Filling up flooded lead acid batteries

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Fallingwater

Fallingwater

Flashlight Enthusiast
Joined
Jul 11, 2005
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Location
Trieste, Italy
When I bought a new battery for my scooter they gave me the battery empty, and a separate bottle of acidic solution, with instructions to fill it up with that and then occasionally top it off with demineralized water.
My question is: since I have half a bottle of acidic solution left, why not use that to top it off? Doesn't the addition of water progressively dilute the solution, damaging the battery's capacity?
 
What they told you is correct. The acid in the bottle is supplied at the right strength for the battery. Over time, water evaporates from the battery making the acid more concentrated. When you top it up with demineralized water you are just replacing the water that was lost and bringing the acid back to the original strength.

If you topped the battery up with more acid you would be making the solution stronger and stronger over time, and that would be outside the correct value for good operation of the battery.

(In case you are wondering, the sulphuric acid in lead acid batteries is very non-volatile and it really doesn't evaporate in any significant amount.)
 
Just to add some info, I have even topped up several small batteries that had dried out completely(!) with plain water, and got them to work (acceptably) again.

But a battery that has been through that kind of abuse never will work like new again just so you know, in my case I didn't need that either. 1Ah or 4Ah doesn't really matter if basically all it does is powering the brakelight on a moped. I'm happy as long as it works good and I don't need to buy a new battery for a (previously neglected) bike I just bought... :whistle:
 
:poke:
I'm confused by your use of the word "flooded"...... in your title of OP ? :duh2:

:huh:
Fallingwater said:
When I bought a new battery for my scooter they gave me the battery empty, and a separate bottle of acidic solution, with instructions to fill it up with that and then occasionally top it off with demineralized water.
My question is: since I have half a bottle of acidic solution left, why not use that to top it off? Doesn't the addition of water progressively dilute the solution, damaging the battery's capacity?
Click to expand...
 
Uh...... You are supposed to " Fill " the battery cells , NOT "Flood" them.

Improper use of English language.

Floods are what happens when it rains too much.

Flood implies EXcessive filling.

It is not recommended to Flood the cells with too much.

Fill to proper level. :)
.
 
Flooded cells refer to (generally) Pb Acid batteries that require a liquid electrolyte in this case and acid diluted in water. There are also sealed lead acid some use a fiber fill with acid in it others a gel.
 
Think Fallingwater's OP was perfectly understandable.
...although I'm as eager to nitpick as the next CPF'er when the
subject is worth it.:duh2::twothumbs:thinking::green:
 
hopkins said:
Think Fallingwater's OP was perfectly understandable.
...although I'm as eager to nitpick as the next CPF'er when the
subject is worth it.:duh2::twothumbs:thinking::green:
Click to expand...

well ...... I dis-agree with you

Too many thread titles are too vague and require expenditure of too much grey-matter to comprehend the nature of the thread .

:D
 
digitor said:
Like it or not, that's what these batteries are called! It is the correct terminology.

Cheers
Click to expand...

O.K./sorry/I'll drop it

If you are saying there is a lead acid battery somewhere in the world that is named "Flooded" or is referred to as a "Flooded" battery ......... then excuse me for not being aware of it please.

I just didn't see how or why you would fill up something that was flooded.

Guess that goes to show I don't know everything. The whole thing has confused me.

I must go now , and fill up my flooded pool with water.

My hot water heater is working fine but my cold water cooler is not chillie enough to cool it.

ta-ta
.
 
Last edited:
Mr Happy said:
What they told you is correct. The acid in the bottle is supplied at the right strength for the battery. Over time, water evaporates from the battery making the acid more concentrated. When you top it up with demineralized water you are just replacing the water that was lost and bringing the acid back to the original strength.

If you topped the battery up with more acid you would be making the solution stronger and stronger over time, and that would be outside the correct value for good operation of the battery.

(In case you are wondering, the sulphuric acid in lead acid batteries is very non-volatile and it really doesn't evaporate in any significant amount.)
Click to expand...
Makes sense.
However: what if I dumped all the liquid out of the battery, refilled with just the acidic solution and then resumed topping it off with water?

I ask because I think due to incorrect refilling on my part, the various cells are now unbalanced as far as the acid concentration goes. A complete solution change should bring them back to balanced status.
 
Fallingwater said:
Makes sense.
However: what if I dumped all the liquid out of the battery, refilled with just the acidic solution and then resumed topping it off with water?

I ask because I think due to incorrect refilling on my part, the various cells are now unbalanced as far as the acid concentration goes. A complete solution change should bring them back to balanced status.
Click to expand...
So long as you do it without allowing the cell plates to dry out. That will spell doom for the capacity of the cell. After doing so. Give the battery an "Equalizing charge". Basically it's an overcharge. You charge the battery until all cells are bubbling. You may need to top them up with demineralized (Distilled is OK too) water if any of the cells gets low during this process. Unless you're sure that your call caps are "venting types" remove them for this equalizing charge. Take one off and rinse it in the sink really well. Then blow throught it with your mouth. If you can blow air through it. Leave them on during charging. It will help control spatter. You will hear that "if you don't remove the caps, the battery can explode". If you can blow air through them, there's no way that battery will out-gas fast enough to build pressure. If you're still nervous about it. Remove them and place a clean rag over the battery during this equalization charge. Flooded lead acid cells work just fine with overcharges. They toilerate it better than any other battery chemistry. It's recommended by manufacturers for deep cycle batteries. Your battery will do just fine with it too. Just DO NOT let the cell plates go dry.
 
JimmyM said:
Give the battery an "Equalizing charge". Basically it's an overcharge. You charge the battery until all cells are bubbling.
Click to expand...

Just thought I would give safe charging practices a mention, especially during the "Equalizing Charge", which will cause a significant outgassing of hydrogen and oxygen.

According to the University of Wisconsin, 2300 are injured every year in the USA alone from exploding lead-acid batteries; with most of the trauma's occurring to the face and eyes.

They actually publish one of the more readable battery maintenance & safety protocols on the subject, which is intended to keep us all "bright eyed and beautiful".
 
Sounds like you might want to get a hydrometer to test the acid level - they are made just for testing battery acid levels and can be found in most auto supply stores and don't cost a lot either.
 
Regarding this thread's secondary discussion on semantics, it appears that the Gold Star goes to Fallingwater.

From the University of Wisconsin's battery maintenance & safety protocols, under the heading Lead-Acid battery Basics :

During normal operation, water is lost from a non-sealed (or flooded) battery due to evaporation.
Click to expand...

And I just learned another new thing about batteries here on CandlePowerForums...
 
Bones said:
Just thought I would give safe charging practices a mention, especially during the "Equalizing Charge", which will cause a significant outgassing of hydrogen and oxygen.

According to the University of Wisconsin, 2300 are injured every year in the USA alone from exploding lead-acid batteries; with most of the trauma's occurring to the face and eyes.

They actually publish one of the more readable battery maintenance & safety protocols on the subject, which is intended to keep us all "bright eyed and beautiful".
Click to expand...
2300 are injured. But 50% are injured due to explosion. The other 50% are injured due to lifting and handing.
Batteries "explode" because of the generated hydrogen and oxygen ignites. Definitely keep the area well ventilated. Removing ventcaps is not recommended. The need to remove them is much akin to causing a battery to go dead by leaving it on concrete. Hogwash.

Matrixshamen also gives good advice. A good Hydrometer is the truest way of determining the state of charge of a flooded lead acid cell.
 
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