Just thinking outside the box. I am not to familiar with all the volt mechanics so...
I wonder if you can run the charger while car is motion.
You could make a pack of say four 16000 mAh li-po packs and run the charger/pack from the trunk. Battery weight is 1290g (2.85 lbs) and around $80 us each. 10c discharge on 4 packs would be over 600 amp capability
So 64000 mAh pack @ 16 volts = 12 pounds. Maybe 5-10 pounds for an 12v to 110 inverter. You could charge this pack up while at work with a 110 volt charger.
Also how are the accessories run, 12 vol motors or higher off the main pack as the accessory pack could help run fans etc and save on keeping the 12 v battery charged(does it have one)
Anyhow just throwing out a bone
I was going to make an electric car but the Quebec Government made it impossible to legally safety it so lost interest these days. Personally a Zenn with a lith pack is all most of us need (just take the speed restriction out of the programming lol).
Cheers,
Paul