Our FD has a group 26R battery installed June 2022 from O'Reilly. The car is pretty much a garage queen, but does get driven occasionally. I periodically charge the battery (at a 10A rate) until the charger's green LED comes on (about 12.6 volts). But a few days later the battery reads 12.3 volts. I checked for leakage current, but it's only about 17 mA. Do these batteries typically hold up for only 3 years on a 5-year battery?

 

I don't know the answer to your exact question, but the battery in my FD is now 13 years old. I credit its long life to keeping it on a battery-tender when not in use (99% of the time). Batteries often die due to repeated low charge due to small parasitic drains like your 17 mA reading.
Related thread in Golf GSW forum:
https://www.vwvortex.com/threads/bat...post-114322385

 

If your battery is a standard wet lead acid battery, you will need to check the temperature corrected specific gravity of each cell to really determine its true state of charge. Extrapolating its charge from the voltage, particularly in the absence of a load test, isn’t very accurate.

Your leakage current sounds about right. Mine measured around 13ma.

 

Thanks to both for your responses.