[RE-wrenches] Outback FXR: Battery voltage exceeds settings

[William Miller]

Friends:



I maintain a system with 16 AGM L-16 batteries.  Eight were installed in
September of 2021 and 8 were added in March of 2022.  This is 5 months
apart.  I have understood that when you install a string of batteries you
have one year in which to add another string before the first string ages
to the point it is contraindicated.  When I added the second 8 I put 4 new
batteries and 4 old batteries in each string.



About a third of the batteries are discovered to bulging on top.  I assume
this means the batteries are damaged.  I checked the FXR and Outback
Extreme Charge controller settings and all were set to absorb at 58.8, and
float at 55.2, as the manufacturer recommends.



I downloaded the charge controller log and got 129 days of data.  In that
log I see 68 days where the batteries exceeded 60 VDC. This is over half
the days.



I wonder this:



1.   Why did the voltage go up above 58.8 on so many days even though it
was set at 58.8. (I set the EQ voltage at 58.8 just in case, but EQ was
never engaged.)

2.   Did the excess voltage damage the batteries?

Any input is appreciated.



Sincerely,



William Miller



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985
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