Yesterday i did the shutdown procedure for the first time on my 3phase Multiplus 2 systeem and disconnected the batteries, reinstalled it and restarted the system.
Today i noticed that the DC Watts provided by the multiplus not match VxA anymore (-8983W | 51.76V | -191A). And it does not match the Watts provided by the smartshunt anymore.
I’ve set the maximum inverter power in ESS on 9000W for a long time and in my opinion it always handles is very well, but now the Amps pulled were higher than normal and i noticed the difference.
What should i do? What could be causing this problem?
measured Watts will not match the VA on the system, this is usually due to the power factor of the load not being 1.0 generally this is not a problem unless the ratio of W/VA is less than 0.8
Correct, but they are asking about the DC power specifically. In the screenshot theres 8983W on DC, but 51,76V times 191A is 9886W, so 903W are missing on the DC side
Inverter efficiency. add on to that, measurement errors and zero power errors. Power in the DC line does not actually come from a multiplication of the dc volts and amps, but seems to be measured as the effective output power of the dc/ac inverter. This is then split between the feed in (another set of measurements from CT’s) and the load side (another set of measurements).
Oké, could be me, but I’ve never noticed this much of a difference between the multiplus and the smartshunt.
Problem is i’ve set the maximum inverter power of 9000W because the Amps on the DC side stays around 175A for not warming up the cables to much (i cannot set a discharge Amp in DVCC). Charge Amp is on 175A.
So i should set the maximum inverter power lower as 9000W? I thought the simple math of VxA=W would be enough
That sounds ok to me. Theres both conversion losses and power factor playing into this.
If you assume that the Multiplus is 95% efficient, and you take 9886W on DC as the base, then on AC you would get 9392VA (Apparent power), with the measured 9000W (Real power) on AC this would mean a power factor of 0.96 which sounds ok (Remember on the AC side VA is not necesarely equal to W)
