DOH - New transmission needed

I noticed some oil leaks below Electro the other day - yes, oil leaks. Although Electro is an EV, it still has the stock VW transmission, that has gear oil. This apparently is leaking through the differential seals that connect to the front drive axles.

So I took Electro in to a local VW shop to get the seals replaced. They looked, and basically assessed that the differential is shot and that I will need a whole new tranny. OOF.

The good news is (believe it, there is some) the tranny replacement can be done from underneath the car, and with no removal of the upper battery racks or cables. Even the motor will stay connected by one mount (the one opposite the tranny). Because of this, the VW shop has bid the job and will do it over the next week - for $1500.

I believe this is the last part of the original drivetrain, and it will soon be replaced.

Final connection pics

I forgot to upload pics of the final battery connections, so here they are. The front:
and the rear battery pack:

Here's a close-up of the connections:

As you can see, each cell monitor straddles its respective cell, and the copper interconnects go between cells. The monitors are daisy-chained together in a large wire loop that terminates at the BMS unit in the rear of the vehicle. If any one cell encounters a problem, it notifies the BMS, which can then cut power to the charger.

Right now I only have per-cell protection from over-charge, but not per-cell protection from over-discharge. The Zilla motor controller is providing protection of the pack as a whole from over-charge, with a low voltage limit of 130V (2.5V/cell).

20 miles... without breaking a sweat.

I took Electro on a preliminary range test, laptop collecting data along the way. I was fairly aggressive with my acceleration and choosing hills to climb, so I had some healthy current draws from the pack, sometimes reaching peaks of 300 battery amps on some of the steeper hills (this would equate to over 500 motor amps in some cases). I did not drive on the freeway, but man, I had the acceleration to go there easily.

Although I don't have my meter installed yet, I do know the floating pack voltage has a range of ~170V (full charge) to ~162V (lower advisable limit) - it's really a flat discharge curve. I drove 20 miles (again, with gusto) and recorded the floating pack voltage basically staying between 168-170V. Phenomenal.

I think it may be time to promote Electro to my daily driver.

It's official... I am peelin' out once again!

I had set the Low battery voltage limit too high at 152V (2.9V/cell under load) on the hairball computer yesterday, which did not account for pack voltage sag under load and hence resulted in overall sluggishness in acceleration or up hills. After dropping this limit to a more reasonable 130V (2.5V/cell under load), I could (and did) peel out from a standstill. HUGE EV grin!

I don't want to do this too much, but it is fun to have that torque when I need it.

Maiden Voyage today!

Matt and I took a fully-charged Electro, satellite radio blaring, on a 12 mile jaunt through Edmonds. Not too far, just enough to ease the batteries in and check how the newly set parameters in the motor controller are working out with the new pack.

In general, things are working well. The float voltage did not appear to drop at all from ~170V (3.27V/cell) during the whole 12 miles. I know the discharge curve is relatively flat, but this is encouraging for range!

As usual, I think my initial battery current limit or voltage limit is too constraining on the Zilla - up hills are sluggish. More tuning required there.

A few more (and longer) trips before I start going to work with this puppy!

Traction pack goes LIVE

Over the weekend I made the last of the battery connects, hooked up the DC/DC, and started the first charge. My pack voltage started at ~166V (3.2V/cell), and I was tuning the charger to push the pack to ~176-187V (3.4V-3.6V/cell).

The last thing I need to work on before maiden voyage is the instrumentation, which hopefully will be tonight. Pics soon!

Cells installed, interconnects in process

I wasted no time in getting the cells into the front and rear battery boxes. Since they don't fit exactly (I knew this in advance), I spent the first part of the day crafting some pieces of lumber to tighten up the cell packs in each box. Here you can see the front box:
and the cells in the rear battery box:


Once the cells were packed in pretty tight, I set about working on the interconnects in the front. This includes the interconnects themselves, and sandwiching cell monitors on the cells. Pretty close work, so I purposely worked on broken series sets of cells. Here is how it looks so far:

Notice the painters tape over the connects not made yet - safety first! This is where the 'light show' is going to start to become evident. Each cell monitor has a green and red LED. Green indicates the cell is in the correct voltage range. Check out the way it looks with the lights out...

Work tomorrow on the rear pack, which has twice as many cells!

Hello my pretties!

Went down to Lacey, WA today to pick up my 53 SE100AHAs. Here's a picture:


The cells came with interconnect hardware, check out this pile of copper and steel:

The interconnects are stacked sets of solid copper, with a shrink-wrap middle for insulation. Here's a side view of one of them:

I will be doing a test fit in the battery boxes this weekend. Stay tuned!