50A Shore power neutral to Growatt 6000T?

[Munson]

Hello everyone! I'm new here and struggling a bit trying to set up my first inverter (a Growatt 6000T) in my 5th wheel (a 2021 Jayco Pinnacle MDQS). I have attached a crude wiring diagram to hopefully explain my current situation. First, I built a battery and installed it in the front storage where the generator would typically go on my trailer. The trailer is "generator prepped" and gives me great 6/3 AC access to my transfer switch from the front storage. Next, I put a Growatt 6000T in the battery compartment which is also in the front storage. I wired the Growatt to the battery and "generator" wiring. Viola! Everything works great! The inverter can power the whole coach off the battery... The next step is getting the "AC input" wired up. This is where I'm running into my first problem.

I ran the 3 wires the Growatt wants (Hot1, Hot2 and Ground) from the inverter up to the transfer switch. I disconnected the shore power from the transfer switch (Hot1, Hot2, Ground and Neutral) and connected the Hot1, Hot2 and Ground to the Growatt. I didn't know what to do with the neutral so I capped it and turned on the power. Immediately, the surge protector (connected between the receptacle and coach plug) got really angry and turned red saying that it wouldn't supply power as the RV has no neutral connected. The coach runs fine on the Growatt using the battery, but I need to use the pass through function as well as charge up the battery when needed. The solar is still not connected. I tried bonding the neutral to ground but the surge protector did not like that either. I had considered removing the surge protector from the equation, but wanted to get a little clarity before proceeding with any potentially dangerous experiments. What is the correct way to connect this neutral wire?

I have a couple other questions about my system setup, but want to tackle the issues one at a time. Namely, I'm concerned about the 12v converter that came with the coach and the whole 48v/12v "interface". The 30A breaker to the DC/DC converter is currently tripped to allow the factory converter to charge the 12v system on its own. Once the Growatt powers the 48v bus from its AC input (Charging), I will remove the factory converter and allow the DC/DC converter to power the 12v system. Also, are there any concerns with the two 12v SLA house batteries in the system? I kept them in to reduce the surge when drawing high amp DC loads (levelling jacks/slideouts), but had originally planned to remove them. They fit, so I was hoping to keep them as long as there aren't any issues.

Thanks so much in advance! I'm extremely satisfied with the progress so far and the "proof of concept" watching the inverter crank away producing 4,500 watts continuous from the battery I built. Now just to figure out this neutral wire!
~M.




Also, here's a picture of the battery I built... Just because I'm so proud of it!

 

[Munson]

Anyone?

 

[Rogerb]

Am I correct in reading that the trailer does NOT have the generator indicated in your schematic?

 

[Munson]

There is a generator, but it's just a small portable one. I am considering wiring a plug for it to the exterior of the trailer... However, now that you pointed it out, I wouldn't want it hooked up the way that it is shown in the schematic... I would want it to connect to the Growatt to charge the batteries while providing power to the loads.

Perhaps I need to keep the shore power and generator line input connected to the transfer switch, then send the transfer switch output to the Growatt and the return lines (AC out from the Growatt) directly to the coach.

However, I'll still need to find somewhere to connect the neutral wire from the transfer switch out...

 

[Munson]

So, to be clear:

Surge protector reconnected to the shore power on the transfer switch

New wiring to the generator input on the transfer switch

Disconnect the coach from the output of the transfer switch

Connect the 2 hots and ground from the transfer switch output to the Growatt (What do I do with the neutral from the transfer switch?)

Connect the Growatt output directly to the coach AC Load (which was disconnected from the transfer switch) This is what I'm using the original 6/3 "generator" wiring for...

Make sense? Still need to figure out the neutral...

 

[Rogerb]

You have a basic understanding with your first response.
But since you don't have an installed generator, get rid of the transfer switch, and get a 30A to 50A adapter for your Champion genny.
At 2kW, it won't let you do much in the trailer, but for charging purposes, it should work well enough.
Attached is a revamped schematic, with the ATS and 12v charger removed, and a switch on the DC-DC adapter to 12v bus bar.
Also the neutral is to go to the 120v panel and tie all of them together.
You have specc'd the fuses for the wire required for the 48v and 12v systems, yes?

 

[Rogerb]

If your DC-DC converter is able to be switched off remotely, that would be good, but keep the switch, just in case.

 

[Munson]

Duh! It's amazing what a fresh set of eyes can see. I will be removing the transfer switch tomorrow! Of course it just makes sense to plug the trailer directly to the genny. As for the neutral, it also makes sense just to bypass the Growatt entirely and go straight to the panel. Fortunately, all the wires are already in place so it's just a matter of rewiring at the transfer switch location.

I have slightly oversized my wires throughout, and the breakers and fuses are sized correctly (perhaps slightly conservative). Right now it's a bit of a mess just getting everything working together. Once it's working, the main concern will be cable management to prevent chafing while travelling.

The dc-dc converter doesn't have a switch to turn it off, just a 36v-60v In, 12v out and a ground. I have put a 30a breaker on the 48v input which I can trip to cut the power as needed. That wire is 8 gauge and approximately 8 inches long in total.

I can certainly put a switch between the converter and the 12v bus. Thanks for all the help! I'll be wiring it up tomorrow and will report back.

 

[Munson]

Alright... So things have been all over the place with this build. First, I wired everything as depicted in Roger's updated schematic. I used the opportunity to hard wire the surge protector into the location that was previously used for the transfer switch. As soon as power was applied, the surge protector shut the system down giving an error for a missing neutral (I guess it didn't like the neutral going directly to the loads).

So, after some consideration, I removed the surge protector from the mix. I wired everything directly as described in the schematic bypassing the surge protector. The Growatt powered up and everything seemed to be working perfectly. I tested the system and came away with some promising results. Upon disconnecting the shore power, the inverter immediately switched over to battery as expected. Upon reconnecting shore power, the battery began charging at approximately 30 amps, which seems pretty decent considering the ~3-4kw continuous load on the line from 2-3 space heaters running continuously.

Within 30 minutes of testing, I had my first failure. This was an overload (E51). As indicated in the manual, I reset the inverter. I reduced my loads, and everything appeared to be working properly. Yesterday morning I woke up to another overload. This time, I smelled slight burning. When I tried resetting, I saw and heard a few large sparks from within the inverter. I immediately shut it back off. I have left the inverter off, disconnected the battery and in the meantime rewired the trailer Shore power -> Surge Protector -> 120v Loads. Everything is back to normal for now, but it appears I have a fault somewhere in my wiring or in the inverter itself.

There were a few things I noticed while the inverter was "working properly" that may help in diagnosing my problem:

First, in the ShinePhone App (Growatt's App), I noticed that no "Load Consumption" was appearing while I was connected to the grid. I assumed that this meant that the inverter was working in passthrough mode and so was not registering any load on the inverter itself.

I was averaging approximately 50W "Import from Grid" continuously. I assume this was the standby power for the inverter. The approximately 3kw to 4kw load was nowhere to be found within the app.

With the space heaters in the trailer running, I did notice the fans on the inverter were on at full power. This seems unnecessary in passthrough mode.

No power was ever taken from the battery and it has remained at 99% SOC since the inverter first charged them up. The inverter was set to Utl mode (essentially UPS)

Does anyone have any ideas? I'm happy to provide any additional information, photos of the system, settings or screenshots of the ShinePhone app if relevant. I'm at a loss as to why this failed this way. I plan to keep the system off until I can uncover the cause of the sparking and failures.

Thanks!

 

[Rogerb]

I re-read your initial post, and then your last post. The surge protector is telling you no neutral from your shore power.
Double check that your shore power is wired correctly.
Is the Surge protector this one:

50 Amp Bluetooth Surge Protector - Portable - Hughes Autoformers

Our new Power Watchdog Smart Surge Protector offers 6,100 Joules of advanced surge protection for your coach and includes our patented Bluetooth connectivity so you can monitor live park power conditions on your smartphone using our free mobile app.

hughesautoformers.com

Or this one:

50 Amp Bluetooth Surge Protector with Auto Shutoff - Hardwired - Hughes Autoformers

Our new 50 amp Power Watchdog Smart Surge Protector offers 6,100 Joules of advanced surge protection for your coach. It features advanced circuit analysis to shut off power in an emergency* and includes our patented Bluetooth connectivity so you can monitor live park power conditions on your...

hughesautoformers.com

 

[Munson]

Thanks for the reply! My surge protector is the second one, only the portable version... Which I disassembled and made it hard wired. Either way, it is wired in now with no issues and working great. That suggests that whatever it doesn't like is downstream. Any more thoughts?

 

[Rogerb]

You have it plugged into shore power, and it's all green now?
But get an issue if you connect it to the growatt without the neutral?
Just making sure I'm understanding right.

 

[Munson]

You are correct.

When connecting the Growatt, I did it exactly as shown in your schematic. I sent the 2 hots and ground to the Growatt from the surge protector. I tied the neutral from the surge protector to the neutral output *from* the Growatt and the neutral for the loads. The surge protector did not like that and gave the error message.

I then removed the surge protector from the equation. I sent the 2 hot lines and ground to the Growatt. I tied the shore neutral to the neutral output from the Growatt and the neutral for the loads. The Growatt ran... And then failed as described.

 

[Munson]

Just in case it wasn't clear, after the failure, I rewired everything back to the the way it was before I connected the Growatt.

and in the meantime rewired the trailer Shore power -> Surge Protector -> 120v Loads. Everything is back to normal for now, but it appears I have a fault somewhere in my wiring or in the inverter itself."

I am living in this trailer and didn't want to have my electric heat continually cutting out (best case) or start a fire (worst case). At this point I'm not sure if the Growatt is safe or not. It did appear to work after resetting it, but it seems to be pretty unhappy with something in my setup so I have it disconnected until I can find out more. I definitely don't want to fry it any more! Thanks!

 

[Rogerb]

Hmmm, are you able to tie the neutrals in the main panel, not at the Growatts neutral?
that might be the difference, but I can't see why it would.
Gonna show my electrician friend the 2 pics and see if he has any suggestions.

 

[eXodus]

I had my first failure. This was an overload (E51). As indicated in the manual, I reset the inverter. I reduced my loads, and everything appeared to be working properly. Yesterday morning I woke up to another overload. This time, I smelled slight burning. When I tried resetting, I saw and heard a few large sparks from within the inverter. I immediately shut it back off. I have left the inverter off, disconnected the battery and in the meantime rewired the trailer Shore power -> Surge Protector -> 120v Loads.

As I understand the Growatt software - as soon as you charge - it's drawing all power from the Grid, it's not inverting anymore

So you got your load + the charge rate coming from the grid.
I don't know about the 240V models - but my Growatt 3000w 120V version is not monitoring input.

So I get an overload condition when charge with 2kw and also add load like a Microwave or A/C
When I'm grid connected - I'm reducing the charge rate - so that I'm not overloading the Inverter.

For instance - I thought - I can charge with 2kw and run loads of 3kw - that's wrong.
Charge + loads the total can not be more then 3kw.

So I assume that with heavy charging + space heaters you overloaded the growatt. Further - depending how your RV outlets are wired - maybe you overloaded one leg. But also - you could just have gotten a bad Unit. - happens once in a while

 

[Munson]

Thanks so much for the replies. It's very strange. The first overload definitely happened while the battery was charging and the second definitely happened with a fully charged battery.

Perhaps the inverter "kicked on" to top up the battery, but shouldn't it just be float charging with a low amperage?

So, eXodus, if I understand correctly, you're saying that the output of the inverter in passthrough mode is limited to the 6kW it can invert? If so, this is an extremely unfortunate as I can pull 12kW directly from the wall on shore power alone. If anything, I would have thought the inverter would have been able to boost my output by adding inverted current from the batteries as needed, not bottlenecking my system while on shore power.

These are interesting points to consider. I still do not understand the sparks I saw a video from Malaysia where the installer used mesh to block the fan holes from "suicidal lizards" and am wondering if something found it's way in there to get warm...

I also don't understand the lack of data logging while I was pulling my 4kW base load... The app simply showed the 50w "import from grid". I'll attach screenshots.

Lastly is the neutral problem. I can't understand why the surge protector will not recognize the neutral when it goes directly to the panel... More investigation underway...

 

[Munson]

 

[eXodus]

o, eXodus, if I understand correctly, you're saying that the output of the inverter in passthrough mode is limited to the 6kW it can invert? If so, this is an extremely unfortunate as I can pull 12kW directly from the wall on shore power alone. If anything, I would have thought the inverter would have been able to boost my output by adding inverted current from the batteries as needed, not bottlenecking my system while on shore power.

correct - the pass through is limited to the 6KW (2x 3000w if I'm not mistaken) not what your outlet can provide.

The major issue with this - the Growatt doesn't monitor that. So you can pull a lot more - and then the internal wiring goes up in smoke.
It's like running a wire with a much to large breaker.

I've installed a 30A breaker now for the input of the Growatt (you would need a double 30a) to prevent it from overloading it's internals.
And I've already tripped that breaker. (which would be 3600w)

 

[eXodus]

View attachment 78559

it doesn't look like it was doing much when it had it's error.