Varta AGM Silver BMV 712 settings without solar

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gargi asked Sep 24, '23

Varta AGM Silver BMV 712 settings without solar

Hello,

I have two Varta SIlver AGM 95ah batteries in my van. What settings do you suggest for this batteries to get the measurements as precise as possible? Varta is sharing only dimensions of this batteries not the actual specifications. My van has 200amp alternator and I do not have a solar. I am charging only by drive. I am currently on 2 months roadtrip and my current settings are on the screenshot. What values shoul I put in? Because default values was making some strange jumps in my history.

Thank you for your help! :-)

BMV Battery Monitor AGM Battery

img-2788.png (188.4 KiB)

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pwfarnell answered · Sep 24, 2023 at 09:04 AM

The 13.6V for charged current is too low and you are probably seeing the SOC jump to 100% before the batteries are full. This needs to be 0.2V below the voltage your alternator charges at. If the batteries charge at 14.5V then set the charged voltage to 14.3V. The tail current sjould probably be 1% or possibly 1.5%, chevk what current you get down to when charged.

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Answer 1 · 2023-09-30T16:55:29Z

gargi answered · Sep 30, 2023 at 04:55 PM

Hello! Thank you for your answer. Yes, I can see strange jump to 100%. The smallest current I see after 5 hours of continious drive or more is 0.5A, I never saw less.

So if I will have it setup correctly than it should show 100% exactly when the current will be less or equal to 0.5 and the voltage will be over 14.1V (because alternator charge it with 14.3V).

Do I understanf it correctly that to have it this way I should just adjust charge efficiency factor. If 100% will be sooner than current is 0.5A then I should lower the charge efficiency factor. If 0.5A is sooner than 100% than I should increase charge eficiency factor. Right?

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Answer 2 · 2023-09-30T17:08:38Z

pwfarnell answered · Sep 30, 2023 at 05:08 PM

Your understanding is correct. I think your 0.5A setting might be too low and suggest you keep your setting of 0.5% for synchronisation (0.95A) because as the batteries degrade or at higher temperature the tail current will be higher so you need some margin.

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Answer 3 · 2023-10-02T17:44:33Z

gargi answered · Oct 02, 2023 at 05:44 PM

Thank you very much for your answers, you have enlighten my knowelage about batteries and charging. :-)

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