Solar Design - Any Issues? -> Inverter Connected Direct to A/C (Shoreline) Spot of Travel Trailer

[Xtinabritannica]

Does anyone see any issues with this design? (See image) The fuses and DC Switch are not in the picture to make it easier to read for this thread.

The idea is to use the A/C Out from the EG4 Off-Grid Inverter and connect it straight to the 120VAC Shoreline IN on the existing circuit board/breakers.



SPECS/Info:

• 32ft Keystone 2003 Travel Trailer (will be stationary for a while)
• Parallax 7300 120VAC -> 12V Converter already installed with circuit board
• EG4-LifePower4 Lithium Battery | 48V 100AH
• EG4 3kW Off-Grid Inverter | 3000EHV-48 | 3000W Output | 5000W PV Input | 500 VOC Input
• 3x 345W SunPower in PARALLEL
  • Rated Voltage (Vmpp) 57.3 V
  • Rated Current (Impp) 6.02 A
  • Open-Circuit Voltage (Voc) 68.2 V
• Keep the 12v 27DC Marine Battery??

I spoke with Signature Solar a couple times, and they seem to agree that this will work; but my buddy who does installs for boat solar felt like he wanted me to connect the 48v battery to the DC with its own little inverter/converter setup, rather than this A/C Shoreline idea.

Thoughts? Am I nuts?
Also, can we keep the 12V 27DC Marine Battery for backup?

TIA. I've learned solar from scratch starting less than 2 months ago, so I hope I have the right idea <3

 

[sunshine_eggo]

Does anyone see any issues with this design? (See image) The fuses and DC Switch are not in the picture to make it easier to read for this thread.

The idea is to use the A/C Out from the EG4 Off-Grid Inverter and connect it straight to the 120VAC Shoreline IN on the existing circuit board/breakers.

View attachment 100117

SPECS/Info:

• 32ft Keystone 2003 Travel Trailer (will be stationary for a while)
• Parallax 7300 120VAC -> 12V Converter already installed with circuit board
• EG4-LifePower4 Lithium Battery | 48V 100AH
• EG4 3kW Off-Grid Inverter | 3000EHV-48 | 3000W Output | 5000W PV Input | 500 VOC Input
• 3x 345W SunPower in PARALLEL
  • Rated Voltage (Vmpp) 57.3 V
  • Rated Current (Impp) 6.02 A
  • Open-Circuit Voltage (Voc) 68.2 V
• Keep the 12v 27DC Marine Battery??

Yes. Some 12V loads may be higher than your converter's max continuous. Plus it's another element of "backup".

I spoke with Signature Solar a couple times, and they seem to agree that this will work; but my buddy who does installs for boat solar felt like he wanted me to connect the 48v battery to the DC with its own little inverter/converter setup, rather than this A/C Shoreline idea.

I disagree with your buddy. The downside to your solution is that your 12V loads will be at about 75% efficiency due to the DC to AC to DC conversion. Your 12V loads are probably pretty small, so it's a small price to pay to have a little extra 12V backup and not having to modify the stock system.

Thoughts? Am I nuts?

Only if I am.

Also, can we keep the 12V 27DC Marine Battery for backup?

Again, yes.

TIA. I've learned solar from scratch starting less than 2 months ago, so I hope I have the right idea <3

Just to make sure I understand...

You're going to have an on-board "off-grid" power system that you "plug" your RV into? When you have shore power available, you'll actually plug your inverter AC-in to shore power and let that propagate through the system.

If that's the case, I'm in 100% agreement.

 

[12VoltInstalls]

can we keep the 12V 27DC Marine Battery for backup?

I’m an advocate of this, and like the idea of separating the “converter” from the system: simply add 100-200W of panels and a small ($50-$60) Epever mppt to maintain the 12V house battery. Then utilize the 48V system for AC loads only. (If you have room I’d add one more panel to the 48V system.)

Just to make sure I understand...

You're going to have an on-board "off-grid" power system that you "plug" your RV into? When you have shore power available, you'll actually plug your inverter AC-in to shore power and let that propagate through the system.

If that's the case, I'm in 100% agreement.

A variation (that often solves a few future-think items) would be to not hardwire the shorepower - provide a shorepower socket that is hardwired to the AIO so you can feed the onboard 120V service from either shorepower or the AIO. This effectively eliminates the detail of dealing with proper grounding/switching. In other words leave it such that the shorepower cord is always the feed to the RV service entrance panel.
Maybe that’s what was meant and I didn’t infer well.

 

[Xtinabritannica]

I’m an advocate of this, and like the idea of separating the “converter” from the system: simply add 100-200W of panels and a small ($50-$60) Epever mppt to maintain the 12V house battery. Then utilize the 48V system for AC loads only. (If you have room I’d add one more panel to the 48V system.)

A variation (that often solves a few future-think items) would be to not hardwire the shorepower - provide a shorepower socket that is hardwired to the AIO so you can feed the onboard 120V service from either shorepower or the AIO. This effectively eliminates the detail of dealing with proper grounding/switching. In other words leave it such that the shorepower cord is always the feed to the RV service entrance panel.
Maybe that’s what was meant and I didn’t infer well.

I think that's what was meant? I'll try to rephrase it, to see if we're talking about potentially the same idea ???

We effectively were going to grab the existing shoreline 30A cord, and snip it into two pieces.

The half that is already wired into the circuit will then be wired to the AIO's A/C Out port.

The other half will be wired to the AIO's A/C In port, with the 30A plug still on the end.

Then while plugged into shoreline, or the generator, we can adjust the AIO's priority to choose the shoreline over the solar.

Is that what you(/we) meant?

We actually have one more 345W, but we're currently using it on a separate 12v system that powers our off-grid chest freezer.

 

[12VoltInstalls]

s that what you(/we) meant?

Not certain sunshine_eggo meant this. But I meant leave the cord as is, feeding the rv entrance panel no matter where it is plugged in. But also provide a 30a socket in the camper. The socket will be wired/fed from the AOI output and N-G bond handled at AOI. Plug into the onboard socket for solar power, or run it out the umbilical port and plug in to a shorepower stanchion for shorepower. Shorepower then handles N-G bond.

Alternatively if you want shorepower pass-through your method would work- assuming the AIO breaks the bond when plugged in to shorepower. Not all do

 

[Xtinabritannica]

Just to make sure I understand...

You're going to have an on-board "off-grid" power system that you "plug" your RV into? When you have shore power available, you'll actually plug your inverter AC-in to shore power and let that propagate through the system.

If that's the case, I'm in 100% agreement.

Yes, exactly ?

After both your replies, I am considering the health of the 12V, as the system is set up to charge the 12V whenever shoreline is running the system.

So perhaps even if we don't separate DC from AC, we need to add a charge controller between the RV and the 12V.

 

[Xtinabritannica]

Alternatively if you want shorepower pass-through your method would work- assuming the AIO breaks the bond when plugged in to shorepower. Not all do

Good question. @SignatureSolarUS thoughts on the EG4 3000W breaking the N-G bond when the RV is plugged in?

I think it has an automatic transfer switch, but I'm new enough at this, I wouldn't quote me on anything.

 

[12VoltInstalls]

So perhaps even if we don't separate DC from AC, we need to add a charge controller between the RV and the 12V.

The onboard ’converters’ that manage 12V charging in an oem RV are often very inefficient. If you leave it connected so the 48v powers it you can lose almost 50% of the watts.
That’s why I suggested the separate solar panel and charge controller- autonomous uptime with minimized system inefficiency losses. Then disconnect that converter and you’re maximum efficiency for the components selected.

 

[Bad Decisions RV]

Good question. @SignatureSolarUS thoughts on the EG4 3000W breaking the N-G bond when the RV is plugged in?

I think it has an automatic transfer switch, but I'm new enough at this, I wouldn't quote me on anything.

This question...
I have spent hours and hours researching a very similar system for my RV with the EG4 3k. It is why I am here. It is why I keep reading and studying, and calling people, and messaging people...

...this question is where I keep finding myself...

"What about the N-G bonding?"
?