[Top] [All Lists]

Cold cranking

To: Will Zehring <>
Subject: Cold cranking
From: Len Bugel <>
Date: Wed, 31 Jan 1996 11:16:12 +0000
Will asked about using two 12V batteries in parallel instead of two 6V  
batteries in series. You do indeed add the current in the parallel 
configuration, while in the series config the voltage adds. It may seem 
like therefore the 12V parallel config would increase your cranking 
ability. HOWEVER - in reality if the batteries in question are about the 
same physical size, the 12V batteries will individually have much less 
current capability than the 6V. All lead-acid batteries are  made up of 
individual cells of 2V each, three cells per 6V battery and six cells per 
12V battery. If the batteries are  the same physical  size, the cells in 
the 12V battery must be only half the size as the ones in the 6V battery, 
and the current they can supply is proportional to the total area of the  
plates in the cell.
        Automotive batteries generally  have a 'Cold cranking amps' 
rating. If the 12V batteries each have more  than half the  cold cranking 
amps as the 6V batteries, then the 12V parallel system wins. If not, 
stick with the 6V.

        Len Bugel '50  TD

<Prev in Thread] Current Thread [Next in Thread>
  • Cold cranking, Len Bugel <=