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Need assistance. Renogy 3000w inverter tripping internal GFI with Air Conditioner

babybober

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Jan 27, 2021
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Wondering if anyone has any ideas. I am installing a lifePo4 battery system ( 12v/600ah) with a 3000w renogy inverter in our 5th wheel camper. At this point I have everything mostly installed and am testing. No issues running microwave, coffee maker, etc. While not critical I was hoping I could use the 13.5kbtu AC unit at times. When I attempt to run it all is fine when the fan is on but as soon as the compressors kicks in the inverter shuts down instantly and the GFI light comes on. Note, not the over current led. I have a 300a fuse before the inverter and that doesn’t blow. I am wired off of the high power terminals not the AC outlets on the unit. AC runs fine on house power. Ideas?
 
What is the exact model of this inverter so I can look up the user manual and read it?
 
OK, I just read the manual.
You do have AC Volt meter, correct?
I would like you to check the ACV on the AC output terminals.
1) Measure between GND and Neutral.
2) Measure between GND and Line.
3) Measure between Line and Neutral.

Then you will measure the ACV between the AC output terminals and one of the AC outlet (just to be sure, you do know which is Line and Neutral on the AC outlet, correct?).
1) Measure between GND the AC output terminals and Neutral of the AC outlet.
2) Measure between GND the AC output terminals and Line of the AC outlet.
3) Measure between Line the AC output terminals and Line of the AC outlet.
4) Measure between Line the AC output terminals and Neutral of the AC outlet.

What is the make and model of the Aircon?
I still think the surge of the compressor is causing the problem,
for example:
The PH3100Ri is rated at 3000W (25.0amps@120V) and has a peak capability of 3150W (26.25amps@120V). Typical starting surge amps for 13.5K A/C units range from 25-32 amps..
 
OK, I just read the manual.
You do have AC Volt meter, correct?
I would like you to check the ACV on the AC output terminals.
1) Measure between GND and Neutral.
2) Measure between GND and Line.
3) Measure between Line and Neutral.

Then you will measure the ACV between the AC output terminals and one of the AC outlet (just to be sure, you do know which is Line and Neutral on the AC outlet, correct?).
1) Measure between GND the AC output terminals and Neutral of the AC outlet.
2) Measure between GND the AC output terminals and Line of the AC outlet.
3) Measure between Line the AC output terminals and Line of the AC outlet.
4) Measure between Line the AC output terminals and Neutral of the AC outlet.

What is the make and model of the Aircon?
I still think the surge of the compressor is causing the problem,
for example:
The PH3100Ri is rated at 3000W (25.0amps@120V) and has a peak capability of 3150W (26.25amps@120V). Typical starting surge amps for 13.5K A/C units range from 25-32 amps..
Bud, thank you. Due to family obligations it may be a couple days before I can take measurements. I am an EE so , yes, I do have a proper volt meter and do understand the difference between growing and neutral, etc. my gut says it might be overload as you mentioned and could put a soft start on the AC but what is throwing me is the over current error led is not tripping it is the gfi. I really don’t want to spend $300 on a soft start till I am sure it is the issue. Btw, this is the AC unit. https://www.dometic.com/en-us/outdo...ners/dometic-penguin-ii-high-efficiency-74975.
 
Do you have Fluke clamp on Amp meter that can capture peak current reading?
Did you try it with big shovacc or anything with high surge that last more than 3 ~ 4 AC cycle?
BTW, you can verify if it is true Ground Fault condition that trip the GFCI circuit or not by disconnecting the Ground wire to the Aircon since GFCI circuit looks for imbalance of the current in the Hot and Neutral line, so if no ground connected then there will be no path for the leakage current (>5mA) to flow back to the source via ground wire to trip the GFCI circuit, so make sure there is no ground path from Aircon back to the inverter to do the test and do not touch the Aircon exposed metal body during test.
Some badly design GFCI will fault triggered on noisy load switching.
 
Last edited:
I just found your thread while searching for "soft start" and GFCI issues, can you swap out the GFCI outlet on the inverter like I'm about to do?

 
LIke @HRTKD mentioned in the other thread, does this inverter have a hard wiring option? Might be too much for a 15 or 20 amp outlet. My 3000 watt Samlex has a 20 amp GFCI outlet or a 25 amp hardwire.
 
The more I look at this problem, the more I'm thinking about biting the bullet, buying one more 200ah battery, and going to 24VDC. I just bought three 12V 200ah batteries, 600ah, and am searching for an inverter and have been reading thread after thread about the same issues. It seems that there is a limit to what you can power with a 12-volt inverter, no matter the capacity you have feeding it, given the surge factor. I picked up a sweet 1988 28-foot class C RV on an E350 chassis cheap back in May. It has a 30A system, and I wanted the same capacity with the battery system. I bought a 15k BTU rooftop because I got it on sale right after I purchased the RV. It's for when living on shorepower, but I wanted to be able to use it on batteries for short periods. I know others who can, but they're using a 24-volt system. The manual claims 13.5 amps running on high but doesn't give the starting amps; not much help. I plan to have a 6k BTU window unit in the back, 3.5 amps/400watts, for boondocking, and a ten cu. ft. refrigerator along with a small microwave. From everything I've read so far, even that 6k window unit will give me starting issues with a 3000 to 3500-watt inverter. It seems that going to 24-volts tends to solve this problem. Thoughts?
 
Just for reference, my Victron MPII 12/3000/120x2 can run my 15k btu ac with soft start running off of 2xSOK 12V 206Ah batteries. Pulls 115A. The MPII is hardwired to my AC panel so no GFCI.
 
I just found your thread while searching for "soft start" and GFCI issues, can you swap out the GFCI outlet on the inverter like I'm about to do?

Unfortunately I am on a hard wired port and the GFCI is internal circuits
 
LIke @HRTKD mentioned in the other thread, does this inverter have a hard wiring option? Might be too much for a 15 or 20 amp outlet. My 3000 watt Samlex has a 20 amp GFCI outlet or a 25 amp hardwire.
I am on the high power hard wired port.
 
I also have a problem with the 3000 watt inverter. It trips the GFCI every time my desktop computer is turned on. I know this computer has a 850 watt power supply but that is way under what this inverter should handle. It does finally start but it takes two or three times. Not knowing enough about all the things that go in with dc to ac I'm sure it's something with the draw my work around is make sure the TV/monitor is off. Once the PC is on I can then turn on the TV. I also am thinking about switching to a 24 volt system. I live off grid in a newer travel trailer on land I bought a few years ago. Since I'm retired I have had to build my system little at a time.
 
I was able to resolve my issue by putting a soft-start on the AC unit. It was overcurrent.
 
I wound up here because I have been experiencing a similar problem with my brand new inverter. I cannot run a chest freezer and a refrigerator at the same time on my setup, which is ridiculous (see my profile for system components). Then, after watching many videos and reading lots of blogs and threads on the subject, none of which seemed to solve my problem, it dawned on me that maybe my battery to inverter cables were undersized. I thought 4 awg wires would be good, but apparently I need at least 0 awg or, better still, 4/0 awg, whatever that means! Now I am thinking the GFI is tripping when the second compressor kicks back on in either the fridge or the freezer. Particularly since the inverter has no problem running one or the other alone. I’ve ordered the 5’ 4/0 awg cables from Renogy and will find out soon if this was the problem. I’ll come back here and post the results if anyone is interested.
 
I cannot see why you would want to run a cable that could not supply 300A to an inverter that can produce 3000W.

I understand copper is expensive, but buying copper that will not be used what so ever is even more expensive.
 
Wondering if anyone has any ideas. I am installing a lifePo4 battery system ( 12v/600ah) with a 3000w renogy inverter in our 5th wheel camper. At this point I have everything mostly installed and am testing. No issues running microwave, coffee maker, etc. While not critical I was hoping I could use the 13.5kbtu AC unit at times. When I attempt to run it all is fine when the fan is on but as soon as the compressors kicks in the inverter shuts down instantly and the GFI light comes on. Note, not the over current led. I have a 300a fuse before the inverter and that doesn’t blow. I am wired off of the high power terminals not the AC outlets on the unit. AC runs fine on house power. Ideas?
Im having the exact same issue with my Renogy 3000w inverter. Ground fault, not overload. I found out, if I turn of the fridge, or breaker to it. It works most of the time but not all. Also seems to be messing with me. So I'm thinking I'm right at the edge of some power limit for the inverter I'm pretty sure I don't have a wiring issue in the camper.
 
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