Re: My NiMH cells reversed polarity! Oh no!


"John Woodgate SNIPPING MANIAC "

Yes. Several cells have failed and have been charged in reverse by the
others.


** Failed ???

No need for cell *failure* to occur for the polarity to go reverse during
the discharge of a battery. When a cell is fully discharged, the internal
impedance goes very high so it can easily take up a small reverse voltage.

While not desirable, it takes a lot more to kill a rechargeable cell than
this.


Or will charging fix the problem?

No; it is likely to make matters worse, by causing further cells to fail.


** Ridiculous nonsense !!

The reverse voltage cells will recover normal polarity when charged as
usual and there is NO bad effect on the cells that have not reversed.

The Wood Duck is quacked.

Phil, he's measuring the TOTAL voltage as negative,



** WRONG - that is simply quite impossible.


so there are more reverse-charged cells than good ones.


** Not possible in the scenario as described.

The PC cuts out the battery load at a positive voltage.

The Wood Duck is more Quacked than I thought.


It's what he told us


** The OP's heading say "cells" .

The OP's text alone is ambiguous.

You failed to exclude the impossible.

That is a massive blunder.


If it's wrong, it's not my error.


** Believing impossible things is your error.

Your claims about cell failure are in error.


Quack, quack, quack ......





......... Phil


.

Relevant Pages

  • Re: Diodes for Li coin cell protection
    ... > allow an RTC to be powered by both a Li coin cell and the power rail. ... > Diodes are the right idea, but primary Li cells have a very low ... > tolerance for reverse current. ...
    (comp.arch.embedded)
  • Want to write function/macro for DNA reverse-complement
    ... I have a spreadsheet in which I need one cell to automatically get the ... reverse-complement of a DNA string that's in another cell. ... The reverse of the string is the characters read in ...
    (microsoft.public.excel.worksheet.functions)
  • Re: My NiMH cells reversed polarity! Oh no!
    ... No need for cell *failure* to occur for the polarity to go reverse during ... the discharge of a battery. ... impedance goes very high so it can easily take up a small reverse voltage. ... The PC cuts out the battery load at a positive voltage. ...
    (sci.electronics.design)
  • Re: reverse biased Ni-Cad cells
    ... A voltage reversed NiCd is typically due to a weaker cell ... burn out the reverse section. ... can continue until a new battery pack is obtained. ... failure - battery pack was permitted to discharge well beyond ...
    (sci.electronics.design)
  • Re: reverse biased Ni-Cad cells
    ... A voltage reversed NiCd is typically due to a weaker cell ... burn out the reverse section. ... can continue until a new battery pack is obtained. ... failure - battery pack was permitted to discharge well beyond ...
    (sci.electronics.components)
Quantcast