How much power does an Inverter use just sitting there idling?

[Hedges]

I want to put in an automatic switch DC to AC grid when the batteries get too low...

What kind of batteries? How deep do they cycle and how often?

If you deep cycle lead-acid batteries every night, their lifespan could be reduced from 10 years to 2 years (or other figures depending on exact type.) In this case having a regulated DC voltage source (probably through a diode) or battery charger settings that stays off when PV keeps batteries higher could extend life, save cycling for times of AC power failure.

If lithium, may be OK for a decade of such cycling.

 

[Roswell Bob]

Cycling power from batteries to inverter would be repeating that current surge into capacitors.
High temperature (within spec) burn-in of electronics never did much to improve reliability, but temperature cycling does expose faults (cracks in solder joints or PC boards.)
So there is a cost to cycling. Perhaps turning off all night to save power is worthwhile, but a sleep mode disturbed dozens of times a day would not be.

My Sunny Island is 25W operating, 6W sleep, per inverter. Operating efficiency ranges from 91% to 96% except at very light load where the 25W consumption dominates.

Yes, power cycling is what counts. When I was young engineer I worked for a guy who produced standard fan/pump kind of motor drives. One day he comes to me and says, "we're going to be developing a servo drive." He shows me this little 6pack IGBT module and asks me what I think. I looked at it handed it back and said."Looks kinda small to me." That was the end of the conversation. Well he goes and ships a few of these things. Meanwhile I am taking upper level ECE class where the complete semester is based on state-space analysis of transistor junction temperatures. I finish the class about the time he starts shipping these things. I told him he would be seeing these things coming back in a few weeks,. Long story short is his junction temperatures were going up and down about 60c whenever he accelerated/decelerated the motor. A few weeks later he is scrambling to put bigger modules in.

 

[Roswell Bob]

My aims 10k uses 150watts

Yep. my 6kW aims pulls about 2A for near 100W. Turn it off at night.

 

[DUKMAN]

In 2014 I drove a converted bus/motorhome around Australia with a Powerstar W7 inverter that had a stand by function to run my electrics. When no power was drawn it would go to sleep using the auto/standby function. It would monitor the output for load every 5 - 10 seconds and start up when someone put a load on the line or if the fridge thermostat turned on. I had 450AH of batteries @24v being charged by 850Watts of solar through a Tracer solar controller. I ran a 315lt domestic fridge and never went without power. The only reason I had to go into town was to empty the black and grey tanks (250L each) and fill the water tank (1000L). The standby would use a couple of milliamps every 5 - 10 seconds to check the line for load so was not heavy on battery at all for the convenience of just turning it on and leaving it alone.

 

[unsubscribed]

The Victron Multiplus will do this. IIRC, the standby power in that mode is 8 watts. (24/3000) A.E.S. mode, where the S stands for "Search" I think.

 

[Joe Samra]

Thats going to depend on the hardware you have. Expensive units are typically more efficent (use less power when the load is off). My 3kw "inveter" is an all in one so it has a SCC and a processor to handle load shareing with other units and a graphic display to drive etc so it consumes more power itself than a typical unit. However it also has a standby mode that will shut down several sections of the unit to conserve power under no load conditions.

In short, buy a clamp meter and run the tests yourself. amps in vs amps out. the difference * volts is how many watts your unit is using.

Hello how are you?
I have a Growatt SPF5000ES and it consumes around two amperes from the utility grid whit no load connected, is this your case? Could this be normal?

 

[Hedges]

That wouldn't be normal.

230V x 2A = 460W, if it "consumes" that, would grow noticeably hot.

A "reactive" capacitor or transformer load could draw 2A out of phase for 460VA but 0V, however I don't think that is likely. Especially for a high-frequency inverter.

Is it charging batteries? Feeding downstream AC loads?

 

[Joe Samra]

That wouldn't be normal.

230V x 2A = 460W, if it "consumes" that, would grow noticeably hot.

A "reactive" capacitor or transformer load could draw 2A out of phase for 460VA but 0V, however I don't think that is likely. Especially for a high-frequency inverter.

Is it charging batteries? Feeding downstream AC loads?

Thank you for your reply, i haven't purchased batteries yet, and even when i turn off the AC output breaker (no loads connected) it keeps withdrawing 2 A, could it be defected? It is a brand new inverter, installed for just one week, i noticed this matter yesterday

 

[timselectric]

Thank you for your reply, i haven't purchased batteries yet, and even when i turn off the AC output breaker (no loads connected) it keeps withdrawing 2 A, could it be defected? It is a brand new inverter, installed for just one week, i noticed this matter yesterday

Are you checking this with a good clamp meter?
And did you zero it out, first?

 

[Hedges]

How do you determine 2A?

If no heat is observed, it wouldn't be 460W.

What I do at work, and at home, is use a digital oscilloscope with current and voltage probes. A proper transformer or choke, I can capture waveforms an observe 90 degree phase shift. Something I hand wound on a solid metal (not laminated) core got hot fast and current was almost in phase with voltage. That's the difference between "W" and "VA".

Some people have Kill-a-Watt, compact device which provides similar measurements (for about 1% or 0.1% the equipment cost.)

But I kind of doubt 2A draw at 230V no load. 2A in and out of decoupling capacitors at 50V is more likely, but still seems odd for no load.
As Tim said, "zero" being off is a possibility. But more of a problem for a DC ammeter than an AC ammeter.

 

[Joe Samra]

Are you checking this with a good clamp meter?
And did you zero it out, first?

Yes i trust my clamp meter (Uni-t), what made me notice first was the KWH quickly added to the energy meter, yes it is zeroed out, i also have also an amp meter in the panel which indicates the same.

 

[Hedges]

Three out of three redundancy, so something is happening.
Which unit has the kWh meter? That's the only one that wouldn't read the same for VA. But some measurements might be confused by switching frequencies.

After it has run for a while, check for heat. If that's 2A at 230V for 460W, it is a moderate size space heater and should feel warm, or have warm air coming out the vents.

What is the source of power? AC grid? PV?

I would assume this is undocumented behavior, although defect is a possibility.

 

[timselectric]

Are the fans running, during this odd draw?
Something else is causing this amount of draw. Not just idle consumption.

 

[Hedges]

5000W rating and 97% peak efficiency suggests up to 150W no-load.
But could be less, probably more like 97% at 1000W, for 30W self consumption.
Is no-load consumption in the specs somewhere?

 

[timselectric]

Just checked my SPF-5000-ES.
80.54 watts , at idle with fans running strong.
70.7 watts , at idle with fans running barely.
This is what it should be.

 

[HRTKD]

If my Cerbo GX is to be believed, the idle draw of my Victron Multiplus 12/3000 is less than 19 watts. I don't have it configured for the super secret dark matter search mode.

 

[Joe Samra]

How do you determine 2A?

If no heat is observed, it wouldn't be 460W.

What I do at work, and at home, is use a digital oscilloscope with current and voltage probes. A proper transformer or choke, I can capture waveforms an observe 90 degree phase shift. Something I hand wound on a solid metal (not laminated) core got hot fast and current was almost in phase with voltage. That's the difference between "W" and "VA".

Some people have Kill-a-Watt, compact device which provides similar measurements (for about 1% or 0.1% the equipment cost.)

But I kind of doubt 2A draw at 230V no load. 2A in and out of decoupling capacitors at 50V is more likely, but still seems odd for no load.
As Tim said, "zero" being off is a possibility. But more of a problem for a DC ammeter than an AC ammeter.

 

[Joe Samra]

Yes i zeroed the amp meter and still 2A, please find a video attached, a friend of mine installed the same exact model, i checked with him and he confirmed that when the AC input breaker is on it is drawing 1.9 A, the Growatt displays the load on idle as 0.1% on its LCD screen but the amp meter says different.
I will check tomorrow with another multimeter connected in series to recheck.

 

[time2roll]

A battery voltage based relay could control a transfer switch to move the loads to utility power. Possibly turn the inverter off depending on the existing switch control circuit. Or control a battery charger to come on as needed. Controlling a battery charger would enable continuous inverter power without risking the load resetting from switching to utility power direct.

Inverters will commonly burn 10 watts at idle for every 1000w rating. Some are better than others, some have a sleep mode to turn back on when a load is presented.

 

[Joe Samra]

Three out of three redundancy, so something is happening.
Which unit has the kWh meter? That's the only one that wouldn't read the same for VA. But some measurements might be confused by switching frequencies.

After it has run for a while, check for heat. If that's 2A at 230V for 460W, it is a moderate size space heater and should feel warm, or have warm air coming out the vents.

What is the source of power? AC grid? PV?

I would assume this is undocumented behavior, although defect is a possibility.

The source power is AC grid, actually where i live (Lebanon) there is a lot of power shortage from government electrical grid, so local generators provide power to some buildings, they installed energy meters in order to charge their customers but their charges are expensive, so i installed the solar panels and the inverter in order to save some money (attached is a picture of the energy meter). Everything runs fine when the only input of the inverter is the DC input from the panels, but when turning on the AC breaker i get 2A even though the AC output breaker is turned off.
I conducted a test the other, i turned on a small heater that draws 1A using only solar power, the AC output is a round 1A, when i turn on the AC input breaker i get 2 A on the AC input cable and 1A on the AC output, this is very weird and is confusing me. A friend of mine installed the same inverter, i asked him to test it, he gets also 2A on the AC input with no loads.
What could be the issue here?