...what is the advantage/disadvantage of having a 24v system
rather than a 12v system in our motorhomes??

24+ smaller wires and you can run a bigger inverter

24- It's 24vdc

12+ Almost every thing is designed to run on 12vdc. This even include my TV and WDTV plus my 2 and 4 tb disc drives. Now we come to furnaces, refrig, exhaust fans.

Having done and know a lot of others who have done bus conversions, 24 volts is a pain in the a**. Most of the 24vdc folks install a 12vdc alternator and run dual systems. Few bit the bullet and converted the whole bus to 12vdc.

In summary WHY would I want a 24vdc RV?????

As Gary says, the only reason to go 24V is to run smaller wires.

If there are a whole lot of high current wires, long runs and the wires are made of gold, you could save money with smaller wires.

Another advantage is the smaller wires have less weight. This is why most large aircraft have 28v systems or higher.

Considering the small number of copper wires of reasonable size in our coaches, neither cost or weight would be that different to make it worth the inconvenience using other than 12V, IMHO.

Recently there was published info that cars will gradually be switching to 42V...

and

https://en.wikipedia.org/wiki/...lt_electrical_system

Good morning;

In looking at the papers cited, there does not really seem to be any real movement to a higher voltage or a dual voltage automotive electrical system at this time. Even the first early paper cited mentions that there has been a reduced interest in pursuing this path, due in part to other advances in automotive power techniques for the peripheral driving functions; not just the main task of power for vehicle movement.

Other discussion and papers from the late 1990s also show a trend away from the high voltage or dual voltage automotive electrical systems.

So, it would seem that for the near future, we will continue with the rather popular "12 VDC" automotive electrical system, where the nominal design system operating voltage is 13.8 VDC that is most compatible with the still cost effective Pb-PbO2-H2SO4 electrolyte batteries that we all have come to know and love.

Enjoy;

Ralph
Latte Land, Washington
with an SOB motor home

Further to this:

Most all of the modern electronics is and must be operate at low voltage. Automotive computers and controllers operate with internal voltages of 5VDC, 3.3VDC and in some super high speed applications around 1.8VDC. LED lighting is also low voltage.

All of these systems require some sort of power supply to reduce and stabilize the operating voltage. Power supply design over the years has improved with efficiency approaching or exceeding 90% but still a 10% loss to convert power is a big deal when a lot of systems are on line. Loss usually produces heat, starting from a higher voltage results in more actual loss so more heat is produce and must be dissipated somewhere.

Take a look at the newer LED head lamp replacements. They all have either a large copper fin radiator behind the LED assembly or a fan attached to cool the assembly. The LED does produce a lot of heat but the most heat is from the power converter. The power converter converts 12VDC-24VDC to around 3VDC that the LEDs operate at.

LEDs are diodes and in that respect once they start to conduct at around 3VDC if the voltage is raised more, more current will flow thru the LED, the voltage can not rise as it is limited by the forward conduction of the LED. Therefore, the power converter only controls the current (amperage) and regulates that to the value that will not burn out the LEDs.

Again, starting from a higher voltage will result in more loss and greater heat.

Motors on the other hand operate much more efficiently at higher voltage. Much less copper loss for a given HP output. Tesla automobile motors operate in upwards of 400 Volts and that is converted to either variable AC or variable DC for propulsion. Same for the Prius, Chevrolet Volt and others.

In my first bus conversion 40 years ago I had the entire bus at 24VDC (24VDC-28VDC) and the coach was full of 24VDC to 12VDC converters, not easy or good.