Overcharged 6 volt battery

[Bob Watkins]

I need to jump in this thread with more questions. I have a restored 1947 John Deere B. 6 volt system. positive ground. New generator/wiring and gauges. I keep all My tractors in a heated garage (never below 35 degrees). I bought maintenance chargers 6/12 volt for each of my tractors to promote battery life. These are Black and Decker Chargers which can be switched from 12 to 6 volt for a variety of uses.
A green light on the charger flashes when charging and stays green when charged. I start my tractors every month to lube all internal engine parts, keeping in good repair. I noticed the charger on this B never stopped charging and after several days I took it off and tried to start the tractor. The starter turned real slow as if the battery was low. I checked the battery with a hydrometer and it shows overcharged.
I see no swelling of the battery case or leakage of acid. Can I turn on the lights and un-overcharge the battery? Can the battery be saved? Is my best option get a new battery? Could there be a reason the maintenance charger overcharged other than a bad charger?
I will appreciate any help anyone can give me.
Thanks,
Bob

 

[Lee B]

I'd just let it sit for a day or two and then measure voltage, correct fluid level if that's necessary or even possible and then attempt another charge with a good charger/maintainer before getting a new one in there. It might pull out of it and be just fine. It should be very low on electrolyte. I would call it a bad charger but would test it on another battery for a short time to see if it wants to do the same thing there first - this battery may have had a shorted cell causing the overcharge to take place as voltage would never reach maintainer level of 6.65 volts. $8 harbor freight voltmeter cheaper than maintainer, get one and use it to double check that they are working correctly and/or find problems before they get this far out of whack. My hunch is a shorted cell in that battery which makes it worthless other than a core for the replacement. But at current battery prices, I would be sure of the problem first.

 

[Indiana Ken]

I have two battery testers to check specfic gravity, each read to a maximum of 1300 (1.3) however, neither tester has an "over charged" range. What specfic gravity are you calling over charged? The fact that your charger did not go to charged mode and the slow cranking, point to a bad battery.

The specfic gravity of each cell should be within 30 points. A cell that is lower than 30 points of the others indicates a bad cell.

 

[Bob Watkins]

Thank you!

 

[Bob Watkins]

thank you, very helpful.

 

[pauldeere]

Bob, you say the "B" is pos. ground, how did you connect the charger? I use nothing but Battery Tenders if they are connected wrong they will flash a reverse polarity code.

 

[Bob Watkins]

I connected the red charger clip to the positive battery post and the black charger clip to the negative battery post.
thanks,
Bob