[MRCA] D Cells in Parallel

[damichael at verizon.net]

How does this happen with the power switch off? There should be no current flow to cause reverse charging.
Old R/C systems used to put a diode across each cell to prevent reverse charging if the NiCad pack discharged unevenly. And the diode would keep the R/C rx running on reduced voltage in till all cells went dead.
73, Mike W3TS
------ Original message------From: B. SmithDate: Mon, Apr 23, 2018 13:30To: mrca at mailman.qth.net;Cc: Subject:[MRCA] D Cells in Parallel
         Its military rally season and just a word of warning about    using D cells in parallel. Several of us have experienced "D Cell    Runaway" when using two D cells wired in  parallel.  Evidently one    cell charges the other and the battery chemistry changes resulting    in a very low resistance of one battery resulting in high current    drain of one of the batteries and then the other one goes South. 
          Does this happen every time you use them in parallel?    Ans.    No.    It is random. As a possible preventive measure when using    cells in parallel always use fresh batteries and from the same    package and date code. Also test the batteries under load to make    sure that they are equal. Do not mix different brands of D cells. Do    not store the batteries in a hot environment prior to use such as    the rear of your vehicle.        
         But these new  "Alkaline-Manganese Dioxide" batteries have    plenty of capacity and a single cell can easily power the typical    1.5 volt filament circuits found in most of our older military    radios. So why bother using two batteries in parallel?
    
           When using the FT-501 holder for the BC-611 - - - I would    modify the fixture to  just utilize  1 D cell. 
    
          This runaway phenomenon usually  occurs with the radio  power    switch OFF!
    
    WARNING: DO NOT STORE any radios or battery packs with D cells in    parallel      -      -     - REMOVE the batteries.
    Z
    
    
    
    
    
    
    set on or off
    BC611 battery adpataer
    do not store
    
    
    duracell
    
  
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