Strange happening: Batteries

http://www.eham.net/ehamforum/....msg528564#msg528564

"I'm not aware of a battery chemistry that can spontaneously assert a reverse charge.  The only way I've ever seen it is if it was charged that way. This can happen if cells of different capacity are used in a series string.  The weakest one will discharge to zero, then the remaining better cell(s) will put reverse current through it and force a reverse charge.

A plausible explanation is the two cells you picked were at different capacities, likely the reversed one was dead or nearly so when you put it in there.
Alkalines in particular have a pretty linear open circuit voltage vs state of charge.  A quick check with a voltmeter will tell you how much is left, 1.10 being dead and 1.535 or so being new/full.

Mark K5LXP
Albuquerque, NM"

I did automotive repair for several years and the only way a battery can have a reverse charge is if it is charged in reverse or the battery was manufactured wrong. However most batteries will not take a reverse charge without doing something first like sparking at the terminals. I am not familiar with small batteries and their abilities but most 12 volt car batteries will take a charge only in the correct polarity.

With smaller household batteries you might be able to charge the battery in reverse for a few minutes without much problems other then the battery leaking or popping off(blowing up). As for charging 2 or more batteries together in series I don't recommend it unless you know what you are doing.

Lee Fritz

Specifically, what kind of batteries did you use?

John, These were Rayovac alkaline with exp date2024

Very odd, I've never seen that with a primary cell.   I've seen rechargeable batteries, specifically NiCad, with a reverse charge.  In the bad old days, I'd use a large capacitor to "ZAP" them and attempt to restore them.  It worked a lot of the time, but not always.

BOBBYD,

Thank you for this link, there is one reply that seems to fit what happened here. The set of batteries in question came from the new pack of batteries that I had recently opened, they were not of a mixed consistency, all were brand new. Looks like maybe bad from new. I will watch for more of this from that package.

Ray

http://www.eham.net/ehamforum/....msg528564#msg528564

K0BG Member Posts: 10248 RE: Have You Ever Seen An Alkaline Battery Reverse Polarity? « Reply #1 on: July 26, 2011, 12:34:01 PM »   I'm tempted to say only yes, but that would be a bit brusk. When alkaline batteries go bad, they will sometimes take a reverse charge, due in part to a change in their internal chemistry.

Walmart has been really pushing Rayovac batteries at a good price, but I'll never buy them again. I recently changed out some AA in window candles and also some AAA in a LED flashlight in the kitchen junk drawer and found several have leaked. As far as reverse polarity, I had a white MTH 8.4 volt that had reverse polarity. They all go in the garbage as soon as I receive a used engine with one installed. 

THANK YOU  for Battery info, 

KB2AGP  73,

Happy New Years. 

kb2agpjohn@aol.com