Graeme Smith wrote: Hi Guys.... As part of my current project recycling old computers.... for charity, I have come accross a few old battery packs, left over from lap tops... Thinking about what someone had said about there usually only being a few bad cells in a pack, I cracked one open, to take a look inside. Sure enough, there were a few bad cells, and a few extra components I hadn't expected to find. Taking apart a second, different type of battery pack, has added to my confusion, and just increased the number of questions I have.... I figure one old 10 hour laptop battery should have more than enough power for a PIC for quite a while, so I was looking at the design, in order to figure out how to borrow parts of it for my PIC'N. Anyways, I figure the radial lead unit that looks like a cap, with a pointed cap, is some sort of temperature cut-out element that breaks the circuit if it overheats, its labeled micro-temp, so this seems likely. and I figure the square cross-section but long can, with the Isuzu label on it, is probably an auto-rated breaker to cut the circuit if it goes over-amps.... But what I can't figure out, is why the only two cells that have anything wrong with them are the ones these two circuit elements are connected to? The battery pack is supposedly a NI-MH type, rated at 12V and 2.2A for 10hrs. it has 10 "Sanyo TWICELLS" rated at 1.2V each. But a similar phone pack, using the same Ni-MH technology, has cells rated at .6v each.... Am I right in assuming they are hiding two cells in the TWICELL cylinders? and that the base voltage of a Ni-MH cell is .6V? Or are the phone cells simply under-charged? GREY Hi! All accus (NICd, NiMH or LiOH) have cell rated at 1.2V. You have an undercharged accu. When you try to charge that cell use source of constant current with aprox. 1/3 of nominal capacity (1/3 of 2200mA is ~700mA) for about 4-6 hours. You should discharge cells first with same current. Neven Skender ____________________________________________________________________ Get free e-mail and a permanent address at http://www.netaddress.com/?N=1