I have a MultiPlus-II 48/5000/70-48 with no AC input, just battery and SmartSolar MPPT 150/100. Everything seems to work fine. I’m powering a 160W air pump with AC out.
But the VRM shows only half the output? What is wrong please?
Can you verify the Heatpump is actually consuming more than 89W?
Just because it is rated at 160W max doesn’t mean it will consume 160W whenever turned on.
hmm, on second look, you have 126W from battery and 68W from solar, so consumption should be higher.
Not sure if this may be caused by the difference of reactive-power (if air pumps are causing that)
I will measure the output tonight, but I’m also basing my question on the output not equaling the inputs from the battery and PV.
Thought about this for a while.
At 90 Watts load, the Multiplus 5000 is operating at around 80% inverter efficency. So, sustaining a 90W Load requires about 112,5W DC Discharge.
That brings the actual vanishing difference down to 81,5Watts (126 + 68 - 112,5)
Within that 81,5Watts, there are consumption of the Mppt, losses due to cabling, measuring imprecisions, measurement timing offsets - and eventually drain caused by reactive power.
For the later issue, there is a topic created yesterday, where it is asked if reactive power is causing a DC-Discharge or not, see:
Nut sure if all that is enough to sum up to 81 Watts, but the bottom line is, that you will never see the values adding up perfectly, when passing the AC/DC border.
I’ve measured the current at the outlet when the air pump is running.
230V and 1.38A
Means the heatpump consumes 317VA, and if we take the 89W the Multiplus is reporting, that makes a powerfactor of 0.28 (89W/317VA)
Not nice, but also not impossible
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how can i best measure the wattage if I’m unsure of the multiplus value?
With a watt meter. Some clamp-on current meters have the option to simultaneously measure voltage, enabling them to calculate real, apparent and reactive power
Answer: With an energy meter that uses a shunt. Sometimes the hall effect ones don’t catch much below 4A accurately. Depends on the size.
Although really when inverting the DC readings are more important as that is the heart of the system
Power factor doesn’t affect it and is also incudes system self consumption.
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So I’ve now measured the watts with a watt meter at the socket whilst the air pump is running and it’s 300 watts and the meter has power factor of 0.48.
Why does the VRM show only 98W on the AC OUT block?
I’m getting trying to determine if I’ve configured something wrong
OK, I think i understand it better now.
The VRM is displaying real power. The apparent power reading from the watt mater includes the reactive power. The low PF due to the air pump creates this discrepancy.
However, I didnt realise that the reactive compponent of apparent power doesnt consume battery capactiy in a DC system. Thats why victron probably chose not display it.
Does any one have experience with improving the power factor in a victron system - what should I be looking for. connection capacitors?
If it not causing loss of capactiy from my batteries, is a poor PF just reducing the potential power that could be produced by the inverter?
You can correct a bad power factor, but not generally by adding capacitors. Loads tended to be inductive in the past, consisting of transformers and motors. But nowadays most things are electronic, transformers got replaced by capacitor-droppers, motors have VFDs infront of them. So you cant generalise anymore, a bad PF can not be corrected by just adding capacitors, you may need to add inductors.
In order to know which way you need to correct, you need to know if the load is capacitive or inductive. Your wattmeter can measure that, and should display it, usually next to the PF number, like 0.48C indicating capacitive load.
Theres also PF correction and filtering modules, used at the input of a load. Your air pump should have one, loads should aim for a PF of 1, but thats a component that is not strictly necessary so its a way to save money for the manufacturer. Or it might be broken, depending on the age
Some also use the sign for it, where a negative PF means capacitive and a positive is inductive.
Manual of the meter should unveil that 
Forget about power factor, I guess it’s a firmware problem.
Do you got a parallel system?
I have two Multi II 5k running single phase, since the update to 558 yesterday, AC-Out shows exact half of the watts drawn from AC-Oou…
Mode was inverter-only, VRM showed 1000W on battery and 500Watts on AC-out, I connected a 2kW heater: 3000watts battery and 1500 Ac-Out…something is wrong!
Or maybe I made a mistake setting it up again, as the config was lost(not converted properly).
May be my fault, but I have done this a few times yet and think I know what I am doing…my guess it’s firmware issue, but I can’t really find more about this online…
@lxonline : do you got a hint/link for me?
On a power socket: There are simple devices you can plug in, giving you another socket where you connect your load( those also can count over time),…
On the Ac-Out of the Multiplus: Measute voltage(Duspol, multimeter) and amps(with a clamp-ampere-meter) and multiply them…
Measure Ohms:
Measure voltage, connect a load of about 2kW(measure amps to be sure) and get a second reading of the voltage.
When you know the voltage drop, you can calculate the resistance…
Fun fact: this measurement is much more exact than those done by 3000$ expensive devices….
Way to dig up an older post 
the firmware from then is certainly not what is on your system now.
Not going to comment because i know that in some systems in parallel i have seen some strange readings and i can be attributed to current sharing and set up. I saw one installer 'fix some weirdness by looping an extra breaker on one inverter output.
For the sake of discussion I am going to assume everything is programmed right and the wiring is symmetrical etc. Is this a new install?
Roll back the firmware?
If it fixes it let us know. If it doesn’t -then an official up the chain to HQ message needs to be sent for further investigation on 558
@lxonline Thanks !
Now I can confirm, that the problem relates to VRM VenusOs large 3.67
…with 3.64 all is ok, when I update again, I get wrong values…
Beta I haven’t tried yet…
Ah interesting so not the inverter firmware? Yet that was the trigger?
I have updated all together…
I also have changed cabeling:
Before 4m an 2,5m 6mm² ac in and out( not done by me)… , now both same length, 4m, 4mm²
With the roll back on the GX do you also roll back the inverters?
A wiring change is a huge change.. they weren’t done and tested separately. Its going to be interesting to sort out whats what.
So the next thing i am going to ask is what is your shut down and start up procedure.
It is also a common cause of weirdness.