Solar Project Momentum 21G

[bbinge]

I bought a Momentum 21G last year, and I've been a classic forum lurker for about a year. I've read (and seen) with awe over some of the projects that the members here are doing, it is simply amazing, and I've learned a ton. One of the big lessons is that no one Grand Designs solar system is the same! And I've got a question around the system that I found in my 21G.

The 21G that I bought came with the "upgraded" solar/power package, so a 300W panel (in theory, not sure how to verify that), 1000W inverter, generator, etc. Of course, within a week the Jabroni Bluetooth module plugged into the MPPT, a SC-BTM (which leaves A LOT to be desired, even when it's working) crapped out, so I lost all insight into power generation, etc. I got a new one sent to me from the dealer and that one lasted about 3 weeks. Also, my batteries are OLD (2 6V trojans) and I haven't been taking care of them for the last few years, so with what seems like not the greatest solar components and old batteries (the 12V fridge sometimes doesn't make it through the night with throwing low power errors) I started my current solar component upgrade project.

I live in the high mountains of Colorado (10,000') so the trailer is in storage at 7,300' about an hour away and I can only get out there on weekends - can't bring it home yet, still too much snow. So, as I was designing my system based on posts here, I had assumed there was a physical ATS between the AC panel and the inverter. However, yesterday, as I was decommissioning the old system, I ran across something that I haven't seen in the forum yet. The 1000W inverter included in the solar package (WFCO WF-5110RS), seems to have an ATS built into it and I may have made a rookie mistake with my Renogy 2000W inverter that doesn't seem to have a transfer switch.

Ok, no problem, I just need to get an ATS (any recommendations would be appreciated!) but the there is some cabling that I'd love to verify first. The AC output from the inverter is hard wired internally to that inverter and disappears behind the wall, and there is a "pass through" cable as well, plugged into a standard outlet on the wall like so:



I'm a little confused. I'm assuming the AC Output (red line) goes into the AC fuse panel (sorry lack of better term) somewhere, and I'm assuming I'll have to cut this cord, put a "regular" plug in and plug it into the new 2000W inverter?

And my next guess is what the manual calls the "pass through" (green line above) is actually 110 AC power that comes from the fuse panel when the the shore power is on, and I'll have to wire that into an ATS?

And, I know not providing enough information can be harmful, too, so my system is generally designed like this one, with a couple of differences:

• Obviously, a different inverter, oops!
• 200ah Renogy Lithium Battery (probably going to buy another one shortly)
• Instead of seperate MPPT and DC-DC charge, I went with the combined unit - Renogy DC-DC MPPT
• 300W Solar Panel (hopefully, that is what the paperwork for the trailer said!)

Sorry for the long post, but in summary here are the 4 questions I have:

• Can I to cut the AC Out cord out of the old 1000W inverter, put a 3 prong plug on it and plug it into the new inverter?
• Can I run the "pass through" cable into an ATS? It comes from a regular 3 prong receptacle and disappears into the inverter, too
• What ATS should I use to hopefully make this relatively painless?
• And generally, how is the ATS wired?

Thanks in advance - this is an amazing community!

[acoleman43]

bbinge

I also have a 21G. Mine is an early 2021 model (more similar to 2020 I'm finding).

Mine had a Magnum inverter with a Magnum ATS. I think that's what you were expecting

First, a bigger picture. Skip this if you already know this . A 1000W inverter is not capable of providing power to all AC loads connected to the distribution panel. With this in mind, understand that GD designed the inverter system to power select AC outputs in the trailer, nothing more. To do this those select outputs are wired to a subpanel that should be to the left of your main distribution panel.

This subpanel (if it's like mine - pictured below) will have 2 breakers: Main and Kit/Bed/TV (or something similar). (The Kit/Bed/TV are the outlets powered by the inverter). You moan distribution panel should have a breaker for the Inverter.




This is how it works: when plugged into shore power (or the generator is running), the power flows directly to the main distribution panel and out to each open circuit.

If the inverter DOES NOT have an ATS: When shore power (or generator) flows through the Inverter circuit on the main distribution panel, it will go to the ATS. If the ATS senses power, it will bypass the inverter and go directly to the subpanel thus powering the subpanel and all circuits connected to the subpanel.

If the inverter DOES have a built in ATS, when shore power (or generator) flows through the inverter circuit on the main distribution panel, it will go to the inverters built-in ATS. If the built-in ATS senses power it will bypass the inverter and send the power directly to the subpanel and all circuits connected to the subpanel.

So, knowing this, let's look at your RED AC output in your picture. That should be going directly to the MAIN circuit of your subpanel.

The GREEN pass through in your picture should be connected to the "inverter" circuit on the main distribution panel. If you pull the main distribution panel you will probably find an AC cable running from the inverter breaker to that outlet on the back side of your exterior storage which your inverter was plugged into.

Now that the WFCO inverter is gone and you will be using your new Renogy inverter you will have to make some easy changes.

First, as you pointed out, you will need an ATS. A quick search came up with this one: https://www.amazon.com/KISAE-Technol.../dp/B00IKVHA9K This one is a 20 amp ATS. There is also a 15 amp ATS for a little less money. You will need one that plugs into an inverter.

Once you get the ATS, you will plug the AC plug into one of the 3 outlets in the back of the Renogy inverter.

Second you need to wire the ATS. An ATS will have 2 inputs and 1 output. 1 input will be from shore power/generator (comes from your main distribution panel), the other input will be from the inverter. The output will be to your AC loads (in your case the subpanel to the left of the main distribution panel).

The ATS will have an input and an output you will have to wire.
The output should be connected to the RED AC out you have in your picture. This should be easy.
The input will need to be connected to the Inverter breaker from your main distribution panel 9the outlet on the back side of your outside storage). A few ways to do this. I'd be tempted to run an new wire from the inverter breaker on the main distribution panel to the ATS bypassing the outlet (you would have to disconnect the outlet from the inverter breaker first)....or, if the existing wire is long enough, you can disconnect from the outlet and connect to the ATS.

A couple additional things: Now that you are using lithium batteries, make sure your charger/converter connected to the main distribution panel is made for lithium batteries. IF not, it will shorten the life of your lithium batteries.

My 21G had the Jaboni 300W panel on the roof. If you climb in the roof and there is a large solar panel that covers most of the roof behind the AC, it's the 300W panel.

I hope this llooonnnggg answer helps.

Allen

[Enzo0903]

bbinge

I also have a 21G. Mine is an early 2021 model (more similar to 2020 I'm finding).

Mine had a Magnum inverter with a Magnum ATS. I think that's what you were expecting

First, a bigger picture. Skip this if you already know this . A 1000W inverter is not capable of providing power to all AC loads connected to the distribution panel. With this in mind, understand that GD designed the inverter system to power select AC outputs in the trailer, nothing more. To do this those select outputs are wired to a subpanel that should be to the left of your main distribution panel.

This subpanel (if it's like mine - pictured below) will have 2 breakers: Main and Kit/Bed/TV (or something similar). (The Kit/Bed/TV are the outlets powered by the inverter). You moan distribution panel should have a breaker for the Inverter.




This is how it works: when plugged into shore power (or the generator is running), the power flows directly to the main distribution panel and out to each open circuit.

If the inverter DOES NOT have an ATS: When shore power (or generator) flows through the Inverter circuit on the main distribution panel, it will go to the ATS. If the ATS senses power, it will bypass the inverter and go directly to the subpanel thus powering the subpanel and all circuits connected to the subpanel.

If the inverter DOES have a built in ATS, when shore power (or generator) flows through the inverter circuit on the main distribution panel, it will go to the inverters built-in ATS. If the built-in ATS senses power it will bypass the inverter and send the power directly to the subpanel and all circuits connected to the subpanel.

So, knowing this, let's look at your RED AC output in your picture. That should be going directly to the MAIN circuit of your subpanel.

The GREEN pass through in your picture should be connected to the "inverter" circuit on the main distribution panel. If you pull the main distribution panel you will probably find an AC cable running from the inverter breaker to that outlet on the back side of your exterior storage which your inverter was plugged into.

Now that the WFCO inverter is gone and you will be using your new Renogy inverter you will have to make some easy changes.

First, as you pointed out, you will need an ATS. A quick search came up with this one: https://www.amazon.com/KISAE-Technol.../dp/B00IKVHA9K This one is a 20 amp ATS. There is also a 15 amp ATS for a little less money. You will need one that plugs into an inverter.

Once you get the ATS, you will plug the AC plug into one of the 3 outlets in the back of the Renogy inverter.

Second you need to wire the ATS. An ATS will have 2 inputs and 1 output. 1 input will be from shore power/generator (comes from your main distribution panel), the other input will be from the inverter. The output will be to your AC loads (in your case the subpanel to the left of the main distribution panel).

The ATS will have an input and an output you will have to wire.
The output should be connected to the RED AC out you have in your picture. This should be easy.
The input will need to be connected to the Inverter breaker from your main distribution panel 9the outlet on the back side of your outside storage). A few ways to do this. I'd be tempted to run an new wire from the inverter breaker on the main distribution panel to the ATS bypassing the outlet (you would have to disconnect the outlet from the inverter breaker first)....or, if the existing wire is long enough, you can disconnect from the outlet and connect to the ATS.

A couple additional things: Now that you are using lithium batteries, make sure your charger/converter connected to the main distribution panel is made for lithium batteries. IF not, it will shorten the life of your lithium batteries.

My 21G had the Jaboni 300W panel on the roof. If you climb in the roof and there is a large solar panel that covers most of the roof behind the AC, it's the 300W panel.

I hope this llooonnnggg answer helps.

Allen

I have a question? I have a 2022 21G. Based on what you said it appears I may have an inverter somewhere? I have the large panel going across the back of my roof as you described and the inside is as you show. My dealer said it only had the 175W panel and no inverter. Do you think they were wrong and the inverter is installed somewhere else?

[acoleman43]

I have a question? I have a 2022 21G. Based on what you said it appears I may have an inverter somewhere? I have the large panel going across the back of my roof as you described and the inside is as you show. My dealer said it only had the 175W panel and no inverter. Do you think they were wrong and the inverter is installed somewhere else?

Hello. My guess is you have the inverter prep package. If you had an inverter you would be able to see it when you looked through the access door on the backside of your exterior storage.

Below is a picture of mine with the back wall of the exterior storage removed. You can clearly see the inverter.

[Enzo0903]

I appreciate the help. That was my next thought. So if there is no inverter should those breakers be turned on? Also if it is prepped is the wiring already there for me to connect an inverter? I know the plug is obviously but not sure about the other wires>

[acoleman43]

I appreciate the help. That was my next thought. So if there is no inverter should those breakers be turned on? Also if it is prepped is the wiring already there for me to connect an inverter? I know the plug is obviously but not sure about the other wires>

I'll tell you what I think, but you will need to verify.

I think the inverter breaker is connected to the Main breaker in the subpanel (which provides power to the subpanel). If this is the case, keep it switched on.

I'm also assuming most wiring for an inverter is already there. You would have to verify your wiring to make sure.

Keep in mind, it is prewired for an inverter to power ONLY the outlets described on the subpanel (Kit/Bed/TV) and nothing more. The inverter will only power the breaker in the subpanel.

[howson]

I appreciate the help. That was my next thought. So if there is no inverter should those breakers be turned on? Also if it is prepped is the wiring already there for me to connect an inverter? I know the plug is obviously but not sure about the other wires>

To add to acoleman43's response, the "prep" is likely a loop of orange wire that you'll find in the same cabinet as the solar controller (example picture below). GD's intent is (WITH ALL POWER OFF!) for the installer to cut the orange wire and then insert the inverter into the system.



How you'll wire in the inverter depends on the type of inverter being installed. One of the most significant variables is if the system will need an automatic transfer switch (some inverters have them built-in so an external ATS is not required). It is critical to understand the capability of the inverter being installed, to read the manual , and understand the inverter OEM's wiring diagram.

Howard

[bbinge]

I wanted to post an update and to thank acoleman43 - you were right, I was expecting that Magnum ATS based on earlier posts by you, but thanks to your explanation here I got that ATS and it should be working, but something weird is going on. So, I know this thread got a little off track, but I'm back with an update and another question!

This is the project midway - I've actually got the DC-DC charger installed, too, just didn't take any pictures today:


In case it helps anyone, I'm a total newbie and managed to learn a lot and get pretty far, thanks to these forums and the smart people posting projects and answering questions.

Here are the components that I've added and changed:
- Renogy 200ah LiFePo battery
- KISAE Automatic Transfer Switch
- Renogy 2000W inverter (no ATS in it!)
- Mini circuit breakers for the solar panels (panels are still the stock 300W ones, I did verify)
- A fused distribution block for the common positive power
- A distribution block for the negative
- A new converter (WFCO WF-9855 LIS Deck Mount) (although when I cracked the distribution center open, the stock one had a "smart detection" sticker on it, so it was probably fine)
- Renogy DC-DC MPPT charger / solar controller (not pictured) - (one BIG learning here, this device can only handle less than 25 volts from the panels! So, I'm just using this as a DC-DC charger and have a separate solar controller on the way that can handle the voltage)

So . . . after I held my breath and turned everything on, none of the fuses blew or breakers tripped. I was shocked! (Well, not literally.)

However, the system does not work on battery, and I'm a little confused:
- On AC shore power, everything works (inverter powered, fridge, lights, battery is charging from converter, etc.) and I am getting expected voltages everywhere.
- When I pull shore power, the inverter remains powered on, and the output from the ATS (lower left black cable on the ATS) is getting 120v, tested at the ATS but nothing works, no fridge, no lights
- That cable physically is going to the "sub panel" next to the main AC distribution center and I haven't taken that apart yet to see if the 120v is getting to it
- Is that my next step? Am I missing something? Should this be working or did I miss something simple?
- I haven't wired the generator back up to the battery yet (the initial + cable was too short, so I need to run another one into this compartment), but that's not it, is it?
- There were a bunch of wires on the old batteries on the tongue, and I don't think I hooked all of them back up, but I couldn't find a reason for them, could it be some wires that were on the tongue with the old batteries?

I'll be pulling apart the subpanel tomorrow to see if 120v is getting there, but if anyone has any ideas, I'd be happy to hear them!

Thanks again.

On battery:

[howson]

bbinge

When it's stated "the system does not run on battery" is 12vDC making it into the camper? In other words, disconnected from shore power do the lights in the camper turn on?

May seem like a head-slapper of a question, but is the Renogy turned on when trying to invert (use battery power)?

[bbinge]

Good question, and I hope I am not wrong in just assuming the battery is on. Here is why I think it's on:

- With a multimeter, the battery is reading ~14v at the terminals with shore power unplugged
- The fused distribution block also reads that voltage on all terminals
- The inverter is on, and I don't think that would happen if the battery wasn't powering it.
- The ATS output is reading 120v (presumably because it is plugged into in the inverter).

I Am going to pull off the sub-panel (next to to the main PDP) and see if the 120v (from the battery via the inverter via the ATS) is getting there, but I don't know why it wouldn't be when I'm measuring 120v on the output leg of the ATS.

[acoleman43]

bbinge I think I know where Howard is going.

The battery in your picture....is that the only battery you have? Is you fridge a DC ONLY fridge? When you unplug from shore power, and the inverter is on, do the outlets connected to the inverter work? If the answer to those questions is yes, I think I know the issue.

[bbinge]

acoleman43 The answer is yes to all of those questions!

I'd love to hear any suggestions!

And I forgot to answer howson's first question - no the lights do no turn on in the camper when disconnected from shore power.

[acoleman43]

acoleman43 The answer is yes to all of those questions!

I'd love to hear any suggestions!

It looks like you need to run another set of +/- cables from battery +/- busbars) to your main distribution center.

When shore power is disconnected, you have no DC power to your main distribution panel.

When shore power is connected, your converter is providing the DC power.

Looking at your battery, it's max continuous discharge rate is 200A. The inverter is 200W (or 167A @ 12v). I'm not sure what your distribution panel is rated at (mine was 70A DC). So....if your distribution panel is rated at 70A, I would use 2awg or 4awg able from your positive and negative bus bars to your main distribution panel. If it's 100A use the 2 awg cable.

I hope this fixes the problem

Edit: After thinking about it, you probably disconnected the battery on the trailer tongue. You just need to "transfer" those cables to your new battery in the storage area.

This is important because the connections to your tongue jack, emergency brake, and generator (starter) are included. You need to make sure all those are connected to your new battery.

[bbinge]

Good news and that makes sense. I had no idea there would be a separate feed to the main distribution panel; I was under the impression that when the inverter fed the sub-panel with 120v everything labeled in that sub panel would magically work!

Good news is thatI have plenty of 2 and 4 gauge wire (and others) but I'm hoping to verify that in hooking it up to the right place. This is from the WFCO manual, are these the right locations for the positive and negative from the battery?



Thanks!

[acoleman43]

Good news and that makes sense. I had no idea there would be a separate feed to the main distribution panel; I was under the impression that when the inverter fed the sub-panel with 120v everything labeled in that sub panel would magically work!

Good news is thatI have plenty of 2 and 4 gauge wire (and others) but I'm hoping to verify that in hooking it up to the right place. This is from the WFCO manual, are these the right locations for the positive and negative from the battery?



Thanks!

You should already have the wires there. When GD manufactured the trailer, they add the appropriate wires to the tongue of the trailer where the battery normally sits.

I'm assuming you disconnected the "original" battery from the trailer tongue. The wires/cables that were attached to that "original" battery are the cables you need to attach to your new battery.

If you can just re-direct those cables to your new battery, you will be set.