I am using rechargeable AA cells with a combination auto 12volt and household 110 Volt charger. works very well, came with 4 batteries. Now I always have a spare and can recharge anywhere. Bought it by referencing pages on Geocahce site. Unit is Powerx MH-C204F. Both recharges and conditions either nicad or NiMH batteries. Etrex unit doesn't seem to use much power so I probably went to a little overkill,but I also don't like buying AA batteries all the time.
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