Monday, 28 October 2013

Vacuum assist here we come.

Ok so I promised myself that now the kids birthday parties are out of the way and I have been driving the car with decidedly dodgy brakes for 2 weeks it was time to fix the vacuum brake assist.

I had already had an explanation of what was require by Steve as he also needed a vacuum assist on his MX5 conversion.

I had also passed this on to my mechanic who had fitted the vacuum sensor and pump, however he had fitted the sensor in line with the pump and vacuum chamber and try how I did to get the vacuum to work it would either not seem to switch on an off correctly, it either ran constantly (blowing 1 £40 sensor due to my idiocy of not fitting an extra relay to separate the motors high current from the sensors relay contact, Dummy!) or not to run enough ie. No vacuum!

After a little thought (it helps) It became obvious that because the sensor is in between the pump and the chamber it would switch off before the chamber had reached its fully evacuated state.

The solution to this was to move the sensor from the T in the pipe to the chamber itself, in fact the best spot turned out to be obviously the furthest point from the motor and there was a convenient flat point on the chamber on the opposite side to the motor tube outlet.

Of course this meant breaking down the entire hydraulic master brake cylinder, disconnecting the brake pedal from the master  cylinder and removing the whole vacuum chamber, separating the master cylinder from the chamber and drilling and tapping a hole for the sensor to screw into, luckily I had a tap and die set that had just one imperial sized tap and die, 1/8 of an inch exactly what I needed.

So after breaking it all down and drilling and tapping on Saturday afternoon/evening I cleaned up the surface corrosion around where the master cylinder joined the vacuum chamber and rust treated it with some Jenolite I had kicking around  primed it with the part 2 Jenolite treatment and once this was dry around 10:30 Saturday evening, I finished it off by slapping some black enamel on it ready for Sunday’s reassembly.

Spent Sunday morning reassembling the whole shebang and testing it, worked a treat and now I have fully functioning vacuum brake assist, however this merely pointed out that the beat has s#!t brakes! :-(

So I guess I am now in the market for some new brake pads until I can get some 15” deep dish wheels (as recommended by Brad a work colleague who knows and likes his cars) according to Brad I have 14” x 5” wide wheels/tire’s on the rear and 13” x 4.5” wide wheels/tires on the front, he has recommended I get at least 8” & 9” wide wheels for the extra grip that I am now decidedly lacking.

Update on what is left to do

1) Get the Tax disc Done
2) Repair and get my 12Kw EMW charger working.
3) Fix speedo issue
4) Test brakes properly and fix if necessary Vacuum Assist Done, better brake pads needed!
5) Fit last battery box and test PSU/DC-DC converter. Done
6) Full test of all systems, lights, indicators, brakes, windows, anything that draws current from the 12V batt whilst the car is driving around the garden. Done, PSU works treat (Thanks Steve)
7) Assuming charger is working now, fit into Ali box and test again
8) Fit charger into car and wire J1772 (there are issues here that Valery and others are trying to resolve)
9) Wire J1772 plug through an adapter to my supply at home and test all systems work as expected.

Extending voltage sense cables

Spent Saturday morning extending the Voltage sense wires into the back parcel shelf of the interior, found some new speaker cable I had laying around cut each of the 6 wires on each of the 4 banks in each of the 2 boxes in the rear of the car (third one’s in the front) and soldered an extension in each wire cutting/soldering and shrinking each connection as I went after all these are live wires to the cells.

This all went swimmingly and after re-purposing an old racer tire inner tube for covering all the wires into a neat bundle threading and zip-tying each end I now have a neat easily accessible bundle of plugs that plug straight into my battery monitor widget, all tested fine after I had finished, Job well done (makes a change!)  

The first two weeks on the road

All looking good so far, still have the brakes to sort (get the vacuum assist working) and fuel gauge to fit along with cable extensions to make all the battery bank voltage test wires available from inside the car without the need to keep taking the soft-top rear part out (several screws) and removing the engine J motor bay service panels out to get to the bank sensor wires.

Each of my batt boxes has a circuit board for each series bank of 9 paralleled cell packs which breaks out the voltage sensory wires, in effect this means that I can sense the voltage on each individual cell string of 4 series banks in each box (12 banks in all to give me the 222v I need for the motor)

So when I plug my 20 quid battery voltage sensor widget it shows me 5 voltage readings, this is because I am using 5S cell packs, each cell pack having 5 actual cells in series, hence the 5S.

However as the voltage sensor boards are all connected in series across the box what I am actually sensing is the voltage of a single string of 4 cells, 1 for each series block.

So the first voltage reading on the widget reflects the voltage of cell 1 in block 1 + cell 1 in block 2 + cell 1 in block  3 + cell 1 in block 4, the second shows cell 2 in block 1 + cell 2 in block 2 etc.

This way I can at least tell if any of 1 string of 4 individual cells in that box is low it should show and if it does not recover after balancing (something I have not even got into yet, coming very soon) then I can remove that box for further investigation and once the box is open I know exactly which 4 cells to check individually to identify a bad cell and replace it if need be.

On the road at last :-)

Well it has been a very busy few weeks since my last post and things have really moved on.
As of Monday 14th October 2013 my EV is officially on the road (if not entirely finished!) as my charger is still awaiting parts (must chase these ASAP) Steve has been very helpful in lending me a couple of his Zivan chargers to get me on the road with my full 220V pack.
My partner had a serious car accident a week last Friday (4th) and wrote off our lovely VR4 Galant/Legnum twin turbo monster, I know I have been looking to replace this car as it eats petrol like I breathe air but this is not what I had in mind, thankfully my partner Mikki and my two daughters were fine other than Mikki sustaining an air bag blast wound, the car however is fugged :-(
Check the photo below!

Anyway I took the next week off work to give Mikki a break to recover and spend some time looking for alternative transport, however this also gave me a week to finish off the Honda Beat EV and get it on the road once and for all :-)

So Friday the 11th I took it for its first proper road test, I tested the "Beat" on a run to and from my work at Sussex Uni junction on the A27 this afternoon, in the rain, wipers going lights on for only half the journey (Bottled it!) ran the fans to clear the windscreen a little and "it were great", started out with 164.5v on the twin pack and 82.5v on the single, after getting back it was 152.2v on twin, 76.2v on single, I think that is approx. 22mile round trip (would need to check the clock, which I forgot to do today!)

Spent the weekend tweaking and charging to max safe voltage (84v per pack) after checking with Steve it seems my safe max voltage is 84v and LVC should be set at 70v this gives me a 14v range of “Fuel level” i.e. 84v on each pack means full pack 70v per pack means empty pack.

It is now Tuesday 15th and I have been driving the EV to work proper for a day and a half, so far so good, managed to get me to work drop my oldest  to school and do three circuits of Sussex Uni campus with friends to demo the car (they have been waiting a year for this)  after getting home I still had 76v per batt box, just under half empty.

The devil is in the detail

So near and yet so far, I spent a while tinkering with the brakes over the weekend as the vacuum switch did not seem to come on after the ignition was switched on, and now the vacuum sensor appears to have packed up, no apparent reason why but now it won’t switch on at all.
What with that and the blown IGBT DC-DC and IGBT driver chips on my charger, I am not having the best of times with the getting the car on the road.
However my partner is attempting to get the DVLA to give me a TAX disc today (we will see just how easy this wasn't tonight)

All in all it has been a little depressing this week with the failures, still I did manage to get the IGBT’s ordered they are not cheap at £69 each, bought two as I am intending to build another charger for the second EV which we have not started as yet.