Any way to revive an unused, but older battery?

[Domush]

4 years ago I bought a new battery for my boat. It's one of those massive dual purpose start/deep cycle batteries. I ended up selling the boat before I used the battery, so it has sat on a shelf for 4 years. I recently tried to charge it, but it won't hold enough charge to start my tractor (the use I was hoping for it, now).

Is there any means to bring it to life? I know it isn't used up, as I've never even used it. It cost me over $100, and I'd hate to have to throw it out. Am I screwed or is there hope for it?

[Texan4Life]

not sure how you charged it, but I would put a 2amp charge on it for how ever long it takes (depending on size could take 12-24hrs or more). I have had "dead" batteries come back to life using a 2amp charge instead of 8 or 10 amp.

Also if it was completely dead you may need to jump it to get an automatic charger to even start charging it.

[Domush]

Thanks texan! I had no idea there was a difference in charge time for size. I thought all lead acid batteries charged in the same amount of time. I only charged it for about 7 hours at 2 amps. I was afraid of doing damage to it by overcharging, but apparently I didn't nearly charge it enough.

If the temp ever drops below 100F I'll throw it back on the charger for a full day. I really hope I can use this, as it seems like it will be perfectly suited for my tractor.. plus it adds some nice ballast to the front end

[Taylortractornut]

They sell a special slow charger called a pulse charger Im looking to buy one for the shop at work as we go through alot of batteries.

[crazyal]

It's always been hit or miss when trying to breath new life into a dead battery. I think it comes down to two things, the first is how many times it was drained flat and the second being how long it was left dead before trying to recharge it. I have had some luck with a desulfating charger but they are not cheap. I would just leave a trickle charger on it for a couple of weeks.

[edlegault]

If it is not a sealed battery, make sure to check the water/acid level. Fill it with real distilled water.

[yelbike]

What about warranty? Do you have the receipt? Even prorated you should get most of your money back to put towards a new one. Good luck.

[Texan4Life]

Thanks texan! I had no idea there was a difference in charge time for size. I thought all lead acid batteries charged in the same amount of time. I only charged it for about 7 hours at 2 amps. I was afraid of doing damage to it by overcharging, but apparently I didn't nearly charge it enough.

If the temp ever drops below 100F I'll throw it back on the charger for a full day. I really hope I can use this, as it seems like it will be perfectly suited for my tractor.. plus it adds some nice ballast to the front end

yep, assuming you have an automatic charger (majority are now days) leave it on until it says its done charging... I have had a dead lawn mower battery take about 5 or 6 hours and a pretty low car battery (sitting for 6 months still hooked up) take over 24hrs (i was surprised to see it only at about 65% charged when I checked it the next morning which was about 12hrs after i hooked it up). This is on an automatic charger that says when it is fully charged. I have never used a manual charger before so if you have a manual one that may be different.

[tungularafishcamp]

Sometimes you have to hit it with the boost charge to get it to take a charge, dont do it too long tho couple minutes max.

You can find those smart chargers that will desulfate and bring back old batteries for under 60 bucks now also.

[SSdoxie]

Any lead acid battery will loose charge when not used for long time. Charging at low amps for longer time will bring battery closer to its full charge then higheramp for short time. Also let the battery set for 30 minutes after recharging with charger disconnected before testing or using.