These batteries were charged for 36 hours at 100mah. (2300mah battery x 1.4 = 3220mah needed for the first full charge, as per the website, 36hrs at 100mah = 3600mah.) I had the problem only with the Tx battery on Wednesday, as soon as I turned on my radio (for the first time with this battery, so it wasn't even used, just turned on), so a trainer at the field threw it on his peak charger. It charged up all the way that day but I didn't use it. Today I put the Tx on the 100mah charger for an hour in case there was any natural loss of energy since Wednesday, took it to the field, and turned it on. Like I said, it turned on and read full power. It was turned off, then back on again, and the voltage plummetted. And again, the Rx battery is working just fine. I really think there's something wrong with the Tx battery.