Hybrid solar inverter grid power efficiency

[pant]

Hello I have a POWMR 5KW hybrid inverter and I have notice that when is on bypassing mode (SUB) from grid even if there is no load (battery disconnected so no charging) and all output loads are turned off is still drawing 2.2A @240v from grid.
If I start drawing some load lets say 1kw its beeing added on top of that. Am I missing something here or they are that bad?
My goal was to combine solar with grid to reduce my electricity bill but this high consumption from this inverter renders the hybrid function unusable.

Are all hybrid inverters like that or this POWMR is a pile of junk?

Thank you

 

[AshleyL]

No, it is a standard "features" of all Voltronic OEM inverter.
The inverter is still active and require power for its own operation (50w - 70w) even if there is no output load.
The reason for the power draw is the inverter need to fill its capacitors in anticipation of sudden power load if you don't have battery installed. Cue the extra 500w?

 

[pant]

Hello. Thanks for your help. I have tried also with a battery connected and in a full state to ensure no power goes there but with the same results. I could understand a 50w to 70w draw on idle but 500w is crazy

 

[SeaGal]

Something doesn't sound right to me. 500W is too much for just idle power. If it were dissipating that much power all the time it would be getting quite hot. Are you sure you are measuring it accurately?

 

[Solar Guppy]

Measuring AC power isn't like DC and a clamp on ( only ) meter does not have the ability to know the phase relationship between voltage, so real vs apparent or reactive power can not be distinguished and the amps displayed is missing what the voltage component is to know real power.

So no, that is not 500 watts being consumed, but the current interacting with the AC filtering out of phase likely sub 10 watts range

Here is a discussion for more in depth explanations

 

[pant]

Edited after respond #5

 

[pant]

Measuring AC power isn't like DC and a clamp on ( only ) meter does not have the ability to know the phase relationship between voltage, so real vs apparent or reactive power can not be distinguished and the amps displayed is missing what the voltage component is to know real power.

So no, that is not 500 watts being consumed, but the current interacting with the AC filtering out of phase likely sub 10 watts range

Here is a discussion for more in depth explanations

Ok that's interesting. I have an efergy meter connected to it that it measures the same consumption but it works the same way. Its a clamp connected to a meter. Do you know a more accurate way to measure the consumption? Thank you for your valuable input sir

 

[pant]

duplicated reply

 

[Hedges]

Using a scope with current probe and voltage probe, I would see how far out of phase they are.
A power transformer carries relatively high current even no-load, because they use the smallest core they can get away with. That stores energy, then returns it, as an inductor. e.g. draw 500VA apparent power but return 430VA, leaving 70W real power.

I would have thought inverters like Powmr were SMPS not transformer type. They could have a poor power factor with rectifier-capacitor front end, but at light load that wouldn't carry high current. So I don't expect them to do what you see.

Try your efergy meter.

It says it compensates for power factor by simultaneously measuring voltage an determining phase relative to current. I would rather it showed VA as well as W and reported power factor.
Phase angle applies to inductive or capacitive loads. Would not properly deal with power factor of loads like cheap LED lights that draw a burst of current only when grid voltage is above capacitor voltage (what I expect light weight inverters to do.)

Efergy True Power Meter - Efergy

efergy.com

"The Efergy true Power Meter monitor shows you the real time usage in Watts and the cost per hour (or kWh if preferred), based on true power consumption. It follows the utility voltage and measures phase angle to compensate for power factor."

 

[pant]

Using a scope with current probe and voltage probe, I would see how far out of phase they are.
A power transformer carries relatively high current even no-load, because they use the smallest core they can get away with. That stores energy, then returns it, as an inductor. e.g. draw 500VA apparent power but return 430VA, leaving 70W real power.

I would have thought inverters like Powmr were SMPS not transformer type. They could have a poor power factor with rectifier-capacitor front end, but at light load that wouldn't carry high current. So I don't expect them to do what you see.

Try your efergy meter.

It says it compensates for power factor by simultaneously measuring voltage an determining phase relative to current. I would rather it showed VA as well as W and reported power factor.
Phase angle applies to inductive or capacitive loads. Would not properly deal with power factor of loads like cheap LED lights that draw a burst of current only when grid voltage is above capacitor voltage (what I expect light weight inverters to do.)

Efergy True Power Meter - Efergy

efergy.com

"The Efergy true Power Meter monitor shows you the real time usage in Watts and the cost per hour (or kWh if preferred), based on true power consumption. It follows the utility voltage and measures phase angle to compensate for power factor."

Hello. If I put the clamp of my efergy meter to the cable that provides grid power to the inverter it shows around 520 watts. The clamp of the multimeter shows around 2.2A. So both are close enough but I don't know as Guppy said at #5 if its real consumption.

 

[Hedges]

If it doesn't feel like a 500W space heater, it isn't real consumption.

I suspect efergy meter measures RMS current and phase, attempts to correct for phase shift impact of PF as the mention. What it doesn't do is high sample rate data acquisition and point by point multiplication of voltage times current.

If current draw is 2x as high but a pulse 1/2 as wide, RMS calculation reads twice as high. The 2x amplitude is squared, 4x. The time cuts it in half, to 2x. It is a good calculation of resistive heating in wires, but not of power delivered without considering voltage.

The fact it is poor PF, high VA but low W, doesn't matter when fed by the grid.
If poorly behaved loads like this are powered by an inverter, that reduces its efficiency.

LED bulbs have poor PF. Older Dell computers also (OK to use MSW UPS), while newer ones are PF corrected (need sine wave UPS.)

500W is 1/2 kW. What is the resolution of your utility meter? With everything else turned off, wall wart and fat snake power cords unplugged, you could leave the inverter powered for a few hours, see what the meter reads.

 

[pant]

If it doesn't feel like a 500W space heater, it isn't real consumption.

I suspect efergy meter measures RMS current and phase, attempts to correct for phase shift impact of PF as the mention. What it doesn't do is high sample rate data acquisition and point by point multiplication of voltage times current.

If current draw is 2x has high but a pulse 1/2 as wide, RMS calculation reads twice as high. The 2x amplitude is squared, 4x. The time cuts it in half, to 2x. It is a good calculation of resistive heating in wires, but not of power delivered without considering voltage.

The fact it is poor PF, high VA but low W, doesn't matter when fed by the grid.
If poorly behaved loads like this are powered by an inverter, that reduces its efficiency.

LED bulbs have poor PF. Older Dell computers also (OK to use MSW UPS), while newer ones are PF corrected (need sine wave UPS.)

500W is 1/2 kW. What is the resolution of your utility meter? With everything else turned off, wall wart and fat snake power cords unplugged, you could leave the inverter powered for a few hours, see what the meter reads.

That is my plan for tomorrow I will leave it on for 4hours to see what the utility meter will register.