Quattro Amp * Volt calculation is off

Q&A and troubleshooting
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1

afbeelding
afbeelding838Ă—740 42.1 KB

this is structural - in the screenshot above (bottom section) you see that 103 * 26.6 = 3175. The graph above (measured by shunt) reports the correct (imho) wattage used: 102 * 26.6 ~ 2719.

What does the Quattro wattage as reported mean here?

2

I’d think the watts are on the ac input side

3

nope, doesn’t look like it.

afbeelding
afbeelding858Ă—1428 66.3 KB

4

How much ac-out do you have on the quattro ?

5

this is the full picture. As you see the numbers also don’t add up but so far i have been blaming losses for this.
In: 3503+153 = 3656 W
Out: 334+2810+98 = 3242 W
DC power is calculated (no shunt), but the main user there is measured with shunt Trojan below with 16W usage. Can’t imagine there’s more than 10W for other users.
So all-in-all the following questions:

  • how is DC power calculated - it’s not even the actual missing watts
  • how is Quattro reported wattage calculated
  • are the missing 400W all heat losses and in line with expected efficiencies?

afbeelding
afbeelding1722Ă—1556 233 KB

6

The battery monitor section for the inverter is reporting the AC current going towards charging

3503W - 334W = 3169W, the display states 3170W, I will take that as the same within rounding error.

The battery is being charged with 2810W, 153W is coming in from solar, 98W is apportioned to DC loads so the inverter is supplying 2755W. This is from 3170W inpt so this suggests an efficiency of 86.9% which is reasonable. The trouble with adding and subtracting power is that it does not account for voltage loss between the inverter and MPPT and the batteries which loses Watts, the calc really needs doing in Amps.

Therefore, everything fits.

The DC box is calculated if you do not have a shunt, the system knows the battery Amps, the MPPT Amps and has a figure for the charging Amps from the inverter (which may or may not have the same accuracy as the battery shunt). The system then calculates the DC loads as the difference of the 3 known currents. See the FAQ.

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