From: ben4ord@gmail.com   
      
   On Friday, June 4, 2021 at 3:57:01 AM UTC-5, Phil Allison wrote:   
   > Dave Platt wrote:    
   > =====================   
   > >    
   > > >    
   > > >How can batteries get reversed polarity???? Thats a new one for me....    
   > > >(Of course if they were made in China, so anything is possible I guess).    
   > >    
   > > I believe that can happen if you have several batteries wired up in    
   > > series (as here) and one or more of them is substantially weaker than    
   > > the others. If you keep operating the device beyond the point at    
   > > which the weakest battery runs down to zero, the other batteries will    
   > > keep pushing current through it. This can create a situation called    
   > > "over-discharge", and depending on the specifics of the battery    
   > > chemistry it can cause the over-discharged battery to "charge up in    
   > > reverse" a bit, and develop a reverse-polarity output voltage.    
   > >    
   > > Over-discharge will damage NiCd (and I suspect NiMH) cells, and I    
   > > believe it can cause alkaline cells to start leaking.    
   > >    
   > > The better brands of alkaline batteries usually come with an    
   > > on-the-package warning that all of the batteries in a set should be    
   > > replaced at the same time, and that you shouldn't mix different types    
   > > of batteries in a set. This is why. You really want 'em all to run    
   > > down at the same time.    
   > >   
   > ** +1    
   >    
   >    
   > .... Phil   
   Would not have expected to ever find a battery with reversed polarity, but   
   yep,    
   there it was.  Very weak charge, which made sense when I sussed it out ..   
   especially   
   as it was one of two AA batteries in the device I was using (the other one   
   tested Strong).   
   I replaced both with different-brand-off-the-shelf-out-of-the-pa   
   kage-pre-tested-verified-fresh-new-batteries.     
   If the situation happens again, it will be very interesting to try and map the   
   occurrence back to the   
   device itself, as perhaps it's internal wiring could be the root cause.   
   And   
   that   
   is   
   all   
   I   
   have   
   to   
   say   
   on   
   that.  Cheers mates!   
      
   --- SoupGate-Win32 v1.05   
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