Eg4 3000ehv voltage on neutral?

[timselectric]

Mine is behaving just like that one. This inverter is powering outlets through the "Pass Through" function of another inverter. I have checked the outlets of that inverter and it does not show any voltage between neutral and ground. Though once I use the growatt as the shore power it does. There does not seem to be any neutral ground bond in the ambulance panel that I can see, but the pass through inverter does have a ground wire coming off of the back of it and I imagine it goes to the chassis.

Your Growatt is not providing a N/G bond. This is easily solved. But how depends on how you are using it and connecting it.

 

[llpancholl]

What makes this more interesting, is that when I am plugged into shore power. Then the hot neutral disappears.

 

[llpancholl]

Your Growatt is not providing a N/G bond. This is easily solved. But how depends on how you are using it and connecting it.

So, when plugged into shore power the hot neutral disappears. I can hear the thing doing some switching in there. The line AC out will end up at this fusebox connected by 20 ft of 3C 8 AWG8 wire and by the looks of it, it does not have a neutral ground bond. Are you telling me if I create a bond in this panel between the neutral and the ground that I will no longer have a hot neutral coming out of the inverter?

 

[timselectric]

So, when plugged into shore power the hot neutral disappears. I can hear the thing doing some switching in there. The line AC out will end up at this fusebox connected by 20 ft of 3C 8 AWG8 wire and by the looks of it, it does not have a neutral ground bond. Are you telling me if I create a bond in this panel between the neutral and the ground that I will no longer have a hot neutral coming out of the inverter?

It's not a hot neutral.
It's just two wires (L1, N) that provide 120v.
Without a N/G bond, both wires are floating (ungrounded).
Which is why you are reading approximately 60v to ground from either one.
Don't create the N/G bond in that panel in the picture. Because you may want to actually plug another shore power source in it.
The N/G bond should always be at the source of power.
If the Growatt is never going to have anything connected to its AC input. You can create the N/G bond by placing a jumper between the neutral and ground of its output.
But if you ever connect a source to its input. The jumper will have to be removed.

 

[llpancholl]

It's not a hot neutral.
It's just two wires (L1, N) that provide 120v.
Without a N/G bond, both wires are floating (ungrounded).
Which is why you are reading approximately 60v to ground from either one.
Don't create the N/G bond in that panel in the picture. Because you may want to actually plug another shore power source in it.
The N/G bond should always be at the source of power.
If the Growatt is never going to have anything connected to its AC input. You can create the N/G bond by placing a jumper between the neutral and ground of its output.
But if you ever connect a source to its input. The jumper will have to be removed.

Is the Growatt faulty?? Or is it just a shitty design? Would I be having the same issue with a different inverter?

And if I were to put a jumper wire directly at the output, between the ground and the neutral, how much current should I expect? Could I put a small switch of some kind on that jumper wire that I could switch on and off if I needed to plug into shore power and charge the batteries? Would a light switch be robust enough?

 

[timselectric]

Is the Growatt faulty?? Or is it just a shitty design? Would I be having the same issue with a different inverter?

And if I were to put a jumper wire directly at the output, between the ground and the neutral, how much current should I expect? Could I put a small switch of some kind on that jumper wire that I could switch on and off if I needed to plug into shore power and charge the batteries? Would a light switch be robust enough?

Zero current will flow on the jumper. Unless there is a short. It's only creating a ground. The grounding system only carries fault current.
If you want to put a switch on it that's fine. Just make sure that it's on or off at the appropriate times.

 

[Zwy]

So, when plugged into shore power the hot neutral disappears. I can hear the thing doing some switching in there. The line AC out will end up at this fusebox connected by 20 ft of 3C 8 AWG8 wire and by the looks of it, it does not have a neutral ground bond. Are you telling me if I create a bond in this panel between the neutral and the ground that I will no longer have a hot neutral coming out of the inverter?

Did you disconnect output and unplug input, inverter off, then measure for continuity like I asked?

Anything else is a waste of time. There has to be continuity with the inverter off. That indicates N-G bond is present.

Do not add a N-G bond in your electrical panel or anywhere else. Do not add a switch. If the unit does not bond N-G, then return it as it is defective.

Signature Solar has been known to sell inverters with the screw removed that provided bonding in some models. My suggestion is if this unit does not have continuity as I mentioned between N-G with the unit off, then return it. I purchased my unit from Watts247 and it does bond N-G when under inverter power and removes the bond when plugged into shore power.

 

[Zwy]

Zero current will flow on the jumper. Unless there is a short. It's only creating a ground. The grounding system only carries fault current.
If you want to put a switch on it that's fine. Just make sure that it's on or off at the appropriate times.

The problem with that is he could see hot skin as the grounding system will be a parallel path if he forgets to disconnect the jumper or switch.

He would be a path between the RV and ground.

 

[Zwy]

Is the Growatt faulty?? Or is it just a shitty design? Would I be having the same issue with a different inverter?

Test N-G continuity as I described first. Measuring voltage between N-G when under inverter power without a load can be misleading.

And if I were to put a jumper wire directly at the output, between the ground and the neutral, how much current should I expect? Could I put a small switch of some kind on that jumper wire that I could switch on and off if I needed to plug into shore power and charge the batteries? Would a light switch be robust enough?

Do not install a jumper. This is dangerous as the system is floating, that is not tied to earth. If you forget to remove the jumper and plug into shore power, you have created a parallel path when you are standing on the ground and touch any metal on the RV/ambulance.

I am quite familiar with hot skin. https://diysolarforum.com/threads/p...ain-breaker-due-to-distance.66653/post-839280

 

[timselectric]

The problem with that is he could see hot skin as the grounding system will be a parallel path if he forgets to disconnect the jumper or switch.

He would be a path between the RV and ground.

There would never be a hot skin issue.
Only a double N/G bonding issue. Which would put neutral current on the grounding conductor.

 

[Zwy]

There would never be a hot skin issue.
Only a double N/G bonding issue. Which would put neutral current on the grounding conductor.

Panel grounding to rod at location (not to main breaker due to distance)

I don’t agree with not grounding them. Unless people are going to put rubber boots on their metal ground mount arrays this makes no sense. Another thing is each time a metal frame panel mount touches the ground its basically doing the ground path thing there anyways so were back to might as...

diysolarforum.com

When you feel the tingle, you know you are a path. I never touched the trailer plugged in while it was raining, lucky for me I guess.

A double bond on a floating system plugged into shore power is dangerous.

 

[timselectric]

A double bond on a floating system plugged into shore power is dangerous.

Definitely
But in this case both bonding locations are outside of the vehicle. (Plugged into the shore power of the vehicle)

Or at least this is what I believe we have been told.
There's an existing inverter with shore power connection on the vehicle.
The Growatt's output is being Plugged into the shore power of the vehicle.
I guess that this needs to be clarified, before providing any more recommendations.

 

[Zwy]

Definitely
But in this case both bonding locations are outside of the vehicle. (Plugged into the shore power of the vehicle)

The vehicle chassis and body need to be bonded to the electrical panel on the grounding busbar in case of any short to the chassis or body. Doesn't matter when on shore power or inverter power, the vehicle needs to be bonded to grounding system. With N-G bond at the vehicle electrical panel, when plugged into shore power there will be 2 N-G bonds present and a parallel path created. This makes the grounding system energized with objectionable current. Standing on the ground and touching the vehicle will lead to another path thru earth back to source as the entire vehicle is now energized. If resistance to earth is low enough, current will flow thru the body.

Or at least this is what I believe we have been told.
There's an existing inverter with shore power connection on the vehicle.
The Growatt's output is being Plugged into the shore power of the vehicle.
I guess that this needs to be clarified, before providing any more recommendations.

Any RV or vehicle that plugs into a shore power connection needs to have the vehicle bonded to the EGC system. Shore power is providing the N-G bond.

When under inverter power, the inverter needs to bond N-G as it is source. Again, the vehicle needs bonding to the EGC system. One could have N-G bond in the vehicles AC power electrical panel but it can't be plugged into shore power without creating hot skin when plugged into shore power.

The only other choice is to use the Growatt with a receptacle and the shore power cord plugged into that receptacle. But the Growatt would need to provide the N-G bond or use a generator bonding plug on the cord if the Growatt is not bonding N-G. I do not recommend using a bonding plug until it is confirmed the Growatt does not bond N-G. This needs to have the continuity test done between N-G with outputs/inputs connected and inverter off.

 

[llpancholl]

Did you disconnect output and unplug input, inverter off, then measure for continuity like I asked?

Yes, tested continuity with unit off, no line in or line out connected. solar array disconnector off, battery breaker off.
No continuity between neutral and ground. The only continuity is between the line in ground and the line out ground. There is continuity between both grounds and the case of the inverter. No continuity between the either of the grounds or the case and the skin of the vehicle. The inverter and batteries are secured in a plywood box inside the interior of the ambulance. The solar panels are connected to the aluminum skin so their could be a ground path there.

Do not add a N-G bond in your electrical panel or anywhere else. Do not add a switch. If the unit does not bond N-G, then return it as it is defective.

Signature Solar has been known to sell inverters with the screw removed that provided bonding in some models. My suggestion is if this unit does not have continuity as I mentioned between N-G with the unit off, then return it. I purchased my unit from Watts247 and it does bond N-G when under inverter power and removes the bond when plugged into shore power.

Admittedly I got the Growatt because it was inexpensive. I am not entirely confident that I will be able to effect a return as their customer service is shit and I bought the inverter in Jun 2022, over a year ago. I will reach out and try to return it, but frankly I don't want to get jacked around with the waiting game. So I could just order another inverter from Watts-247, but Growatt has left a bad taste in my mouth.

Signature Solar has been known to sell inverters with the screw removed that provided bonding in some models.

Lets imagine, that right now I buy another 48V Growatt SPF 3000TL LVM from Watts247 that works correctly. Then at some later date, I move these inverters out of the ambulance, and put them in a 100% off grid cabin. Is it forseeable to be able to remove the case covers and add and remove ground screws to safely use them in tandem for 220v, even if they were purchased from different distributers?

Definitely
But in this case both bonding locations are outside of the vehicle. (Plugged into the shore power of the vehicle)

Or at least this is what I believe we have been told.
There's an existing inverter with shore power connection on the vehicle.
The Growatt's output is being Plugged into the shore power of the vehicle.
I guess that this needs to be clarified, before providing any more recommendations.

To clarify. The vehicle is 2000 Wheeled Coach Ambulance. There is currently a shore power plug, that I plan to delete and make a connection to the AC output of the Growatt. I was hoping to make a self contained system with the Growatt, solar and batteries that could just power the existing ambulance as its own 'mobile shore power'.



Solar is 1560 watts I forgot to put on the wire diagram
New stuff on the right, existing stuff on the left.

 

[timselectric]

The only other choice is to use the Growatt with a receptacle and the shore power cord plugged into that receptacle.

This is the case, as I understood it.

 

[timselectric]

To clarify. The vehicle is 2000 Wheeled Coach Ambulance. There is currently a shore power plug, that I plan to delete and make a connection to the AC output of the Growatt. I was hoping to make a self contained system with the Growatt, solar and batteries that could just power the existing ambulance as its own 'mobile shore power'.




New stuff on the right, existing stuff on the left.

So, the Growatt and the existing inverter are both going to be installed on the vehicle?
Still the same as far as N/G bonding. When Growatt is inverting it or you need to establish a N/G bond. When the Growatt is passing power through from another source the only N/G bonding should be provided by the other source.
If the Growatt isn't doing it for you, automatically.
And you don't want to have to remember to do it manually.
You can add a relay to do it automatically, whenever power is applied to the Growatt's input.

 

[Zwy]

Yes, tested continuity with unit off, no line in or line out connected. solar array disconnector off, battery breaker off.
No continuity between neutral and ground. The only continuity is between the line in ground and the line out ground.

Unit does not bond N-G then.

Most likely SS had it built with the screw removed. I went back and watched that video you linked hoping it would show the location of the screw he removed but it didn't. Do not test like that YouTuber, he is doing it incorrectly and doesn't know what he is doing.

You can search around to find a video where it shows the bonding screw location. A screw can be sourced locally or have SS send you one. Open up the unit and see if the bonding screw is present. If there is a screw in the correct location, the unit is defective as the bonding relay is not working correctly. If a screw is not present, install the screw and retest for continuity between N and G. If you have continuity, then you are good to go. The unit will bond N-G under inverter power and disable the N-G bond on shore power using the relay.

There is continuity between both grounds and the case of the inverter. No continuity between the either of the grounds or the case and the skin of the vehicle.

You will need to bond the skin and chassis of the vehicle to either the EGC busbar in the electrical panel or to the inverter. Most likely the electrical panel contains this bond, check for continuity between the EGC grounding busbar in the electrical panel and the vehicle skin and chassis. If this checks out, all that is needed is an EGC ran between the inverter and electrical panel with L and N.

The inverter and batteries are secured in a plywood box inside the interior of the ambulance.


Admittedly I got the Growatt because it was inexpensive. I am not entirely confident that I will be able to effect a return as their customer service is shit and I bought the inverter in Jun 2022, over a year ago. I will reach out and try to return it, but frankly I don't want to get jacked around with the waiting game. So I could just order another inverter from Watts-247, but Growatt has left a bad taste in my mouth.

It isn't Growatt's fault, it is probably the build spec from SS.

Lets imagine, that right now I buy another 48V Growatt SPF 3000TL LVM from Watts247 that works correctly. Then at some later date, I move these inverters out of the ambulance, and put them in a 100% off grid cabin is it forseeable to be able to remove the case covers and add and remove ground screws to safely use them in tandem for 220v, even if they were purchased from different distributers?

It would actually work out very well as you need one inverter bonded and the other not bonded. That is how I run my LV6548's, one inverter still has the screw and the other doesn't. You want the source to be bonded.

To clarify. The vehicle is 2000 Wheeled Coach Ambulance. There is currently a shore power plug, that I plan to delete and make a connection to the AC output of the Growatt. I was hoping to make a self contained system with the Growatt, solar and batteries that could just power the existing ambulance as its own 'mobile shore power'.

View attachment 162387

Looking at this wiring diagram I'd question leaving the Vanner unit connected. The Vanner is rated at 1050 watts. I looked for a pass thru rating, my assumption is pass thru is 1050 watts. It would be best to directly wire the Growatt to the electrical panel or wire the electrical panel with the shore power cord allowing a choice between the Vanner output, the Growatt or shore power. If you do go with the shorepower cord to the electrical panel, you could use a generator bonding plug for use with the Growatt. This would not allow for battery charging on shore power unless you add another cord to the Growatt.

Personally, I'd hardwire the Growatt to the electrical panel, then add a receptacle to the Vanner for a backup power source so a shore power cord could be plugged into it. Run a shore power cord to the Growatt input so the transfer switch will switch automatically between inverter power and shore power when plugged in. This allows battery charging with the Growatt.

Or just remove the Vanner, sell it or repurpose it if you don't want the extra weight and free up space.

 

[llpancholl]

Looking at this wiring diagram I'd question leaving the Vanner unit connected. The Vanner is rated at 1050 watts. I looked for a pass thru rating, my assumption is pass thru is 1050 watts

You can add a relay to do it automatically, whenever power is applied to the Growatt's input.

First, to the both of you, I can't thank you enough for taking your time to solve other peoples problems.
I was hoping to do as little modification to the ambulance as possible at the moment. My main objective was to get an Air Conditioner working, and I have managed to get that done.

The vanner pass thru is 12 amps at 120v that is 1440 watts. Funny I thought it was more, The AC (800 watts) and the Kettle (700 watts) and multiple fans and lights and phone chargers work without issue through shore power at the moment.




All the information you guys have given me in the last 12 hours is going to take a while for me to digest. But, that being said, with knowledge of the pass thru limitations I submit to you a revised wiring diagram to be able to make use of the additional power the Growatt is producing.



EDIT I think I had the wiring diagram wrong, I think the vanner is after the fuse panel

So my current plan is this. I am going to buy a second Growatt from watts247. Install and check that it is doing the neutral ground bond automatically as it should be. Then if this is the case I will continue communicating with SignatureSolar and see if I can get a better understanding of if this unit is defective, or just missing a screw, or whatnot. I will report back my findings if they are noteworthy. Later based upon this knowledge I can use them in tandem when I get my offgrid cabin built.

Once again, thank you all so very much for your time!! And dont forget to look at my updated wiring diagram and tell me if you think it is okay to place a power strip where I have indicated, provided I get the neutral ground bond worked out with the new growatt.

 

[Zwy]

Instead of the power strip, add a breaker panel and wire in outlets for it.

Power strips on inverters sometimes cause problems. There are some threads out there with this problem. Second, installing a breaker panel allows you to take full advantage of the Growatt increased output and pass thru capacity. Power strips can be a fire hazard if overloaded. You will have 25A available from the output of the Growatt and you should take advantage of it.

Email Ian and ask him if the units he sells have dynamic internal N-G bonding so you have that covered before you purchase one. He is very responsive to questions and support. My unit came from him and it works very well for my application.