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tstr7119 asked

Battery settings in MPPT and Multiplus 2 for NMC battery

Hi all

I have a off grid system consisting of repurposed Nissan leaf batteries(NMC) in 14s2p giving me approximately 280Ah @ nominal voltage 53,2 with min/max cut-off's at47,6V and 57,4V. coupled to a 150/60 Solar MPPT and dual Multiplus2 48/5000 in parallel.

When battery has reached float it seems the loads are taken from the battery and not from the solar MPPT even though its daytime. I am not really concerned to keep battery at 100% since its at 4,1V/Cell and should not affect longevity to keep it there during daytime hours.

Is there a setting somewhere to change this in order to keep batteries at 100% until dawn?

vrm page for system

https://vrm.victronenergy.com/installation/99094/share/8fb0c93e

MPPT ControllersMultiplus-IILithium Battery
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3 Answers
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tstr7119 answered ·

Noone knows if its possible to have the Multiplus utilise solar panel and not battery as 1st priority?

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tstr7119 avatar image
tstr7119 answered ·

Will a Cerbro GX solve this for me?

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klim8skeptic answered ·

7 July your battery went into float at 13:15, and until 18:00 there seems to be no major discharging happening.

float-at-1315.png



float-at-1315.png (40.2 KiB)
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tstr7119 avatar image tstr7119 commented ·

You are correct, there is no major discharging, but there is a steady slow drain. Float should happen at 57.4V Which is corrsponding to a cell voltage of 4.1V. I would like to be able to keep voltage there until sunset, currently around 22:30.


Writing this now I realise that on sunny days battery is being held constant at 56,7V and the MPPT is then showing constant 57V. So maybe I can just compensate for the 0,3V drop between MPPT and battery by setting Absorbtion voltage to 57,7 and float voltage to 57,6 giving voltage at battery 57,4 Absorbtion and 57,3 Float ?


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