New boat,

[Fritojay]

So I bought a 2006 gregor mx580. Runs great BUT previous owner had two Duralast Gold wired for the trolling motor. Model 34DLG 800 cranking amps. They are dead and won't take a charge but my real question is are these even marine or deep cycle batteries? Doesn't say that anywhere on the battery. Was just wondering why he would of been using those for the trolling motor. The starting battery is a optima blue top dual purpose and it seems fine.

 

[Snowshoe]

They are not a deep cycle battery. https://www.autozone.com/autozone/parts/_/N-5yc1s?itemIdentifier=31693

 

[ccm]

That's an easy question to answer. Some people are cheapskates, the automotive batteries wont last but probably 1/2 a year but some people just can't see spending more money up front for the proper deep cycle batteries. A good deep cycle battery will last 3-5 years with proper care but it comes with a higher upfront cost from $70 - $300 according to what size & brand you get. Interstate, Trojan, & Optima make good deep cycle batteries even Everstart ( wally worlds brand ) have good batteries at a reasonable price.

 

[Stumpalump]

The warranty is much better on a car battery. Maybe that's why he bought them. If it won't take a charge then slam it on the concrete as hard as you dare about 10 times. Raise it up 8" and slam it down. That knocks the sulfate off of the plates and sometimes you can get a little more life out of them.
That works well on Optias as well. Putting a good batter in parallel will trick these new chargers into working on seriously dead batteries is another trick to bring one back from the dead.

 

[Fritojay]

Thanks. It's like the 007 of batteries lol

 

[harleydoc]

You can reverse the leaded from a good battery one and off a few time to blow the sulfate off as well and they make charges that will do it as well most of the time that is all they need and will charge up

 

[onthewater102]

If you can find a charger with a recondition setting that will do it. After trying to break up the internal corrosion, if you can measure some voltage you can also rig them in parallel with a good battery and charge the whole setup for a while until the stone dead battery registers enough voltage on its own for the charger to recognize it.