I got a bad battery with my 2.4 from Airtronics two years ago. It lasted 2 months. There is a forum about Airtronics radios and many got bad batteries too....and many were replaced under warranty. If you have a battery cycler, you need to find out what the capacity of the battery actually is now. If it is the rated mAH or close to it, then the radio has an issue. If less than 70% of rated value, get a new battery. A lot of my JR receiver batteries have lasted less than 2 years. I think there is a problem with the battery manufacturer, but who knows.

Some of the best batteries money can buy are from SR. I think the website is www.srbatteries.com. They are a little expensive, but last much longer than others. I am sure you are not doing this, but remember to charge at C/10. Some people buy a larger battery and use the same wall charger or charge at the same low setting. The guy with the 2700 mAh battery pack is hopefully charging at 270 mA or more, otherwise may never be fully charged. Compare that to most wall chargers that are 50-70 mA chargers.

A new guy at our field crashed his plane last season. Turned out, he bought a 6.0V 2000 mAh receiver battery pack. He had been charging using the charger that came with his radio. After a few weeks of charging at 4.8V, 50 mA, he was guaranteed of doom.....

bob