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alank avatar image
alank asked

Victron 100/50 smart controller charging a new LiFePo4 battery set with inbuilt BMS

I have a Victron 100/50 Smart solar controller driven by 840W of solar panels with a 24V house battery LiFePo4 that has inbuilt battery management. I cannot get the system to charge to maximum power or anything over 250W. Is there a way to set to Victron to simply supply a set voltage and deliver the max current without regulation etc?

MPPT Controllers
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klim8skeptic avatar image klim8skeptic ♦ commented ·
What battery?

The mppt will charge at the max (available) current until the absorption voltage is achieved. Then the mppt will reduce the current to hold the battery voltage at the absorp value.


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alank avatar image alank klim8skeptic ♦ commented ·

The batteries used are the Fusion LFP24-150P (bank of 4 in parallel.

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alank avatar image alank klim8skeptic ♦ commented ·
I get the MPPT charging at max available until absorb V met. It’s not working. I get wild fluctuations in power levels and don’t much over 250W. It can go from 250W to 45W within 60 sec Without any external changes (cloud etc).
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klim8skeptic avatar image klim8skeptic ♦ alank commented ·
Could be batt BMS tripping from cell overvoltage. Can you see cell voltages? What absorp voltage?


Could also be array voltage being to close to the battery voltage. What are the specs of the panels?


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alank avatar image alank klim8skeptic ♦ commented ·
The panels are 19-21v each, three in series. Voltage indicated varies from 45-65
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alank avatar image alank klim8skeptic ♦ commented ·
The battery BMS is working fine with the main charger wired in parallel. Dont think the BMS is tripping out due to over voltage
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klim8skeptic avatar image klim8skeptic ♦ alank commented ·
@AlanK interesting problem.

Post a screenshot of the mppt's "detailed" history so ppl can see what the mppt has been recording.

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Mike Dorsett avatar image
Mike Dorsett answered ·

You do need a control link from the BMS to the Charger, so the BMS can regulate the charge current at the top 20% of charging. Without this you won't get proper equalisation, and risk the BMS disconnecting on cell over-voltage as mentioned above. Problem with the built in BMS on the Fusion batteries is there is NO external communications - from what I see of the data sheets.

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alank avatar image
alank answered ·

Hi sedged, I could not find such a setting in the VictronConnect App. Any tips on where to locate it?

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klim8skeptic avatar image klim8skeptic ♦ commented ·
@AlanK sedged seems to be an AI bot. As such has been sent to the naughty corner.
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alank avatar image alank klim8skeptic ♦ commented ·

A screen shot of some history. I a thinking the MPPT control is competing with the battery charge control. Is there a way to turn off the MPPT? The other alternative is that I play with the Float and Absorption voltage settings.img-7021.png

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img-7021.png (457.9 KiB)
klim8skeptic avatar image klim8skeptic ♦ alank commented ·
@AlanK What was the battery voltage during that period?

Any loads or other chargers in use?

What was the mppt state? Bulk/absorp/float?

Post a screenshot of the mppt's battery settings.


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alank avatar image alank klim8skeptic ♦ commented ·

Battery voltage is/was 27.5. The main AC mains charger is in float mode. There are loads that vary.img-7025.png

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img-7025.png (245.5 KiB)
klim8skeptic avatar image klim8skeptic ♦ alank commented ·

@AlanK there would appear to be some interaction between the mppt and mains charger.

On a nice sunny day switch of the mains charger and monitor how the mppt performs.

You could probably reduce the float voltage to 27.6v .

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