From: Robert Bruninga via EV<[email protected]> That's 300 mA at 250 VDC.
Jan Steinman via EV wrote:
The voltage doesn't really matter, does it?
It does indirectly. We're charging Prius packs. Each 6-cell module is very flat, and sandwiched tightly between its neighbors. It has almost no exposed surface area for cooling. So when you apply 350 ma continuously, it is generating about 9v x 0.35a = 3 watts of heat. It turns out that this *is* enough to make its temperature soar.
There is also the potential for thermal runaway. This can happen when you use a regulated power supply or "smart" charger. As the cells heat up, their voltage goes *down*. This fools the charger into think the cells aren't fully charged, so it fails to shut off, and may even *increase* the current.
What I know (from personal experience) is that continuously charging nimh cells *will* cause their temperature to climb, even at low rates. If the charger doesn't shut off, this will continue until the cell is destroyed.
-- Sometimes when you innovate, you make mistakes. It is best to admit them quickly and get on with improving your other innovations. (Steve Jobs) -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
