deep cycle battery won't fully charge

Thread Starter

LAOADAM

Joined Nov 21, 2018
273
Measured the cell voltage, got 5 X ~2.1 V, but the one near the negative terminal has 0.04 V only, is this mean that cell is internal short ? any way to repair it?
 

AlbertHall

Joined Jun 4, 2014
10,230
What can happen in a liquid electrolyte Pb cell is that some of the plate material detaches from the plate and makes a heap at the bottom of the cell. When the heap gets high enough it can short the cell.
 

mvas

Joined Jun 19, 2017
537
Whether the lead acid battery is ...
a) flooded
b) agm
c) gel cell
dendrites can form between the plates and cause a short.
Each battery type has its own probability of this happening.
 

Ylli

Joined Nov 13, 2015
976
Whether the lead acid battery is ...
a) flooded
b) agm
c) gel cell
dendrites can form between the plates and cause a short.
Each battery type has its own probability of this happening.
Yup. Take a big cap, charge it up to more than the battery voltage, and dump it across the battery. That will *sometimes* clear the short for a while. But those shorts usually come back.
 

Thread Starter

LAOADAM

Joined Nov 21, 2018
273
Whether the lead acid battery is ...
a) flooded
b) agm
c) gel cell
dendrites can form between the plates and cause a short.
Each battery type has its own probability of this happening.
Thanks.

One of my GEL battery can be charged to 11 V, but can't hold, dropped to 7 V just a night. What can be?
 

AlbertHall

Joined Jun 4, 2014
10,230
Is it supposed to be a 12V battery?
In which case the fully charged voltage should be over 14V.
My vote is you need to buy a new one.
 
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