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Comment by IrishTechie

7 hours ago

Also found it fascinating, although on the discussion about brakes I thought about how regen braking turns off in my EV when the battery is full, because there is no where to put the power. So you either keep some of the battery always available to soak up braking energy (and hope people never charge to full at the top of a mountain and exhaust the buffer) or you include a set of normal brakes for when regen is not possible, both options negating the weight savings. Right?

i wonder how much heat you'd have to dump if you just used a resistive load and heatsinks. aluminum isn't very heavy. Look at the size of a rotor and brake shoe on modern cars, it can't be that much larger surface area as a heat sink to dump the charge. Although someone would have to test it. Since EV are so smart, wouldn't they know that all routes generally are downhill, and thus stop the charge at 80% or something? Further, the absorption phase means you have to dump excess current somewhere anyway if you're over 80% charged.