Jay, *do* write this up to your batteries getting old. It has been documented many times here on the EVDL. With age, the "full" voltage drops, so the charger never reaches its threshold and starts *over* (not *under*) charging your batteries. Luckily lead-acid is robust and can handle it within reason. Due to your relatively short time-out the damage done to your batteries is limited. You may notice that your pack is warming up (further reducing the voltage) due to the charger pumping power into full batteries. If you let them cool for several hours and restart your charger, you will see that the indicator will go higher due to the colder batteries. Possibly it will even hit the threshold voltage to stop charging... But as long as the batteries are old, the charger relatively wimpy and the temp high, you will face this situation where you go from battery charging into thermal runaway or at least a toast-em till timeout.
Hope this clarifies, Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: [email protected] Private: http://www.cvandewater.com Skype: cor_van_de_water XoIP: +31877841130 Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 -----Original Message----- From: [email protected] on behalf of Jay Summet Sent: Wed 7/10/2013 8:57 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] 2nd charge cycle -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 07/10/2013 11:30 AM, SLPinfo.org wrote: > Hi folks, > > My Quick Charge Select-A-Charge charger is getting old as are my lead acid > batteries in my S-10 http://www.evalbum.com/3739. I've been using them for > about 2 years and have about 450 cycles on them. > > For the past several weeds the charger never seems to get up to the target > voltage. The display seems to get stuck at about 55-60% (varies a little > from one day to the next) and then it just times out after about 11 hours. > Using my DVM it looks like it's hitting about 135V or so which is quite low > for my 120V pack. Clearly I'm undercharging my batteries. I sort of knew > this would happen as I bought the charger used and it's only rated for > batteries up to 150 AH and mine are 170 AH Trojan T-875s. It also only > puts out 10 amps at 110V so I may have been undercharging since day 1. > I don't have an answer about your plug, but have you tried starting a 2nd charge cycle after the charger times out? (e.g. charge your batteries twice before using them?) 10 amps isn't a lot of current, but it's not horribly horribly low (it's better than c/20, but not c/10). On the other hand, if it's still in the bulk charge stage (50-60% would indicate this) it should be putting 10 amps into the batteries for 10 hours which should be 100 amp hours. Do it twice and it should be able to charge even a brand new 170 amp hour battery. Do you have a Kill-A-Watt to verify that the charger is actually drawing 10amps? Do you have an amp meter on the pack to verify that the batteries are taking 10 amps? If the charger can't get the pack to 140 volts or higher during the 2nd charge it might be a problem with your batteries, or a problem with the charger, or even a problem with the power cord going to your charger (to long, too much resistance, etc...) But I wouldn't put it down to just the age of the charger or batteries before confirming how many amps you are actually putting in. Typically when lead acid get older they have less capacity, but you can still charge them up to a full voltage (using less Ah than when new!). Jay -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iEYEARECAAYFAlHdhFQACgkQSWJjSgPNbM+okwCeLCVIMPt1Uxav/nCmv7D1li+z vI8An3M3ThbkMne9z3VgPZ7nfKDVAcgp =8E62 -----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) _______________________________________________ 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)
