Suggestions for 45' Motorhome conversion to 48V or stay 12V?

[steined]

I currently have
4 12V 300AH LiTime
1 Magnum 2800 Watt inverter w/ 120 Amp charger
1 Victron 100/50 MPPT Solar charge controller
4 Newpowa 220W Solar Panels in series (880W)
1 Victron 500A Smart Shunt

I cannot run ACs, Cooktop (220V), Dishwasher, Washer, or Dryer with the current inverter setup.

I have room for 4 more 220W panels easy, and probably 6 -7 more to total from 8-11 panels total (1760-2420 watts flat mounted) (Can likely do more but may augment with some ground instead)

DO I
KEEP 12V

Replace Magnum and get 2 Multi Plus 2 12/3000 2x120 and run them in split phase and add more charge controllers?

Or

CONVERT to 48V

Get 2 Multi Plus 2 48/3000 and run them in split phase
Upgrade to 150/70 Victron @48v charging
Wire existing batteries in Series
Get a 48V to 12V DC-DC converter

Reasons I like the Victron
1.) Grid assist (sometimes we're on 15A or even lower outlets and we can use from AC and it will augment the load)
2.) Ecosystem is nice

Would an EG4 6000XP or some other all-in-one provide what I'm looking for with easy grid assist as well? Any other suggestions?

My power sources are 50A Shore and 48A 240 Generator into an auto transfer switch. That goes to Inverter/charger, inverter charger then goes through some mystery load management system and to the main breaker. If I presented 220 to the myster load management system it would likely think I'm on 50A and all would be well.

I think I have plenty of battery, just need more solar and inverter power to be able to live fully off grid w/ Washer/Dryer and some occasional AC use.

Thanks in advance!

 

[DIYrich]

I woul upgrade to 48v. You are pretty much maxed out at 3kW with 12v. Upgrade to 48v and you can get 6kW with the 6000xp.

The 6000xp can take generator/shore power. I believe it switches to the AC input, rather than being able to supplement (part solar, part shore power). In your situation, I don't think that is a big issue. It can use solar/battery when adequate, and switch to shore power when not.

 

[jberger]

Are you sure your RV is 240?
That would be very rare in the US for an RV based on my experience.
Almost all RV's are actually 120v 50a wired as (2) 120v legs from the 50a side.
Even the larger coach units usually are 120v with the loads split across separate inverters to handle the load.

As an example,
Mine is wired with (2) Magnum 2812's and they are split to service the Left and Right sides of the RV, with each one also hosting an HVAC unit. This setup covers the induction cooktops, HVAC, Washer and Dryer, etc. The center AC is not wired to either inverter so it only operates on shore or generator power.

You mention having some sort of Energy Management System, I'd start by figuring that system out and understanding what loads are supported via the EMS, what priority the loads are shed, etc.
It's possible your heavy loads are just not wired into the EMS or are set for shedding early so they don't appear to work on inverter.

The main issue with converting from 12v to 48v is knowing what is actually wired into the 12v side today and being able to still service those loads with 12v. You can't just move them to the engine batteries and hope for the best since that might leave you stranded. Other things to consider are high amperage draws like the levelers. Even if you add a 48 to 12v converter, you might smoke both the converter and the leveler motor during heavy draws.

48v is certainly more efficient and usually cost effective for a brand new build, but you need to make sure it's worth it when retrofitting a 12v chassis.
One more consideration is the batteries you currently own, you will need to consider adding a battery balancer to keep those 12v packs from becoming imbalanced over time.

Nothing wrong with Victron if you can afford it.

 

[steined]

Are you sure your RV is 240?
That would be very rare in the US for an RV based on my experience.
Almost all RV's are actually 120v 50a wired as (2) 120v legs from the 50a side.
Even the larger coach units usually are 120v with the loads split across separate inverters to handle the load.

As an example,
Mine is wired with (2) Magnum 2812's and they are split to service the Left and Right sides of the RV, with each one also hosting an HVAC unit. This setup covers the induction cooktops, HVAC, Washer and Dryer, etc. The center AC is not wired to either inverter so it only operates on shore or generator power.

You mention having some sort of Energy Management System, I'd start by figuring that system out and understanding what loads are supported via the EMS, what priority the loads are shed, etc.
It's possible your heavy loads are just not wired into the EMS or are set for shedding early so they don't appear to work on inverter.

The main issue with converting from 12v to 48v is knowing what is actually wired into the 12v side today and being able to still service those loads with 12v. You can't just move them to the engine batteries and hope for the best since that might leave you stranded. Other things to consider are high amperage draws like the levelers. Even if you add a 48 to 12v converter, you might smoke both the converter and the leveler motor during heavy draws.

48v is certainly more efficient and usually cost effective for a brand new build, but you need to make sure it's worth it when retrofitting a 12v chassis.
One more consideration is the batteries you currently own, you will need to consider adding a battery balancer to keep those 12v packs from becoming imbalanced over time.

Nothing wrong with Victron if you can afford it.

Well, one circuit for my cooktop is. It is an induction 220V unit. I know because I had to replace it of course

One other reason for the 220v is I would like to install a 18k BTU mini-split which requires 220v, so rather than spend the money on an autotransformer for a 120V output, I figure 120V split / 240 is the way to go. I'd also like to install a 220V outlet to share power with other RVs and/or an RV casita if/when needed. We ran into some super sketchy power down in Baja this year and I just want a way to power myself if I need to for a while. Running the generator is fine every few days if you run into clouds or something, but Diesel is expensive, and not convenient to fill up for 45ft rigs.

I guess one of the things that is appealing to me about the 6000XP is that it APPEARS to me to be able to handle unbalanced legs, whereas the dual Victron setup in split phase might require an autotransformer maybe?

As for the 12V loads, it appears the Levelers and Hydraulic slides are on the Chassis side (obviously need to confirm), and my max 12V loads are around 40-50A so I think a 48v - 12v converter should be fine. Meanwell makes some super powerful ones up to 1000W if needed but probably not enough for the rear electric slides or hydraulic levelers and front slides like you said.

 

[DIYrich]

Well, one circuit for my cooktop is. It is an induction 220V unit. I know because I had to replace it of course

One other reason for the 220v is I would like to install a 18k BTU mini-split which requires 220v

48v. no doubt about it. How do you plan to get 6000 watts out of 12v batteries to run two 3000 watt inverters (6000 watts is 500 amps at 12v)?

 

[steined]

48v. no doubt about it. How do you plan to get 6000 watts out of 12v batteries to run two 3000 watt inverters (6000 watts is 500 amps at 12v)?

I guess I thought it would be ok with 1200AH and that being < 0.5C but that is a lot of current if I maxed it out. Signs are pointing to converting to 48v for sure. That's why I asked. I researched a ton but figured people have real world experience and I can benefit from that.

If I want 220, would I need an auto transformer to balance the loads on the victron? I think the mini split maxes out at 1700w and is way less typically. The cook top maxes at 3500 watts but again is usually not near that. At 220 that would be split evenly. Don't need both of those at the same time maxxed out.

 

[time2roll]

48

 

[Skypower]

The main thing people keep saying about a 12 volt inverter is how big the conductor, breaker, fuse and battery capacity must be, but few mention how much more efficient it is to start with a higher battery voltage to begin with. The less you need to boost the DC power source, the easier and more efficient it’s going to be to make high voltage AC.

 

[DIYrich]

Lots of 48v 120/240v inverters available. You don't have to do it the hard way.

 

[Checkthisout]

Go 48

No suggestion on equipment other than if Victron is in your budget definitely do that.

 

[DVD]

Are you sure your RV is 240?
That would be very rare in the US for an RV based on my experience.
Almost all RV's are actually 120v 50a wired as (2) 120v legs from the 50a side.
Even the larger coach units usually are 120v with the loads split across separate inverters to handle the load.

Actually the 50A power pedestal in RV parks is generally 240/50A split phase. Otherwise twin 120/50A would require a 100A neutral.
I mentioned “generally” because some RV parks are allowed to run two legs of 3-phase Wye into pedestals. Still results in 2 hot lines of 120 each , but only 208 between the two hots. No big deal if nominal, but could be problematic if the feed is on the low end and the appliances are voltage sensitive.

 

[highwaypirate]

I would say 48V. At 12V you would have one hell of a storage bank, but with 48V you can go mad with more solar, not need massive gauge cables and it would be a lot more efficient than 12V.

I'm also going up to PowerQueen's 300AH (literally the exact same as LiTime) but will be staying put at 12V. Your capacity, regardless if it's 12V or 48V is very well-sized for a motor home!

 

[Lt.Dan]

As someone who lived full time in an RV with 48v main system and 2x MPP LV6548, I'm actually going to be the guy that says to stick with 12v.

Going to 48v adds another level of complexity with the 12v side that was always a pain for me. If the Victron 2x120v inverter was out when I did my install, I would have went with that.

You can stack 2 of them, and it wont power the entire motorhome with 3x AC's and the induction cooktop, but on those rare occasions you can start the generator.

Yeah 500a at 12v sounds like a lot, but its just some more cabling.

 

[highwaypirate]

A good point you mention Lt.Dan! I'd say (as with a few other things) it all depends on what the users requirements and situation looks like. Atleast with battery connections, you can always try 48V for a while; if you don't like how it is, stepping down to 24V or even 12V wouldn't be much of a hassle.

 

[chrisski]

I think you need a realistic power requirement first. Then figure watt hours for the battery and panel wattage to supply this. 48 volts, 24 volts, or 12 volts, the requirements are the same.

I have my fifth wheel filled with 1650 watts of panels and I put 1200 more on the ground to total 2850 and I can run any one of your high wattage devices and then run limited low wattage stuff and charge the battery with 300 watts.

To me, it seems like you’re asking for a 6 kw invverter. 26 kWh battery pack, and 8 kW of panels.

 

[highwaypirate]

I have my fifth wheel filled with 1650 watts of panels and I put 1200 more on the ground to total 2850 and I can run any one of your high wattage devices and then run limited low wattage stuff and charge the battery with 300 watts.

That's massive!

 

[chrisski]

That's massive!

Yes, but all that is enough to run a single 15 k BTU, with a little left over to charge. 25 amps max single phase 120 VAC jumpered so both sides of the Circuit breaker bar have power. Trick is to get enough power to run what you want and charge batteries. Still not enough to run the AC and dishwasher

The OP wants to run ACs, Cooktop (220V), Dishwasher, Washer, or Dryer. I doubt I could run more than any one of those at once. A 50 amp hookup at an RV park can provide around 10 kW of power, and I think living comfortably with the devices above would require close to that 10 kW, and if power is not conserved could pull between 50 kWh and 100 kWh a day.

 

[highwaypirate]

Ok, I get what you mean.

50-100kwh a day? Doesn't the average home only consume 4-5kwh per day? Or did I mix something up here... lol.

 

[Lt.Dan]

Ok, I get what you mean.

50-100kwh a day? Doesn't the average home only consume 4-5kwh per day? Or did I mix something up here... lol.

Average home is in the 30-50kWh a day.

My home? 80-120kWh a day.

 

[highwaypirate]

I'm shocked! With my 12V coffee maker, diesel heater and desktop, I barely break 0.4kwh a night... but I guess a home does have more power-hungry appliances.