question

bbuster avatar image
bbuster asked

Configuring LiFePO4 with MultiPlus & Smart shunt

I have bought 2 LiFePO4 batteries (300Ah each with 200A BMS). This is connected to a Cerbo GX (Raspberry Pi).

From the batteries GND terminal, i go to the Smart Shunt 500A, and from there i go to the MultiPlus Compact 12 | 2000 | 80 - 30


All of this is installed in a motorhome which is now connected to the grid. I tried to disconnect the grid and suddenly everything turned off. I connected the motorhome to the grid again and now the batteries are charging.

Is this normal, should i wait till the batteries are 100% full before checking this again?


Also i connected via the MultiPlus and set the charger to LiFePO4 (used VEConfig).

What i don't know how to setup is the protections (over voltage, under voltage etc). How do i do that?

This is what is have setup:

tempimagesthdas.gif


These are the settings from the batteries:
65272-img-1662.jpg


I also did setup the Smart Shunt (like in the victron energy video's) but the state of charge is calculated automatically. I have a voltage / state of charge table from the batteries but i assume i cannot set this up?


There are my Smart Shunt settings

img-1707.png


img-1706.png

MultiPlus Quattro Inverter ChargerLithium BatterySmartShuntBattery Protectlifepo
tempimagesthdas.gif (9.9 MiB)
65272-img-1662.jpg (69.5 KiB)
img-1707.png (188.5 KiB)
img-1706.png (164.8 KiB)
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3 Answers
Alexandra avatar image
Alexandra answered ·

@bbuster

You can't really set overvoltage protection. You can however set an alarm on the VRM for the overvoltage so you will know if it is happening.

The other option is in DVCC, but should be unnecessary, is set the max charge voltage you find the system is overshooting the target. But if it is then the battery is possibly not coping with the charge amps (Due to slow balancing) so it is best then to tune that down, also in DVCC.

The inverter should only charge to the bulk voltage set. What you do need to do though is check it is reading correctly with a digital multimeter. So check what the inverter says it read against what voltage is actually there. This is a normal set up comission step anyway.

You can however in the inverter tab set the low DC cut off (similar to under voltage protection) set it a bit higher than the cut off though maybe at the restart value. This will allow for cell imbalances and prevent a the BMS having to protect the system.

Ideally you never want the battery to switch off, the inverter should do that first.


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bbuster avatar image
bbuster answered ·

Thank you, i have set it up like this now, is that okay?

tempimager0dpv9.gif



I have tested a bit today and i notices the MultiPlus has restarted a few times (without knowing why). When i turn on the fridge on 12V i see the wattage being drawn is about 230 / 250.

When i turned off the fridge, all power turned off (I think the inverter restarted).

I was at another time measuring something in the garage (where the MultiPlus is) and i noticed it turned on (so probably turned off a few seconds before).

Could this be a wrong setting? Apart from installing the shunt with LiFePO4 batteries, nothing has changed


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bbuster avatar image
bbuster answered ·

No one? How can i see what can cause this problem. Is there a reboot log or something?

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