new battery with -3.5 volts

[38racing]

I just bought some new batteries so I can stop moving one from machine to machine. Before using I put them on an schumacher automatic charger. Today when I went to use one I was surprised that it was warm from the charger since I expected that since it had been on a long time any charging would have stopped. I installed it in a rider and it would not crank , not even click the solenoid. When I checked it showed -3.4 volts. If I reverse the lead contacts it of course shows +3.4 volts. I have a small maintainer which also detects the - by showing reverse polarity light. I assumed that I had hooked up the original charger with the correct polarity and sense it has a circuit board that requires voltage before it will charge I assumed that the charger would not operate if connected in reverse polarity anyway. Any consensus as to whether it was a defective battery or I made it so. Funny thing too is after I placed another battery in the rider I got only a click of the solenoid. Turned out I had a seized starter and had to swap it out to get unit to crank.
edit found this in the manual:
No sparks should occur when the battery clips come together or when connected to a
battery, even if connected in reverse polarity. Charge current will only flow when properly
connected and after a 3 to 5 seconds delay. The charger will not respond to a battery so
depleted of charge that its terminal voltage is less than 3 volts.

[mwerles]

If the new battery was stone cold dead, it could have reverse charged,otherwise not.You could completely discharge it and try again or since it is new ,return it.
Les

[KE4AVB]

I know I am going to get feedback on this one.

First I would return the battery if you just purchased as it is defective. It could been assembled backwards or initialized backwards at the factory. Also I would now check that alternator on the mower and make sure it is still working and that it is not putting out AC only.

Now with that said I have working on electronics and analog circuits since I was a teenager now nearly 55. I have seen only a couple car batteries that had reversed their normal charge. At least I never installed them as I normally check the charge voltage after charging. With lead acid batteries this is possible but us usually don't intently recharge a dead battery in reverse. As with all us we do make accidental mistakes. Believe or not that how so the best inventions came to be.

If these are older batteries I would slowly drain them until completely dead (no voltage at all and it takes a few days to do this) and then attempt a normal slow recharge at the correct polarity. This may bring the batteries back to life. As if you continue use in reverse charge you will damage the plates as the internal construction is designed to use in the correct polarity.

Now to the automatic charger. Personally I don't trust these as I seen 6 here to go bad in a short time for my brother. I got an older style charger with an 8 hour timer that I normally use. My charged batteries with these automatic chargers did even have enough of a charge on a battery to start a mower then I charge the same batteries with my charger and batteries worked fine.

[KE4AVB]

Les so I am not the only one that has seen this...Good.

I know this is very rare but does happens.

[mwerles]

I have heard of a procedure to rejuvenate old batteries,by reverse charging them for a while and then draining them and charging the correct way.I have never tried it and probably nevere will.
Les

[Deere2me]

Its a bad battery, take it back, sheesh!

[bobodu]

Bought six T96 light bulbs last week, TWO were DOA.

[38racing]

Its a bad battery, take it back, sheesh!

Assuming that my charger did not make it a bad battery.

[bobodu]

If you don't have a manual charger, try draining it and charge it off the car ( or whatever) to get enough voltage so a charger will operate.

[Arkie]

Bought six T96 light bulbs last week, TWO were DOA.

You wrote:
I just bought some new batteries so I can stop moving one from machine to machine.


First take ALL the bad bats and bulbs back ASAP for warranty.

How many of the 6 new batteries were testing bad AFTER YOU CHARGED THEM. (also most AUTOMATIC solid state type battery chargers will not reverse charge a battery)