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Growatt grossly inaccurate on Load reporting?

BajaDave

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May 29, 2022
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I have a Growatt 12000 SPF, Solar Assistant, and Victron BMV 712. I just installed the BMV712, and noticed a large discrepancy between the AC load in watts as reported by the LCD panel on the growatt (and also matched in Solar Assistant reports), and the load on the batteries as reported by the BMV712. Basically, the BMV712 was consistently saying about 400-500 watts more were being drawn out of the batteries than were showing on the Growatt panel.

I first thought that perhaps I was seeing a really heavy inverter load from the two fans, or some horrible conversion inefficiency, but I stuck a clamp meter on each leg of the AC Output of the inverter (5A x 120 on leg, and 1A x 120 on the other leg = 720 watts) , and it roughly matched what the BMV 712 was saying as far as consumption.

So my conclusion is that the Growatt is under reporting load watts by 400-500 watts. Has anyone else noted this reporting inaccuracy on the Growatt inverters? Turning on appliances does seem to show the approximately correct wattage increase (i.e. a 1500 watt hair dryer bumps up load watts by 1500), so perhaps there's a baseline adjustment factor that is just wrong? And one could manually add 450 watts to get an approximate load value from the inverter? Now that I have the Victron battery monitor, it won't matter so much in terms of battery management, but I would like to have more accurate info on what my house is consuming.
 
Sorry to bring up an old post but did you ever get to the bottom of this @BajaDave
Nope, still scratching my head. Here's an example of the last 6 days. For Oct 2, for example, my total load was 18.8 kw. But my solar production was 28.8kw. So I should have had a surplus of 10kw to put back into the battery. However, I ended up not even getting back to prior day SOC. Given that my battery has been below 80% for a week, the Solar PV numbers minus some losses for efficiency are probably a more accurate statement of actual load drawn by the house.
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Have you measured the amps drawn from the battery?
I know growatt equipment has a large standby draw, as well as a crappy conversion at very low loads.
Maybe it's both?
 
Continuing this thread in case anyone else has this issue. I notice very strange readings from my Growatt 3000TL all in one. The Growatt will show 95 watts being drawn from the battery, while my Victron smart shunt installed between the Growatt and the battery shows readings of 45w. I don’t know how the Growatt measures the current but it seems quite off target.
 
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