I have a Powertap G3 that is about 10 months old. The last time I replaced the battery I started getting a low battery warning after about 1 month (50 hours.) I have been getting a low battery warning on my Garmin 510 every ride since then. I've put another ~75 hours on the battery with no issues so I don't plan to replace until the power readings start dropping out mid-ride. I have/had been getting 150-200 hours between battery changes. I live in Southern California so it's not weather related. Is this something that can be fixed with a firmware update?