Fridge kicks off inverter

[tmcblane]

I gave my friend a small apartment fridge out of our rv, we replaced it with a freezer so the fridge runs fine. She has a 1500 watt pure sine wave inverter, 200 am hours of lithium batteries and 400watts of solar. The fridge in my rv was powered by a 1000watt inverter and was never an issue but when she uses it, it randomly kicks the inverter off. Any ideas what I should check for her?

 

[SparkyJJO]

Startup surge possibly - her inverter may not have as much tolerance?
Anything else running on the inverter?

 

[DJSmiley]

Inverter should be able to handle it fine. What error message shows the inverter? Overload or low battery?

If the wires are too thin, or connections are crap, inverter might shutdown due to low voltage, even if the inverter itself can handle it fine. Voltage drop over cables (or bad connections / automatic fuses) can cause these issues

 

[timselectric]

Also check for a grounding issue. If the inverter is a high quality.
Edit: probably unlikely, if it's an intermittent problem.

 

[tmcblane]

Startup surge possibly - her inverter may not have as much tolerance?
Anything else running on the inverter?

No, its a chinese inverter but says 3000watt surge. Dont really know when it kicks it off but most likely when the compressor kicks on but just strange that my 1000 would run it. And for reference the GFI has never popped.

 

[tmcblane]

Inverter should be able to handle it fine. What error message shows the inverter? Overload or low battery?

If the wires are too thin, or connections are crap, inverter might shutdown due to low voltage, even if the inverter itself can handle it fine. Voltage drop over cables (or bad connections / automatic fuses) can cause these issues

No message at all it just turns it off. The fridge is within 4' of the inverter so I dont think it is undersize wire, she has 14ga which should handle 15 amps no problem. I have to get a copy of the manual offline cause she thinks she threw it away, I wanna check and make sure that it doesnt have some automatic shutoff timer on it.

 

[tmcblane]

Also check for a grounding issue. If the inverter is a high quality.
Edit: probably unlikely, if it's an intermittent problem.

I am going there next Tim, it isnt a high quality inverter. As it sits now she has the inverter grounded to the chassis but not the battery that I have seen and her 110volt outlets I dont see any grounding outside of the GFI on the inverter. Would the battery need to be chassis bonded, What would be the difference if it was sitting in a garage without a ground as in a grounding rod? What I may try is maybe temporarily finding an external ground or put a rod in the ground and tie to it to test.

 

[timselectric]

That shouldn't make a difference.
As far as a grounding issue, I meant something going to ground that shouldn't.

 

[Delmar]

Was your 1000 watt inverter low-frequency, meaning heavy with a big transformer? My 1000W UPS can start my full-size fridge. If her inverter is high-frequency it may not have the surge capacity to start the compressor.

Also make sure when the fridge turns off it doesn’t restart for at least 30 minutes. The high-side pressure has to bleed down, otherwise the locked-rotor surge on restart will be massive. Could happen if she frequently opens the door.

 

[DJSmiley]

Well.. a chinese one... I would derated that by at least 50%.

I think the inverter simply can't run it. A decent brand 1000W inverter can run 1000W... continously.

A 3000W chinese inverter can run 3000W.. for 5 sec till the smoke comes out.

 

[SolarGarden]

I would check the internal resistance of the battery pack. See if you can run it a a lower load and let us know what the drop is on and off load across the battery. Some freezers (maybe fridges?) have a very high start up current. My freezer runs at 50W but requires 450W for about 5 seconds to start sometimes.

 

[circus]

If the wires are too thin, or connections are crap, inverter might shutdown due to low voltage,

fridge is within 4' of the inverter so I dont think it is undersize wire, she has 14ga which should handle 15 amps

Thin wire feeding the inverter, feeding the fridge.

 

[tmcblane]

Thin wire feeding the inverter, feeding the fridge.

2/0 to inverter from lithiums, and 14ga is standard in housing for 15 amp circuits feeding full size fridges, I dont think either of those is the issue.

 

[Abodyofscience]

There should be a high voltage short duration spike into the inverter because the compressor is an inductive load.
You could gamble a few bucks and put a surge suppressor between the fridge and the inverter.
Figuring out how many joules for the suppressor is another issue.
Random tripping proly means not much suppression is needed.

 

[timselectric]

Try plugging the fridge directly into the inverter. And, you'll know for sure.

 

[tmcblane]

I think maybe I found it. She has 3 outlets connected to the inverter and one of them had the wires reversed. When I put my plug checker in it showed reverse polarity, so I started pulling the outlets and the last one on the line had the wires reversed. I fixed that and plugged the fridge back in and letting it run to see if it does it still. She had a small 200 watt heater plugged into that last outlet but it wasnt on. Will see what happens!

 

[Abodyofscience]

it randomly kicks the inverter off.

How many days or weeks before you figure this reversal fixed it?

 

[circus]

Any ideas what I should check for her?

I tested my new inverter with a Kill-a-watt meter.

 

[tmcblane]

How many days or weeks before you figure this reversal fixed it?

I just found it today so I have it running now to see how it does.