Battery Failure Mode

Thread Starter

GKP

Joined Aug 15, 2014
12
if the charger stayed in full charge mode snd could not reach float voltage levels, i would suspect a SHORTED cell in the battery. the high temp in in one cell further confirms the shorted out condition. being AGM type it is not possible to wash out the cell and remove the short.
So if I have this correct; either shorted or high resistance cell will both cause elevated temperature readings? (when on charger)
 

Kermit2

Joined Feb 5, 2010
4,162
a high resistance cell will heat up if the battery is shorted or heavily loaded, it will also show larger than normal voltage drop on heavy load.
a shorted cell will heat up when battery is under bulk charge, it will also keep battery from reaching float voltage levels/taper charge.
Since your problem occurs when charging, then most likely failure mode is shorted cell.
 

Thread Starter

GKP

Joined Aug 15, 2014
12
a high resistance cell will heat up if the battery is shorted or heavily loaded, it will also show larger than normal voltage drop on heavy load.
a shorted cell will heat up when battery is under bulk charge, it will also keep battery from reaching float voltage levels/taper charge.
Since your problem occurs when charging, then most likely failure mode is shorted cell.
OK . I would like to know once the charger is removed from 24 volt 2 battery bank with one shorted cell how is the output differ from a good battery bank when a load is applied?
 
Last edited:

Lestraveled

Joined May 19, 2014
1,946
So if I have this correct; either shorted or high resistance cell will both cause elevated temperature readings? (when on charger)
What occurs with a battery with a shorted cell is that the other cells will be pushed to a higher voltage which will cause them to heat up. The shorted cell will dissipate very little heat. In other words, it would be the same as putting a 10 volt battery on a 12 volt charger.
 

Kermit2

Joined Feb 5, 2010
4,162
a shorted cell is a non emf producing cell. you treat it like a piece of metallic conductor, which, in this case, is metallic lead.
A 12 volt battery has 6 cells which generate about 2.1 volts each. imagine those cells as if each was an individual battery all connected in series with wires. noe imagine you remove a cell and replace it with wire. now you have 5 cells in series giving a total of 10.5 volts. charging it at a voltage normally used on 12 v batteries will cause to much current to flow and otherwise muck up the battery.
a fully charged 24 volt set up will measure 25.2 to 25.4 volts. if charged recently the voltage could be higher but will not be lower unless there is a problem.
 

Thread Starter

GKP

Joined Aug 15, 2014
12
a shorted cell is a non emf producing cell. you treat it like a piece of metallic conductor, which, in this case, is metallic lead.
A 12 volt battery has 6 cells which generate about 2.1 volts each. imagine those cells as if each was an individual battery all connected in series with wires. noe imagine you remove a cell and replace it with wire. now you have 5 cells in series giving a total of 10.5 volts. charging it at a voltage normally used on 12 v batteries will cause to much current to flow and otherwise muck up the battery.
a fully charged 24 volt set up will measure 25.2 to 25.4 volts. if charged recently the voltage could be higher but will not be lower unless there is a problem.
 
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