting for a year and so the grease had gotten stiff.

Tested the car with new wheels and tyres, feels great loads of grip, they do feel heavier though and this will probably affect my range, so I may get a couple of 185/40 R15’s for the front to avoid the slight rubbing on the plastic guard at full lock.

Still need to balance them may get the tracking done at the same time although it feels pretty good.

New 15” alloys for more grip in the wet!

After driving the Beat for 3 weeks it had become apparent after the first of the many winter rains to come that now that the EV has three times the torque it had as an ICE car it was severely lacking grip especially in the wet.

I nearly lost it one morning on the way to work after I put a little too much pressure on the pedal pulling out of a mini roundabout and had to correct some serious unintentional drift (That got my heart rate up!)

At that point I decided that it was time to invest in some wider alloys, a week of searching on eBay turned up some very nice reconditioned 15” 7” wide BBS style alloys for £250, I bought these and collected them from Burgess Hill at the weekend in the EV.

Unfortunately I was pushing my range limit (Still don't have the LVC cut off fitted! SHIT!) and I had not factored in the extra 30kg of alloy that I would be carrying so I ran out of juice about 20 meters from my front door, managed to coast it the last 20 meters with the car learching from an uneven power delivery.

Took me around 5 minutes to get the car in and on charge, I was rushing to get both chargers plugged in and charging ASAP as I understand from speaking with Steve that if I take the cells too low for even a few minutes I can kill them dead (as I did with the 12v LIFEPO last week! Which is now fugged).

I think I was very lucky on this occasion as all the cells seem to have recovered fine and I gave the whole car a good full charge to make sure, checking each cell on each series bank with my widget to make sure it all looked good.

I immediately went inside to start looking at getting the LVC wired & working.

My first EV breakdown!

Ok so even EV’s are prone to human stupidity! And I surprise myself at just how daft I can be sometimes, Last Thursday after leaving work I got back to a dead EV! A quick check and I spotted the culprit, I had left the sidelights on and drained the 12v LIFEPO flat, Damn!

Checked the Voltage it was way low < 2v.
“In my infinite stupidity” I thought that I may be able to use the 12V PSU to feed current from the good Traction Pack to the 12v block by defeating the contactor! (“WHAT ARE YOU MAD!”)

Yes I realise now that this was infinitely stupid thing to do as there is obviously a limit to the current the PSU can take after all its not a battery charger but a PSU, luckily I realised my mistake when the PSU turned into a nice electric heater for a couple of minutes and I disconnected it before I blew that up!

However whilst I was attempting to defeat the contactor using my battery cable, I inadvertently (in the dark) used the wrong +ve from the twin pack rather than the one from the single pack, which would be at 155v not 220v this promptly blew the 40A fuse I had on my battery connection lead and took out the contactor at the same time, SHIT! (I am guessing that current tried to flow back into the 3rd pack?)

After checking with Steve my friendly local EV expert it appears that my thinking was not entirely wrong here and Steve replied with
“Hmm the PSU SHOULD be able to charge the 12v pack OK – I’m guessing you mean that you shorted across the contactor so as to bring full input voltage to the PSU? I used to carry a real small 12v pack in the boot with a couple of croc clips – that way, if the 12v voltage dropped below the 9v required to operate the contactor I could touch the terminals with the little pack and supply enough power to close the contactor, at which point the PSU would kick in and recharge the 12v system.

However, this is only safe if the 12v pack doesn’t go below 8 or 9v.
That will be why the PSU started to creak then as I mentioned my 12v block was sat at less than 2v for several hours killing it dead me thinks, I have since tried to charge it but I think it has given up the ghost.

So I switched the 12v battery over to the lead acid that came with the car, same small size and it is quite a good Yuasa the original from the car so that should do for now, can't afford another LIFEPO at the mo.
After driving the car home on Friday lunchtime I felt sure the lead acid was working well and gave it a good charge to make sure.

So to summarise this week I have blown a 12V £100 LIFEPO due to leaving the lights on! I blew my 12v battery charger trying to recover said 12v LIFEPO £70, and I thought I had also blown my contactor  although after my long range test drive this weekend amazingly the contactor sprang back into life and is now working normally, following my stupid mistake last week when I blew a 40A fuse I have since swapped it for a 30A and charged successfully without blowing that fuse, so I will stick with 30A on that one.