How is your system wired? It would help to post the schematic too.
When you say AC loads exaggerated - by how much? AC Loading will be measured by the Quatro, but low level loads are likely to be less accurately measured.
If the Battery BMS is talking to the GX device, then you should not need the shunt as a battery monitor.
I will grab a picture of the schematics provided by the producer of the motorhome - it’s a big install (for a motorhome!). When I say exaggerated you can refer to the screenshot I attached earlier: I’m consuming 353w from batteries, but the quattro see 515w of AC loads so it guess DC is generating (while it’s a load) 198w..
I don’t know exactly how much is really my DC load but would guess 100w? so AC readings is wrong by 250w…
working on the peak ac power of 8kW, that’s ~3% error. so not so much. Problem with digital measurements is that people expect them to be 100% accurate, where as in reality, there is always an analogue stage to these measurements, and an A/D converter buried in there. These lead to errors, especially at low levels.
ok with the battery monitor.
Error is measured as % of full capacity of the inverter. Even with no physical load, a Quatro will give some indication of load current due to circulation currents - usually capacitative in nature for light or no load.
regrettably, this always happens.
It would be nice to have higher resolution AC measurements in both Quatro’s and Multi’s, but that would inevitably lead to higher costs.
Power measurement is particularly prone to error as it is the product of two or 3 other measurements, each with their own inaccuracies. The 3rd measurement is phase angle (between voltage and current) if V and I are measures as rms, or just two if instantaneous values are used, and rms power subsequently calculated.
