Hi Chen: I recently have done a lot of experiments charging Ni-MH batteries. Ni-Cad batteries have a chemistry that does not get hot when fully charged, but Ni-MH batteries will get very hot at the end of charge. This overheating of the battery will degrade it's future performance. One way of avoiding overheating in fast chargers is to monitor the battery temperature with a thermistor built into the battery pack. Another way is to use a "Burp" charger that every now and then provides a strong discharge pulse. A series string of batteries is very similar to a chain. The amp hours you can pull from the battery is the same as the amp hour capacity of the weakest cell. But this does not mean that you can not make up your own long strings. I'm having good results with strings of 10 cells. For more see my web pages: http://www.pacificsites.com/~brooke/5590BA.shtml = battery adapter that uses 20 AA Ni-Cad cells http://www.pacificsites.com/~brooke/BatChg.shtml#Burp = Burp Charging Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Date: Tue, 25 Oct 2005 09:43:36 +0800 From: Chen Xiao Fan To: "'Microcontroller discussion list - Public.'" Subject: RE: [EE] Charging NiMH Message-ID: <3B8AEFFADD3DD4118F8100508BACEC2C0A289351@spex> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Precedence: list Reply-To: "Microcontroller discussion list - Public." Message: 24 Got any recommended generic Battery Charger brands or models which follow the recommended procedures? Or is it better to buy the chargers which are produced by the battery manufacturers? I bought a Sony 1-hour quick charger and find out the batteries are not really charged very well and the charging current may well be too high. My Nikon Digital Camera comes with a charger as well and the quality is also not very good. I am afraid that the chargers are killing the rechargeable batteries. Or is it better to throw away batteries every two or three years? Regards, Xiaofan -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist