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henrytoles avatar image
henrytoles asked

Cerbo-s gx to smartshunt as energy meter troubleshoot

I built a 48V battery of 24x 40ah LTO cells. Currently this smart shunt is running perfectly as a battery monitor. I installed a JKBMS, and I learned I can install the driver so that it can communicate with the Cerbo-s gx as a battery monitor. I want to turn the Smartshunt to an energy meter, ‘dc system’, So when I use large loads during the day when I have full sun, my Cerbo will allow extra power to come in to offset the 1500watt load, but still restrict charging to the batteries to 8Amps.

I’ve tried changing the settings in my cerbo and smart shunt as instructed in the manuals and online troubleshooting guide. To no avail. The shunt as ‘energy meter’ ‘dc system’ does not show in the Cerbo.

When I switch the shunt to “energy meter’, the battery values are inverted, which the troubleshooter indicates that shunt MUST be installed in reverse, but it cannot be because it works perfectly in “battery monitor “ mode.

Battery main neg -> jkbms -> smartshunt. -> main neg busbar -> all loads and chargers

I have the temp sensor on the shunt, and the ve direct cable to the Cerbo.

MPPT RS 450/100 & Multiplus II 48/5000/70 & Orion 48/24-16amp

Something wrong, I can’t insert pictures here…


SmartShuntEnergy Metercerbo s
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2 Answers
delf67 avatar image
delf67 answered ·

The smartshunt is just a "flow meter" that measures the current flowing in either direction. Which direction it considers to have a positive or negative value will depend on the configuration, it is not fixed.

For example a current flowing through it in one direction would be displayed as negative if it was defined as "energy meter" "generic load" and positive if it was defined as "energy meter" "generic source".

Just turn it around and it will display correctly.

Yes, it would then display inverted values if you changed the config to battery monitor, but you're not using it as a battery monitor, so It doesn't matter.

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jetlag avatar image
jetlag answered ·

The smart shunt has a clear marking printed on where the battery negative should be and where the "system" should be connected. Then it will work fine.

Configure it as a energy meter and it will be the battery's master for the whole system.

If you want to reduce current into the battery, you can use the JK serial-battery driver for VenusOS. That can be configured to set a CCL (charge current limit). You can even set a CCL in depends to cell voltage or cell temperature. This works fine in my system with LFP.

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