Inverters - bonded/floating ground and reversed hot/neutral

[time2roll]

Here are some things I have used my handy power x with. Air compressor, coffee maker, space heater, charging my Eco flow. The space heater takes 1500 watts on high and it seemed to do fine with that. The protection looks like it's for under voltage and over voltage from the battery / alternator. Or probably if it detects some other error situation. Something interesting that happens with my Chevy traverse is that if I don't have a load on the inverter it goes into an over voltage situation and then the protection kicks on. And I have to restart it. Annoying but seemingly if I have something plugged in it won't do that.

Yes I believe the Traverse is a bit light on battery power for anything much over 1500 watts for a few minutes or maybe 600 watts continuous. Probably keep your fridge running but maybe not the furnace. And yes the alternator may press the voltage above 15 when the computer senses the battery is desperate and then you have no load.

If you had a diesel truck with two batteries and larger alternator you would probably have better luck.

Might be workable with some additional battery but truly there is just not the continuous power available that you expected.

 

[harrymanimus]

The inverter ran the space heater at 1500 watts for many many hours during the storm. It's only when there is no load on the inverter, nothing plugged in, that something between the traverse and the inverter happens triggering an over voltage. I just made sure to always have something plugged in and turned on. I'm almost 100% sure it would have run my furnace if I had a bonded ground situation. The furnace is only drawing 600 watts.

The Handy power x claims that most any car will run this inverter because I guess the alternator is taking over. I haven't really tried it on any other car though.

 

[time2roll]

If you run a 60 watt incandescent light from one of the outlets will the power stay on? Use a separate outlet to run the furnace. Did the furnace indicate open ground? I did not realize any furnace had this function.

How are you plugging in the furnace? Extension cord?

 

[harrymanimus]

If you run a 60 watt incandescent light from one of the outlets will the power stay on? Use a separate outlet to run the furnace. Did the furnace indicate open ground? I did not realize any furnace had this function.

How are you plugging in the furnace? Extension cord?

I didn't specifically test something as low as 60w. I probably will at some point. But if I quickly unplugged the heater, and plugged in the coffee maker I could keep the overvoltage from happening. If I took more than, say, 10 seconds, the overvoltage would trip and I'd have to go restart the vehicle.

I posted on AC forums about why the furnace fan would run but the natural gas jets would not seem to flame up properly to blow warm air using both the EcoFlow and the inverter. It was a consensus from those discussions that the furnace needed a bonded ground to flame up properly. Neither of my power products provide that.

I was plugged in directly with a 25ft 10 gauge, then another 25ft 16ga. When testing the EcoFlow I was just using the 25f 10ga extension.

 

[Delmar]

If you backfeed your breaker panel (no different than connecting a generator) then the neutral and ground automatically get connected to panel ground and outside driven ground rod. This should eliminate your open grounding issues. And eliminate a tangled mess of extension cords.

You can first test for an inverter “live neutral” by putting a small fuse in the neutral line. My Reliable 2500W 48V inverter has the floating 60V line & 60V neutral when not grounded, but has no problem operating when connected to ground. However I always connect to the panel before switching on the inverter. It successfully ran my gas furnace during the great Houston freeze.

 

[time2roll]

I can't imagine the ground would have any effect on the burner flame. Gas valve opens and the fire burns. There is no throttle or halfway on this.

 

[GXMnow]

My guess is that it has to do with microprocessor electronic controls. To make a modern gas furnace "Safe" they have several checks and safety devices. My Carrier furnace is over 10 years old now, but it is quite complex. Once it gets a signal to make heat, it goes through a multi step process before it finally opens the gas valve. It spin up a draft fan, checks for proper air flow with a differential pressure switch. If air flow is good, then it turns on the hot surface igniter. If air flow was not correct, it shuts down with an error code. When the hot surface igniter get's hot, the IR eye "sees" if it is hot enough, it will then open the pilot gas flame. Again, not hot enough, then it shuts down with another error code. Then there are a pair of wires in the flame, it measures the impedance through the flame and can detect if it is burning or not. If all is good a this point, it opens the main gas valve and the pilot flame ignites the main burners. If it does not detect the pilot flame, it shuts off, with yet another error code. If all 4 flame tubes do not get hot, it shuts off. Again, another error code. I think it has at least 8 error codes just for heat mode. If the flame tubes are hot, then it turns on the blower to push the hot air into the house. It also has a 2 speed draft blower and 2 stage gas valve for low and high heat modes, and a 6 speed inverter blower.

Without a proper ground, maybe it won't even try to light. Or a poor ground is making the signals noisy enough that it can't properly read the IR sensor or the flame detector. I never tried to run mine without it having the neutral and ground still tied into my main panel with a bonded neutral. Bu tI have run it from both my generator and my inverter without a problem.

 

[Bud Martin]

The furnace running on AC has safety ground which is bonded to the Neutral so if the fault current occur the circuit breaker will blow.
The electornics module used in the furnace has it is own DC power supply that is supplied by the incoming AC, the cold side of this DC power supply circuit has its circuit ground connected to the chassis of the furnace. the flame dectector (flame diode type) use chassis as current detector path, it does not care if the chassis is connected to safety ground or not.. My gas furnace will still run with no problem if I lift the safety ground.
If you inspect inside of most equipment with 3-prong power cord, you will see that the cold side circuit grond will be connected to the chassis which is connected to safety ground.
Follow-up: I also use my EB70 that I just bought to test run my furnace, it works just fine.

 

[harrymanimus]

I thought I'd report back with my solution for running my central heat (and other 120v plugs/appliances) of my house.

I had installed a female 220v plug attached to a breaker in my garage. (Maybe I'll charge an EV someday.) I have a cable with 2 standard 3 prong male plugs to plug into 2 outlets on my EcoFlow, and a male 220 plug on the other end.

Power goes out, flip the main breaker and the sub-panel breaker and back feed all the 120v circuits. This achieves exactly what I want, a way to run all my 120v household equipment for emergency purposes. Just no stove top, oven, or AC.

I tested this and had my central heat, fridge, freezer, many lights going. (The digital iron did trip my EcoFlow circuit protector at first, forgot to unplug that).

Yes, you could get in a bad situation if you were not careful, but I'm willing to live with that as I'm going to be the only one touching this setup.

I have another post going here about my inverter quality for charging my EcoFlow.

Pure sine wave inverter quality (from automobile) for lithium ion charging

I have 2 products. An inverter for my car, and an EcoFlow Delta Portable Power Station. My goal here is to charge my EcoFlow Delta (also have a Pro version on order) from the car inverter in a non detrimental way to the life of the EcoFlow product or battery. Inverter Product...

diysolarforum.com

 

[watchdoc]

I have a Handy PowerX as well and love it. My wife uses it connected to our RV batteries to make her morning coffee. so we don't have to listen to the generator. I even did a short test to see if it would charge my Nissan Leaf and it worked! It was rapidly discharging the batteries though. I plan to add some solar and more battery power and see if I can sustain charging my Leaf for several hours. The stock EVSE pulls 1440 watts so I plan to get a Zencar Level 1 adjustable EVSE. It will charge all the way down to 6amps @ 120 volts.

 

[harrymanimus]

Update on my setup: I now have an Ecoflow Delta Pro. The Handy Power X outputs floating neutral 60v to ground, which when I use that to charge my Delta Pro, the Pro outputs the same floating neutral setup. I don’t want that going into my house plug. I tried another decent brand of inverter off amazon, it also had the floating neutral, sent it back. So my solution was convert the AC of the HPX to DC for charging the Delta Pro thru the DC charging port.

This is how the power flows in my setup: Automobile —> Handy Power X —-> Switching Power Supply AC to DC —-> DC input to Delta Pro —> Delta Pro DC to AC —> House.

During an extended power outage, with conservative power usage, and the larger battery of the Delta Pro, I don’t expect to be running my auto constantly. Maybe once a day for 4 hours or so is a guestimate.

Considered getting a second delta pro to run my AC at 240v, but instead I’ll buy a window unit to “get by” in the summer that can also do double duty at my camphouse.

 

[GooseF16]

My guess is that it has to do with microprocessor electronic controls. To make a modern gas furnace "Safe" they have several checks and safety devices. My Carrier furnace is over 10 years old now, but it is quite complex. Once it gets a signal to make heat, it goes through a multi step process before it finally opens the gas valve. It spin up a draft fan, checks for proper air flow with a differential pressure switch. If air flow is good, then it turns on the hot surface igniter. If air flow was not correct, it shuts down with an error code. When the hot surface igniter get's hot, the IR eye "sees" if it is hot enough, it will then open the pilot gas flame. Again, not hot enough, then it shuts down with another error code. Then there are a pair of wires in the flame, it measures the impedance through the flame and can detect if it is burning or not. If all is good a this point, it opens the main gas valve and the pilot flame ignites the main burners. If it does not detect the pilot flame, it shuts off, with yet another error code. If all 4 flame tubes do not get hot, it shuts off. Again, another error code. I think it has at least 8 error codes just for heat mode. If the flame tubes are hot, then it turns on the blower to push the hot air into the house. It also has a 2 speed draft blower and 2 stage gas valve for low and high heat modes, and a 6 speed inverter blower.

Without a proper ground, maybe it won't even try to light. Or a poor ground is making the signals noisy enough that it can't properly read the IR sensor or the flame detector. I never tried to run mine without it having the neutral and ground still tied into my main panel with a bonded neutral. Bu tI have run it from both my generator and my inverter without a problem.

in fact many of them will shut down the fire if the NG bond is lost, for example if you had your inverter xfer in pass thru, and you pulled the plug out of the wall, where it loses its bond, and runs on inverter.. often times the unit will shut down, and run the fan for a bit and shut down and fault a loss of ground code.. thats how mine works.. had to put a bond plug on the case of my inverter.. had the chance to test some tonight on it..

 

[timselectric]

A lot of modern equipment will throw an error code, if it doesn't see a ground.
And to clarify... it's not a system ground, if it's not bonded to the neutral. Otherwise, it's just an earth reference.