Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!orion.oac.uci.edu!ucivax!ucla-cs!oahu.cs.ucla.edu!chao From: chao@oahu.cs.ucla.edu (Chia-Chi Chao) Newsgroups: comp.sys.laptops Subject: Re: Batteries Message-ID: <1991Apr4.182847.1515@cs.ucla.edu> Date: 4 Apr 91 18:28:47 GMT References: <9L9uZ4w161w@nstar.rn.com> Sender: usenet@cs.ucla.edu (Mr. News Himself) Organization: UCLA Computer Science Department Lines: 21 Nntp-Posting-Host: oahu.cs.ucla.edu In article <9L9uZ4w161w@nstar.rn.com> jackw@nstar.rn.com (Jack Wiggins) writes: >Look at your circuit again. You can't "reverse charge" batteries in a pack >unless the current is flowing backwards in ALL of them. When NiCad is being discharged, positive current comes out of the positive terminal. When it is being charged, positive current goes INTO the positive terminal. When you put cells in series to form a battery pack, the weakest cell will reach 0V before the others do. It becomes a "load" in the circuit, and positive current goes INTO the negative terminal -- same as charging the cell backwards. I am not an expert at this, but this has been discussed in sci.electronics many times. >Also, if you do get >a reduced charge capacity because of the memory effect, a couple of full >discharge-charge cycles will bring the battery back to snuff. You can only reduce the memory effect, not totally eliminate it, especially in a battery pack. -- Chia-Chi Chao chao@cs.ucla.edu ..!ucbvax!cs.ucla.edu!chao