question

mryoshii avatar image
mryoshii asked

Max Mid-Point deviation on AGM

Hi i got two 230Ah AGM batterys. they are 3 months old and now i get a alarm that the mid-point is more than 2% when charging. How much is normal on AGMs?


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BMV Battery Monitor
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1 Answer
JohnC avatar image
JohnC answered ·

Hi @MrYoshii

I don't know what the 'rulez' are on this, but I wouldn't be happy at all seeing my own batts this far apart. That's like over half a volt at Absorb V level.

Are they together or far apart? Do they show differing temperatures, either by their location or because of current flow? Check the probe with a multimeter to confirm it's reading correctly.

Sometimes new batts need 'breaking in', but one would hope they break-in before they break-down. Is this 'old' or has it just come to light?

I'd be asking the supplier for warranty replacement, and in the meantime drop the Absorb charge setting to compensate for the high one being well over what you really want. The supplier may want you to persevere and wait for improvement, but if that never happens then hold them to the date you complained..



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