Thor Forums

[Beau388]

Originally Posted by DavidEM

There is a lot of hard data on depth discharge vs cycle life for GC batteries from Trojan and others, but nothing from AGM manufacturers.

My gut is that a true deep cycle battery like the Trojan golf cart battery has about the same cycle life vs depth of charge capability as an AGM. AGMs shouldn't have the same sulfation problems which is the bane of FLA batteries.

And to the PPs comment above, both AGMs and golf cart batteries lose life if routinely discharged below 50%.

Firefly carbon foam batteries are supposed to tolerate 80% depth of discharge well but I don't know why. And of course lithiums can go to 90% routinely.

David

If you look at the flooded life cycle charts you will see that the depth of the discharge and the time the battery is left in the discharged state effects the number of useful cycles. For some reason 400 cycles was chosen as the optimum. To have 400 cycles and still have 75% of the useful battery amperage available when fully charged, the battery can not be discharged below 50% capacity. The less the battery is discharged the greater the number of cycles possible.



For me the problem I find with flooded batteries, as they reach near the end of their useful life, they require a lot of water. My original Harris batteries only need about a cup of water every month during the summer for the first two years. During the third year, I was using about a pint of water every two weeks. I changed to a couple of Walmart's flooded batteries the 4th year and have only add a table spoon of water every other month.