Any one know how to tell if a deep cell battery is bad.

I have one for my troling moter but it's from 03 i'm not using it to start any thing just to run my troling moter this weekend. i was going to have it load tested tomarow i just don't want to get out and have poop on me after a half hour

Charge it and see how long it takes to discharge and then recharge.

yeah when you go get it tested tomorrow you will find out. thats your best bet, and if you go to like kragens or any auto parts store the testing is mostly free, I know kragen is. plus you may get a turn in credit for a new one .

A digital volt meter is helpful to have. After you charge it, take the charger off and then check it after 24 hrs. 12.65+ =100%, 12.55=90%, 12.45=80%....and so on. Then check it again the next day, it should stay the same. A hydrometer is helpful to check each cell, you can tell if one is bad then also. They should all be about the same.

A load test is the only way to test unless you look at specific gravity of cells:

Read section #6: http://www.batterystuff.com/tutorial_battery.html#6

the last two post are correct .......can you remove the caps? if so check the level of the acid it might be low... add only distilled water if low to fill mark. if you can hit it with a good load tester it will kick off all the crap off the plates and give it longer life.

 Good news

Took my battrey to auto zone and had it tested. It tested good but low on charge I'm charging it for 24 on a 2amp charger. Saved me $75.00. Just to let every one know auto zone has a speciale tester for deep cycle batterys. The guy using it was a little confused but the old timer knew just what to do..

 Going fishin Saturday      

to keep that battery in good condition charge them as soon as you get home from a fishing trip, and depending on how low it is, you might need more that 24 hours on that 2 amp. is your charger auto? if it is I would leave it hooked up for 2-3 days to make sure it is charged 100%.

My boats have onboard chargers on them. as soon as I get home from using them. they get plugged in and left plugged in. The only time that my chargers are not plugged in is when I am using the boats. this way the batteries are always good. the biggest thing is to put them back on charge fast as soon as you get home