I have a 42 foot RV with 50 amp service. The generator is 8000 watts but it is only 120 output.
I want to be able to charge my EV from my generator or batteries when no power is available. I would like to do two inverters in split phase. I cannot find Anyware on Victron’s web site or Youtube if I can use a Multiplus II 2X120 in split phase to achieve this or do I have to get a standard Multiplus II and do it in split phase.
Thanks for the help
Just testing my reply email is working
Are you wanting to charge the EV with 240v split phase off of the inverter?
What kind of generator is that? I’ve never seen a generator of that size that didn’t have split phase 120/240. Same with the rv 50a, that should be wired for split phase 120/240 (though not actually utilizing the 240 split phase only dual 50a 120v as it needs to be compatible with 15/30a single phase input)
With the multiplus or Quattro 2x120 you can only get pass-through 120/240 split phase, the inverter only does single phase 120. If you want 120/240 split phase from the inverter you need to use a pair of single phase inverters in split phase operation or an auto transformer (which has its limitations)
I have a similar unit, 43ft with 6500w onan (120/240v split phase), 50a shore power (120/240v/208y). I use a multiplus 2x120 so that I can utilize both legs of my shore power and generator for charging the batteries and running heavy electrical draws in the trailer and a guy can still rig up a 240v split phase plug if you wanted to use that with shore/gen power.
Thank you for the response.
I would like to the the ability to charge the car with the generator. So I was going to install two Multiplus II inverters programmed in split phase. I am trying to understand what would be the best inverter to use for this. Do I use two of the Regular Multiplus-II or two of the Multiplus-II 2X120
I am going to rewire my class a rv like this. Going to take the power from the existing rv transfer switch to the new Multiplus’s and from the new Multipluss’s back to main panel. Thus the entire panel is hot with one leg from each inverter.
I would check your gen, it would be very rare for it to not have a pair of 120v/240 split phase outputs
In that case, a single multi plus 2x120 is all you ‘need’ (depending on what kind of wattage you want from the inverter while running on battery). You can pass through the 240v from the generator or shore power, and the rest of the trailer won’t care that it is only single phase operation while on the inverter
If you are after more wattage from the inverter side, you will need to run parallel units, in that case a pair of regular single phase units running in split phase is what you need. This would also give you the ability to have 240v split phase while on battery/inverter power
Ok, I thought I checked this already. I will check again. So then you are suggesting that if I want 6000 watts I would just use the 2X120 and get two of them and run them in parallel. That is if the genset can give me 120/240.
If I only get 120 out of my genset then what would your thought be on using two of the different inverters. I can’t find anything or think of anything that says to use either inverter. Other than if one broke and I had selected the 2X120 I could use it as stand alone and use both legs.
That is exactly how I wired my trailer. Original 50a transfer switch handles the shore/generator switching, sends power to the inverter and from there goes to the dist panel
When you do finally decide on which hardware you go with, make sure you get an inverter that has the 50a transfer switch as you run the risk of fire or damage if the multiplus only has a 30a transfer switch and you push 50a of shore/gen power through it.
I’m a little confused in your response, Are you wanting 6000w of inverter power, or 6000w from the generator? The generator power passes through the inverter transfer switch so the inverter size is moot other than the transfer switch size. If you have a multi plus 2x120 with a 50a transfer switch the full 8000w from the generator can pass through the inverter to run the EV charger
Both transfer switches I am looking at have 50 amp pass through.
Thank you for your help
Double check your generator. But I’m very certain a single multi plus 2x120 is going to do what you need as long as you don’t require any more than the 2400w inverter power. Thats all I run and it runs the 15,000btu a/c no problem, I’ve even used the microwave at the same time
If you need more inverter power you can parallel them.
If your generator for some weird reason is in fact only single phase 120v, I don’t know if you can use the 2x120s to generate split phase you may need to go with a pair of single phase or an autotransformer
Thanks
I will go to my storage and start my genset and open my panel and or transfer switch and
test for 240
What are the specs on the ev charger you are wanting to use? I’m assuming if you want 240v it’s probably a higher capacity charger that’s going to be in the 30a+ range?
I just went to storage and tested the voltage of the genset output and it is 120 volt. So I do have to do the split phase system to get 240 volt out when on generator power.
My car charger is adjustable, I can do 240 23 amps if I want or 30 amps or more if wanted and connected to larger amperage.
That sucks!. Stupid question but you measured the voltage from phase to phase not phase to neutral/ground right?
You can still get away with a single phase inverter, and go with an auto transformer. That will give you 240v split off of a single phase, but you are limited to 28amp continuous. If you want more than that, your best bet is to use a pair of single phase and set them up to deliver split phase
Yes. Just so you know, I have been an electrical contractor for 38 years.
I agree I need to do two inverters so I may have 6kva.
I just don’t know what inverter to select between the Multiplus II 3000 or the Multiplus II 2X120 3000
I am trying to think about what the benefits would be one vs the other. I think they both will work. I think they both will do the job. Just trying to figure out what the advantages would be of one model or the other.
I know I need two of them and set them up in split phase.
No advantage that I can think of to using a 2x120 in this case as you’re just paying for the extra switch gear inside that won’t get used.
Personally I would go with a pair of single phase multi plus’s over using a transformer. That’ll double your inverter capacity as well as allow you to utilize full generator output for the 240v charger.
Yes that is what I was thinking as well.
Thank you
For the minimal cost difference between the single phase and the 2x120, I would go with the 2x120 just in case you ever decide to go parallel instead of split phase. I am of the school of thought “better to have it and not need it, then to need it and wish you had”.
Thank you.
That was exactly what I was thinking. I just was not sure the 2X120 would have any other benefits or drawbacks.
I cant talk to anyone at Victron. They just want you to call one of the dealers. Problem is that the dealers want to do the work and if they are not doing the work they don’t want to give you advice. I Talk to several dealers, and they tried to tell me not to do split phase it was do much of a pain. I think they just have not done it.
Thanks again for your response
One benefit to parallel vs. split phase in your situation would be if you spend a lot of time off grid and depend on the generator for battery charging. With single phase output of the generator, and the inverters in split phase, L1 inverter will pass thru and handle charging, while L2 inverter will continue to invert to supply L2 of the split phase output. This means any power being used on L2 during this time is taking away from battery charging, and you are limited to 70 amps dc charging. In parallel configuration, both inverters will pass thru and charge, giving you a combined maximum dc charging of up to 140 amps. All something to considers. There are obviously pro’s and con’s to either setup.
Thank you.
I think that is how I will move forward