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Yaesu FTA 750L Hand Held Question


Well-Known Member
Aug 20, 2008
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I've use a Yaesu FTA 750L handheld radio with an external antenna for many years that I use in my J3 C65 with a C85 engine out of a Towered airport (CKB). It's been working great until this year. When the overnight OAT drops in to the low 40F range, my fully charged SBR-12Li battery won't fire the radio up the next morning so I can fly the airplane. When I put the alkaline battery pack in, she works fine. After the SBR-12Li battery warms up some, she works fine and indicates "full charge" as it was the day before when working fine and warm. Rapid heating with an external space heater doesn't help and putting the battery back on the charger for 5 minutes doesn't help either. It is subborn, and only gradual warming up will make it work. IF I don't have my alkaline pack, I'm grounded until that thing gradually warms up. So I have a couple of questions:
1. What is going on? Apparently the battery gets "cold soaked" at 40F and refuses to put out any juice. It didn't seem to do this when it was younger, but.. maybe it did when it got down to 25F or so, at which point I didn't fly the cub anyway. My personal minimum to enjoy Cub flying it is about 35F, although I've gone lower. In WV we have 4 pretty well balanced seasons. I do try to fly it in the winter as often as I can though.
2. Could this be a result of an aged battery? Will buying a new on help? They are about $77 bucks at aircraft spruce which is cheaper than buying a whole new radio. Having the Li battery is more convenient that using the back up Alkaline pack.... especially in the summer.
3. I could just keep this battery in my warm house from fall to spring and take it to the airport when I want to fly. If I forget it (which might be a lot since Cub flying can be spontaneous), I could just use the alkaline battery pack and keep plenty of those batteries around. They have a good shelf life, even in the cold.
What would you do? Thanks. WV-GWS

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