Cons of 48v setup for RV?

[BrianG]

@BrianG another option I saw someone else do that had a 24v system was they had a separate 12v battery just for their electric/hydraulic jacks. You’d have to charge them separately somehow but it’s an option. Their reasoning was that their current dc-dc converter was only 30A or so which wasn’t enough to handle the load of their jack.


i will have electric/hydraulic jacks that come with my trailer as well but I don’t know how much the load is. Once I know that I’ll figure out the best path forward for me. I’m leaning toward dc-dc converter though

A separate 12v battery for the jacks and maybe the slides seems like an overly complicated approach to the issue. 24v hydraulic pumps are used in marine applications and changing out the 12v motor for a 24v motor might be an option although I couldn't resource that change on any online resource that I scanned.

There are a number of resources for high current 24v to 12v converters available with prices that don't seem too bad:
Daygreen 24V to 12V 100A DC DC Step Down Converter 24VDC TO 12VDC 100AMP Voltage Regulator Reducer Module Transformer Buck Heavy Duty US $57.00 - 76.00
Has anyone determined the current draw for the leveler jack hydraulic pump and/or for the slide motors

 

[DW SD]

Brian,
All jacks are not created equal. I have a 40k lb bus camper. it has bigfoot brand levelers. At times, they draw as much as 160 Amps total. They have hydraulic motors / pumps @ each corner. It has a 200 A main fuse.
I had a prior bus which had a centralized motor / pump system. It drew 300A at high lifting load.

You might check the installation instructions for yours and see the fuse rating.

Suspect there is a direct correlation between draw and weight of your unit.

I considered switching my bus to 24V house batteries and then using the 12V start batteries to drive the leveling jacks. But, the whole house is 12V, so I figured the energy loss in the step down converter wasn't worth it. That's 80% of my use @ 12V.

Maybe if your energy usage is mostly AC, you might be better with 24V and a converter.

Doug

 

[Supervstech]

I am always surprised how many RV and trailers use a 30A shore hookup vs. the 50A version.
There is just so much more that can run from the 50A 12000W hookup!

 

[DW SD]

I am always surprised how many RV and trailers use a 30A shore hookup vs. the 50A version.
There is just so much more that can run from the 50A 12000W hookup!

I think the campgrounds drive some of this. Some campgrounds only have 30A from long ago. Some upcharge for 50A service vs 30A.

I might be wrong, but believe most modern campers are wired for 50A plug.

Easy to buy a connector that adapts 50A to a 30A plug if that's all that is available. That's usually only good for one AC unit, where you need 50A for 2 or 3.

Doug

 

[Heap64]

Most single A/C travel trailers are 30A with dual A/C 50A unless you are able to order it upgraded for future A/C. At least that seems to be what I have noticed.

 

[Firstascent]

My trailer will have a 50A hookup with 3 A/C units. Although the end goal is to use as much solar as possible so don’t expect to be running all 3, or even 2 haha. My solar setup won’t be That big haha.

the leveling system is the Lippert Level Up, I did speak with some current users with this system and ive been getting answers of just under 80amps. I’m told these units ship with an 80amp circuit breaker for the leveling system so I think I’d be good with a 100 amp dc-dc converter.

 

[orangeminnie]

With 48v, if you lose one cell, you have no battery bank.
With 24V, you still would have half your bank.
I would go with 24V.
As to 30A vs 50A: The dividing line is usually whether the RV has one or two air conditioners.

 

[Firstascent]

With 48v, if you lose one cell, you have no battery bank.
With 24V, you still would have half your bank.
I would go with 24V.
As to 30A vs 50A: The dividing line is usually whether the RV has one or two air conditioners.

THIS. This is a good point I didn’t think about. And just may be a deciding factor. Everything else so far is great but I still felt I could go either way comfortably.

but since I’d be on the road I’d rather have at least half my bank than none if that ever were to happen.

Thanks for bringing this up to me.

 

[mapguy525]

With 48v, if you lose one cell, you have no battery bank.
With 24V, you still would have half your bank.
I would go with 24V.
As to 30A vs 50A: The dividing line is usually whether the RV has one or two air conditioners.

30A vs. 50A? Or electric heat, washer/dryer, and or electric hot water. Or generator size -if present.
24v? Redundancy is a plus. A little more wiring/wiring gauge is a negative.
48v ? Or availability of mobile rated devices that make provisions for ensuring that proper neutral bonding and grounding are maintained during power inversion using multiple power sources at one time.
Or life safety issues of the higher voltage. 48v can kill easily. This means the neutral bonding and grounding system must be designed to properly include all system devices such that any electrocution hazard potential is contained under the expected operating conditions.

 

[acecard]

30A vs. 50A? Or electric heat, washer/dryer, and or electric hot water. Or generator size -if present.
24v? Redundancy is a plus. A little more wiring/wiring gauge is a negative.
48v ? Or availability of mobile rated devices that make provisions for ensuring that proper neutral bonding and grounding are maintained during power inversion using multiple power sources at one time.
Or life safety issues of the higher voltage. 48v can kill easily. This means the neutral bonding and grounding system must be designed to properly include all system devices such that any electrocution hazard potential is contained under the expected operating conditions.

Just noticed that you posted this here which is relevant to a discussion on a thread of mine. How might grounding and neutral bonding be incorporated in a mobile environment to negate this issue?

 

[avatar123]

Maybe the question was targeted for me?

I kept my system 12V native. An alternative might be to find 24V hydraulic motors.
I don't run Air Con via inverter. I can run a convection oven, but won't often nor for long.
DC to DC converter is another option. But likely pricey for something to deliver high current (>30A) 12DC.

Doug

What size bank do you have? Inverter?

 

[DW SD]

I have home grown 560Ah 12V LFP bank (8 Eve cells). With Victron 3000 x 12 inverter charger.

 

[time2roll]

I stayed with 16 cells assembled at 12v, 2000w inverter, 675w solar. My trailer is smaller and I like simple. Works well for me.
May have gone higher voltage with a larger RV. Maybe even 32 cells.

 

[toms]

I have found in applications that have existing high current 12V requirements, it’s cheaper to use several seperate 12V systems.

In your application with the levelling jacks i’d price up components for one 12V battery pack capable of running your highest DC load - then use this pack on a 12V inverter for your airconditioning and any other short term high current AC circuits.

Build another 12V system and use this for low current 12V DC loads, and a 12V inverter sized to cover the rest of your AC needs.

The only disadvantage of 12V DC is the high current DC side, use a high current busbar situated as close to the battery as possible, and keep your inverter and charge controller as close to the busbar as possible.

Keep in mind that a typical situation with a large inverter (eg 4kw) is that your aircon will be drawing constant 1kw, and other transients, eg (toaster/hairdryer/vacuum/microwave) only run for a few minutes - meaning wiring heat may not be an issue. I wouldn’t recommend running a constant 4kw@12V, but if you size your wiring for 400amps (remember there will be less than 50cm runs) and only ever have short bursts of high current use as in a typical RV situation - you may find this system is the most suitable.

 

[12VoltInstalls]

there is definitely 12v items on board I

had a separate 12v battery just for their electric/hydraulic jacks.

The windyNation 200W kit with the little P30L pwm to charge your 12V battery (batteries) is a good option imho. Basic lights and everything work fine, and let the 24V system do the demanding work