Is there a way to eliminate inverter idle draw?

[Janne]

Hi!
I tried manny different google search words to find some hack to reduce the dc/ac inverter power consumption when idle/standby.
My idea is that some kind of automatic on/off switch that will turn off the inverter (instead of the manual red on/off) at an certain low voltage and then turn it on again at an higher voltage.
This in a attempt to eliminate the idle power consumption of the inverter and that way minimize the cost/size of the battery bank.
Any ideas how to make this idea to work or is it impossible?
Thanks!

 

[gnubie]

There are actually inverters that shutdown their output if they don't sense a load. They periodically wake up and send a pulse of power out to see if there is a load and if there is go into full operation. Load sense, economy, auto shutoff are some terms you can Google search with to turn up a selection of inverters.

That sort of thing is fine if you have dumb loads such as basic thermostat fridge but with the way pretty much everything has a microcontroller in it these days there is almost always a load of some time present and power cycling can result in less than optimal operation of the device. Fridges might go through excessive defrost operations and actually use more power than the idle cut off saves.

Depending on the inverter (power rating, design etc) you might find you are burning 12 - 24 watts with no load.

 

[Rider]

I can't help but think cycling 12VDC power to the inverter just can't be good for the inverter. The constant on/off stresses components.

If the capacitors discharge when it's off, you get the in-rush current to recharge them, which might exceed the savings of turning it off.

Or am I just blowing smoke here? As I've said somewhere before, size the system to account for the idle current use, and it's a non issue.

 

[gnubie]

No smoke there apart from what might come out of the inverter. Removing DC from the inverter wasn't something I thought about, rather turning it off / on via the control circuit. Frequent heavy inrush current would degrade definitely degrade the caps.

 

[Rider]

Ok, using the control logic to turn it on/off is better, but if the on/off switch requires voltage for the logic circuits to work it's still drawing current. Just how much....dunno. Have to measure it.

 

[gnubie]

My Giandel draws 2/3 of nothing in soft off, down in the milliamps. A DIY arduino solution wouldn't add much to that but there's probably prebuilt stuff to retro fit an existing inverter if you are having to push things to the limit.

 

[Rider]

Nebermind.... Just measured it. @12.86VDC, my AIMS 1000w inverter uses 1.17A = 15watts at idle. When I use the remote logic switch to turn it off, it draws 0.0A, 0.0w. Tripping the logic switch, on my AIMS anyway, would work.

 

[Janne]

There are actually inverters that shutdown their output if they don't sense a load. They periodically wake up and send a pulse of power out to see if there is a load and if there is go into full operation. Load sense, economy, auto shutoff are some terms you can Google search with to turn up a selection of inverters.

That sort of thing is fine if you have dumb loads such as basic thermostat fridge but with the way pretty much everything has a microcontroller in it these days there is almost always a load of some time present and power cycling can result in less than optimal operation of the device. Fridges might go through excessive defrost operations and actually use more power than the idle cut off saves.

Depending on the inverter (power rating, design etc) you might find you are burning 12 - 24 watts with no load.

Thanks for the suggested search words!
You got a bit to technical for my comprehension thou on the dumb load thingy. So I don’t know if my following question makes any sense.. If I would use a grid connected ac/ac automatic transfer switch combined with with a turn of and on switch for the input of the inverter, would that eliminate the problem?

 

[Craig]

So are you looking to turn inverter off at a certain time or times or remotely or if there is no load on the inverter.

 

[gnubie]

I think I see where you are coming from now. You want a standby power system to run your load if grid power fails, but you want to preserve battery capacity when grid power is present, and you want it to all be automatic. If that's what you are after there may be a solution for you already.

You can get inverter/charger units that charge your battery from the grid, automatically switch their output to grid power and turn off the inverter, and then automatically switch back to battery power if grid power fails. You can even get units that you can connect to solar panels too.

There's quite a few threads on here about them, check out the MPP Solar units. There's a lot more out there than just the MPP Solar units, but if they look like the sort of thing you are after we can help you towards something that is right for you.

 

[Janne]

So are you looking to turn inverter off at a certain time or times or remotely or if there is no load on the inverter.

Only to turn off the inverter when the voltage is “to low” and then turn it on again when the batteries voltages is high.

 

[Craig]

Only to turn off the inverter when the voltage is “to low” and then turn it on again when the batteries voltages is high.

Ok I think you can get a cheap drok device that will sense voktage then you can wire that in to the on off switch of inverter.

 

[Craig]

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/303181391497.
Something like this

 

[Janne]

I think I see where you are coming from now. You want a standby power system to run your load if grid power fails, but you want to preserve battery capacity when grid power is present, and you want it to all be automatic. If that's what you are after there may be a solution for you already.

You can get inverter/charger units that charge your battery from the grid, automatically switch their output to grid power and turn off the inverter, and then automatically switch back to battery power if grid power fails. You can even get units that you can connect to solar panels too.

There's quite a few threads on here about them, check out the MPP Solar units. There's a lot more out there than just the MPP Solar units, but if they look like the sort of thing you are after we can help you towards something that is right for you.

If you are referring to UPS then that was not my question ( excuse my lack of knowledge if not so) I have a battery bank about 115 ah 24v (sorry should read 80 ah)[edit}. My specific problem is that during the low input from long winter nights and various clouding/sun conditions the inverter is drawing inproportuanaly

 

[Janne]

If you are referring to UPS then that was not my question ( excuse my lack of knowledge if not so) I have a battery bank about 115 ah 24v. My specific problem is that during the low input from long winter nights and various clouding/sun conditions the inverter is drawing to much in idle (the automatic transfer switch kicks in when the battery gets to a certain low point in my existing system). Tanks for you’re replay

 

[Janne]

Sorry something technical happened, posting from my iPhone. Please ignore the duplicate answer..

 

[Sojourner1]

A snippet from my Magnum manual. Which has the function you're basically asking about. My "Search" function is turned off, I don't turn my inverter off and it consumes 2ah or 48 per day.


[When the inverter is turned ON, it operates either by “searching” or “inverting”, depending on the connected AC loads.

Searching – When the inverter is first turned ON, the automatic Search feature is enabled. This feature is provided to conserve battery power when AC power is not required. In this mode, the inverter pulses the AC output looking for an AC load (i.e., electrical appliance). Whenever an AC load (greater than 5 watts) is turned on, the inverter recognizes the need for power and automatically starts inverting. When there is no load (or less than 5 watts) detected, the inverter automatically goes back into Search mode to minimize energy consumption from the battery bank. When the inverter is searching, the inverter’s green LED flashes (fast).

Info: The factory default value for the Search feature is 5 watts. It can be turned off or
adjusted from 5 to 50 watts using a remote display.
Inverting – When a load greater than 5 watts is connected to the inverter output, the MSH-M Series inverts the DC power from the battery and supplies 120 VAC power to your sub-panel. The inverter’s green LED fl ashes once every 2 seconds (medium fl ash) to indicate it is inverting. The amount of time the inverter can be inverting and providing power is directly related to the amount of AC loads that are connected, and the capacity of the battery bank. Refer to Figure 3-1 to see the flow of power from the DC input to the AC output while in Inverter mode.]

 

[gnubie]

Oh, now I understand. You have an existing inverter and an existing ATS that already changes your load to grid, you just need a way to turn the inverter off too, and I'll add on in such a way that won't degrade the inverter over time. Some inverters have a remote on / off button that does the same thing as the button on their panel. The trick is its often a momentary switch to turn the inverter on and off, push/release to turn on, push/release to turn off. My Giandel branded inverter has this and even comes with the remote button. What is the make and model of your inverter? It might have a socket for a remote button already, which would make tapping in a controller to turn it off / on much easier.

If you could buy a new inverter you could get one that has the auto low power mode and it'd be perfect for what you are doing.

 

[Janne]

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/303181391497.
Something like this

Thanks !

 

[Janne]

I am learning, thanks to you, I have to go to bed now. It’s 12.20 at night over here in Sweden. Thanks so Mutch for you’re reply’s and helpful tips! Please continue, thank you very much!