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manta avatar image
manta asked

Battery charging when inverting

I have the multiplus 2 installed with Cerbo gx and a smartshunt. Strange behaviour when inverting, the smartshunt is measuring power going into the lifepo4 battery when in inverter mode? It is connected the right way. Battery BMS is incompatible with Victron soni use the smartshunt to determine SOC. pxl-20230731-093835038.jpgpxl-20230731-093823131.jpgImage CaptionLAST IMAGE SHOWS THE ISSUE. Any suggestions?


SmartShunt
pxl-20230731-093835038.jpg (3.5 MiB)
pxl-20230731-093823131.jpg (3.8 MiB)
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Alexandra avatar image
Alexandra answered ·

@Manta

A negative on the shunt when in means consumption.

So it is correct.

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manta avatar image
manta answered ·

Okay, but why charging 32watt when inverting... there is nothing else (solar ect..) attached.

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Alexandra avatar image Alexandra ♦ commented ·

I missed the words under the figure - my apologies.

Is the Shunt set as the System battery monitor or as a DC meter?

Are all the loads on the load/charger side? (only the battery must be connected to the battery side) - this is usually what gets mixed up in the install.

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manta avatar image manta Alexandra ♦ commented ·
In the Cerbo the shunt is used to display the battery as the battery monitor. but i tink you are referring to setting in the smartshunt, ?? will check that. All the loads are after the shunt (exept the BMS)
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Kevin Windrem avatar image
Kevin Windrem answered ·

The tile with -32 watts is the DC-System tile, not the battery. It show a CALCULATED value when all known powers are removed. Usually, this any DC Loads connected to the battery but could also be charging sources.

The ACCU (battery) tile shows 16 watts, but that is a value without sign. That is, both charging and discharging would show a positive value. The text above the power indicates the direction BUT there is a "idle" zone around 0 watts. For values of 30 watts or less (charging or discharging) the absolute value number can be very confusing. The clue is that the current is always displayed with the appropriate sign. In this case -0.6 amps is -15.9 watts (a discharge).

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manta avatar image manta commented ·
Yes, very confusing, underline "naar accu" means "to battery" and "van accu" means "from battery" it,s confusing. But as you said the amps are correct. I think the value should be right on the Smartshunt. I am going to check the shunt settings if it's set at DC load or Battery monitor. That would explain the issue. Thanks for explaining.
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