Thanks guys. The transmitter is a Futaba T8UAFS. It originally had a battery pack with 8 cells stacked in two layers. The guy that originally had it wired in one of those battery adapters that accepts individual cells. He said he did that so he could use off the shelf batteries from wherever he wanted to get them. Right now it has Sanyo Cadnica 1.2V 700mAh Ni-Cd cells in it. I have not flown in about 2-3 years but I charged them yesterday. After a full charge they showed almost 11 volts on the transmitter digital display but dropped to 9.8V in a matter of minutes after I started my plane and let the engine run awhile. I wasn't even exercising any of the servos besides the throttle. I don't know how to test these batteries to see if they are any good but I know they are fairly old. I thought maybe I could run to Wal-Mart for the time being and pick up some Ni-Mh cells to replace them. Of course the brands I would be able to get would be Energizer or other normal brand. If I did do that, what mAh would be best to get? I noticed a couple of people said get the lower mAh ones.