Refilling a Car Battery 6 volt, 40amp/hr

[Penlan]

Probably be told "Don't do it".
I have a 6 volt 40 amp/hr car battery - For a 1934 Austin 7 - the other day I came to power up the car and it didn't have the strength to turn the engine over with the spark plugs in, feeble when there were no plugs.
I had charged it up twice, the max voltage fully charged was 6.23 volts, I would expect there to around 6.7 volts.
The battery has always been OK for the last 4 years.
I've bought a new battery and the engine turned with gusto.
When I bought the 40 amp/hr battery, I received excessive quantities of sulphuric acid, which I still have.
On the assumption I can tip the existing contents out* of the battery, what mix should go in? 
* being mindful of all the enviromental needs.

[brianusa]

>>>>>>>>>>>>>>>>>Probably be told "Don't do it".>>>>>>>>>>>>>>>>>>>>>>

 

Sound advice!

     Brian.

[Enterprisingwestern]

 

An anecdote, not a recommendation.

I once read in a 1950's ish Car Mechanics magazine an article on how to saw into one of the rubber type batteries so as to clean and refurbish a dead cell. Frightening nowadays, especially as the article didn't go into any great depth on the safety aspect of the operation.

 

Mike.

[Nearholmer]

Leaving aside all the, highly relevant, safety issues for a moment, this is a useful intro to the topic of managing traditional lead-acid cells https://www.engineersedge.com/battery/specific_gravity_battery.htm ........ the essential tool is a hydrometer, with which to measure the specific gravity of the electrolyte.

 

Now, back to safety ........ making-up electrolyte from distilled water and concentrated sulphuric acid is a process that can go horribly, horribly wrong if you do it in the wrong order, showering you in concentrated acid, so unless you really know what you are doing, its very best not to go there.

 

And, did you really get given sulphuric acid, or were you given pre-mixed electrolyte? If not, could you buy pre-mixed electrolyte? (Possibly not, because it’s sale to the general public is now limited or banned, I think)

 

Attempting to dredge-up ancient memory, so not guaranteed, I think electrolyte for a starter battery should have an SG of 1.26-1.28, and will be nominal 37%.

 

 

Edited July 8, 2019 by Nearholmer

[Penlan]

Many thanks for the replies,  I shall check the Acid I have, and I am aware there are dangers, even at my age, 76.
I will advise latter.

[Penlan]

I've now been and checked the box it's in...
There's 4 x 1 litre containers in unopened cardboard boxes,

plus a another plastic litre bottle with approx. 0.75 litres in it.
When these were delivered originally it was for one 3 cell battery,
the courier was not prepared to take the remainder back.
SG = 1.28, so that's in the right area.
Again, many thanks to you all.

Edited July 9, 2019 by Penlan

[PatB]

Some years ago, I discovered just how much one could get away with, regarding batteries. My ageing Suzuki motorcycle ate its voltage regulator, as ageing Suzukis were wont to do. The resulting spectacular overcharging boiled the battery dry. Ah, the nostril hair shrivelling tang of boiling sulphuric acid ;-). My finances being in their usual parlous state, the tenner for a secondhand regulator cleaned me out completely. possessing neither fresh acid nor the means to purchase it, in desperation i simply filled the sorely abused cells with tap water and hoped for the best. To my utter astonishment it worked, and the battery continued to start the bike with a moderate degree of reliability for the next year.

 

On the OP's battery, I'd say that 4 years irregular (I assume; if not, I dips me lid to you sir ;-)) use probably isn't too bad a battery life. Not great, but certainly within normal bounds. Long enough, anyway, that I probably wouldn't be bothering to muck about with corrosives in an attempt to revive it.

[34theletterbetweenB&D]

18 hours ago, Penlan said:

...On the assumption I can tip the existing contents out* of the battery, ...
* being mindful of all the enviromental needs.

You live in the most perfect location to this end. Ditch it down a closed mine shaft. It cannot be any worse than what's already down there, and there's plentiful water to dilute it safely. (It's a natural product, volcanoes push it out in huge quantity without asking permission.)

[Penlan]

20 hours ago, PatB said:

..................... On the OP's battery, I'd say that 4 years irregular (I assume; if not, I dips me lid to you sir ;-)) use probably isn't too bad a battery life. Not great, but certainly within normal bounds. Long enough, anyway, that I probably wouldn't be bothering to muck about with corrosives in an attempt to revive it.

The previous battery managed 14 years 
I've looked into the cells, one lot of plates don't look that tidy, so I think off to the recycling, the scrap metal merchant - they pay for old batteries - not the County Re-Cycling.
I have a few old batteries about, not all mine, so should pay for a couple of rounds of beer with the lads.
I shall have to check where to dispose of the other sulphuric acid, not down a mine shaft, as per 34thlett....'s suggestion, somethings bound to go wrong......

[PatB]

If you know anyone who does a lot of silver soldering they might want the acid for pickling, although I think most have now gone to the (safer but slower) citric option.

 

On that note, the late Keith Wilson, prolific builder of fine live steam locos, claimed to use sulphuric acid pickle, at about the same concentration as battery acid, with no protective clothing, not even gloves, with no ill effects. I've been known to be a tad cavalier about such things but I'm not sure I'd go quite that far. 

[34theletterbetweenB&D]

It's not that corrosive, says he blithely. When I were a lad, one of the analyses that was then standard involved titrating into hot oleum (look it up) which was a bit hairy. On intrduction of this analysis the teak bench tops had to be quickly replaced in stainless, due to their propensity to catch fire if it did splash (which also ruined that particular analytical specimen) and once in a while you would get it on your skin, 'cause it had gone through the lab coat. A few scars, none serious. (The lab coats would disintegrate on their third laundry trip.)

 

How tame it all became when the first XRD was installed and wet chemical analysis was redundant. I moved on realising that the fun was over, and also the danger money...

[Guest CLARENCE]

DON'T  mess about with acid! I did National Service (1956-58) in the RAF as an electrical mechanic, and my main job for my last six months was servicing aircraft batteries and filling/charging new ones; I regularly mixed fresh electrolyte, and went thro' several pairs of overalls due to splashes and a fair few acid burns, I still have a few scars. Of course I was only 18 at the time, and didn't know any better, but by god, I wouldn't do it now!!

Buy a new battery, they can't be that expensive! And get rid of that acid!

Edited July 15, 2019 by CLARENCE

[2mmMark]

From my earlier years at BA, I well remember the Battery Shop in one of the old BOAC hangers (Technical Block A).  It seemed like a particularly unhealthy place to be, full of wizened-looking technicians with huge rubber gloves. Mind you, they'd sort out any vehicle battery problems you'd have!

 

As for repairing lead/acid batteries, I would be tempted to have a look at some of the electronic battery desulphaters now available. It is possible to desulphate using a chemical called EDTA but I understand that removes some of the active coating from the plates, losing a bit of battery capacity.

 

From https://www.mgownersclub.co.uk/news/uk-restrictions-sales-acid

 

"The new legislation doesn’t stop there as from 1st November 2018 it will become an offence for any unlicensed individual to hold any quantity of battery acid, so those who have small remaining quantities of battery acid from their last dry battery purchase will be committing an offence to keep or use it after 1st November.  Clearly the advice has to be to dispose of any existing quantities of separately stored battery acid before that date so there is no possibility of you ever being caught out by circumstances that you may never believe could occur.

 Note that acid that remains in a battery is not restricted, but empty it out for any reason and as soon as it becomes separated from the battery is immediately restricted and an offence for any unlicensed individual to hold."

 

It's unfortunate that use of acids for nefarious purposes has caused problems for legitimate users.

 

Mark

[Oldddudders]

We haven't heard from Penlan since Wednesday in this thread. I do hope he is still with us. 

[Penlan]

Yes, I'm still here.
I decided to take a responsible stance on this, got £10 for the old battery at a Metal recyclers and a local motorbike shop said they would have the Acid in the containers for a a few £'s.
So the fish in the Harbour are still alive and the plants in the stream that runs past our house down to the harbour are still green. 
I could have sworn the old battery was a 80+Ah one, but when I pulled it out, twas only 40Ah.
The new battery is 80Ah, which is what I like for my A7.
And plenty of ooomph.
Right back to the layout.....
 

[Nearholmer]

Beautiful car.

 

Can the charging system replenish an 80Ah battery without driving to Wick and back without using the lights?

[Penlan]

No problem recharging, the main thing with 6 volts is to ensure everything is earthed DIRECTLY back to the battery, so all the lights etc., and even the starter motor have direct earth cables back to the battery, no using the bodywork? to conduct the electric (earth) path back.
The new fangled LED light bulbs now available, and getting cheaper by the month, are a great help in reducing the current required. 
Yes it would make sense to go to 12v, but most A7 users are happy with 6v, a factor of being an 'oldie',  but it does mean that at a rally, or on a run, etc., spares are compatible, easy to swop.