New deep cycle battery-drain it or not?

[BLACKJACK]

Just bought a new deep cycle trolling battery for my fishhouse lights and will also use it in my boat. The guy at Fleet said that I should run it completely empty, then charge it up because of the 'memory' in the battery, but I thought I saw a post here that said not to run them all the way down. Which is it?

[Norsky]

DO NOT drain the battery, unless you simply want to shorten its life span and buy a new one next year. Just make sure you charge it up after EVERY time you use it, and don't overcharge it (this is where an onboard charging system that charges at different strengths pays off), also make sure there is enough fluid covering the plates inside the battery. NiCad batteries SHOULD be drained before recharging.

[FRESHWATER PETIE]

Very well said!! True about getting your battey charged ever time used. #1 reason how batteries go out prematurely.

[kslipsinker]

One more thing to remember on deep cycle batteries is to check fluid level at least a couple of times a year. Constant charging and hot weather can delete water. Gel batteries are not an issue.

Lead acid batteries do not have "memory".

[Giant_Jackpot]

Norsky’s got it right. Fleet Farm is giving out advice that will only shorten your battery life.

[BLACKJACK]

Quote:

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don't overcharge it

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So how do I make sure I don't overcharge it? When its in my shop, I usually hang the charger on it at 2 amps and let it run til the next day. I 'assume' that the charger will stop charging when its full. Is that correct? In the boat, I 'assume' that the onboard charger will keep it full without overcharging it.

Thanks for the advice so far guys!

[Big Roy]

What kind of charger do you have? If it is running at 2 amps most likely it is still putting out 2 amps the whole time. You might want to think about investing in a 3 stage charger.

[sbro73]

Never run the battery down, Fleet Farm has done this ploy to get you to come back and buy a new one! also, keep it off the concrete floor ,that will drain the life out of any battery. Check Sears out for Marine batteries,the warrenties and return policy is the best,and have chargers there manual and automatic.

[Giant_Jackpot]

If that 2 amp charger is not automatic, then you can use a voltmeter to get a god idea when the battery is charged. When it hits about 14.8 volts it is done. The 3 stage charger mentioned by others is definitely the best way to go.

And a quick note on the concrete floor thing…… That used to be true back in the day but modern batteries are constructed with better insulating material so it is not a problem anymore. With that said I always keep my batteries up on a bench in the winter.

[fishin magician]

I was told that storing batteries on a concrete floor is a old myth. Batteries plus had this on their HSOforum and said that it will not effect the shelf life of the battery.

[BLACKJACK]

I double checked my charger last night, its a Shumacher brand that I bought 15+ years ago at Fleet Farm. It has switches to put out 2/10/50 amps. I read thru the book, it did say that it will automatically shut down once the battery hits 14 amps. Looks like I'm good to go, just don't run it down to nothing. Just for a test, on Sunday I had a 12 volt trouble light on the new battery, it ran 10 hours just fine - the old battery was dying after 45 minutes....

Thanks for all the advice!