The Stovebolt Site Forums The Shop Area The Electrical Bay New dead battery

Bought a new battery for the Sub 2 years ago. It has been sitting on a shelf under my bench most of this time except for a couple stints in the truck when I was doing the wiring. Now it is completely dead and will not take a charge. I have heard or read somewhere that a battery that is completely dead and wont take a charge can be brought back to life by somehow zapping it and then charging it. Am I dreaming this? Anybody out there ever heard of this or successfully done it? If so how is it done? Do I have to go in hock for another new battery?

Weeds

I believe resurrecting a battery that has sat for two years is not going to happen.

If it wont take any kind of charge then you are most likely dead in the water.

IF it takes some kind of charge then watch the temperature and keep charging. Sulfation can be reversed but it takes a high voltage ie 15 or 16 and LOW current to do it.

Dan Bentelr

You might be able to recharge it if you leave it on a slow charge rate for 24 hours or so. Some chargers won't start if the battery is below a certain voltage. If your charger has an 'override' button or something other than just on and off, push that button after connecting the leads. But make sure your charger connections are correct before starting the charger- if the battery is completely dead and you connect the charger backwards, and it starts, it will charge the battery with reversed polarity- if it will charge. If you don't have some kind of override, connect another charged battery in parallel to yours, then connect the charger and turn it on. Leave the two batteries connected for a few minutes, then shut off the charger and disconnect the 'good' battery. Then try again to charge the dead battery. You might have to do the parallel battery connection again if the charger does't start up after the first attempt.

So as not to misinterpret the charger indications, a completely dead battery has high internal resistance that limits the charging current to a very low level. The charger ammeter may not show a charge current for several minutes after starting, so leave the charger connected for an hour or so before concluding that the battery is not charging. You should have a voltmeter connected to the battery when you are charging it. If the voltmeter comes up to 13 or 14 volts when you turn on the charger, good sign, even if the ammeter needle doesn't move. If you have charging voltage, leave everything alone for a while, but check for the charging current to increase after an hour or so.

If the dead battery charges, leave it on the charger for 24 hours or so. If you don't have a battery hydrometer, buy one, preferrabley one that is temperature-compensated if you can find one, but non-compensated is all right- and they are most readily available. When the specific gravity reaches around 1.280 warm, the battery is charged. A little over 1.280 is all right, but much below that level when the battery is warm means it still needs charging.

If it were my battery, and if it charges more or less satisfactorily, I would next discharge battery completely with a low discharge rate, like car low-beam headlights or parking lights, and let the battery stand dead for 12-24 hours. Then recharge the battery to 1.280 specific gravity. At two years old, it is quite possible that it will return nearly to full capacity.

After all the charging is complete, if it is, wash the exterior of the battery completely with water and baking soda and dry it completely. Don't get any of the soda solution inside the cells. That will neutralize the acid and undo all your efforts.

Hope this helps.

Harvester

There are a couple of tricks to getting a sulfated battery to take a charge. One is to add a very small amount of fresh acid, not more than an ounce or so, to each cell before connecting the charger. It's necessary to get a small amount of current flowing to begin breaking down the lead sulfate and get the acid back into solution. If you can turn the voltage up enough to get a charge current of 5 to 10 amps, the sulfated plates will begin to re-configure back to lead on the negative plate, and lead dioxide on the positive, with the electrolyte converting back to sulfuric acid. As the charge progresses, the acid will gain strength.

Lead sulfate forming at both positive and negative plates is a normal byproduct of a battery discharging, but it is a spongy material initially. At that stage, it re-dissolves easily as charge current is applied. If the battery stays discharged for a time, the sulfate converts to a hard, stable crystalline form which is very hard to dissolve. Charge the battery until the specific gravity stops increasing, then run it all the way down with a headlight bulb or other slow, continuous discharge. Slow charge again, discharge, recharge, etc. If the battery is salvageable, it should begin holding a partial charge about the 5th. or 6th. charge/discharge cycle. It might take 10 or more cycles to get full capacity, if at all. Normal full-charge specific gravity is about 1.265 to 1.300, measured with a hydrometer. Discharged specific gravity will be close to 1.000, same as water. Once the battery starts accepting a charge, DO NOT add more acid. The acid trapped in the plates will re-combine with the water to give the specific gravity rise needed.
Jerry

Edit: I recovered a 6V battery that had been sitting in a stored car since 1981, about a year ago! Not perfect, but good enough to start a 216 without boosting! 12 volt batteries don't usually do as well for some reason.
Jerry

Harvester and Jerry, many thanks for the information. This is exactly what I was hoping to find for an answer. Maybe I can save this thing after all. You guys are fantastic. Thanks again.

Weeds

If anyone is still interested in this topic, Jerry's suggestion of adding a small amount of fresh acid to the battery to help start the charging cycle brought to mind some of the 'battery rejuvenators' that have been sold in the past. I think sulfuric acid , battery acid at 1.280 specific gravity, was sold as an additive for that purpose, but I don't know of a brand name. Another of those was a product called VX-6, which I think was cadmium sulfate, and came in a package of three or six tubes for 6- or 12-volt batteries. Another 'rejuvenator' was epsom salts, which is mangnesium sulfate, and I believe was also sold as a solution to be added to a 'dead' battery. The common point in all of these additives is the sulfate ion that transfers charges within the battery (sulfuric acid can be thought of as 'hydrogen sulfate' if you like). Add a few more sulfate ions, and you get a little more current from the battery, but none of these treatments was/is a substitute for properly charging the battery, or replacing it if necessary.

Also, Jerry's observation that 12-volt batteries don't seem to have the recovery potential of 6-volt batteries has been my observation as well. I think that difference might be because 6-volt batteries typically had/have thicker plates, which allowed a 'natural' recovery after running one down quickly, as with a hard-starting engine. It was possible to draw a 6-volt battery down to the point of no-crank, but if left alone for 10-15 minutes, it recover enough to crank the engine fairly fast for a few more seconds. A good 6-volt battery would do that two or three times before there would be no more recovery. And charging was necessary-- and correcting the engine problem.

Just in case anyone is still interested...

Harvester