Xantrex inverter and generator issue with Air con start.

[Chandler1]

I installed a Xantrex inverter a couple of years ago to run off batteries. I did this when installing a solar system on the roof. The system works great with one exception. When I turn on air conditioner the surge current needed to start ther a/c is enough to drop the generator voltage for a second and the inverter decides the voltage is not good and shuts it off. This shifts the a/c to my batteries and if I'm not fully charged I get a low voltage error for the dc.

I've tried several things. The generator is running good and I added a new start capacitor and hard start cap to the a/c on the roof hoping to help it over the starting issues.The issue still happens.

Were heading out next week and so I decided to rewire the incoming voltage and bypass the inverter with my air conditioning load. My incoming line now goes to a 30A circuit breaker and the output goes to the inverter and another 20A circuit breaker. The 20A circuit breaker goes to the air conditioning hot line in the RV's stock circuit breakers. Inside my new circuit breaker box I tied the nuetral's together and tied the grounds together. Assuming everything is ready I plugged in shore power to our house with circuit breakers off.

When I plugged in I immediately tripped the GFCI in the garage. This is with no voltage being passed.I thought the box had an issue with the neutrals and so removed them and wire nut them together. Same issue. I'm assuming it's something with the grounds and nuetrals and the way.

During my troubleshooting I removed the nuetral wire connection for the new air conditioning line that goes from the 20A circuit breaker into the old RV circuit breakers. The wiring to the actual air conditioning unit still has the nuetral connected to the bus and also the main line output from the inverter still has nuetral connected in the old rv circuit breaker.

With the nuetral for that one line disconnected my gfci trip went away. I enabled the new 30A circuit breaker and the incoming shows on the xantrex gauge. Next I enabled the 20A circuit breaker and the air conditioning fired up. Everything works and also the generator fires up the airconditioning without issue. The inverter still shuts off the mainvoltage output during air conditioning srtatup but since I wired around the inverter, the air conditioning starts fine and after a few seconds the voltage output is restored to the inverter.

Right now I'm just checking if anyone has an idea why the nuetral connection tripped gfci when this is the same way it was always wired without the inverter. The old main input would be wired to the main circuit breaker and not the airconditioning though.

I'm going to try to maker a schematic for what I did next week to help someone give better feedback.

[christopherglen]

I opted to install one of these. The transfer switch is between the inverter output, and my subpanel on the inverter input. It is set up so if I have shore / generator power, the ac is powered off that, if I don't, it switches the AC to the inverter. My subpanel powers the inverter's 2 30 amp inputs, both ac's, the electric water heater, and my 100 amp converter. The converter is for when all I have available is 20 amp service, I can use double conversion and use the microwave, toaster, coffee pot, and the girls can use the hair drier all at the same time - not for long, but other then the hair drier everything is quick, and the batteries recover at 100 amps.

[Chandler1]

I think I may have figured it out. I think I connected the input and output neutrals of the inverter together by tying into the main old power bus. I need to remove the neutral of the wiring that goes to the air conditioning unit itself and connect it directly to the neutral wire I removed earlier from the bypass to complete the circuit and eliminate any connection to the inverted output. My old main circuit breaker box has the inverter output running into it. When I connected my neutral for the direct air conditioning wiring to the main bus I inadvertently connected incoming and outgoing neutrals of the inverter.

[Chandler1]

I set the trip points on the Xantrex as loose as possible in the on screen controller. The lowest incoming allowed is 78Volts. The Xantrex is also tripped when I shut off the air conditioning and the high allowed voltage is set to 140V. Shutting off the Xantrex doesn't help any if the main AC for the coach passes through it. I can disable the inverter while passing the AC but still have the control problem shutting off the AC when air conditioning starts.

[Chris_Bryant]

Chandler1 wrote:


During my troubleshooting I removed the nuetral wire connection for the new air conditioning line that goes from the 20A circuit breaker into the old RV circuit breakers. The wiring to the actual air conditioning unit still has the nuetral connected to the bus and also the main line output from the inverter still has nuetral connected in the old rv circuit breaker.

I'm having trouble with this part- you shouldn't be able to remove connections and still have it work- though I'm not sure why or if that would cause the problem with the gfi. Keep in mind the Xantrex *may* bond neutral and ground while running.

I would question why you didn't either set the "trip" points looser on the Xantrex, or even just turn it off while running the air.