Battery shows negative -2.5V?????

[skuhleman1524]

Okay guys, I have a question for yall.

A couple weeks ago we bought new US-2200 batteries for the marathon. It ran fine for a week or so, and just the past few days it goes from full charge to wont move within a mile. So I started checking voltages. 5 batteries read 6.5V and the last one reads -2.5V. all batteries are hooked up properly and as they were before the were replaced. If I place the positive probe on the positive terminal, and the negative probe on the negative terminal. I show -2.5V which means the polarity somehow got reversed. Well tomorrow Im going to try to get them to warranty the battery. Is this a defect in the battery or is it something we managed to do to it?

Thanks for all of the help.

[Sir Nuke]

to be honest......tell them it "JUST HAPPENED", if you offer much info, or tell them you were "messing with it" trying to get it to run.....depending on who you get the batteries from, they COULD try to blame it on you.

just tell them is just died, like it did as you described it to us, and let it go at that.

OBVIUSLY that battery is toast......for some unknown reason.

[skuhleman1524]

Yea... It really did just happen... Im just curious what would cause something like that to happen.

I don't want it to happen to the new battery... Needless to say I will definitely be checking all of my wires again to make sure it is indeed all hooked up correctly.

it is not uncommon

Battery reverse polarity - YouTube

Battery reverse polarity - YouTube

[gwh1bass]

Is it possible that internally it is hooked up backwards?

[bigstik40]

What may have happened is that the one bad battery has a storage capacity that is way less than the other 5 batteries. The voltage on the bad battery went to zero long before the other 5 batteries. When this happened, the 5 good batteries continue to deliver current to the motor through the dead battery. This reverses the polarity on the bad battery(and basically charges it backwards) causing the polarity of the bad battery to reverse. Have the shop replace the bad battery and you should be good to go. Make sure you equalize the entire pack after replacing the bad battery. There may be additional explanations from the experts as well. RAY

so... if your theory is correct then he could drain reversed battery dead and then recharge it correctly to re-reverse polarity and make battery useable ?

[cgtech]

I have seen incorrectly installed batteries reverse polarity. it destroys the battery that was installed incorrectly. if forced to live a life of incorrect polarity it will reverse polarity. That battery is ruined....

[yurtle]

Originally Posted by cgtech

I have seen incorrectly installed batteries reverse polarity. it destroys the battery that was installed incorrectly. if forced to live a life of incorrect polarity it will reverse polarity. That battery is ruined....

That sounds like a bad joke waiting to happen.

Gender bender, AC/DC, taking juice up the wrong end, etc.

[yurtle]

Even Trojan warns us about the problem of "incorrect polarity". Notice the big male chasing a smaller male on the upper right-hand corner. Also notice it has a big international "NO" symbol across it.