10-Minute Electric Car Charging

[Mormegil]

I remember using fast charging on my electric RC cards when I was young.

My question is, which is more energy efficient? Slow or fast charging?

If an ultra capacitor is required for the "dump" - there must be some energy conversion loss there (maybe negligable?).

What about on the battery itself? Does it use more total amps to charge it the same as a slow/trickle charge?

We know it gets hotter, but that's because the charge happens in 10 minutes. But is this waste heat more or less than the total waste heat during a much longer trickle charge?

I would also expect the power to cost more, as it's going to be at a commercial station and often be at peak hours.

[drees]

Originally Posted by Mormegil

My question is, which is more energy efficient? Slow or fast charging?

In general, charging faster will be less efficient due to resistance - which in turn will raise the temperature of your conductors and raise resistance some more.

But since all batteries lose some amount of charge over time, charging too slow will also be less efficient.

So there is some sweet spot where charging will be most efficient - it will likely be a fairly wide range of currents.