First trip to Work and new Tyres

I drove the Vogue to work for the first time today - partly because the tyre place is over the road and partly because a couple of colleagues that have been following progress are leaving at the end of the week.
I now have Hankook 185/65R13 Enfren tyres on the car.

The Vogue on it's new silicone.

The guys (and gals) at work were uncondionally supportive and it was a immense relief to have other people see the car actaully working, not just a web page.
The trip went without incident. To and from work is 30km total, the other 8km was joy rides which cost me around 15km in range - hmmm! (Whoops. I realised that I didn't take Eastlink so my trip was 17.1km one way - possibly more going home. That makes more sense.)
By the time I arrived home tonight (Odo=110km), the total was 38.21km travelled with 9.01AH taken from the pack. At 600V that's 5400W/hr with equates to 142wh/km. The dash showed remaining range as 29.40km to 80% DOD (I allowed 16AH for use).

While we had the LEAF on trial we got around 170wh/km so I'm really happy with the figures.
The drive to work was on 70km/h and 80km/h roads so the 67km projected range for 16AH is pretty much on the button from Woody's (AEVA) spreadsheet.
Since the trip to work was on the old cruddy tyres, next time should be even better.

I still have a tailshaft issues which I think now must be differential pinion angle.
My target for the moment is VicRoads approval so everything else can wait. I pick up the polycarbonate partition for the boot tomorrow and I'll be preparing the car for inspection over the Christmas to new Year break.

Boot (Trunk) Partition

In order to satisfy regulations regarding not being able to touch the cables carrying EV traction battery voltages, I will need a plastic partition in the boot. The old fuel tank cover handles the switchgear on the left of the boot.

I will be using 3mm polycarbonate and it will be mounted just this side of the four packs along the rear firewall. It will be a bit fiddly as it has to be cut around the boot hinges.
I thought I'd get some quotes on cutting and drilling polycarbonate before I bought a piece at Bunnings (hardware store) and did it myself. The second quote was only just a bit more expensive than buying an uncut sheet. So, I dropped this drawing

into

Plastics for Industry P/L

13/189 Cheltenham Rd

Keysborough VIC 3173

today. Ashton was a pretty easy guy to deal with.

It should be ready early next week so I can instal it over the Christmas break - assuming I got all the measurements correct.

Oh, and my tailshaft is ready for pick-up.

Tailshaft Wobble

Yes it's definite. I put the Vogue on axle stands and removed the rear wheels. Above 70kmh the wobble gets worse and worse.I removed it last night and took it up to the driveshaft people this afternoon. I hope to have it back Friday or early next week.

Pack Balancing and Charger Modifications

With all the manual(ish) pack balancing I do, I had already designed a small circuit that would automatically deliver 3A until the pack's BMS cut out, then dial back to 180mA - the balancing current for my packs. I wasn't looking forward to making these, nor fitting them.
With that in mind I thought I would try again to find a schematic of the Kingpan chargers that I am using. I found a thread on Endless-sphere that (somewhat indirectly - I can't figure out now how I found it) pointed to a site in Europe where a guy (thanks Albert) had reversed engineered some other brand of charger based on a TL494 chip (my favourite PWM controller).

I grabbed the circuit, pulled the lid off one of my spare chargers and - guess what - yes they are practically identical. There are a few resistor values that are different but just about everything is the same. It was relatively easy to devise a small daughter board that used the Op-amp that was driving the transition of a bi-colour LED on the charger to trigger the changer to cut it's current from 3A down to 180mA. The challenge was to be able to do the modifications without having to remove the main PCB from the case - with all the complications of re-seating power devices on heatsinks. I found that the best was was to remove one resistor and solder on four wires to a daughter board. The daughter board is circled in red. The heatshrink gets cut down, shrunk, then glued to the nearest strong component. I'll improve that toroid's mounting too - while I have the Sikaflex out.

Now this charger has built-in balancing tailored to my pack's BMSs.
I don't have to do all the chargers at once, just as I get around to them.

Driver Seat Fixed

As per a previous post, following the fourth drive Laurel didn't like the way the upholstery was behaving on the driver's seat - so out it came. I pull all the clips off, removed the back upholstery and foam and revealed the problem. We deliberately did not glue the seat velour down to the raised parts of the seat - the grey bits shown. The issue arises when you get in or out of the car you tend to rotate in the seat which pulls the velour slightly.

Now it's glued thoroughly - and the seat is back in the car.

Battery Packs all Good

I have been a bit slack with the blog this week. Last weekend, following dis-assembling pack #2, I  charged all packs as per normal then used my single balancing charger to "top off" each pack. I got the job done over the weekend - way better than the 2 weeks using two chargers last time. Some packs balanced up within 3 hours, maximum was 10 hours.
All the packs took 3 Amps for over 3 hours on the full charge so overall the cell balance is looking pretty good now.

I also got to the bottom of the AH difference from Vogue display to actual.
I stupidly was assuming that the current sensor put out 2.5 volts for no current (correct), then 5V for +100A and 0V for -100A - WRONG. Upon careful reading of the specs. I realised the the sensitivity spec. 20mv/A means exactly that. 20mv/A then 200mV/10A then 2000mV/100A or +4.5V for +100A and 0.5V for -100A. Curiously when we set up a 12A current flow to calibrate the sensor, it was only 17% out - not 25%. Anyway it's now calibrated to within 200mA - the resolution of the Digital to Analogue input on the dashboard PIC micro processor.
That also means that we really did pull 14.3AH from the pack which also means that all cell pairs are pretty much OK.
So the total range for 16AH that was projected as 80km is closer to 70km under those driving conditions. That's still good - old tyres, no front end alignment yet and it was a lot of stop/start driving (137Wh/km).