# Deep cycle marine batteries

**URL:** <https://community.cartalk.com/t/deep-cycle-marine-batteries/32467>\
**Category:** Maintenance/Repairs\
**Created:** [June 27, 2009, 4:04pm UTC](https://community.cartalk.com/t/deep-cycle-marine-batteries/32467 "2009-06-27T16:04:10Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![rswheeler1](https://avatars.discourse-cdn.com/v4/letter/r/7c8e57/32.png) [@rswheeler1](https://community.cartalk.com/u/rswheeler1)\
**Post date:** [June 27, 2009, 4:04pm UTC](https://community.cartalk.com/t/deep-cycle-marine-batteries/32467/1 "2009-06-27T16:04:10Z")

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I need some advice on charging a boat battery that I use to power an electric trolling motor. How often should it be charged when not being used, like over the winter?

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [June 27, 2009, 4:31pm UTC](https://community.cartalk.com/t/deep-cycle-marine-batteries/32467/2 "2009-06-27T16:31:49Z")

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I don’t recharge my deep cycle battery until I put it back into service. Deep cycle batteries are designed to be deeply discharged and recharged. Unlike with automotive starting batteries, if the charge isn’t maintained, the battery sulfates and turns into junk.

Tester

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**Author:** ![rswheeler1](https://avatars.discourse-cdn.com/v4/letter/r/7c8e57/32.png) [@rswheeler1](https://community.cartalk.com/u/rswheeler1)\
**Post date:** [June 27, 2009, 5:28pm UTC](https://community.cartalk.com/t/deep-cycle-marine-batteries/32467/3 "2009-06-27T17:28:09Z")

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So I should let it sit over the winter and charge it in the spring. I use a trickle charger and let it charge all night. Does that sound about right?

Thanks for the reply.  
Scott

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**Author:** ![TwinTurbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@TwinTurbo](https://community.cartalk.com/u/TwinTurbo)\
**Post date:** [June 28, 2009, 5:11am UTC](https://community.cartalk.com/t/deep-cycle-marine-batteries/32467/4 "2009-06-28T05:11:01Z")

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They’re designed to survive a deeper discharge than a starting battery but they still are much better off if recharged immediately. If you let it sit discharged, it will sulfate the same as any other lead-acid battery. I trickle charge mine once a month, same as all my starting batteries.

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**Author:** ![rswheeler1](https://avatars.discourse-cdn.com/v4/letter/r/7c8e57/32.png) [@rswheeler1](https://community.cartalk.com/u/rswheeler1)\
**Post date:** [June 28, 2009, 3:29pm UTC](https://community.cartalk.com/t/deep-cycle-marine-batteries/32467/5 "2009-06-28T15:29:39Z")

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Hi TwinTurbo,  
Thanks for helping me out with this problem. My last deep cycle last about 6 years, but I didn’t charge it over the winter. I’ll start charging it monthly.

```
      Scott
```

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**Author:** ![Wha-Who](https://avatars.discourse-cdn.com/v4/letter/w/9f8e36/32.png) [@Wha-Who](https://community.cartalk.com/u/Wha-Who)\
**Post date:** [June 28, 2009, 8:32pm UTC](https://community.cartalk.com/t/deep-cycle-marine-batteries/32467/6 "2009-06-28T20:32:07Z")

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Harbor Freight has a float charger for only a few dollars.