New Deep Cycle Battery

[ventura67]

I picked up a new DC battery from Napa today. The sales guy said I should completely discharge it after installation and then fully recharge it because they have "memory".

Any truth to that?

What's the best way to fully discharge the battery, seems like the overhead lights will run forever on it.

[ldgregory]

I picked up a new DC battery from Napa today. The sales guy said I should completely discharge it after installation and then fully recharge it because they have "memory".

I don't believe this is correct. From everything I've read on deep cycle batteries, You try not to discharge below 40% remaining capacity, and never discharge below 20% remaining capacity. Below 20% you can permanently damage your battery, and consistently depleting below 40% will significantly shorten the life of the battery.

Here's a really good resource.

http://www.ccis.com/home/mnemeth/12volt/12volt.htm

[JimS]

I picked up a new DC battery from Napa today. The sales guy said I should completely discharge it after installation and then fully recharge it because they have "memory".

Any truth to that?

What's the best way to fully discharge the battery, seems like the overhead lights will run forever on it.

He is absolutely wrong, lead - acid batteries do not develop a memory.

[AustinBoston]

I'd find a different parts store.

Austin

[tlhdoc]

The parts guy is wrong.  Maybe he wants you to buy another battery sooner instead of later.

[James]

From what little I know about deep cycle batteries, every one that has replied is correct.  Deep cycle batteries, though more resiliant than starting batteries, are not designed to be fully discharged.  Discharging them shortens their working life.

James