Can these batteries be saved?

[s/v Breakaway]

Hi,
I have three, 12v Group 29 wet cell batteries that have been sitting uncharged since 2015. The plates are covered with water.
Can these batteries be saved? If so, how? I am guessing equalization won't help.
Thoughts?

Thank you.

[Sailmonkey]

What’s the battery voltage right now?

There is a slim chance that if they’ll even accept a charge that equalization will help, but chances are very good that they’re completely shot.

[S/V Illusion]

Maybe. But why guess? Guessing games can be fun but in your case, the only way to know is try.

[john61ct]

Does your use case require reliability?

If so, even if they do "work" for a while by some definition of work

personally I would not bother.

[letsgetsailing3]

Reliably?


No.


If reliability isn't a concern, you can certainly give it a try.

[Emouchet]

Dead for sure. They may take the charge, but will poorly keep it.
They will not provide enough current for the anchor windlass for sure.

May be able to power a phone for a few hours !

[a64pilot]

I’ve seen them come back, more than once or twice, but used as starter batteries, so I don’t know about capacity loss.

Only way to know is to charge and I’d also equalize, plus for reasons that I don’t understand it seems that a few deep cycles as I’m take them down to 10.5V and immediately recharge seems to help.
I believe that may be called a reforming charge, although that may come from my Ni-Mh days.

A lot has to do with how they were stored, if stored outside in freezing weather, or stored in Summer in a metal shed, that doesn’t help

[stewie]

If the plates are not visibly bent you could try what my father used to do. Empty the acid out and dispose of it safely. Turn up side down and GENTLY tap the bottom of the battery to dislodge any sediment. Rinse out until the water is clear. Re-acid and charge and keep you fingers well gloved - and crossed....

[Mike Banks]

They will be completely sulphated after being discharged for so long.

However--

If you have one of those fancy chargers that will pulse charge, you could possible get them working, then run a series of discharge and re-charges to "soften" those hard plates again. To get the battery charger to work, there needs to be an initial voltage of about eight volts or it will not switch on--so you need another battery to put in parallel with the dud ones just to get the charging program started. Once the indicator lights show the charger is working, remove the other battery you used to get things started. It may take a few days, but sometimes they can be re-charged. How long they will last once cycled a few times remains to be seen--

But, in future if you wish to store batteries, fully charge the battery, then empty out the acid into a suitable container and store it safely. Wash out the empty battery with several changes of distilled water, then store battery upside down on wooden blocks in a plastic kitty-litter tray, with the caps loosely inserted. They will store for years like this.

When you wish to use the battery, re-fill with the acid and recharge.

[sailorboy1]

Originally Posted by S/V Illusion

Maybe. But why guess? Guessing games can be fun but in your case, the only way to know is try.

would seem to be obvious wouldn't it

[lvictorlucas]

You did not state the manufacturer and model or SKU number. You can try but without knowing the battery details it is hard to tell. Some battery manufactures make various grades of batteries. Rinse out the electrolyte with distilled water several trying to knock lose any sediment each time then add fresh acid and try to pulse charging for an extended time.

[Compass790]

. Are they deep cycle batteries? If they are I'd give it a try. If the sides are bulged out I don't like yr chances. We got given some old 6v Crowns that had been sitting for a long time & a modern 7 stage switchmode charger bought then back to life. Dont know about capacity but we use them on the boat for everything including starting & they run a fridge 24/7. Have had them for 3 years & still going.
I don't know much about electricity, just relating our experience

[TrentePieds]

Batteries are "consumable supplies". Better to just face that and get new ones.

TP

[s/v Breakaway]

Put a charger on them for a few hours. No voltage per the meter and four balls down on the hydrometer. Dead as a door nail.

Thanks for the input.