Older Deep Cycle Marine Battery... things to look out for?

[coolapples]

Found an old deep cycle marine battery in my uncle's shed. He says it's been sitting for like 5 years or maybe more. Charged it up and it has like 13 volts, which seems good, and I just hooked it up to an old trolling motor and it's been spinning away on high speed for like an hour already.

It's not the lead acid kind of battery. It says "sealed maintenance-free".

How long do these stay good for? Anything I should do or know? Any tests I should run? Any other info would be greatly appreciated.

thanks!

 

[roscoe]

They last anywhere from a month, to 10 years.

Careful running that trolling motor, keep it in a trash can full of water, so as not to over hear the electric motor.

 

[coolapples]

thanks! Yeah, it's in a bucket. But good looking out!

I just want to make sure that a) it's not going to explode or anything, and b) if it seems to be running this motor for like 3-4 hours, it's not going to work in my garage and then crap out on me on the lake or something.

thanks again for the reply

 

[smokeonthewater]

That IS a lead acid battery... Just has a sticker over the vents to keep you from adding water.

It's like any other battery, it'll work till it doesn't...

Should be fine.... But bring a paddle or a crystal ball.... Whichever you trust more..... ;-)

 

[mr 88]

Just because it reads 13 volts does not mean it has any amps to start a motor. I would be okay using that for a trolling motor but wouldnt trust it for my main starting battery,untill I load tested it. Most,not all, marine batteries seem to have a shelf life of about 3 years

 

[JoshOnt]

Why not use it as a spare if you are worried about reliability

 

[Jeep Man]

Use it but have a spare on hand. The best thing you can do for it is use it. Running it down and recharging it is good, but do not run it down below 3 volts.

 

[coolapples]

good advice from all. thanks!

 

[smokeonthewater]

3 volts!!!!! NOPE!

If you want it to last never discharge below 50% charge which is 12.2 volts

 

[Watermann]

The main thing with deep cycle batteries on a TM is when they get old they won't hold up to the draw for long and start to die off real quick. When you put a load on the motor pulling a boat is the real test.

 

[coolapples]

hm. Interesting.... so, I just unplugged it, because:

It sits at like 13 volts when fully charged, but when I run it with no load (i.e. I even took the prop off) it goes down to about 5.5 volts over the course of an hour. Then it sat at 5.5 volts for like 4 hours or however long it's been running until just now when I unplugged it.

Does that mean it's basically just dead?
thanks

 

[bruceb58]

It's dead. It was likely dead after it sat non charged many years ago.

 

[Watermann]

It's worth 5 bucks as a core for a new one. Not sure what size it is but I wouldn't go any smaller than a group 27 as a replacement.