Battery. Why is it so?
Submitted: Wednesday, Aug 03, 2016 at 12:52
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henpecked
My van has 2 X 6 volt batteries in series. The SOC is showing 100% & voltage 12.7.
I have just disconnected & removed the batteries in order to
check water levels and hydrometer
test. 5 cells in the green & 1 on border of green/white.
My question is: Why is it that when I re-installed the batteries the SOC has dropped to 65%?
The same problem occured when I last checked the batteries and it took several days, using both the solar & charger, to restore SOC to 100%.
Cheers
Ted
Reply By: The Bantam - Thursday, Aug 04, 2016 at 18:52
Thursday, Aug 04, 2016 at 18:52
First and above all ... adding water to your batteries WILL effect the state of charge.
Lead Acid batteries are a water / acid reaction .... adding water will dilute the acid and effect the state of charge.
This is why when doing battery maintenance you do you observations and measurements before you top them up, THEN you put them back on charge till they are fully charged.
Second remember reading voltage ( which is what your battery managment system does) is not a bang to rights measure of state of charge and may be effected by errors.
Third ..... every cell in a battery is an individual ...... they will all have differences ....... as batteries are charged and discharged normally the differences between these cells my widen.
This is why it is wise to equalise batteries from time to time ...... basicly you give em a good flogging.
Your batteries may be on the way out ..... remember the basic life span of a Lead acid battery is 2 years in service ........ by some minor chemical trickery from the manufacturers the practical service life can be extended to 5 to 7 years ...... if treated very
well.
If ya batteries are in the 3 to 5 year age ...... yeh you getting bonus life and should be thinking about replacement sometime soon.
It is very much worth running a couple of equalising and resting cycles on your batteries ...... looking at your hydrometer readings ....... this my bring you some more life out of your batteries ...... or it may show the suspect cells to be on their way out.
Full points for looking at your batteries in the first place.
cheers
AnswerID:
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