This is somewhat academic (because the cost for a BMS is still surely cheaper), but couldn't this be done electronically instead of with contactors?
Since the current would be zero when the cells are switched from a series to parallel configuration, it seems that using IGBTs (or whatever) would be possible. Peri -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of EVDL Administrator Sent: 08 March, 2014 9:48 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] NiMH availablity ... On 8 Mar 2014 at 5:04, Marcus Reddish wrote: > Am I crazy or could bottom balancing be done at 3V with all the cells in > parallel? Unless you plan to disconnect and reconnect every single cell every time you charge, which would be pretty tedious, you'd need a contactor for each cell, one that's capable of handling full driving current. For a ~140v battery, that's 40 contactors! Assuming this isn't a toy ride-em car ;-), to use contactors you'll need (1) the extra space to mount one near each battery; and (2) a sizable chunk of money (the cheapest Kilovac is arounc $115 each). You can get a 40-cell LIthiumate BMS (for example) for less than 1/4 that amount (~$1000), or a Mini-BMS for about 87% less (~$600). (Not that I'm endorsing either BMS, it's just that those are the ones I've heard of.) David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to "evpost" and "etpost" addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = _______________________________________________ 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) _______________________________________________ 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)
