# How to optimize the life of a Lead Acid deep cycle battery?

I have a lead-acid battery : HANKOOK DC24MF DEEP CYCLE 80Ah 12V.

In hope of extended this battery's life, I was thinking about buying an identical one and put it in parallel. This way by using "80Ah", instead of emptying one battery, both will drop to 50%. (Simplifying the math here of course.)

1 - Is this method good to extend both batteries life ?

2 - They are rated for 550 cycles, but emptying only half doesn't count as a full cycle right ?

3 - I considered 12V as "Empty" and 14.2V as "Full". Are these good numbers to save battery life ?

EDIT: Battery would loose warranty after 4 years or if below 10.6V

• They are rated for 550 cycles Sure but from my experience: an SLA battery in a UPS is (trickle) charged continuously. After 5 years the battery has worn out (less than 20% of original capacity left) even though it has gone though less than 5 full charge-discharge cycles. My point: how the battery is used can have a significant impact on its lifetime. For my UPS example, using two batteries in parallel doesn't help much. It is better to just keep the money and buy a new battery when the 1st one has worn out. Commented Jul 29, 2019 at 12:59
• I will use it almost non-stop as a buffer (ideally using as much Watts as generated) between my solar panels and my electric system. (On load ~14h a day.) Are you saying that keeping it almost at full charge will damage it as quickly as full charge / discharge cycles ? Commented Jul 29, 2019 at 13:03
• SLA batteries are anything but linear and are really quite complex. But if they were linear, then 2*550 = 1100 days or about 3 years. In reality probably more like 1 year. I wonder if Maxwell energy-storage capacitors might be a better fit for this. Higher initial cost but longer life expectancy. Commented Jul 29, 2019 at 13:17
• That's extremely expensive, I would rather try to save bucks here and play it smart. I might go Li-on in the future, if the prices are reasonable. (but now 1000\$ for a 80Ah no thanks.) Commented Jul 29, 2019 at 13:39
• There are many more battery technologies on the horizon. HP and others have been working on solid glass cells, promising 10x the performance of current. We'll see... Commented Jul 29, 2019 at 14:53