Different Brand Batteries in Parallel
I have two M27MF Delco 12v no-maintenance deep cycle batteries in parallel. I have used them this way for many years in our 16’ fishing boat mainly to crank the motor and run the trolling motor. The...
Forum Discussion
RJsfishin wrote:
Capacity make no difference whatsoever ! A group 22 will run perfectly w/ a group 31, or even an 8-d.
Brand makes no difference,....as if a 12v system knows what brand a battery is !!
Age in itself doesn't make any difference either, only that age usually coincides w/ voltage.
As Ivylog said, its all in the voltage. The closer the voltage is between paralleled batteries, the better. But even then, only to a point.
The problem is that the internal impedance of different battery types varies considerably as does the internal impedance of the same battery types but of different ages.
The batteries varied internal impedance does not allow for equal load sharing nor does it allow for equal charging levels and can therefore cause damage when high currents flow.
Plus, the batteries will have circulating currents between them which wastes energy due to losses within the internal impedance (extra heat and boiling).
I would not mix battery types or batteries with significantly different ages.
