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mi-breds avatar image
mi-breds asked

Batteries

I have two Victron AGM 110ah batteries supplying power an off grid cabin. I have been advised to set the inverter to shut off at 11v because it seems that batteries were not holding the charge. Within 5 days of being 100% charged the BMV was showing 50% with a draw of 10w for surveillance equipment plus the inverter. Are these settings correct or are the batteries past their best after 12 months (mostly kept in storage during the build) or is the wiring faulty? How do I sort this out? Appreciate advice. Thanks

battery charging
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2 Answers
kai avatar image
kai answered ·

Some back of envelope numbers:

Load of approx 12W (10W surv. equip + say 2W for inverter quiescent + inefficiencies)

This means 1A constant draw. 24 hours / day * 5 days = 120AH

You have 2x 110AH batteries. 50% sounds pretty much spot on...?


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tony-c avatar image
tony-c answered ·

I believe that 11 Volt is too low. If you look at the table below getting into the red does permanent damage to AGM batteries



1597659935739.png (11.7 KiB)
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