12v or 24v Camper Electrical System, Advantages and Disadvantages

[Nitromethane43]

Just wanted to get some insight from people who have a 24v electrical system on their campers, have there been any drawbacks of having the 24v system over a 12v one?

Currently looking into the planning stages of the electrical system for a new camper, the vehicle has a 12v system, after looking around it seems that going 24v on the camper has some advantages without much drawbacks, the only two that came up was there would need to be a converter for any 12v cigarette lighter style plugs, and the house battery can not be paralleled with the starting batteries for a jump start if needed.

It seems that the major item which needs power is the fridge, and the same unit can run on either voltage, water pumps, light fixtures, fans, inverters and just about anything else can be had in either voltage. The main drive in going 24v is that solar charge controllers have less work to do and at 900+ watts, the amprage would running most mppt controllers to their higher limits. For lithium batteries 24v systems have more selection to choose from.

If anyone has any experience please share as I would love to know your experiences.

 

[Nitromethane43]

I have read that the 12v appliances are cheaper, in a lot of places, but the appliances would be a fridge and hydronic heater they seem to be the same either way. The stove uses no power and some other items are more electronics will include a computer monitor, printer, networking / wireless stuff, but those will be chosen with power adapters so a dc-dc converter can be used.


Is there something that is overlooked?


There is a very large price difference in charge controllers, batteries, cabling, and circuit protection, 24v seems to be economical.

 

[LeishaShannon]

I wouldn't bother with 24v on a 12v vehicle unless you're planning a large (1000W+ solar) system as the efficiencies gained by using 24v will be lost when you consider the DCDC charging required from the vehicle alternator and the DCDC step down for 12v appliances like lights and cigarette lighter appliances. We have a 24v truck so it made sense to go 24v camper with 12v DCDC step down for the smaller appliances like laptop chargers.

 

[campo]

I suppose your question is about a 24V vehicle?
.
In the past 24V camping equipment was not always available.
Well the price for 12 or 24V equipment is the same, here in Europe, and everything is available.
Only a very few things do not exist like a car radio in 24V.
Therefore you use locally 1 or more small transformers 24V>12V. They are cheap.
.
The small advantage of using 24V is less cable thickness.
The big advantage is that you can use the full power of your driving alternator in 24V to charge your 24V battery pack.
Transforming this 24V to 12V is always problematic. Transforming means lose and low output.
These B2B 24V>12V transformers are only available in low amp versions and we want lots of Amps.
.
But if it’s a 12V vehicle than it has no sense to transform to 24V and lose the other way round.
Your Solar system can without any problems run on 80 Volt (4 x identical 12V nominal panels connected in series).
The MPPT will regulate this down without any problem to a 12 or 24V battery system.
You just have to buy the correct sized MPPT solar regulator.

 

[Nitromethane43]

This would be on a 12v vehicle, the original plan was to go all 12v, but off the shelf lithium systems were pretty limited, unless one was pieced together.

After looking into off the shelf lithium battery options, the 24v systems seem to be more plentiful, better refined, and cheaper. Then looking into the MPPT chargers with 3 or 4 solar panels with 320w or higher output the amperage limits are being reached and two controllers may be required. These are the two factors pushing the 24v system.

For charging on the go there seems to some options in a 12v/60a & 24v/160a or 12v/100a & 24v/200a dual voltage units.

Thanks for the input.

 

[campo]

If it's a 12V vehicle I do not see any advantage to create a 24V system on board.
All models off vehicle auxilliary Lithium (LiFePO4 or LiFeYPO4) batteries exist in 12V ! not in 24V.
Never use 2 MPPT solar chargers where you can do it with a single one.

 

[Kiomon]

If your vehicle is VERY large and 12v simply isnt feasible with the length of runs and voltage drop then maybe. or if you are large enough that the wire savings would offset a quality DC to DC converter, then it could make sense. The other use case would be if you need an inverter over 3KW. For efficiency sake, you are going to want to run as much on DC as possible, and we have presently surprised to find that a lot of household items are easy to adapt to 12v and the market in general easier for 12V.

If you do decide to go 24V, then i would not have individual small converters, they are likely to be very noisy EMI wise, and unless their are quality, present several possibilities for failure. Have a 12v distribution panel fed by a single high quality DC converter, off your 24v Bus.

Also on the off the shelf lithium side, TWO of Victron's 12v 200ah batteries come out cheaper than ONE of their 24v 180 ah batteries, by a lot when you factor in the BMS system for the 24v is about 2.5k, and for the 12v about ~300 all in. There are some 60AMP + Charge controllers out there, that can easily handle a 1kw array, and most of the manufacturers even recommend sizing arrays a bit larger AMP wise, as you wont get full rated output anyway in most cases. Two parrallel charge controllers wouldn't be an issue. We run 3 happily in our rig.

 

[Superfi100]

Its been a few years since the last post but why should your chassis dictate your DC voltage system for you EV? I plan to run a 24V system on a EV based on a Ram 5500 chassis (the chassis is now under construction). I will be installing the dual alternator package but running a 24V alternator as the 2nd alternator instead of a 12V one. My primary reason for this is to use the Victron Energy Quattro 24/5000/120-100/100 120Vac inverter charger. I want the 5000 watt model which is not available in the 12V system. Initially I will be running 400Amp @ 24V Lithium Ion battery bank and will determine if that is adequate or not. On the roof will be 4x300Watt solar panels. All appliances with the exception of the Mircowave and Induction Cooktop will be 24V, including the Espar AC unit. A Victron DC to DC converter will be used for 12V items like stereo and LED lighting.

 

[campo]

Interesting.
It is not so easy.
Consider that if the BMS is opening whilst running 24V alternator that will destroy the diodes.
You will need an emergency circuit of for example 2 small 18Ah AGM batteries that is parralleled and outside the BMS.

An other problem is the capacity of the 24V alternator.
It can overheat when this 24V alternator is delivering more than 1/3th of it's capacity for longer periods.

Careful - Alternator Charging Lithium - Victron Energy

Charging lithium batteries from an alternator, be that in a boat or vehicle, presents some challenges when compared to the straightforward nature of charging lead based batteries. The video in this blog highlights these lithium challenges and shows you what can happen when things go wrong –...

www.victronenergy.com

You can also parallel 2 Multiplus 3000 units instead of 1 Quattro 5000.
The size of the 5000 is so big.
An other option is to use a single Multiplus 3000/12V and limit to 1 plate induction.

The size of the 300Wp panels is to big for off road. The vibrations on the glass plate.
For off road it is better not to exeed the size of +/- 175Wp per solar panel.

 

[shade]

On the off chance jumping is needed it wont hurt to jump from 1/2 the house bank, Or temporarily reconfigure the housebank for that one off purpose.

That, or just carry a good jump pack. I think having a fully independent option is worth the trouble.

Things have probably changed since 2016. From what I've seen in the North American market, there are plenty of 12V equipment options to do whatever is desired. Unless the vehicle is already running 24V equipment or there's some special reason to add it, I wouldn't bother with it.

 

[Sitec]

Hi all. Google bought me full circle back to the EP! So, as I have almost completely clad our Hab Box, I'm now at the point of buying/fitting stuff to it, and have come across the 12v vs 24v conundrum. Originally I'd just assumed that the Hab Box would be 12V and the truck would be 24V. A little research has me now wondering if this is the best way... I already have several Items:-

• Maxxfan 7000 x 2 12v 5 amp (max each)
• Waeco CFX95 fridge/freezer 12/24v 1.25amp
• Vitrifrigo DW180A fridge/freezer 12/24v 10amp (max)
• Truma AquaGo Instant HWS 12v 2.5amp
• Surflow water pump (not purchased yet) 12 or 24v (6.5a -12v, 3.8a - 24v)
• Sirocco fans x 4 Bedroom and living area 12/24v 0.35a on high...?
• Autoterm 4kw diesel air heater 12/24v 5 amps on high fan speed
• Smart TV (not purchaced yet)
• Hab Box CD/Radio (not purchased yet) 12v
• LED lighting throughout (not purchased yet) 12/24v unknown amps...

I will have a gas cooker, 240v a/c, 240v washing machine etc so these do not need factoring in. I plan to go all Victron as I hear nothing but good about it, and know it all works together. I'm now leaning towards 24v as it seems logical, but am yet to learn enough to know if this is the right decision. Any input from those that have done it or are in the middle of it would be welcome...

 

[Tiktaalik]

Are you planning to install solar panels?

If so 24v is the way to go:

 

[Nitromethane43]

If your truck is already 24v and most of the items you plan on add are available in 24v then its more practical to go the 24v route. Just get a dc-dc converter for the truma and fans, you will reduce the size of wiring quite a bit especially on the larger loads inverters, solar wiring, and chargers.

I ran a Victron DC-DC converter for the 12v loads

Orion DC-DC Converters Non-isolated, High power - Victron Energy

Eliminate the need for a high current switch in the input wiring with the remote on/off connector on the Orion DC-DC Converter. Find a dealer near you.

www.victronenergy.com

Currently working on another setup that will also be a 12v vehicle with 24v camper using some takeout BMW batteries. For anyone who plans on having a large capacity battery bank, lots of solar, and /or have high ac loads going with a higher voltage makes sense.

 

[Peter_n_Margaret]

One more option if you have a blank canvas is to go all 240V AC and run everything via an inverter.
Plenty of choice of high quality and low cost appliances.
Cheers,
Peter
OKA196 motorhome

 

[Joe917]

300 Watt panels are not too large. We have two 315 watt panels that have seen 6 years and over 100 00km of on and off road abuse.