Thor Forums

[Pete'sMH]

Originally Posted by Beau388

Self-discharge for a flooded battery is 0.7% to 1% per day. For an AGM is is 0.4% per month. So an AGM will last all winter id disconnected from all drains. On my coach the parasitic battery drain is 0.2 amps. With a 205 ah flooded battery capacity, the drain is 144 ah plus the self-discharge equals a flat battery and up north a couple frozen batteries. Fortunately my village offers 40 foot parking spot a 50 amp pedestal for 40 a month.

0.4% per month? That’s 5% a year and suggests it would still have a useful (50%) charge in 10 years of total neglect. I’m afraid I’m a bit skeptical. But then again, I’ve not done the research. My last travel trailer had a new and expensive AGM that the salesman assured me would last the winter. It was on my workbench with no load whatsoever and didn’t. I kept it’s replacement on a Battery Tender thereafter. It doesn’t take a lot of use to keep a fully charged battery ready to go and you’re supposed to run your coach and your generator regularly for other reasons anyway. Works for me.