Battery Gurus - Question

Olly

Bronze
Mar 12, 2007
1,684
20
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A set of 12 batteries for 24 Volt system have been let run dry but appear to be fully charged giving a reading of 6.4 volts. But they have no capacity.

What liquid should be used to top them up? They are not very old so should have some life left.

Sulfuric Acid 1,27 Specific Gravity

Distilled Water for Batteries?

Olly
 

malko

Campesino !! :)
Jan 12, 2013
4,492
109
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I am no specialist.

I was told to fill up one time with agua distillada, amd the next with "solution".
And also not to use " solution" when they are dry as it corrodes the "plates " ......
Just what my electrician guy told me....
 

MikeFisher

The Fisherman/Weather Mod
Feb 28, 2006
13,271
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Punta Cana/DR
www.mikefisher.fun
appear fully charged?
do you mean you connect them to a charger which says "full"? you don't do that with the batteries still dry, as that would give 'em just the rest tehn.
fill 'em with distilled water first and connect them to a charger. once fully loaded, use them with something that does not discharge them too heavy/not at their crank limits.
then take 1/3 of the water out and replace it with "solution". charge them again and once the charger shows "full", check what power they show.
6.4 Volts on a "charged" 12 Volts battery means mostly "dead". you can recover them as described above for minor use, but they will never again come back to their original powers/never again deliver the originally meant for Amperes.
for what do you want to use those batteries?

Mike
 

Cdn_Gringo

Gold
Apr 29, 2014
7,790
616
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Batteries have a finite limit to how many times they can be discharged/charged. If a battrery is allowed to run dry, the useful life of that battery is over as it will never again function as well as it would have or for as long.

Batteries connected to inversors are receiving a trickle charge all the time. It is really important to check fluid levels regularly. I check mine every two weeks, others I know check once a month.

As to your question, I would say the chances of you being happy with the performance of a revived set of batteries is pretty slim. Since we are talking about 12 batteries, I'm assuming they are connected to a home power system. You may be able to get them to charge to 6V but they won't sustain that voltage for very long when placed under load.

A solution of acid and distilled water in a ratio recommended by the manufacturer is what I'd use in your situation if buying new batteries (for peace of mind) is not in the cards.
 

MikeFisher

The Fisherman/Weather Mod
Feb 28, 2006
13,271
1,437
113
Punta Cana/DR
www.mikefisher.fun
Olly,
sorry, i was reading your OP wrong.
i understood it as 2x 12 volt batteries for a 24V system, hence i wrote that those 6 volts sound very dead.
i just now realize that you wrote " 12 Batteries", lol. sorry, didn't want to misslead

Mike
 

bizzyboneizo

New member
Aug 31, 2010
489
0
0
distilled water works but if you can get some battery acid that would be great. find another battery and add the acid but be careful to not to corrode your self
 

windeguy

Platinum
Jul 10, 2004
33,678
1,552
113
One should never add additional battery acid to a battery that was already in use, unless that acid was somehow spilled from the battery and then it can be replaced by more acid. Distilled water only.
Some claim EDTA can restore a battery, but I have had no luck using it and cannot recommend it from my personal experience.

In the case of the OP, the batteries may charge fully on an inverter after being topped off with distilled water, but the capacity may be so low as to render them useless for their intended purpose.
 

windeguy

Platinum
Jul 10, 2004
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distilled water works but if you can get some battery acid that would be great. find another battery and add the acid but be careful to not to corrode your self

Battery acid would not be "great".

When Should I Add Extra Sulfuric Acid to my Battery?

When you see your battery acid level begin to drop, you may wonder when and if it is appropriate to add acid, or just water.

We recommend that unless a battery was tipped over and all the acid spilled out, that you add only distilled water. Think of it like this: If you were to fill a pot up with salt water, and put it on your stove to boil, what happens? All the water will boil off, and you will be left with only salt. To re-create the original salt water mixture, you simply add straight water, because all the original salt is still in the pan, waiting to be re-suspended in the water. Batteries are the same way. All the chemical needed to make sulfuric acid is still in the battery, it is just the water that is gone. If you add more acid, you will be changing the chemical makeup of the battery which can lead to an incorrect sulfuric content.

http://www.batterystuff.com/kb/freq...-i-add-extra-sulfuric-acid-to-my-battery.html
 

zoomzx11

Gold
Jan 21, 2006
7,648
275
83
Its over for those batteries. You can play around adding all sorts of acids, water, battery viagara etc. but the fat lady is singing.
Been there done that. For the future. Never ever let them get dry. Its a death sentence.
 
May 29, 2006
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Use distilled water and see if you can get a battery hydrometer at an auto place. It's a very simple device that determines the specific gravity of the battery fluid with several tiny balls that float depending on the water to acid mix in the battery. There are also YouTubes out there on how to recondition batteries..

 

windeguy

Platinum
Jul 10, 2004
33,678
1,552
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The YouTube vidoes on so called battery reconditioning are a waste of time and are very misleading.
 
May 29, 2006
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Has anyone tried using fork lift batteries? They are much cheaper than marine batteries and I hear they last for up to 20 years.
 

windeguy

Platinum
Jul 10, 2004
33,678
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Has anyone tried using fork lift batteries? They are much cheaper than marine batteries and I hear they last for up to 20 years.

They costs thousands of dollars, so most people would be put off by the initial price. It would be hard for most people to justify the cost of the new Tesla batteries versus the normal deep cycle lead acid batteries used in the DR
 

jd426

Gold
Dec 12, 2009
8,036
769
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It seems to Vary Greatly with batteries.
Got 2 batteries in a Large Diesel truck.. 11 years old and doing FINE... maintained with only distilled water for top off ..

and then have 2 batteries in a Dump Trailer, DEEP cycle.. which will not take a charge after only 3 short years.. also maintained by trickle charging.. Just replaced 4 batteries in a boat ,cuz we cant take a chance with those.
Once the plates Corrode, imo they cant be "reconditioned".. i highly doubt any of those Epsom Salt videos work. and if it did , it would be very short term.
Since you have this many batteries at stake, I would sacrifice one and cut it open and check the condition of the Plates.. that should tell you the whole story. Remove the Acid solution first and neutralize it with Baking Soda and water.

edit,
but then anything is possible i guess.. .I just recently learned that Plain Vinegar and water completely dissolves RUST.. I never knew that before, so simple
.. it works really well too on tools, anything.. So there may be a way to save those plates also .. I guess you can always experiment with the plates your remove from the one battery, if you got the time... not sure what chemicals or solutions would do that however..
 
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windeguy

Platinum
Jul 10, 2004
33,678
1,552
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jd426.. There is no reasonable way (and I don't think there are any unreasonable ways either) to restore heavily sulphated lead acid batteries. Pulse technology/Epsom salts/ EDTA, etc all do something short term if at all.
 

zoomzx11

Gold
Jan 21, 2006
7,648
275
83
No one wants to toss an expensive battery that they let run dry so they try all sort of things to rejuvenate it. If you want to go down the rejuvenation road dont let us stop you but please come back and tell us how it turned out. Maybe you will be the first! Otherwise get a hydrometer and add distilled water as needed. You will get the maximum life possible out of your battery. The are no battery "secrets" and your battery cannot come back to life anymore than you can.
 

windeguy

Platinum
Jul 10, 2004
33,678
1,552
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Exactly z...x11. In the DR the best I have found are the Trojan T105 RED batteries from a reputable source. La Sirena seems to be a good source.