Thor Forums

[Chance]

True deep-cycle flooded batteries should last much longer than that if maintained properly and not discharged too deeply. I had no issue with my flooded house battery on Class C, and know of others over 5 years old. For van application a flooded isn’t as practical because they are normally installed under floor where they can’t be reached as easily.

Depending on manufacturer, the number of life cycles for flooded can be as high or higher than for AGM, so I wouldn’t expect a longer life just due to it being AGM. For convenience, no doubt AGM wins, but it comes at a higher cost.

Costco may warranty your batteries (at least partially) so if you haven’t tried that already, it may be worth a shot.

My biggest concern would be that if batteries met an early death due to some unknown cause, that the same thing could happen to the more expensive AGMs. However, it sounds to me based on your observation that they were probably not watered properly, or at all.