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pieterpost asked

Set-up BMV-712 with Easysolar 12/1600, 175W-12V Mono panel and 2x hoppecke sun power VR M 12 135

I'm getting lost trying to set up the system in the title. As far as I can tell the easysolar and mppt in it are okay on their factory default setting for AGM batteries, seeing as everything works. However, the BMV-712 says SOC 100% pretty much at all times. The only way I sort of monitor the battery health now is by checking the voltage doesn't drop under 12v. I've been reading the BMV manual but whenever it mentions checking the battery settings I'm not sure what's what because the manual with the batteries is crazy complicated. 

Can anyone point me in the right direction of all the thing I have to manually set-up? I'd be ever so grateful!
BMV Battery MonitorEasySolar All-in-One
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klim8skeptic avatar image klim8skeptic ♦ commented ·
Perhaps post a link to the battery manual?
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klim8skeptic answered ·

the manual with the batteries is crazy complicated

The battery manual is very thorough, but yields the useful info. Your batteries details are at chapter 7.

Absorption voltage of 2.4v/cell. Float voltage of 2.25v/cell. <<both at a temp of 20c. Temp compensation figure of -3mv/C/cell

Victron use a battery temp of 25c for temp/voltage compensation. (need to offset battery voltages by 5c x -3mV. (-15mV). Absorp = 2.385v/cell, Float = 2.235v/cell, both at 25c.

The Victron chargers can be programed for an Absorption voltage of 14.3v, a Float voltage of 13.4v, and a temp compensation figure of -18mV/c.

I would choose adaptive absorption in place over fixed absorption time.

I would disable equalization completely.

You have a problem with your BMV and SOC?

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pieterpost answered ·

Thank you for this!

Earlier I'd changed the charged voltages on the BMV to 14,2 (was 13,2) and the tail current to 2% (was 4%), that seemed the help with the always 100% SOC read-out.

Per your advice I've now changed the Absoption voltage, Float voltage and temp compensation (to minus 18, correct?) on the MPPT via bluetooth. The absoption setting only appears when I enable expert mode but when I do it is already set to adaptive to I've disabled the expert mode again (so I don't mess up any other settings unbeknown to me).

Can I set this for the easysolar charger as well without buying addional externals? I think 99% of charging will be done by solar and/or car alternator so I'm not super fussed if the float voltage is 0,4V too high there if I'm honest.

And lastly, my last question made me think of another question, is it going to be a problem that a 14,4V current from the alternator is going to flow regularly?

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klim8skeptic avatar image klim8skeptic ♦ commented ·

temp compensation (to minus 18, correct?)

Yes, a negative figure, thanks.

Can I set this for the easysolar charger as well without buying addional externals? I think 99% of charging will be done by solar and/or car alternator so I'm not super fussed if the float voltage is 0,4V too high there if I'm honest.

If you are the type that sneaks into town every other week to have a long hot shower, do some shopping and top up the batteries overnight, that's ok, you know the batt specs (and risks).

If you are going to spend days parked and connected to mains power, fork out for the mk3 cable.

And lastly, my last question made me think of another question, is it going to be a problem that a 14,4V current from the alternator is going to flow regularly?

This question is actually easier to answer.

Your batteries are rated to be held at the absorption voltage for 3 hours.. How often do you intend to drive for longer than 3+ hours a day??

Myself, I spent 3 weeks wages on a battery, and another 3 weeks wages on stuff to monitor/protect/program batts.

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