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

[wade0000]

Hello,
Quick question.

I have a 24V 3000W pure sine wave inverter powering two 15A circuits.

The inverter itself uses about 30W running a 500W load.

There are some times that there is no load. Does the inverter still consume the same amount of power then? Or significantly less because it is proportional to the load? It's hard to tell since my usage watt meters are downstream after the inverter.

Thanks in advance.

P.S. - Ultimately, I'd also like to have an automatic switch that would switch to AC if the battery dropped to a preset level AND turned the inverter off (if it is using significant power just to idle)

 

[schmism]

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.

 

[Jim Burrow]

I have the all-in-one PIP-2424LV-MDS controller/inverter. at ideal (safe mode) it is less than 15 watts and no-load less than 50 watts. see in the image and marked in yellow. - home this helps!

 

[snoobler]

Hello,
Quick question.

I have a 24V 3000W pure sine wave inverter powering two 15A circuits.

The inverter itself uses about 30W running a 500W load.

There are some times that there is no load. Does the inverter still consume the same amount of power then? Or significantly less because it is proportional to the load? It's hard to tell since my usage watt meters are downstream after the inverter.

Thanks in advance.

P.S. - Ultimately, I'd also like to have an automatic switch that would switch to AC if the battery dropped to a preset level AND turned the inverter off (if it is using significant power just to idle)

All inverters providing ready-to-use 120VAC have an idle consumption. There is a cost to running the circuitry that generates the 120VAC and 60Hz frequency. My 4kW Victron is about 30W as well.

It's pretty safe to assume that unless your unit advertises low idle power consumption, or it has a standby mode where it checks for an AC load every so often, then it has a 20-30W idle consumption.

 

[RCinFLA]

It depends on model and type of inverter. There two primary areas effecting idle current. High frequency MOSFET drive switching is usually the dominate idle consumption but a poorly designed output PWM low pass filter can add to idle losses by having a high reactive power factor load.

Generally a 3 kW sinewave high freq inverter is 30 to 50 watts of full idle power. A high frequency inverter has two primary stages. First stage is high frequency DC to DC converter that pumps battery voltage up to about 180-200vdc. Second stage is output MOSFET H-bridge that takes the high voltage DC and PWM chops it for sinewave synthesis, follow by low pass L-C filter.

Many high freq first stage DC to DC converters are comprised of several smaller lower power DC to DC converters in parallel. You will see multiple small ferrite transformers in these models. They can save idle power by turning off some of the smaller parallel converters when load is light. Down side of this is it takes some finite time to recognize a surge load and fire up additional DC to DC converters to supply heavier load. At minimum there is a momentary dip in output voltage. At worse it overstresses the converters that were on causing early failure.

Low freq 'hybrid' bi-directional inverters have a large low frequency transformer that doubles as voltage step up and most of sinewave output filtering. They have MOSFET H-bridge on primary battery side of large low freq transformer that creates the PWM sinewave synthesis. Again, some models save idle power by turning off some of the parallel primary side MOSFET's when load is light. This still gets the significant voltage dip on surge loads but less likely to be damaged then a high frequency inverter. Because they generally have less MOSFET's getting switching at high frequency they have a bit lower idle current.

Many inverters have a automatic standby mode. They shutdown inverter to save idle power and wake up every so often to see if an AC output load exists. Issue with standby mode is it takes a minimum output AC load to be detected by inverter. A light load may not be recognized and inverter will just continue its intermittant active-sleep cycle. A low power LED light bulb by itself may just blink on and off.

Most of the Chinese hybrid inverters with integrated MPPT PV controllers have bi-directional first stage DC to DC converters. This approach is even more vunerable to surge damage when partial converter shut down is employed to save idle power, Highly inductive motor startup surge current can be very hard to handle and can be damaging with this approach. There is a video of this happening on Youtube, search for "Did I Blow up the Inverter" by DavidPoz.

 

[Deleted member 9967]

Ok excuse my naivety but. Could you not just flick a switch and turn the unit off when you don't need it?
Then it consumes nothing right?

 

[Rider]

Ok excuse my naivety but. Could you not just flick a switch and turn the unit off when you don't need it?
Then it consumes nothing right?

Yes, you could. But if it's powering a fridge which cycles on and off, it would be rather inconvenient.

 

[Deleted member 9967]

Yes, you could. But if it's powering a fridge which cycles on and off, it would be rather inconvenient.

Thanks, it is what I needed to know.
I was worried it might hurt the inverter mostly.
Thank you.

 

[Rider]

I was worried it might hurt the inverter mostly.

That's always a concern if you turn electronics on and off very frequently, some are more susceptible to the initial power surge and could fail, a cheap switch, etc..... The better the inverter (as a rule) the better the internal safeguards are.

 

[Deleted member 9967]

That's always a concern if you turn electronics on and off very frequently, some are more susceptible to the initial power surge and could fail, a cheap switch, etc..... The better the inverter (as a rule) the better the internal safeguards are.

Thank you.

 

[Hedges]

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.

 

[Deleted member 9967]

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.

I didn't really want to derail this poor guys thread. But I was thinking for on a vehicle. And say you put it away and only use it 4 or 5 times a week. So turn it off once a day and turn it on once a day.
Nothing too strenuous I would think.
Heck, even wire it up and use a common light switch for the powering on and off, no?

 

[JoeHam]

Heck, even wire it up and use a common light switch for the powering on and off, no?

Don’t try that. You need to use a DC rated switch or breaker that can extinguish an arc.

AC switches don’t have that issue as the voltage sine wave crosses zero potential many times each second.

 

[Deleted member 9967]

Don’t try that. You need to use a DC rated switch or breaker that can extinguish an arc.

AC switches don’t have that issue as the voltage sine wave crosses zero potential many times each second.

Aha, I like that insight.
I keep forgetting about stuff like that.
Still new after 8 months. ? ?
Ok then DC switches it is then.

 

[Hedges]

Not to mention 300A. That's more than the (AC only) main breaker in my panel.

But some inverters do have a remote on/off switch; anything works for that.

 

[Bleedingblue]

My aims 10k uses 150watts

 

[wade0000]

Ok excuse my naivety but. Could you not just flick a switch and turn the unit off when you don't need it?
Then it consumes nothing right?

That's what I am doing now.. but have to walk out to the unattached garage and turn it off. Want to avoid that in the winter if possible.

 

[chrisski]

My phone 12 volt 2k inverter draws .99 amp and the tech data says 1 amp, so I say that’s spot on.

For turning on and off, I bought the remote, but you can wire it with your own switch. In the tech data, I’m supposed to give the inverter a “few seconds” before applying a load, so you could probably figure a way to do that.

I’m sure applying the load while powering on the inverter is a bad idea.

 

[Deleted member 9967]

That's what I am doing now.. but have to walk out to the unattached garage and turn it off. Want to avoid that in the winter if possible.

Ah ok. So then just move the switch or add another one closer to a warmer spot.

 

[wade0000]

As information, I just did a test of the inverter decent load versus almost no load:

Inverter:
250W load (confirmed thru measurement) = net of 29W for Inverter itself
2W load just charging a wireless speaker = 21W " "

Thanks for all the help. I want to put in an automatic switch DC to AC grid when the batteries get too low... so I'll have to add some kind of alert on that trigger so I can put in a DC switch to turn off the inverter.

Thanks too everyone who responded. Best forum. Saved a huge amount of time and grief with your expertise previous on cheap Chinese DC breaker issue.