[Scoundreller]

I’d like it to draw enough power to not use the internal battery but avoid charging when driving in a car if it’s at least X percent charged.

I kinda do this with a crappy USB charger in my car.

[jmbwell]

Unless you have an EV charged only with renewable energy, I'm not sure there's any way to charge it with your car in a carbon-neutral way anyway...

[Scoundreller]

Depends where your grid electricity comes from. ICE is a pretty damn inefficient way to generate electricity (and costly when it comes to its excess taxation).