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
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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