question

1. When the Solar controller is connected to the LOAD side of shunt:

You are drawing 91w from the battery, drawing 85w from the mppt, and your load total is 176w.

91 + 85 + 176.

You should only have the shunt connected to the battery and everything else connected to the Shunt.
if you wire the MPPT directly to the battery, you will confusing the shunt and Cerbo and all your numbers will be off, including SOC.

DC Power is your load, not net. It is the total load, except inverter if you have one.
Battery Power is the power in and out of the battery.
MPPT is the solar power.

So as klim8skeptic said.
Battery + MPPT = DC Load, in scenario 1, all numbers displayed are correct.

In scenario 2.
You load is equal battery power.
The DC load is totally wrong as it is adding Battery Power and MPPT for 373W which is wrong since your load is actually only 284W.

Thank you. I guess I was reading it incorrectly. I just hooked it back up with the mppt negative on the load side of shunt (scenario 1). Based on what you're saying, here it looks like I'm using 134W total; the battery is providing 35w and the mppt is providing 99w.

I understand and that makes perfect sense, but I'm not fully convinced. Here's why, when I turn off all my 12v dc items (lights, TV, etc) I get a NEGATIVE DC power reading, which isn't possible?

This is why I it appears the DC power is "net", rather than total:

Here is a screenshot with solar running (and connected to load side of shunt) and showing a dc power use of 111W.

However as soon as I disconnect the solar, my DC power is 146w.

My dc load didn't increase at the same instant I disconnected solar.

Here is a video of me disconnecting solar. Watch the DC power go up as soon as I disconnect it.

This is so frustrating. Something is off and I cannot figure it out.

The DC load is a calculated value. The GX knows the power in/out of the battery accurately from the BMV 712, this has to be all loads / supplies to accurately monitor SOC. The system knows the power from the MPPT and can estimate the DC power in/out of the Multiplus. The GX then estimates the DC load as being what is not accounted for, including for example if you have charging from an engine alternator. Therefore, unless you have a separate shunt on your DC power, the DC power is an estimate, I think you are trying to read too much into it. Also, if properly wired up, the power draw of the GX will be under DC load. It also means that the DC load is where any inaccuracies in the other equipment measurements ends up.

The value in the DC Power tile is a calculation. It is what remains when all KNOWN DC sources and loads are factored out. Unfortunately, the values used in the calculation don't change at the same instant in time so the calculation can be off substantially for "a while". If loads or charging sources are changing, the DC Power number could be off for most of the time.

The fact that the DC Power number went negative means that the UNKNOWN sources exceeded the UNKNOWN loads, and/or the DC numbers were in a state of change.

A better way would be to introduce a shunt for all DC loads and charging sources and use that for the tile. That way the number would be an actual measurement rather than a calculation. Some work is bring done to allow shunts to monitor charging sources and loads but the calculations for the DC Power tile are not yet complete. It also means multiple SmartShunts would need to be added to the system increasing costs.

If the "DC Power" is just a calculation and not always accurate, how do I turn off the DC Power icon/tile?