[MPaulHolmes]

It's a 220v generator. It will be around 6-7 kW but they haven't settled on one yet. It's just a small, 3 wheeled car, so 7kW will go a long way.

The SR controller will have all the necessary stuff on it (which isn't much) to do it all. It has CAN, so it will be receiving each battery voltage. Right now there are 48 of those little buggers. Each battery measurement is accurate to about 0.005v, so all 48, under absolute worst case, the overall voltage monitoring is accurate to around 163.2v +/- 0.24v when fully charged. In practice, it's more like +/-0.1v or something.

CAN was a pain, but now it's wonderful! So, I have a few contactor turn on circuits on the controller control board, so when the amp*hr usage hits a specified value (the voltage won't necessarily drop), I just turn on the generator with the controller (electric start). Then once it's been on for a few seconds, the charger closes its contactors, since the charger and controller are good buddies, sharing everything over CAN. The charger 12v power is on whenever the controller is on. Each one only uses like 1 watt of power (the 12v section), so it's all good. Then the charger takes the 220v from the generator, and, being a big current regulator, just puts out a constant 40 amps at whatever voltage (it doesn't care what the voltage is). At a stop sign, the batteries will be charging. While driving, they will vary from charging to power being sucked out of them. That's it! hurray! Chevy volt on a shoestring!