Panel power to charge 35Ah battery

[PNjunction]

50% DOD down to 80% capacity 600 cycles
25% DOD down to 80% capacity 1400 cycles

Or to put it another way - if you use half of your battery's capacity daily (50% DOD), and you recharge them *perfectly* every day, then you'll get a little over 2 years cycle life before having to buy them all over again.

If you only use a quarter's worth (25% DOD) of capacity daily, and of course recharge perfectly, then you'll get about 3 3/4 years life out of them before buying new ones.

You can see why the usual minimum spec for designing a solar system is a max of 50% DOD - less is preferable.

[inetdog]

Or to put it another way - if you use half of your battery's capacity daily (50% DOD), and you recharge them *perfectly* every day, then you'll get a little over 2 years cycle life before having to buy them all over again.

If you only use a quarter's worth (25% DOD) of capacity daily, and of course recharge perfectly, then you'll get about 3 3/4 years life out of them before buying new ones.

You can see why the usual minimum spec for designing a solar system is a max of 50% DOD - less is preferable.

On the other hand, if you do not care too much about autonomy, the economic balance between getting a small bank and replacing it in a little over two years versus getting twice that size bank and replacing it in a little less than four years seems to be in favor of the smaller bank and greater DOD.