[MPaulHolmes]

I could make a black box that can read various inputs (signals about state of charge and whatever?), and have a microcontroller make decisions based on that information, putting out any voltage/current that you want, as long as it is less than or equal to the voltage of the input into the black box. Let's say it is a 144v charger. The black box would need to have an input of maybe 165v DC (I'm not sure how high the voltage gets when in fast charge mode. Is it around 13.7v per battery?).

Basically, that's all a motor controller is, is something that reads inputs, and puts out a voltage that is controlled by the user. You can control the voltage output by a micro-controller just as easily (with the human removed. No throttle!). You would only need a single 200v fancy mosfet, because the continuous current output of the charger wouldn't be any higher than 30 amps I would think, and 1 of those mosfets can put out 50 amps continuous.

It would be a PWM based charger. The PWM signal would be smoothed out by an inductor (like a motor) that would be inside of the black box. The inductor would just be a coil of maybe 12 gauge wire.

So, how do you make a steady 165v input source? All the charging algorithm stuff is just gravy with a micro-controller!