Dougnuts
Well-known member
Why would a larger battery take a faster charge rate (assuming same cells; e.g. 4680 type)?
The smaller pack would have less internal resistance (shorter current path) and be better able to dissipate heat (surface area to volume).
It's kind of a use case situation, but here's how I understand it.
You can only pour the current to a battery until about 80% capacity is reached, then it must slow down, quite a bit. If you can get by without charging past 80%, your charge time will be drastically reduced. Ergo, a larger battery allows for you to do more with it before requiring charging that last 20%, which could double charge time.
Real world example; If you look at Tesla's trip planner, it will only have you charge over 80% when it's absolutely necessary to get where you are going.
Notes: Some battery chemistries are better at this than others. Also, on some cars, 100% charge is limited to 80% of the physical battery capacity, so they give the illusion of charging to 100% without slowing down, but they really aren't.