RV inverters for 50 amp shore line trailers.

[Elevation]

I have a toyhauler which has a 5kw generator and a Magnum 1000 watt pure sine wave inverter, factory installed, for the residential refrigerator. I have replaced the two original lead / acid batteries with 6 AGMs, 100 ampHrs each. I am installing a Victron 712 smart battery monitor, 6 HQST 100 watt mono-crystalline solar panels on the roof and a Victron MPPT 150V / 60A smart solar controller.
What I have not purchased yet is a pure sine wave inverter capable of supplying the two 120 volt hot legs that supply all 50 amp RVs.
Also if it has been discussed much on this forum, I apologize for not finding it.

 

[Dzl]

I don't have any specific experience or advice, but you may want to piggyback on this related ongoing post

 

[Jcain]

You have a few choices. Run a large inverter (or two in parallel) with a split phase or run two inverters, one for each 50amp leg (theres two hot legs "phases") in a 50amp trailer. You could also do a single inverter and kick out a 30amp single phase plug, then use a 50 to 30amp adapter and basically run both hot legs off one, but you'll soon find out that you'll be trying to manage load

 

[Dzl]

Is your battery bank 12V?

Magnum sells a split phase inverter (4kw) but only for 24v or 48v

Magnum MS4024 PAE 4000 Watt 24 Volt Inverter/Charger

Magnum Energy MSPAE-4024 Pure Sine Wave Inverter is able to parallel up to four inverters to increase output power capability. So it can be expanded as loads are added.

www.altestore.com

Aims Also sells a split phase inverter, but I believe its also only 24v or 48v input

Your best bet might be as @Jcain says. Get two inverters that can be combined for split phase. The Victron Multiplus would be one option.

 

[Jcain]

I run 2 victron 12/3000 victrons on my 50a toyhauler

 

[Elevation]

Thanks guys for the advice. Yes I have my system set up for 12 volts. Obviously everything in the RV is either 12V or 120V.
I would absolutely love to use the Victron 12V / 3000W 50A Multiplus, but it is $2600.00 all by itself. You can see I have already purchased all Victron Bluetooth equipment. Needless to say this project is getting pricey. I’m the type of guy who likes to do it right the first time and this is my first solar build.
Jcain...WoW, two Victron 12 / 3000’s. How does your system transfer from generator to shoe power to solar. Sounds like a really top notch set up.

 

[MattB]

Go Power may have actually want you are looking for They have 2 Inverter/Chargers (2000/3000w). Both have dual 50 amp lines (input/output). I have the 2000w IC for 4 years now. IC is highly configurable with the additional remote.

Inverter Charger Archives

Powerful 3-in-1 inverter chargers. Pair a pure sine inverter, transfer switch and battery charger for easy installation and battery charging.

gpelectric.com

 

[Elevation]

I have another question. My plan so far is to wire two 12V 100W solar panels in series for approximately 24 volt. And then the 3 pairs in parallel to the Victron MPPT 150 /60 smart controller. From reading Will’s book and watching his videos, I assume this is the best way to go??
Thank you, MattB ?? My son might use that?

 

[snoobler]

I have another question. My plan so far is to wire two 12V 100W solar panels in series for approximately 24 volt. And then the 3 pairs in parallel to the Victron MPPT 150 /60 smart controller. From reading Will’s book and watching his videos, I assume this is the best way to go??
Thank you, MattB ?? My son might use that?

Not necessarily. The Victron can handle up to 150V panel Voc, so you could probably string 6 of those in series before you got anywhere near that limit; however your maximum efficiency is probably in the 18-24V range. If you have a long cable run, higher voltage input from the panels is a little more efficient due to less losses in the wire, so 3S2P might be a better choice.

Also, have you ever plugged your 50A into 30A service with an adapter?

 

[Dzl]

I have another question. My plan so far is to wire two 12V 100W solar panels in series for approximately 24 volt. And then the 3 pairs in parallel to the Victron MPPT 150 /60 smart controller. From reading Will’s book and watching his videos, I assume this is the best way to go??
Thank you, MattB ?? My son might use that?

Victron actually gives recommendations in the charge controller manual. In a nut shell, they recommend nominal a PV array nominal voltage that is 2x the battery nominal voltage. For instance if you have a 12v battery bank they reccomend 72 cells in series (i.e. '24v' nominal), a 24v battery bank 144 cells in series ('48v' nominal).

I also agree with @snoobler the most optimal arrangement will depend on your situation, if long wire runs are an issue, maximize series, if not, 2S3P might be the best choice, especially if partial shade is a bigger concern than wiring.

 

[mapguy525]

Remember 50amp RV service is
2 x 50amp 120v service with the potential for 240v branch circuits with proper wiring.
If you want to put all 120v circuits on the inverter. Look for a dual in and out model or use 2 units.
Be mindful of transfer switch and pass thru ratings of the inverter(s) chosen.
In this situation use of UL 458 devices will help overcome some of the complexity of installation.
Premium products like Victron, Samlex, Outback, Mastervolt have guidance for these type installs. Mid market products like Aims, Signeer give little to no guidance for complex installs.
Personally, for this type of install a hybrid inverter like a Victron MultiPlus or Quattro would be my go to due to reliability, OEM support, and vast user community support.

 

[snoobler]

I'm asserting that there is ZERO need to put 240V into a 50A plug UNLESS you have a 240V item in the rig. 30A service is 120V. When you plug into 30A service via a pigtail or adapter, L1 and L2 are jumpered, so you have zero V between them, but each leg is still getting 110V relative to neutral.

I currently power 2X RVs with 50A plugs via a splitter that splits each leg to the 30A plug. Both RVs have full functionality of all systems. I'm running a Victron 5K/48 Quattro. I have L1 and L2 jumpered at the power pedestal.

 

[mapguy525]

@snoobler
Can you pencil out a diagram - having difficulty understanding.
Your situation is different than what @Elevation is trying to do by fully utilizing the amps available on l1/l2 at 120v

 

[CascadeOffGrid]

You have several options to consider with this situation.

1. You can purchase 2 inverters and configure them to output in a split phase configuration. You will have some limitations when running on your generator because your generator is probably not split phase. There is some rewiring to get the maximum output out of your generator.

2. You can purchase an autotransformer so that a single 120V inverter is converted into 240V split phase. Victron makes one of these.

3. AM Solar makes a phase selector. It is specifically designed to solve the problem of a 50A 240V split phase input feeding a single inverter. I have yet to personally install one but you can read up on their website.
AM Solar Smart Phase Selector

 

[snoobler]

When you plug into 30A service with a pigtail, hot1 and hot2 are common/shorted:



That's why you don't lose half the devices in your rig that are on the Hot2 circuit.

Also, a 50A RV plug can handle 50A PER LINE, so you're talking about 12kW. I don't see anybody trying to provide 12kW to their off-grid RV power situation, so the assertion that @Elevation is trying to do this doesn't add up. Why would he try to provide 12kW of off-grid solar power to a rig with a 5kW generator?

50A vs 30A is the power source limitation. Not a property of the RV.

A SINGLE 110V inverter (Victron 5K/24) of the desired power is all that's needed to power an RV with a 50A plug. From a cost perspective, the only reason you should provide 240V to it is if you have 240V devices/appliances.

Again, I'm running TWO 50A plug RVs (33ft 5th wheel, 33ft motorhome) off a single Victron 4K/48. I'm only doing what every 50-30A pigtail adapter is doing.

 

[mapguy525]

More interested in your exact wire scheme at the pedestal or splitting point.
I cannot visualize based on a random image and the describing text.
My experience/knowledge does not agree concerning how an off the Walmart shelf 50 to 30 amp adapter functions. I will test the few I have in my fifth wheel.
I am really trying to understand you setup.

 

[CascadeOffGrid]

I am assuming that you rewired your RV to only use one of the legs of the 50A shore power connection when you plug in. Is that correct? That would be the only way that your Multiplus 4k/48 would be able to supply everything in your RV.

 

[snoobler]

mapguy525 You can see how the Hot1 and Hot2 are jumpered with a red arrow. Both get the same phase 120V with 0V to each other but BOTH legs have 120V to neutral.

CascadeOffGrid it's clear you have no working knowledge of how RV power systems work.

Do you understand than when you don't have 50A power available and use a 50A to 30A adapter (which in only 120V) to plug your 50A RV in to 30A power, you don't lose half of your RV's electrical system, right?

THERE IS NO NEED TO POWER A 50A RV WITH 240VAC POWER UNLESS YOU HAVE 240VAC DEVICES. YOU SIMPLY ATTACH YOUR 120V INVERTER LINE OUTPUT TO BOTH L1 AND L2 ON THE 50A CIRCUIT, AND YOU HAVE FULL 120V AVAILABLE TO THE ENTIRE RV.

 

[CascadeOffGrid]

mapguy525 You can see how the Hot1 and Hot2 are jumpered with a red arrow. Both get the same phase 120V with 0V to each other but BOTH legs have 120V to neutral.

CascadeOffGrid it's clear you have no working knowledge of how RV power systems work.

Do you understand than when you don't have 50A power available and use a 50A to 30A adapter (which in only 120V) to plug your 50A RV in to 30A power, you don't lose half of your RV's electrical system, right?

THERE IS NO NEED TO POWER A 50A RV WITH 240VAC POWER UNLESS YOU HAVE 240VAC DEVICES. YOU SIMPLY ATTACH YOUR 120V INVERTER LINE OUTPUT TO BOTH L1 AND L2 ON THE 50A CIRCUIT, AND YOU HAVE FULL 120V AVAILABLE TO THE ENTIRE RV.

I'm sorry to have upset you. I wire RVs for a living so I have quite a bit of knowledge of how RVs are wired and how shore power works. I think I am just asking a different question. Perhaps you have come up with a solution that might help me in the future...that the point of this forum correct? Just trying to understand here...

I understand how a 50A to 30A power adapter works and understand how it feeds the entire RV. I also understand that you do not need 240V. What I was stating is that a 50A RV park is 240V split phase which is made up of two 120V legs of power. What I don't understand is what happens if you hooked your RV up to a 50A shore power with the way you have it wired.

 

[snoobler]

You haven't upset me.

My RV wiring is stock. If I plug into a 50A receptacle, I get power.

Per my previous post:

"I have L1 and L2 jumpered at the power pedestal."

Thus my 50A receptacle is not wired to spec. If you plug a 50A RV cord into it, it's like you have a 30A adapter in the end of your plug.

My proposal definitely requires a means of isolating the inverter from shore power or genny when needed, but that is likely WAY cheaper than a second inverter, so I should add that qualification to my assertion for clarity. A simple solution, assuming the rig has an appropriate transfer switch, is to literally feed a 50A receptacle with L1 and L2 jumpered with the 120V inverter and plug the RV umbilical into that plug.