David Roden wrote: > On 30 Sep 2002 at 17:22, mechelaere wrote: >> Has anybody experimented with SUPERCAPACITORs parallel to >> batteries to enhance peak power output en protect >> them also to surges . > > Solectria built a system using supercaps to reduce peak > battery load in an EV a couple of years ago. It appeared to > be successful in improving range. They issued a news release > about it, but I can't find it now on their website. > > Note that one can't just parallel the caps and expect much > effect, because of the way they store energy. A sort of > variable DC:DC converter is needed to maintain the necessary > voltage as the caps discharge. I remember reading about an Australian concept EV using supercaps, which had a special motor with an additional low- voltage winding (36V?). There wasn't much explanation but I guess the supercaps were "charged up" to the traction pack voltage, maybe while doing regen, and then a seperate controller would dump them into the low voltage / high current part of the motor just while accelerating, as well as current on the high voltage part from the main pack. Sort of like an "IMA" for EVs! It would be interesting to work out how many farads and amps you would need to boost a 20 second 0-60 EV to 10 seconds! :) Evan.
