My parents have a Pro Com remote control gas logs fireplace. The latching solenoid that opens up to release the gas is rated for 6 volts, and the receiver box holds four AA batteries. The solenoid is sticking now, and even the freshest alkaline AA's won't actuate it. I soldered in a 9 volt snap connector to replace the AA's, and it works perfectly again, but looks jerry-rigged. I was searching for AA batteries that are greater than 1.5 volts and found AA 3.7 volt lithium ion batteries that are rechargeable. Could these work? I read somewhere that they should only be used individually, and that putting them in series could cause problems. But I don't remember what kind of problems.