Tim told me they were supposedly rated 550 mAH. I've built up a 12V stack of them that is theoretically 10 Amp-Hours. I'm probably going to build a charger based on the Maxim MAX713 charge controller http://dbserv.maxim-ic.com/quick_view2.cfm?pdf_num=1666 They have a reference design all ready for a NIMH charger that looks pretty straighhtforward. They also have the thing in kit form as an eval kit. I don't have a price yet on their eval kit, probably not expensive, though. http://www.maxim-ic.com/BuyMaxim/Sales.htm So far, I've been charging with just a voltmeter attached, with an old car battery charger through a current limiting resistor. I watch the voltmeter for a negative voltage slope, then quit. I know from reading datasheets that NIMH batteries have a negative voltage slope when fully charged. What I'm unclear on is, is the negative voltage slope measured : 1. When there is no charging current or 2. When charging current is flowing? I find the voltage floating all over the place while these batteries are charging, and I can't imagine finding the negative voltage slope after watching the voltmeter wander up and down so much while charging with about 2 amps. For instance, I watched the voltage during charging go from a peak of 13.05 volts, down to 12.8 volts, back up to 13.1 volts, wander down to 12.9, then back up to 13.2. All this time, the batteries had about 2 amp charging current. No way they were near charged. Anybody got any clarification on this? -- Lawrence Lile ----- Original Message ----- From: "Ethan Swint" To: Sent: Monday, May 07, 2001 9:08 PM Subject: Re: [AD]: Battery surplus > Most of the AAA NiMH batteries I've seen give a capacity of 500 - 600 mAh, > so that would be in the ball park. If anyone got an extra box of these and > doesn't want all of them, I would like some (~20 packs or so?) for a home > hobby project. > > Ethan Swint > Ethan_Swint@baylor.edu > > ----- Original Message ----- > From: "Brian Reed" > To: > Sent: Monday, May 07, 2001 8:56 PM > Subject: Re: [AD]: Battery surplus > > > > I received my box of batteries today - sweet! > > > > Has anyone determined the battery model used? They seem to > > be from BYD, one of two models. From www.bydbattery.com > > click on "Products List" and see AAA400 & AAA500. The > > "Nominal Capacity" of each is 400 or 500 respectively ... is that > > a mAh capacity rating? > > > > Thanks, > > > > - Bri > > - > > > > -- > > http://www.piclist.com hint: PICList Posts must start with ONE topic: > > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics