-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 This sounds like a "supply" problem more than a "load/draw" problem, so I'd second the advice to check/clean all connections. One thing to do is drive around for a bit, and then quickly measure each connection to find out if one/more is hot to the touch (indicating resistance and a bad connection).
[Obviously, do this in an electrically safe way... like a non-contact IR thermometer, or just using your finger while floating in the air with no contact to anything else ;> ] Also, if you have a BMS or way to log cell voltages, look for one/more cells sagging to zero (or worse?) under load. If you have one bad cell it may now show up as a large voltage drop over the entire pack, but it may be a 100% voltage sag for the cell.... Failing that, if your pack is OK, it may be a controller issue. Jay On 03/09/2014 03:31 AM, Mike Nickerson wrote: > Hi David, > > Yes, that is correct. I used to see higher currents and better > acceleration at low speeds. > > When I'm pulling 60A from the batteries, I will see a drop from > about 147V to about 142V. When I'm pulling 100A from the batteries, > I will see a drop to about 139V. When I'm pulling 150A from the > batteries, I will see a drop to about 135V. > > Those are all current conditions with the batteries a little on the > cool side. The drop will be a little less as the weather warms up. > Because of the temperature and a couple of weak cells, I don't > really expect to get more than 150A. It would be really helpful to > get closer to 100A off the line, though. > > I probably should clean and check all connections. That is a good > idea. > > Mike > >> -----Original Message----- From: [email protected] >> [mailto:[email protected]] On Behalf Of EVDL >> Administrator Sent: Saturday, March 08, 2014 11:12 PM To: >> Electric Vehicle Discussion List Subject: Re: [EVDL] Performance >> Issue >> >> So you're saying that you used to see higher currents and better > acceleration >> at low speeds? Yes? No? >> >> Bill had some good thoughts. Also, have you checked all the >> cells under > load, >> to make sure that each one is doing its part? >> >> I know nothing about the Kelly controllers except what I read, >> which is > that >> they're not exactly top shelf products. This may not apply, but >> I > remember >> the old PMC DCC range of controllers which, if I'm not mistaken, >> used the > E/C >> junctions of the bipolar power transistors as shunt resistors for >> the > current >> limit. As the transistors aged, their E/C resistance rose, >> causing the > controller >> to limit at lower currents (and causing acceleration to weaken). >> A few owners tried cranking up the limit control in response. >> Not too > surprisingly, >> they fried the power transistors. >> >> David Roden - Akron, Ohio, USA EVDL Administrator >> > > _______________________________________________ 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) > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iEYEARECAAYFAlMcsuQACgkQSWJjSgPNbM/RnQCfeezeiE237L4mP1+p4U3agFb2 pnAAnjEQNMp+FlQhc0n303WTkcV6/GFE =7lG9 -----END PGP SIGNATURE----- _______________________________________________ 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)
