question

davidq avatar image
davidq asked

BMV Charged Voltage Parameter

Hello,

I have two series BAT412201084 AGM 12V batteries with a solar system. Its data sheet lists the Absorption Voltage as 14.2v-14.6v.

Questions:

Q1 Should the BMS charged voltage parameter be set using the upper or lower of these values (i.e. 28.4 or 29.2v)?

Q2 Should the charged voltage be set 0.3v or 0.6v below Absorption Voltage (i.e. is the 0.3V in the case of a solar system per battery?).

The possible setting are:

CV = (2 x 14.2) - 0.3 = 28.1v

CV = (2 x 14.6) - 0.3 = 28.9v

CV = (2 x 14.2) - 0.6 = 27.8v

CV = (2 x 14.6) - 0.6 = 28.6v


Thank you.

BMS
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1 Answer
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @DavidQ

BMS <-- do you mean BMV?


if you mean BMV (battery monitor), these settings depend on your charger's settings. 0,3V below absorption sounds about right, when charging with solar, it is easy to get 'false syncs' when solar output is low for a while, therefore I'd set the 'charge detection time' quite long (like 10 minutes) and the charge current reasonably high (depending on battery capacity, charge capacity, etc)


If you describe your system you will get more useful answers from experienced users, the way you asked the question it's all guessing.

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davidq avatar image davidq commented ·

Yes, I mean BMV. Sorry, perhaps that's why my question was not addressed.

Current BMV settings are:

Battery AmpHour 220 aH
Charged Voltage 28.9 V
Tail Current 4 %
Charge Detection Time 3 minutes
Peukert 1.25


I watched the Victron video on setting up the BMV and it said, when using solar, to set the BMV VC paremeter at 0.3V less absorption voltage.

Q1 The Victron Spec gives a range of 14.2v to 14.6v for absorption voltage. Should I use lower, upper or pick a mid value? The range is 0.4V between upper and lower and is comparable to the 0.3v reduction for solar.

Q2 Is the 0.3V for solar per battery or per set of batteries. I have two batteries in series. That is, should I reduce by 0.3V or 0.6V?

The combinations of the above are expressed in my question above.

My system:

  • 24V 220AH system comprising two series Victron Batteries BAT412201084
  • Victron Pheonix MultiPlus 24/3000/70
  • Third party PWM solar charger from 560W panels

Thanks Daniël for your help.

David








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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ davidq commented ·

Hi @DavidQ

These settings depend on the settings of your chargers, if you want a good answer you'll have to tell us how these are setup.

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davidq avatar image davidq commented ·

Hi Daniel,

I will try to tell you my charger settings.

I have three chargers:solar PWM, Multiplus and alternator.

Solar PWM

Multiplus

All DIP switches set to off (I presume it has been programmed by installer)

Alternator

Via Cyrix I

David


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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ davidq commented ·

Then please ask your installer how it is programmed.


And I'd let my installer also make sure the BMV is correctly programmed, that's his / her job...

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