inverter for 30 amp rv

[GlennWest]

I have been looking around around at smaller Motorhomes. Not parting with Teton but one for later use when I retire. 30 amp is 3600 watt service. So seems 4k 12v inverters would be plentiful. Most just skip over 4 and go to 5k. Most 5k are not 12v. On a motorhome I see a lot of advantages on staying 12v. Now Victron does offer an 5k 12v Quattro but they are proud of that unit. Aims have a 4k 12v but I am concerned about their reliability. So what are most using with 30 amp rigs?

[mptjelgin]

21 minutes ago, GlennWest said:

I have been looking around around at smaller Motorhomes. Not parting with Teton but one for later use when I retire. 30 amp is 3600 watt service. So seems 4k 12v inverters would be plentiful. Most just skip over 4 and go to 5k. Most 5k are not 12v. On a motorhome I see a lot of advantages on staying 12v. Now Victron does offer an 5k 12v Quattro but they are proud of that unit. Aims have a 4k 12v but I am concerned about their reliability. So what are most using with 30 amp rigs?

Most folks with inverters are not trying to match the full capacity of their shore-power hookup.  They are choosing enough capacity to run the appliances that they need.  So unless you intend to operate the A/C or the electric side of the water heater, you really shouldn't need all that much.  

We full-timed in a 50 amp RV (12000 watts), but had "only" a 2500 watt inverter. It easily handled everything that we needed, including occasional microwave use. But the A/C, electric water heater element, and 120V electric refrigerator element were not wired into the inverter sub-panel. 

[GlennWest]

Well, first mod I would do is a mini split. That allows ac use with inverters and batteries. And a 3k would likely suffice but seems that a 4k would be the norm. And 600 watt don't sound like much, it is what a high seer mini split uses.

[oldjohnt]

You ask what most people are using, I can only say what I use but have observed a ton of others, so heres my best answer, take it or leave it lol 

On a 30 Amp RV to run ALL EXCEPT AC when dry camped I get by fine with a 2KW PSW and I have plenty of Lithium Battery capacity with solar recharging to supply it.

If you're looking more at whole house and especially one AC, I've seen 3KW as the MINIMUM Inverter.

If you expect to run AC while at the same time microwave and crock pot and hair dryer etc you may need the 4 or 5 KW you asked about PLUS ENOUGH BATTERY !!!!!! Plus enough solar or other recharging

Hope this helps, best wishes

John T 

[GlennWest]

The size I am looking at is 1 ac and 30 amp. As stated I would add a mini split, I am sold on those. A true 3k would work.  And I have never had an onboard generator before. That changed the need. Just saw a youtube of a 2k Aims running an rv ac. Everything else was off and it ran it. Oh, found a Kisae 3k that looks promising. 

Edited December 25, 2021 by GlennWest

[oldjohnt]

1 hour ago, GlennWest said:

Just saw a youtube of a 2k Aims running an rv ac.

Sure a 2 KW in theory can power an AC (Subject to its size)  ESPECIALLY  if it's equipped with a Soft Start  ORRRRRRRR the Inverter has adequate short term surge capacity to allow an AC to start, which some may well have. Again for all EXCEPT AC a 2KW can indeed work while GENERALLY SPEAKING a 3 KW is better for AC or more loads.

PS a Mini Split would indeed be great if you chose a 2 KW

 Your money your choice

John T

[Chad Heiser]

A 3K Victron or Magnum inverter would be my choice.  (Personally, for me it would be a Victron.)  It will provide plenty of power for a 30 amp RV.  I have a 5th wheel in my shop right now that has two air conditioners, a 13.5k and a 15k.  I can run both AC’s (both equipped with micro air soft starts) at the same time with a Victron Multiplus 3K inverter/charger.  You will have to pay some attention to what you try to run at the same time, but overall it will provide plenty of power for a 30 amp RV.  The Victron also offers a ton of connectivity options that very few other manufacturers offer.

[GlennWest]

Interesting. The VA rating of Magnum and Victron has always concerned me. Don't really get what they advertise. Some actually state watts and not VA. 

[oldjohnt]

34 minutes ago, Chad Heiser said:

I can run both AC’s (both equipped with micro air soft starts) at the same time with a Victron Multiplus 3K inverter/charger.

  A Soft Start unit greatly eases the initial start up surge of an AC. The 3000 actual Watts may (subject to load) run two AC's IN THEORY, but if one is already running the Soft Start on the second is a Godsend .........The typical 30 amp RV has but one AC anyway, and I agree a 3KW is what Id use to run an AC via an Inverter even if a 2KW might get you by with a Soft Start........

  Glenn, it's a motors inductive load such as a compressor where Power Factor comes more into play, so the VA rating is an informative spec.......... PF = W/VA or Real Power/Apparent Power. 

 Nice chatting with your gentlemen

Merry CHRISTmas

John T

[GlennWest]

As I understand 3000 VA is more like 2800 watts. 

[Trainer]

Glenn,  The formula for determining the watt rating of  a device in the volts times the current draw, ie amps.  So volts- amps (VA) is the same as Watts.

So, 12 volts with 100 amp draw is 1200 watts.

Or 120 volts with a 10 amp draw is 1200 watts.

Hope this helps you Sir.

[oldjohnt]

11 minutes ago, GlennWest said:

As I understand 3000 VA is more like 2800 watts. 

Glenn if the Power factor is 0.93 (2800/3000) that's right.                PF = Watts/VA

In a pure resistive unity one power factor Watts = VA However that's NOT an inductive motor load lol

John T

[Nathana]

I also run a Victron 12/3000 Multi Plus system with 2000 watts of solar on the roof. On a 100+ degree day I can run both A/C's with soft starts but I can cool my rig with one only, and with a 2000 watt solar input to 800 Ah's of lithium batteries with the Multi Plus 3000 it is flawless.

On a motorhome 3000 watts of inverter is plenty for one standard RV A/C, preferably with "Soft start device". Yes, also a "mini slit system" would cut consumption more than half compared to standard RV A/C unit.

I have to say that the complete Victron system is the best. I don't even think about power since installing the full system.

Best wishes in your search!

[Randyretired]

We have a 2000 watt xantrex inverter.  We run the mini split, residential refer and one other high draw such as a coffe pot or microwave.  Occasionally I wish we had a 3000 but not enough to change out this one.

[hemsteadc]

Outback 3400w at 48v.  

Edited December 26, 2021 by hemsteadc

[oldjohnt]

22 hours ago, Randyretired said:

We have a 2000 watt xantrex inverter

Randy, I had a Xantrex but it failed grrrrrrrrrrr I also get by fine with my Renogy 2KW however, and its performed great. In our smaller RV with moderate energy requirements I don't see any need to change either, as they say  " if it aint broke don't fix it" right ? lol

Best wishes everyone

John T

[Randyretired]

13 minutes ago, oldjohnt said:

Randy, I had a Xantrex but it failed grrrrrrrrrrr I also get by fine with my Renogy 2KW however, and its performed great. In our smaller RV with moderate energy requirements I don't see any need to change either, as they say  " if it aint broke don't fix it" right ? lol

Best wishes everyone

John T

Our Xantrex is still working after 15 years but I had override some of the internal checks after just one year. Actually the first Xantrex failed in a couple of months and was replaced under warranty. Your Renogy  sounds like a good unit.  The 2,000 watt inverter coupled with our mini split and residential refer manages to use most of our 800ah battery as it is.

[GlennWest]

We had an Xantrex Freedom in our Teton originally. It failed about a year after I got it. Think it was factory installed.

[RandyA]

Glenn, while it may be more "convenient" to stay with inverters that have a 12V DC input, once you get to or past 4K AC output it is really better to consider inverters with a high DC voltage input.  Both 24 and 48 volts DC are popular choices.  Using fast and dirty calculations a 12 VDC inverter is a 10:1 conversion.  This means at 4K watts (33.3 amps) your battery load will be 300.33 amps.  This conversion produces significant heat in the unit, requires heavy cabling and connections and thus loses efficiency through energy conversion loss.  Now, consider an inverter with a 48 volt input. The fast and dirty calculation for 120 volts is a 2.5:1 conversion.  The DC amperage draw is now 83 amps at 48 VDC.  The result is the inverter runs cooler (and should live longer) and cabling size is reduced considerably as are connectors.  Efficiency is improved due to less energy conversion loss.  On the battery end using 100 Ah 12 volt batteries you will need at least 4 to meet the input needs of the 12V inverter.  Ironically, (not really) the same four batteries wired in series to provide 48 volts will power the more efficient 48 volt input inverter.  If your new inverter does not have a built in charger there are many battery charger choices providing 48 volts for anything from Lead Acid to Lithium at reasonable prices.  I elected to put 48 volt lithium batteries in my golf cart (100 Ah) with an on-board digital charger.  I added a 2,500 watt inverter with a 48 volt DC input to run specific power tools as I use the golf cart not for golf but a utility vehicle around our property.  Most quality MPPT solar controllers have selectable 12-24-48 volt controller settings.  Four 100W solar panels wired in series on the sunny side do the job nicely. Think about it - sleep on it.  I believe unless you are dead set on a 12 volt inverter you will find it makes more sense.

[GlennWest]

I was concerned about two different voltages on a motorhome. If not an issue I agree on higher voltage. 

[oldjohnt]

16 hours ago, GlennWest said:

I was concerned about two different voltages on a motorhome.

The 24 or 48 VDC to 12 VDC  DC to DC Converter is of course a way to deal with higher voltage battery arrays. I thought we already went through all that a while back ???

Happy New year everyone

John T

[GlennWest]

Yes, but a motorhome has two sets of batteries. For motor and for camper. I didn't know if they were tied together to stay charged. 

[hemsteadc]

3 hours ago, oldjohnt said:

The 24 or 48 VDC to 12 VDC  DC to DC Converter is of course a way to deal with higher voltage battery arrays. I thought we already went through all that a while back ???

Just a few times 

[GlennWest]

22 minutes ago, hemsteadc said:

Just a few times 

But not asking about that. 

[oldjohnt]

3 hours ago, GlennWest said:

Yes, but a motorhome has two sets of batteries. For motor and for camper. I didn't know if they were tied together to stay charged. 

NOPE you can't parallel Lithium with FLA or AGM. HOWEVER people do use DC to DC Converters to allow the engine battery and alternator to charge the house batteries when driving even if different chemistry PROVIDED THAT the DC to DC has appropriate charge settings and proper voltage ????? to match Lithium or FLA or AGM house battery banks.......Ive seen them for 12 volt to 12 volt (FLA or AGM or Li) but not so much higher voltages, check with Victron etc.

 I envision the 24 and 48 volt battery banks and Inverters for larger systems to reduce current and cable sizes coupled with 24/48 Volt to 12 Volt DC to DC for 12 volt coach appliances etc.

 But hey theres all sort sorts of options out there to each their own, straight 12 or 12 and 24 or 48 depending on energy needs.  

 Your money your choice 

Happy New Year everyone

John T