question

dan avatar image
dan asked

Battery loosing charge

Hi all, I have a stand alone solar setup on my truck for the last 12mths, it is not used everyday, most of the time it's on standby.

Setup: 120w solar, 2 x 120 amp AGM exide batterys, 1x 75/15 victron mppt, 1x victron battery temp sence.

Ive noticed lately i have a large voltage drop overnight, I checked a few hours after sunset and it read 13.19v, the victron data screen minimum battery voltage next day levels are around 12.86v,

Exide battery data suggests absorption voltage 14.1 - 14.4v so I left the mppt on default.

Unit is not connected to a earth chassis.

I'm a bit concerned and don't know what's happening or is this normal.


battery charging
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1 Answer
Justin Cook avatar image
Justin Cook answered ·

AGM "resting" voltage is right around 12.8v... directly after charging, you'll read a higher voltage (between 13 and 14v) because the surface charge is higher, but once the charge is removed your battery voltage will settle toward its resting voltage, which is exactly what you're seeing. The good news is that your system is performing precisely as it should :)

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