Tuesday, June 22, 2010


Things are still looking good on the daily commute. The car itself broke 100k miles a couple weeks ago and I'm now at 15k EV miles!

The increase in temperature has made a little improvement to the increasing voltage sag. I think the bottom line is I'm pushing these cells harder than I should for longevity. I believe my commute to work is using >80% capacity and this is taking a toll on capacity. Some mornings I have cell that is very close to fully discharged. I don't know how many miles I have left before at least one cell can't make it and possibly gets ruined to get me here.

I keep going in circles, but I'm leaning towards not selling it now. I'm thinking of making some modifications though now that I see how reliable the conversion itself is. Nothing official yet but here are some ideas I'm toying around with.

Motor controller: The Curtis 1231C has been reliable but I want to get the acceleration back in this car. I'm leaning towards the Soliton1 again for a few reasons.
  • It will increase my motor side amps from 500 to 1000.
  • It's much larger and has great cooling with the option of water cooling if needed. In the hot summer days on my long commute doing 70mph the Curtis is kicking down the amps sometimes.
  • It has many features that will make protecting the batteries, and motor a breeze. I'd like to add some features, but reduce complexity of the build and I think this will be a good step in that direction.
  • I'll have the ability to run a pack voltage that is much higher than the voltage applied to the motor. This allows you to run more smaller batteries allowing you to still get the capacity you want, but make it easier to fit them. It also will remove volt sag during hard acceleration. The pack itself will sag, but if your pack voltage is high enough the motor will receive a steady voltage increasing performance even on those cold days.

Trunk mod:
I think I'll end up cutting out the current trunk and expanding it. There is a LOT of room that is not being utilized under there. This will allow me to add more batteries and even move some of the front batteries to the back giving me room to finally mount that AC that I've been missing.

Currently I'll just add some more cells (I'd like to add another 15 or so) so I can get as much from the existing cells. This should ease up on them and extend there life some on my commute. This will give me not only more capacity but the ability to crank up the motor voltage a bit also to increase high end performance along side of the low end performance I'll gain from the controller change.

I'd like to get the car to a point where I don't have to look at anything and worry about what's going on. I want to simplify this side of things most of all. I want to be able to get in the car, look at my "fuel" gauge and know if I'm good to go. If there are any issues, then be able to connect something and diagnose the problem. I'm looking into some options for a low cost over haul here. The biggest problem with adding more and more cells is the complexity of protecting them.

As always, anything I do I'll document and share with you.

1 comment:

WOS said...

Good to see an update. I have been checking back every once in a while since April. Guess today was a good day to check in on your project. Keep going, keep going! Thanks.