I posted this on another thread, but it is pertinent here...
"The AW IMRs (from what I understand) are rated for about 500 cycles. That is, 500 drains and recharge cycles before they should die. Typically, with rechargeable batteries, especially deep cycle RV/Marine/Solar batteries, this is very dependent on the SOC (state of charge) they are drained to. If it is a lower SoC, for example they are drained to their cutoff voltage, they may not last a full 500 cycles.
If it is a high SoC, they they may very well last far beyond 500 cycles. I would expect to get closer to 750 or maybe even 1000 cycles if I only drained the battery down to 80% SoC instead of letting it run down to cutoff voltage. While you end up charging them more often, because of the larger increase in the number cycles you can put them through, you can get more life out of them in the big picture.
Of course this is somewhat moot when you are talking about a $10 battery, but it is critical when you are talking a large, expensive lead-acid battery that costs $400+ each in a large battery bank.
The point is that the idea of extending the life of most rechargeable batteries is viable by discharging them less and recharging more often verse discharging them more and recharging them less. "
