Inverter that turns on automatically
- Thread starter Roger S
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They kind of do. When nothing is plugged in, they only pull a few watts.
- Jul 6, 2009
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Most inverters can be left switched on, they will as stated consume a small current but ramp up when a draw is made by turning something on. Our Victron 12/2000/80 consumes less than 1 amp when switched on with no load present. When the sun is around our solar (700 watts will run our Dometic three way fridge for most of the day once the batteries are 100 % on 240. Although you are turning 12 into 240 because the 240 is thermostat control it pulls less power the the 12 volt (17 amps) which is constant and not too effective.
Our Victron has AES mode (not the fridge AES) which saves about 20% on standby and Search mode that monitors for a load over 100w (adjustable) to turn on, and turns off below 40w.
On normal standby it uses 13w, AES uses 9w and search 3w.
Have to be careful with Search if you have stuff plugged in with timers/lights etc.
On normal standby it uses 13w, AES uses 9w and search 3w.
Have to be careful with Search if you have stuff plugged in with timers/lights etc.
MisterB
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we have a Renogy 3000w - it uses around 1.5A when not in use. it also has the advantage of providing 240v pass through when on EHU, without having to do anything and also has remote control and a remote switch which can be positioned away from the inverter in a convenient place.
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12V is thermostatically controlled and (correctly cabled) is as effective as mains and gas.
Basically the inverter has to be producing AC so it knows when you switch something on. So it will go in to a low power mode when it detects little or no AC power is being used but is still essentially on. Then when a current flows it turns fully on.
With my victron inverter it has two options for automatically switching out of “standby” when you start an AC load.
Option one: AES which basically leaves the AC on all the time but “thins up” the sine wave to reduce power consumption by 20% when nothing is connected.
Option two: search mode, this switches off the AC but puts a few sine waves out every 2 seconds and stays on if it finds a load. This reduces power consumption by 70% when nothing is connected.
Search mode can easily be fooled by things like a microwave that switch on/off when defrosting as it won’t consume much power at times and the inverter might switch off.
So for me - I congratulate victron for making their inverter so clever - but stick to switching it on and off when I need AC with a good old fashioned toggle switch!
For me the best feature by far on my victron inverter is how it will automatically “chip in” when using shore power if I need more AC than the hook up can give then it adds power from the battery.
With my victron inverter it has two options for automatically switching out of “standby” when you start an AC load.
Option one: AES which basically leaves the AC on all the time but “thins up” the sine wave to reduce power consumption by 20% when nothing is connected.
Option two: search mode, this switches off the AC but puts a few sine waves out every 2 seconds and stays on if it finds a load. This reduces power consumption by 70% when nothing is connected.
Search mode can easily be fooled by things like a microwave that switch on/off when defrosting as it won’t consume much power at times and the inverter might switch off.
So for me - I congratulate victron for making their inverter so clever - but stick to switching it on and off when I need AC with a good old fashioned toggle switch!
For me the best feature by far on my victron inverter is how it will automatically “chip in” when using shore power if I need more AC than the hook up can give then it adds power from the battery.
tinkertaylor
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The Victron Energy Phoenix Inverter has the option for an external switch to turn it on and off, mines wired to the extra switch on the water pump on off switch.
scotjimland
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spot on..
odd how that old chestnut keeps popping up.. harking back to the early days when the 12v was only for maintaining the temperature when driving ..
If I recall correctly, the wattage of the 12 vdc and 240 vac elements are about the same..
- Jul 6, 2009
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According to Dometic the 12 volt will only hold the temp where as the 240 is more powerful. On overnight to Roscoff if we leave the fridge on 12 volt and monitor the fridge temp is stay at a higher temp and uses more power then leaving it on 240 through the inverter even though you are using the same batteries and the inefficient way of producing power. We have medical supplies that must be at a constant temp and had the wiring for the 12 volt side uprated for exactly that reason.
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My Studer AJ275 inverter only uses 0.2 amps on standby 
scotjimland
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Looking at the specs for the range of fridges, there is only 5w power difference on 12v than 240v ..
eg.. 120 / 125 w
I can't find any reference in the user manual to 12v only holding temperature .. in fact 12v is first priority if you have solar ..
Yes - I don't understand why the bigger devices seem to need more on standbyMy Studer AJ275 inverter only uses 0.2 amps on standby
Inverters basically work in two stages 1st they turn the 12v DC from the battery in to a sine wave this is usually about 8 to 10 volts from peak to peak.
The second step is to bring the voltage up to 220v this is done with a transformer - which is a big chunk of iron with wire coiled around it.
A main loss in the inverter is from the big chunk of iron in the transformer, making and reversing the magnetic field inside it uses up energy.
A bigger inverter that can produce a lot of power needs a bigger transformer which has a lot more iron in it so you get more losses from it. These losses are fixed by size of transformer and don’t change much with the load.
So running a small AC load in a big inverter has more losses than the same load on a small inverter with its small transformer.
The losses on a big inverter can be quite substantial. For example a MultiPlus 24/3000 from victron has 33% efficiency at 10W output load and 93.5% efficiency at 400W output.
Hope I explained this well enough!
The second step is to bring the voltage up to 220v this is done with a transformer - which is a big chunk of iron with wire coiled around it.
A main loss in the inverter is from the big chunk of iron in the transformer, making and reversing the magnetic field inside it uses up energy.
A bigger inverter that can produce a lot of power needs a bigger transformer which has a lot more iron in it so you get more losses from it. These losses are fixed by size of transformer and don’t change much with the load.
So running a small AC load in a big inverter has more losses than the same load on a small inverter with its small transformer.
The losses on a big inverter can be quite substantial. For example a MultiPlus 24/3000 from victron has 33% efficiency at 10W output load and 93.5% efficiency at 400W output.
Hope I explained this well enough!
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In short yes, those with search mode feature.
Victron up to 1200va inverters consume 2w in search mode (4ah in 24h). It needs a load of >40w to activate it. Larger inverters may need larger load to turn on.
What do you need it for? Whats the load?
The loads need to activate/deactivate the inverter can be adjusted - if you have the correct interface unit and some free software from victron called VEConfigure. The default for all inverters is I think 40w or less turns off inverter and 100w turns it on.
I never managed to find a level that worked without driving us mad, I guess we just had too much variation in AC usage to find a suitable “just works” setting so switched it off and went back to manual mode with the good old toggle switch!
I never managed to find a level that worked without driving us mad, I guess we just had too much variation in AC usage to find a suitable “just works” setting so switched it off and went back to manual mode with the good old toggle switch!
Lenny HB
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My fridge is 190 watts on 12v and 250 watts on 230v still works quite well on 12v.
The load would be a kettle, coffee machine, microwave all things that are above 40w so that would work
ours is similar to yours, perhaps as has been said the modern fridges have larger elements on 12v
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I find ours is triggered by the display on the microwave, not a problem other than the cooling fan on the inverter can be there at night.
Our 2022 fridge is on a 20amp fuse for the 12v supply, so ours would be similar on 12v I suspect, Perhaps they've made the 230v less
That will work like a charm. In the past, I had a victron 1200va inverter supplying a 950w deep well water pump. The pump was wired to a pressure switch, but, in between the cycles the inverter could sit there for hrs. So I switched it to search mode and worked very well.
And while it's cooling, which was most of our trip, it was using 258 Watts, so ours is the same as Lenny'sOur 2022 fridge is on a 20amp fuse for the 12v supply, so ours would be similar on 12v I suspect, Perhaps they've made the 230v less
- Dec 6, 2019
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That's exactly what I thought. I've recently added a lot of solar, more LFP battery and AC, so I thought I'd put a permanent 12V fridge feed in while I was at it, for when the AC is not required and I have loads of spare electrons.
It's a Domestic RM8400 (2019 vintage) and guess what, no thermostat on 12V it turns out. Really annoying! It unsurprisingly gets too cold.
I was just trying to reduce the quiescent inverter load, but I've just had to go back to using it on 230V.
On the positive side, 3 way fridges are just so inefficient, at least I now have the permanent feed for when it gets binned for a proper compressor fridge.
Steve.
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If that's the only problem, it would be quite easy to wire in a 12V temperature controller. This one can switch 20A, which is OK for the 12V heater supply.
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- Dec 6, 2019
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Excellent suggestion autorouter. I shall have a look at that option when I get back from this current trip. Cheers.
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