On Jan 12, 1:47*pm, Tom Gardner wrote:
On Jan 12, 7:05*pm, bildan wrote:

*On downhill grades, the wheel motors would
switch to regenerative braking to recharge the trailer battery and
save the towing vehicle's brakes.

Is that actually the case? I was under the impression
that the electrolyte will boil if you try to put energy into
batteries as fast as it can be taken out.

I'm more than happy to be corrected, if necessary.

With the old lead-acid liquid electrolyte batteries, that would be
true.

The new "fast-charge" lithium based solid electrolyte electric vehicle
batteries can take a full charge in less than 10 minutes. They also
have a far larger energy density and power density.

However, even this may not be good enough for heavy regenerative
braking - enter the Ultra-capacitor. Ultra-capacitors can charge
almost instantly then trickle the charge into a battery pack at a
charge rate that keeps it happy.