Care and Feeding of AGM Batteries

[Pete]

I have a battery configuration with one Lifeline 8D that does nothing but start the port engine, one series 31 Lifeline that does nothing but start the generator, and a house bank of 4 Lifeline 8D's that also starts the starboard engine. My question concerns charge levels that will give maximum life. The Lifeline literature recommends the following at 77 degrees F. "13.4 volts float voltage when in use, 13.1 or 13.2 float voltage when being stored". I am wondering if the 13.1 volt float level will extend the life of the batteries, versus the 13.4. The penality of less capacity is OK with me as the boat has plenty of capacity for the way we use her. Running your DD mains at less that full load extends their life. How about running the batteries just under full charge?

Pete

 

[MikeP]

Keeping flooded batteries below full charge will eventually prevent them from ever reaching full charge, thus reducing their life. Whether that's the case with AGM, I'm not sure but the basic physics seem to me to be the same so I would ASSUME that the same situation would exist.