A question........

[Ding123]

I have a 3000 Watt inverter , six 12 volt , 90 a h deep cell batteries, connected in series. I have six 12 volt panels charging these batteries.Everything is working fine and they are always topped up. I was wondering, if I devoted my little freezer to this system,. My freezer is 115 ,energy efficient .Would I have any problems? 
Or, should I try it on my neighbours ,first?
The freezer doen't come on that often and there is no defrost to worry about. I will try to upload a pic so you can compare it with the system I have.
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[Madscientist267]

This depends actually more on the inverter's specs than anything.

Compressor motors as a general rule don't like to start with MSW (modified sine wave).

If the inverter is pure sine, it won't be an issue at all. I can start mine with a 1400VA ("900W") pure sine UPS unit, no problem.

Throw my "750W" (1500 "surge") MSW inverter at it and it causes the inverter to trip out on overload, even though "by the book", it is capable of handling it.  

Now if you can get it running somehow FIRST...  

The other issue is startup surge. That compressor, even though rated at 1.2A, that is RLA (running loaded amps). Start requirements are more intense, and are usually indicated by an LRA designation (locked rotor amps), which can be 10-20x the RLA, so you might be looking at as high as 20A or more for a fraction of a second, but your 3kW will not see that as an issue. And actually, 3kW may even be powerful enough to be able to start it even if it IS an MSW (but I'd bet its a pure sine).

If you are in fact dealing with an MSW inverter, there are ways to "trick" it into starting motors such as those found in compressors; sometimes that work, sometimes don't. Let's just say you're not the first to run up against this.  

Best way to find out? Try it. It will either work or it won't.

Steve

[kenl]

 I had no problems running my 1990 model energy hog fridge off a Trace 1512 inverter. From the name plate on your freezer your under 200w once it gets running so as long as you have a decent inverter it should be no problem. A Kilawatt meter should tell you if your batteries have enough storage to support the additional load.
 You could run the 120 through a relay that is controlled by a low voltage disconnect (ghurd controller) and have it switch between grid and battery power depending on the state of charge. But hysteresis will be a problem when your batteries a close to the low voltage trigger point (relay will keep energizing and de energizing). Glen helped me with a circuit to avoid this maybe 4-5 years ago though I never applied it. You may want to see if he can help if you want to go this route. I may even still have the diagram he sent me, I will check in the morning for you.

kenny

[JW]

kenl,

Look into your profle, your avatar (image) is a red X. When I was an admin, i would reset the avatar[for users] too "no image" and that gets rid of the red X (error).

JW

[kenl]

kenl,

Look into your profle, your avatar (image) is a red X. When I was an admin, i would reset the avatar[for users] too "no image" and that gets rid of the red X (error).

JW

Humm, maybe admin is trying to tell me something 

[fabricator]

I've got a chest freezer, about 20 years old, it likes my 5000w MSW inverter just fine, my well pump does too, is your 3000w inverter good for 5000w or so surge?

[Ding123]

Thanks guys for your info. My inverter ,Ener-G plus, is a 3000w with a 6000 watt surge.  I guess I have found out everything I have to know for now.
It's been so long,I had forgotten  what a great bunch is on this site!Happy New Year! Stay thirsty, my friends!!!!

[OperaHouse]

I've run my 5 cubic foot chest freezer for several years on a Harbor Freight 2000/4000W MSW inverter.  Start up current from the battery is about 90A for about 5 seconds.  I run a long AC line to the fridge and have placed about a .8uf 10 ohm RC network across the line to absorb large spikes.

[Madscientist267]

Phew... 5 seconds? Yowch.

Goes to show though... it's starting up kickin' and screamin' 

But if it starts... 

Steve

[ghurd]

Humm, maybe admin is trying to tell me something 

Not that I am aware of.
They usually tell you if there is an 'issue'.
Probably just a glitch.
G-

[musselbeach]

I have run 2 freezers one small danby and a larger one off a 3000 watt MSW $289 inverter now for 7 month and have had no problems.