emnick
Well-Known Member
Can I use sulphuric acid instead of distilled water to to up batteries, will it do them any har / or good.
thanks all
thanks all
battery top up, can I.....
- Thread starter emnick
- Start date
MoodySabre
Well-Known Member
VicS
Well-Known Member
No don't use sulphuric acid to top up, unless you have lost some by spillage. Just use distilled or deionised water to replace that lost by electrolysis or evaporation.
Battery top up water/liquid / fluid is just distilled, or more likely, deionised/demineralised water.
A bit over £3 for 5 litres in Halfords recently.
If you do lose any by spillage top up with sulphuric acid diluted to the correct concentration.
Battery top up water/liquid / fluid is just distilled, or more likely, deionised/demineralised water.
A bit over £3 for 5 litres in Halfords recently.
If you do lose any by spillage top up with sulphuric acid diluted to the correct concentration.
Heckler
Well-Known Member
Vic
its always puzzled me, the only way you can tell the strength of the acid is the specific gravity (realistically) BUT the specific gravity changes depending on the state of charge, therefore how can one tell if the specific gravity reading is telling us the battery is under charged OR the acid is the wrong strength?
Stu
its always puzzled me, the only way you can tell the strength of the acid is the specific gravity (realistically) BUT the specific gravity changes depending on the state of charge, therefore how can one tell if the specific gravity reading is telling us the battery is under charged OR the acid is the wrong strength?
Stu
Bodach na mara
Well-Known Member
Stu, it is unlikely that the acid is the wrong strength, as batteries are filled when new at the factory or at the dealer with the correct strength of acid from a stock solution. During their life, the amount of acid does not change, the electrolyte converts between oxides on the plates (during charge) which makes the acid stronger and the oxygen returning to the solution and combining with hydrogen during discharge (which dilutes the acid) As Vic says, never add acid, only water to make good the small losses due to gassing.
VicS
Well-Known Member
As Wight Dawn says [pedant] provided you substitute the word concentration for strength [/pedant]
You'll find the reactions that occur as the battery is discharged and recharged in your old school chemistry text book. Not a modern one, they don't teach that sort of stuff these days!
You'll find the reactions that occur as the battery is discharged and recharged in your old school chemistry text book. Not a modern one, they don't teach that sort of stuff these days!
Heckler
Well-Known Member
Thanks, I am aware how batteries are filled, I used to work in the middle east and africa and have filled more batteries than i care to remember HOWEVER, vic used the words "unless you have lost some by spillage" and it is that to which i was referring.
Heckler
Well-Known Member
Vic
see the other post, a battery tips over, loses some electrolyte, as you said earlier, how does one decide what strength acid to put back in? OR one has a new boat with a lo hydrometer reading of the battery, again how is one to know whether it is the acid that is the wrong strength or the battery is knackered?
Stu
see the other post, a battery tips over, loses some electrolyte, as you said earlier, how does one decide what strength acid to put back in? OR one has a new boat with a lo hydrometer reading of the battery, again how is one to know whether it is the acid that is the wrong strength or the battery is knackered?
Stu
VicS
Well-Known Member
Difficult.
I suppose if you knew electrolyte had been lost you'd top it up with acid but you'd really want to top it up with acid of the same concentration of that which remained. You could do that if you were able to get some out to measure the density and then dilute some battery acid as supplied to match.
If you don't know the history then you are pretty much in the dark.
I suppose if you knew electrolyte had been lost you'd top it up with acid but you'd really want to top it up with acid of the same concentration of that which remained. You could do that if you were able to get some out to measure the density and then dilute some battery acid as supplied to match.
If you don't know the history then you are pretty much in the dark.
emnick
Well-Known Member
Thanks to you all, thats that sorted, I will give the acid back.
Roger see PM
Regards
Roger see PM
Regards
Kawasaki
Well-Known Member
[ QUOTE ]
If you don't know the history then you are pretty much in the dark.
[/ QUOTE ]
That's the Acid Test!
Sorry VicS , couldn,t resist /forums/images/graemlins/grin.gif
If you don't know the history then you are pretty much in the dark.
[/ QUOTE ]
That's the Acid Test!
Sorry VicS , couldn,t resist /forums/images/graemlins/grin.gif
Alex_Blackwood
Well-Known Member
If you use a SG of 1280 you should be OK. BUT remember ALWAYS add ACID to WATER when diluting. Also wear protective clothing.
boatmike
Well-Known Member
Best plan on spillage is to discharge the battery completely, tip out all old electrolyte, take the opportunity to flush out thoroughly and refill with new electrolyte of the correct SG. Often an old battery with sludge in the bottom will actually benefit greatly from this but you will probably need a high boost charge to get it going again.
boatmike
Well-Known Member
Second that! /forums/images/graemlins/smile.gif
Heckler
Well-Known Member
Excellent, answered the query spot on, also for the cost of the acid, it might be worth doing this to a shagged hi cost battery before binning it if its history is unknown.
Stu
Stu
alanabnala
Well-Known Member
The “Sludge” you refer to is actually lead that once resided on the plates.
Under discharge conditions, acid from the electrolyte is absorbed by the lead as you place a demand on the battery. When the lead has absorbed as much as it can, you would recognise that as a flat battery. If half of the lead content is now lying in the bottom of the battery, the battery will only have half the capacity it once had, regardless of the acid content of the electrolyte.
Under charging conditions, acid is driven from the plate, back into the electrolyte.
The reason a lead/acid battery dies is that the lead gradually falls off the plates and ends up in the bottom of the battery. The more you cycle a battery (charge and deeply discharge) the quicker it will die. Therefore changing the electrolyte will do little (or nothing) to improve its performance. Once the lead has departed the plate there is nothing that will reverse the process.
On top of this you have the possible problem of the battery sulphating when left for protracted periods and once this occurs it is, at best, only partially reversible.
If it was me, I wouldn’t bother wasting time on it, I’d just bite the bullet and buy a new battery, along with the peace of mind that comes with it. /forums/images/graemlins/grin.gif
P.S. I didn’t even broach the subject of how you would be disposing of the electrolyte you emptied from your battery…. /forums/images/graemlins/blush.gif
Under discharge conditions, acid from the electrolyte is absorbed by the lead as you place a demand on the battery. When the lead has absorbed as much as it can, you would recognise that as a flat battery. If half of the lead content is now lying in the bottom of the battery, the battery will only have half the capacity it once had, regardless of the acid content of the electrolyte.
Under charging conditions, acid is driven from the plate, back into the electrolyte.
The reason a lead/acid battery dies is that the lead gradually falls off the plates and ends up in the bottom of the battery. The more you cycle a battery (charge and deeply discharge) the quicker it will die. Therefore changing the electrolyte will do little (or nothing) to improve its performance. Once the lead has departed the plate there is nothing that will reverse the process.
On top of this you have the possible problem of the battery sulphating when left for protracted periods and once this occurs it is, at best, only partially reversible.
If it was me, I wouldn’t bother wasting time on it, I’d just bite the bullet and buy a new battery, along with the peace of mind that comes with it. /forums/images/graemlins/grin.gif
P.S. I didn’t even broach the subject of how you would be disposing of the electrolyte you emptied from your battery…. /forums/images/graemlins/blush.gif