"Jeff Peterson" <jeffreyb.peterson@gmail.com> wrote:
"""
Marv,

any 12v lead acid battery is composed of cells in series.
by stacking 2 ea 12v batteries to make 24 v batttery you have
doubled the number of cells in series, and they happen to be in
two seperate plastic tanks.
"""
Yes, I understand that, we will take that as a given.

"""
In both cases a short in one cell causes the others to be overcharged.
If that happens you are giong to replace all cells.
"""
If a single cell happens to short does the overcharge condition on the remaining cells cause ireeparable damage instantaneously, or is their damage caused progressively by allowing the overcharge condition to continue? At what point do the good cells go from good to bad?

"""
yes you could monitor each 12v battery seperately, but if thats a good
idea why not monitor each cell?
"""
I don't know if it's a good idea, but if it is we can monitor the 12v "stacks" simply because their packaging allows us to do so. Modern day batteries aren't like the old fashioned ones that had the cell interconnections mounted to and accessible from the exterior of the battery case.... we can only get at the 12v ends of the cell stacks.

"""
or, just call the whole 24v stack a "battery"
and replace the whole thing when it acts up or fails a load test.
KIS.
"""
In reality, the whole 24v stack _is_ a battery, it just so happens to be constructed of two managable 12v pieces. Perhaps replacing only 1/2 of the battery isn't a good idea, but if only 1/2 of it is bad is there a good reason to replace the other half? And I agree in the KIS principle, I just don't like the idea of throwing away a $100 battery because its twin failed. You know that old saying about the baby and the bath water?.......

"""
I use odessy in the motorcycle...three years and still ticking.
"""
I got almost twice that out of the one in my bike here in FL, and that's saying something. Typical lead acid batteries don't fare well much beyond 3 years down here thanks to the heat.

Anyway, this is all just food for thought. It's why I brought up the issue in the first place.

<marv>