>-----Original Message----- >From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] >Sent: 13 February 2005 21:42 >To: piclist@mit.edu >Subject: Re: [EE]: Battery repurposing > > >In message <4af9943c4d.philpem@dsl.pipex.com> > Philip Pemberton wrote: >> Compaq Evo n600c series (PP2040 series) laptop battery? >Anyone got pinouts? >> I went and bought two of the things and aside from working >out that >> they're "smart" LiIon batteries (with Japanese cells.. hmm..), I >> haven't done much with them. Mainly because no-one seems to have the >> pinouts... > >Just ripped one apart.. seems it's got a UCC3957 Li-Ion safety >monitor, a Benchmarq Bq2050H Smart Battery Monitor, a 24C01 >EEPROM... and a PIC16C63A. > >I think I've also worked out why it isn't producing any >output... Four cells times 3.6V is 14.4V.. I measured 12.7V on >the battery pack (about 3.2V per cell). Eep. Guess it's flat :-/ > >Now for the million dollar question: How the hell do you >charge lithium ion batteries, anyway? Ideally I'd like to >avoid converting the battery pack into a charred, smouldering >mess in the process, especially seeing as the cells are >actually pretty good quality (Sony Fukushima US18650GR type) >and seem to be in reasonably good shape. L-ion cells are quite fussy about charging. It's essentialy a constant current charge with a very critical termination voltage of 4.2volts. If you try to charge the cells much past 4.2 volts you are likely to end up with a fire. A typical charge rate for laptop batteries are 0.7C, smaller cells can often be charged a little quicker. One important point, if the cell voltage has fallen below 3.0volts, then a trickle charge of 0.1C should be used to bring the cell voltage above 3.00volts before attempting to use the full charging voltage. Do not keep L-Ion cells on a trickle charge, they cannot accept overcharging without becoming potnentialy dangerous. Regards Mike ======================================================================= This e-mail is intended for the person it is addressed to only. The information contained in it may be confidential and/or protected by law. If you are not the intended recipient of this message, you must not make any use of this information, or copy or show it to any person. Please contact us immediately to tell us that you have received this e-mail, and return the original to us. Any use, forwarding, printing or copying of this message is strictly prohibited. No part of this message can be considered a request for goods or services. ======================================================================= -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist