50A RV - Victron Multiplus II 2x120 vs ?

[tab783]

My apologies if this topic has been beat to death but I'm starting to pick components for a solar system on my 50A RV. It has no 240V appliances so there are just two separate 120V buses in the distribution panel.


I have a little confusion regarding which inverter to use. I know the Victron Multiplus II 2x120 will automatically handle 50A vs 30A shore power but is there an alternative Growatt/EG4/MPP Solar inverter that provides the same functionality or could this be implemented with a mechanical bypass switch for an inverter that doesn't inherently have this functionality?


I was originally thinking of going with the EG4 6500EX-48 for it's high 500Voc since I'm planning over 4kW of panels but noticed it has a single 120V input and output. This seems like it would be an issue when trying to utilize 50A shore power or my 8kW genset which provide L1/L2 at 120V.


For reference, my rough plans:
AC Inputs: 50A shore or 8kW Genset (onboard transfer switch decides)
Solar: 4kW+
Batteries: 2-3 EG4-LL 48V100aH
Inverter: EG4 6500EX-48???

 

[time2roll]

Very easy to feed both hots with an external 50 amp transfer switch to utilize the 6500EX.

 

[tab783]

Very easy to feed both hots with an external 50 amp transfer switch to utilize the 6500EX.

My rig has a transfer switch in it already, is there any issue tying the L1/L2 outputs together and feeding them into the single 120V 6500EX input?


I know that's essentially what a 30A-to-50A dogbone adapter does but I'm trying to think through any potential problems since it seems too simple.

 

[time2roll]

Yes that is exactly what works. The transfer switch isolates the inputs so when the inverter power is selected, the cord and generator are isolated. No back feed or cross currents.

Need a second transfer switch for the inverter. Usually the inverter transfer switch would be inserted between the existing switch and the main panel.

The real advantage feature with the Multiplus is the ability to combine power with a limited source. With an 8k generator this is not really needed. Might be helpful if limited to a 15 or 20 amp 120v service. Although there are other methods to get this to work. Probably a rarely used function that just adds cost going Multiplus.

 

[tab783]

Yes that is exactly what works. The transfer switch isolates the inputs so when the inverter power is selected, the cord and generator are isolated. No back feed or cross currents.

Need a second transfer switch for the inverter. Usually the inverter transfer switch would be inserted between the existing switch and the main panel.

The real advantage feature with the Multiplus is the ability to combine power with a limited source. With an 8k generator this is not really needed. Might be helpful if limited to a 15 or 20 amp 120v service. Although there are other methods to get this to work. Probably a rarely used function that just adds cost going Multiplus.

If I'm following this correctly, when I'm running the genset or on shore power then the inverter is getting bypassed as the input AC source for the RV. I would then add a breaker and a run from either leg into the AC input of the inverter so the batteries charge from shore/gen?

 

[Rocketman]

The Multiplus II has a transfer switch built into it - so the ideal place for it is right after your generator/shore transfer switch. That way items (like the clock on the microwave) will not even notice when you unplug from the shore.

However ideal placement run right into the wiring in your rig. A lot depends on how your rig is wired.

The ability to combine power with a limited source is really nice when visiting people. You can just use a 15a from your host - yet still run whatever needed.

 

[tab783]

The Multiplus II has a transfer switch built into it - so the ideal place for it is right after your generator/shore transfer switch. That way items (like the clock on the microwave) will not even notice when you unplug from the shore.

However ideal placement run right into the wiring in your rig. A lot depends on how your rig is wired.

The ability to combine power with a limited source is really nice when visiting people. You can just use a 15a from your host - yet still run whatever needed.

Yea I really like the feature set of the Multiplus but if you go with one Victron component you almost need to go all Victron and unfortunately that prices me out. This is why I've been trying to find another solution that utilizes AIO units.

 

[Bad Decisions RV]

I too am priced out of the full Victron set up. I was considering a twin EG4 3000W setup to run both legs in my rig. I have generator prep but, no built in generator. I use a portable, propane fueled 4Kw when needed (and would like to use it to charge the lithium bank through the AIO eventually). So, I have a transfer switch installed already.

Do I understand that I could just use a single EG4 6500Kw unit with my transfer switch?

 

[PHXBARI]

Most interesting content here. I replaced the house battery bank (6-6V L/A) with 6 BattleBorns. The OEM Xantrex 3000 inverter/charger doesn't have the necessary setting for Li, so my house bank was woefully undercharged. Before I headed out 2 weeks ago I dropped the Xantrex out and installed the Victron Multiplus II 3000. My house bank finally charged 100% per SmartShunt. Now I'm seeking advice on creation of about a 1000W solar array. The OEM panel is still up there and I've been told it's 125W. I added a 180W panel about a year ago. I'm getting the impression from reading here that I'd do well to use a series AND parallel arrangement of 3 or 4 new 200W panels. That leaves the question of can two unequal series ie. (3x200) and (200, 200 & 125) be paralleled? The charge controller I will be using is the Victron 150/85TR. Suggestions re wiring S/P?

 

[Bad Decisions RV]

Most interesting content here. I replaced the house battery bank (6-6V L/A) with 6 BattleBorns. The OEM Xantrex 3000 inverter/charger doesn't have the necessary setting for Li, so my house bank was woefully undercharged. Before I headed out 2 weeks ago I dropped the Xantrex out and installed the Victron Multiplus II 3000. My house bank finally charged 100% per SmartShunt. Now I'm seeking advice on creation of about a 1000W solar array. The OEM panel is still up there and I've been told it's 125W. I added a 180W panel about a year ago. I'm getting the impression from reading here that I'd do well to use a series AND parallel arrangement of 3 or 4 new 200W panels. That leaves the question of can two unequal series ie. (3x200) and (200, 200 & 125) be paralleled? The charge controller I will be using is the Victron 150/85TR. Suggestions re wiring S/P?

You will likely get the advice you're asking for in another forum.
Try the DIY Solar General Discussion.

DIY Solar General Discussion

diysolarforum.com

I'll bet if you pose this question there, you'll get a few hits.

 

[Rocketman]

Putting different panel to the same solar charge controller cause lower wattage than expected.

The best thing is to use all one type of panels on one controller - then get a smaller controller for the other panel (like a 100/20). You can connect many Victron mppt’s together on the same battery.

The problem with connecting a 200 + 200 + 125 is you may only get 375 instead of 525w. And it could be even lower. To figure it out you need to post the entire label of the panels.

Solar charge controllers do better with higher voltage- so put at least 2 or 3 panels in series. Post the labels on the panels and we can help figure it out.

( I put four 200w panels in a 2s2p arraignment on my MotorHome into a Victron mppt 100/50 - works well).

 

[InMyImage]

I have the Victron and am testing it before actually switching over to it.

Pros:
It is dirt simple to install and configure
It doesn’t require any extra electrical equipment to install
It has the Power Assist feature for running on less than 50A shore power
It can directly communicate with other Victron devices to get more accurate data and manage the system more holistically.

Cons:
The “3000” in the name is VA not Watts, it actually is only 2400w continuous and that can be pulled on one half of my panel. We average 1800’ish watts with one of our ACs, TV, residential refer, Apple TV. Throw in the microwave and you pop up to over 2700 watts. We have the same needs on the other side of the panel in addition to the bathroom circuit which has the occasional hair dryer, flattening iron, etc.

It REQUIRES an “optional” MK3 USB adapter to configure it for LiFePO4 batteries, the default is AGM. This includes any and all configurable settings for the battery.

At a minimum It requires the Bluetooth Dongle for monitoring it. You can use it or the MK3 adapter or their other more expensive monitoring solutions to change the input current limit (note that contrary to your stated understanding, it doesn’t adapt automatically to different shore power amperage’s available)

Because of the total wattage issue, until I can afford a second one to parallel them, I’m trying to decide how to separate the two halves of the panel and accept that the second half is going to go dead. Given the target market for this thing is the 50A RV market, they really should have made it a 5000 to 6000 watt inverter.

 

[InMyImage]

Update, used my microwave and coffee maker while monitoring my 5er’s power consumption with a Power Watchdog RV surge protector and each used 1500 watts, so with the AC, TV and Apple TV, wattage jumped from 1800’ish to 3300’ish ?

 

[corn18]

The problem with going big on an inverter with a 12V system is amps get pretty huge. My MPII at full load pulls 284 amps. That’s at 2400w.

 

[InMyImage]

The problem with going big on an inverter with a 12V system is amps get pretty huge. My MPII at full load pulls 284 amps. That’s at 2400w.

Good point but if I’m going to have to get a second inverter I’m still going to be pulling that per inverter out of the bank. My system is going to use 2 packs and hopefully 4 by the end of the year.

BTW, any idea why your inverter is pulling 284 amps at 2400w vs the 200 amps it should be pulling or am I missing something in my understanding of how these things work?

 

[time2roll]

My 2000w inverter pulls about 140 to run the standard Dometic microwave.

 

[corn18]

Good point but if I’m going to have to get a second inverter I’m still going to be pulling that per inverter out of the bank. My system is going to use 2 packs and hopefully 4 by the end of the year.

BTW, any idea why your inverter is pulling 284 amps at 2400w vs the 200 amps it should be pulling or am I missing something in my understanding of how these things work?

I had to look at my notes. The inverter was putting out 2,450 Watts and pulling 238A. I'm guessing that means my MPII is about 85% efficient at full load.

I had some DC loads on as well but those don't count towards the 2,450W.

What do you plan to power with all that power? I am always tripping my inverter because I forget to turn off the aircon prior to using the micro wave.

 

[HRTKD]

I had to look at my notes. The inverter was putting out 2,450 Watts and pulling 238A. I'm guessing that means my MPII is about 85% efficient at full load.

The Multiplus should have an efficiency closer to 94%. A difference of 9% would have me looking over everything to figure out why. But the efficiency isn't the same for all levels of utilization.

 

[InMyImage]

I had to look at my notes. The inverter was putting out 2,450 Watts and pulling 238A. I'm guessing that means my MPII is about 85% efficient at full load.

I had some DC loads on as well but those don't count towards the 2,450W.

What do you plan to power with all that power? I am always tripping my inverter because I forget to turn off the aircon prior to using the micro wave.

It’s a 50 amp RV so there are 2 use cases, the power assist when connected to 30 amp shore power so we can run the RV without any fears of tripping the breaker in the pedestal and in the case of a blackout continuing to service our loads.

Right now, I’m thinking I’m going to have to install a separate panel and put all our critical loads on it and then move all the non-critical loads to the secondary panel and run it off AC-Out 2. I also rout a couple of our critical loads through a Xantrex 1200w inverter already installed in the RV for our residential fridge and some of our power outlets which will reduce some of the demand and then wait till I can afford a larger secondary inverter to handle more load. Will probably want at least one more battery pack before doing that anyway.

 

[DIYVan]

The Multiplus should have an efficiency closer to 94%. A difference of 9% would have me looking over everything to figure out why. But the efficiency isn't the same for all levels of utilization.

You wouldn't be the first to quote that number, and you won't be the last, but it's a PEAK number.

The real numbers are available if you dig past the the marketing smokescreen.

https://www.victronenergy.com/upload/documents/Output-rating-operating-temperature-and-efficiency.pdf