battery acid

it is usually supplied as a premixed battery acid. (sulphuric acid) However if you want to mix your own you need a hydrometer to check the specific gravity around 1200 or is that 1.2 is normal for a charged battery.
Be careful mixing acid into water.
good luck olewill
 
William_H said:
it is usually supplied as a premixed battery acid. (sulphuric acid) However if you want to mix your own you need a hydrometer to check the specific gravity around 1200 or is that 1.2 is normal for a charged battery.
Be careful mixing acid into water.
good luck olewill
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Be careful yes. However acid into water YES. Water into acid NO.
 
I had an idea that it's 35% sulphuric acid but Wiki thinks it's 32% so that would do.

The trouble is that when a lead acid battery is first charged the acid becomes electrolyte and I don't think it's as easy as just putting more acid in a dry battery and charging it up.

The best way forward is to buy a new battery, it will have just the right amount of acid in it at just the right concentration.
 
It's quite variable between manufacturers but a 12V 110Ah battery is likely to need between 10 and 15 litres. Specific gravity for filling is normally 1.270-1.280.
Are these new dry charged batteries? (If not, if they have previously been filled and emptied out, they will almost certainly be useless.)
You should have the manufacturers instructions for volume, s.g. and very important, initial charging procedure. It's not just a case of pouring acid in and it's ready for service.

Correction that's for the two not each sorry.
 
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The Lazy Kipper said:
Out of interest how does that work when we add distilled water into battery acid?
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Battery acid at working strength is diluted so no problems. Creating the correct mix however requires the dilution of concentrated acid. Adding water to concentrated acid can cause it to boil violently as all the acid tries to bond with a small amount of water. Thus one adds acid to water so there is plenty of water for the acid to bond to. Basic chemistry.
 
The Lazy Kipper said:
Out of interest how does that work when we add distilled water into battery acid?
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I guess basically because the acid in your battery is fairly diluted and of small quantity (one cell) and also in confined space. A fair question. Yes you must never pour water into concentrated sulphuric acid as it becomes quite dangerous bubbling and fuming. Yet we do it safely so often in topping up batteries.
However always be careful around batteries and when topping up. Don't get to close. olewill
 
William_H said:
I guess basically because the acid in your battery is fairly diluted and of small quantity (one cell) and also in confined space. A fair question. Yes you must never pour water into concentrated sulphuric acid as it becomes quite dangerous bubbling and fuming. Yet we do it safely so often in topping up batteries.
However always be careful around batteries and when topping up. Don't get to close. olewill
Click to expand...

Once the concentrated acid has been diluted there is no problem adding a water to it but as you say a lot of heat is produced when first diluted.

I'd never dilute conc sulphuric acid without also cooling the vessel in which it was being diluted. Battery acid doesn't quite boil but it gets very hot. Diluting to a higher concentration than battery acid can result in it boiling if there is no cooling..

Adding water to concentrated sulphuric acid is more dangerous that just bubbling and boiling. The added water will almost certainly boil with explosive violence as it hits the acid.

Always wear appropriate protective clothing. Eye protection is the absolute minimum.

BTW whenever asked to prepare "battery acid" I added 250 cm³ conc acid to 1 litre of water. IIRC when cool it came out just a little less than 1.30g/cm³.


Tonights teaser: if you add conc sulphuric acid to melting ice ie at 0C what happens to the temperature. Does it fall or does it rise ?
 
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