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mkswanson avatar image
mkswanson asked

SOC 100%…But it’s not

I recently replaced the 12V system in my RV from the factory-installed Jabroni system with blue gear.

4x 200 aH LiTime LiFePO4 batteries > Power In > Smart Shunt > Lynx Distributor

Distributor has the following connected: DC loads, generator, 2x MPPT, MultiPlus II

MultiPlus is connected to shore power AC in and AC loads in the RV.

Cerbo GX is also connected.

All are Victron except the batteries and the solar panels.

The SOC says the batteries are showing ~13.8V and 100%. When I disconnect shore power, none of the 12V system works. It is all very dead.

I think the state of charge is lying. Which would explain why nothing is charging the battery bank.

Any advice on where to start troubleshooting?

Multiplus-IIMPPT SmartSolarlynx shuntlynx distributor
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2 Answers
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kevgermany answered ·

Default on the smart shunt is to set SOC to 100%. As you've just rebuilt the system, it's to be expected.

However incorrect wiring of the shunt is a common problem and we see many posts here. Check the cabling. There should be only the shunt battery terminal connected to the battery negative. Any other connections, including earth/ground should be on the side of the shunt. No exceptions.

Shunt settings need to be reconfigured for the new batteries.

Do you have a data connection from the batteries/BMS to the GX? If so check where SOC is coming from, probably the shunt. Depending on the BMS, it may control charging, in which case you'll see external control in the Cerbo screen.

Batteries may have been shut down by the BMS due to low actual SOC. If that's the case, you'll need an external charger to bring the charge level up to the point where the BMS allows charging.

Let us know how you get on.

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mkswanson avatar image mkswanson commented ·

Thanks for the suggestions.

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The only connections to the batteries are the connections to the Power In on the left side of the shunt. The one exception is the power to the Cerbo, which I have direct to one of the batteries. Should that be somewhere else?

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This is the area I think I have the problem. I have a support ticket into the battery manufacturer, but am waiting on an answer. I used what I could find online for a similar battery, but it may not be accurate. Or I'm not smart enough. :)

I have 4 of these: https://www.litime.com/products/litime-12v-200ah-plus-lifepo4-lithium-battery-with-200a-bms-max-200a-current-2560w-load-power

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There is no connection between the batteries and the GX.

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I am in the process of charging each battery to 100% individually currently. That will hopefully be done tonight.

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kevgermany avatar image
kevgermany answered ·

Cerbo should not be connected to the battery. But it draws so little current you will find it makes little difference if there's a regular charge..

Please post a shot of the shunt battery settings, could be something there. Battery maker charge instructions as well.

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