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How to revive a lead acid battery

Lando

Arthur Digby Sellers
Joined
Mar 3, 2011
Location
SLC
I let my 240s already marginal Duralast group 24 battery die while I was on vacation and wanted to see if I could revive it. It would not take much of a charge and only read 10.5 V after charging at two amps (trickle) for 12 hours. After following the steps below, it passes a load test and holds 13V over night. Thought I'd share:

SAFETY: Any time you are working with a battery with the caps off you should wear goggles, a full face shield and nitrile gloves. If you get acid on your skin, flush immediately with plenty of water. Read SDS for all chemicals before starting this procedure.

Supplies:
Battery charger
Paper towels
10 gallons of distilled water
8 lb of baking soda
1qt of sulfuric acid (1.28 SG) PN UN2796 available at oreilly's
Nitrile gloves
Full face shield and goggles
Acid resistant container 5 gal (most plastics are good for this)
pH strips or pH meter
Small funnel (small enough for the water ports on the top of battery)

Method:

1: remove battery from car and thoroughly clean exterior of battery.
2: don goggles, face shield and gloves
3: remove caps and carefully dump acid into container
4: neutralize waste acid by slowly adding baking soda and water
5: once acid is neutralized most municipalities allow you dump into sewer, NOT STORM DRAIN! I used a ph meter to confirm the PH was neutral (7.0)
5.5: inspect plates in each cell for mechanical damage. You might see brown crystalline build up on the plates, the next steps should take care of that. Keep in mind the cells with lots of build up may take longer to clean. Also check terminal posts for looseness. A battery with a loose post will not be cured by this method.
6: heat up a medium sauce pan full of distilled water (at least 2qt) and stir in baking soda until it stops dissolving.
7: place battery in empty container and use funnel to add soda water to each cell. DO NOT INSTALL CAPS! The acid base reaction offgasses and could rupture a battery or spray acid everywhere if capped. Let stand for 1 hour or until bubbles stop. This step removes the sulfate layer on the plates that prevents your battery from taking a charge.
8: with all your PPE on, shake the battery carefully and let it react for another 15 minutes.
9: flush a couple of times with distilled water and be sure to neutralize the waste before dumping.
10: drain the water thoroughly, collecting all runoff and neutralizing all waste water.
11: wth all your PPE on and the battery in the empty container, distribute the sulfuric acid evenly to each cell and top off with distilled water.
12: check voltage. Should be above 10V before charging.
13: charge battery in empty container with caps off, over night at no more than 2 amp.
14: top off cells as necessary, check voltage; should be above 12.6V. Trickle charge and top off cells as necessary and install caps.
15: install battery
16: drink a beer
 
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Interesting! Build up inside the battery on the plates and as it settles in the batter will cause it to short out. Depending on cost of the acid, I have been planning to try to revive one. Thanks for your how too list.
 
Interesting! Build up inside the battery on the plates and as it settles in the batter will cause it to short out. Depending on cost of the acid, I have been planning to try to revive one. Thanks for your how too list.

Actually the build up is non conductive so it causes poor conductivity, which reduced the available surface area available for the reaction to take place, thus reducing the capacity.

The acid I used was $8/qt, the baking soda was $1/lb and distilled water was $1/gal. So the total cost was $26. Everything else, I had on hand. The procedure should be cheaper to execute with lye instead of baking soda, but lye was not available readily and I have not tested it.
 
Actually the build up is non conductive so it causes poor conductivity, which reduced the available surface area available for the reaction to take place, thus reducing the capacity.

The acid I used was $8/qt, the baking soda was $1/lb and distilled water was $1/gal. So the total cost was $26. Everything else, I had on hand. The procedure should be cheaper to execute with lye instead of baking soda, but lye was not available readily and I have not tested it.

Caveat emptor. Buying bulk quantities of lye *may* revoke your right to fly.
 
Living in northern Minnesota I don't screw around with old batteries. I buy new ones with the most cold cranking amps that'll fit. A car not starting at -30 really sucks.
Not saying this is a bad idea just that for 150 bucks or less I ain't taking a chance in the winter.
Something I only use in the summer like a lawn mower is another matter. Who cars if the lawn mower doesn't start?
 
Living in northern Minnesota I don't screw around with old batteries. I buy new ones with the most cold cranking amps that'll fit. A car not starting at -30 really sucks.
Not saying this is a bad idea just that for 150 bucks or less I ain't taking a chance in the winter.
Something I only use in the summer like a lawn mower is another matter. Who cars if the lawn mower doesn't start?

I'm with you.

But, this is TurboBricks. Home of the ziptied redblock and 14.99 Virgos.

Topic is relevant.
 
Well, a no start in any weather is a problem. Mine you it’s only in the low 20’s tonight and when I walked today is was 29 degs when I started. I have more cars than I need and I’m in if I can extent the life a few extra years. Every time I visit a pull a part and they have a one of those green batteries with the right build date any if fits any of my heaps it leaves with me. Been meaning to look into this a little but never have. I don’t have no starts issues. When it slow starting I want to know why. I might be most anywhere and don’t need the hassle. Now for you guy way up north, I feel for you. I was in Chicago a few years ago in my SS Chevy in -12 deg weather and I hated to crank my car in the morning. Sounded horrible for a few minutes but I used 15-50 in that car.
Though at the time, I would beg, borrow or steal to get the hell out of there!
 
I'm with you.

But, this is TurboBricks. Home of the ziptied redblock and 14.99 Virgos.

Topic is relevant.

No real risk here. You can visually inspect the condition of the plates and load test it after assembly. Just a fun science project that also saves you money. It only took about 1 hour away from my time excavating a room in my basement (which is also another $0.17/hr job). That being said it's probably a job best suited for when the battery shows signs of failing,not when it stone dead.
 
Since most of my battery dies before the warranty runs out, I'd just get in the zone.

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I've noticed that the newer battery chargers will not charge a really low battery. I was able to bring back to life a battery by just connecting it to a known fully charged battery overnight. The next day the battery voltage on the dead battery was high enough to allow the charger to actually charge it. No issues with the formally dead battery. YMMV
 
Just took my Volvo down to the old dealership I worked at and had them load test the battery with their fancy GR8 battery diagnostic tool. 13.1V and 950 CCA out of a battery only rated for 750 CCA.
 
I have some scooter batteries that are not that old, but not charging. I let them sit for too long between charging..... need to try this trick on them...
 
Interesting...thanks for posting that how to. How old is the battery? Mine is a bit over 5 yrs. old and the cold weather has made it a bit sluggish. May be a good candidate for 'rejuvination'.

Just took my Volvo down to the old dealership I worked at and had them load test the battery with their fancy GR8 battery diagnostic tool. 13.1V and 950 CCA out of a battery only rated for 750 CCA.
 
Interesting...thanks for posting that how to. How old is the battery? Mine is a bit over 5 yrs. old and the cold weather has made it a bit sluggish. May be a good candidate for 'rejuvination'.

Mine came with the car when I bought it over 4 years ago, so it's at least that old. Yours sounds like a good candidate for sure. A trickle charge can desulphate a battery that isn't as far gone as mine, so maybe try that first and then give my procedure a try if that doesn't work.
 
What charging rate would be considered a trickle charge for a lead acid battery? I know that for nicads it's 1/10C.
 
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