And, in most communities, they cannot be tossed... Every store selling Li-Ion batteries in our state is legally OBLIGATED to accept bad batteries, to prevent landfill fires and protect the environment. I just replaced my 5yo Fujitsu Laptop Li-Ion Batteries a few days ago. Cost $60. Best bargain in town. --Bob John Ferrell wrote: > Just be very cautious with Litium technology. There are instances > where this stuff has burned down houses. Do your charging with the > cells outside if possible or at least in a fireproof container. When > they fail it is sometimes like a road flare! > > Properly harnessed they are the best technology available. two years > on my laptop & going strong... > > John Ferrell > http://DixieNC.US > > ----- Original Message ----- From: "Russell McMahon" > > To: "Microcontroller discussion list - Public." > Sent: Monday, February 14, 2005 6:45 AM > Subject: Re: [EE]: Battery repurposing > > >>>> 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. >> >> >> Here's an excellent short article on the subject which addresses most >> points and explains the chemistry behind the process. >> >> http://www.motorola.com/ies/ESG/pdf/motorola.dec.02.pdf >> >> The methods behind the electronics are actually SIMPLER than for NiCd >> and NimH charging - it's just that they are more critical and there >> is a higher chance of REALLY bad things happening if you stray too >> far from the fold. >> >> >> RM >> >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist > > > -- Note: To protect our network, attachments must be sent to attach@engineer.cotse.net . 1-866-263-5745 USA/Canada http://beam.to/azengineer -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist