HI In addition to my experimenting with solar power and SLA batteries I have also done some playing around with NiMH batteries. There are several manufacturers making 2700 mAHr AA cells and 700-800 mAHr AAA cells. I use many sets of these batteries for digital camera equipment and I have tried several brands. I have found the Maha Powerex AA cells to be reliable and conservatively rated. I have 30-40 of them and have never had one fail in several years of use although I have had several batteries from other makers fail or refuse to take a charge.
I also have several chargers including the Maha MH-C801 8 cell fast charger, the Maha MH-C401FS and the La Crosse BC-900. All of these chargers charge each cell separately rather than several in series. They are all microprocessor controlled and will charge the high capacity AA cells in about an hour. A 10 cell NiMH pack can be charged with a solar panel without a controller. As long as the panel supplies around 1/10 C you can leave the batteries on charge almost indefinitely. For the 2700 mAHr batteries this is 270 ma so a 5 watt panel with a 350 mA maximum output could be left connected all day without worry of damaging the battery pack. Don Brown KD5NDB ----- Original Message ----- From: "Leigh L Klotz, Jr." <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Cc: <[email protected]> Sent: Monday, June 12, 2006 12:26 PM Subject: Re: [Elecraft] Battery use with QRP rigs - page updated > Dan, > I have used the same 10 cell AA holder from Mouser for about a year with > the 2500mAH cells from Energizer. I also recently bought the BatterySpace > 2500mAH Lipo pack from > http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2335 and > will be testing the both in real-world condx with my KX1. > > Here are a few suggestions for folks trying the NiMH AA's: > 1. Use a little DeOxit on the springs and tabs and battery ends. > 2. Tape around the + and - ends of the batteries to keep them in tight, > and to protect against shorts; ditto for the two long edges of the battery > case. > 3. If you charge with a pack charger, break down the pack and test the > cell voltages after it's discharged. I found I had some cells that had > fallen to 0.9v but the rest were 1.2v to 1.3v even under moderate load. > I've started using a Ray-o-Vac 4-cell charger that charges each cell > individually, and breaking them down. This seeems to result in more even > charging and makes the pack last longer per charge. I understand that > there are 8-cell and 10-cell chargers that charge each battery separately, > and if I hadn't invested in Lipo I probably would get one of those. The > 4-cell charger was $19, so it wasn't a big cost. _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
