12 volt conversion

[totaljoint]

I'm hesitent to ask this one, sure it's been brought up, but:

Since a common topic here is trouble finding replacment parts in 24 volt (fuel senders, gauges, winches, lights accessories, fuel pumps etc..) and such items are cheaper and more common in 12 volt form, why don't we convert our engines to 12 volt ignition and be done with 24 volt altogether? Would that be easier solution? Why are military vehicles 24 volt when the same civlian versions are 12v?

(Note: this question comes from someone who doesn't know any better )
Ed

[Jim LaGuardia]

In short, it is cost prohibitive.
To start you would have to replace the entire wire harness as a 24V system utilizes smaller wires as less amperage is used at 24V.
Then every electrical item(bulbs, relays, alternator, regulator) would need sourcing.
Hope that answers the Q

[spandit]

I think 24V allows you to use thinner wire, as less current according to Ohm's law. Also gives you more grunt for the starter.

Just realised I'll need to change all the bulbs in my 12V Sankey trailer

[edzz]

In the days when people changed cars running 6 volt systems to 12 volts the wiring harness was much more than adequate for the conversion. Going from 24 volts to a 12 volt system would seriously stress the existing wiring harness (read high probability of electrical fires).

Now for a long winded reason.

Lighter wire can handle more power (watts) at higher voltages. You would need to rewire the whole truck with heaver wire.
As an example the maximum current in amps chassis wiring using 18 agw wire is listed at is 2.3 amps. http://www.powerstream.com/Wire_Size.htm

So using watt’s law P (watts) = V (volts) times I (amperage) we can find that at 12 volts the 18 awg wire can transmit 27.6 watt’s and at 24 volts the same wire can transmit 55.2 watt’s
P=V*I http://en.wikipedia.org/wiki/Watt%27s_Law

12v*2.3amp=27.6 watt’s
24v*2.3amp= 55.2 watt’s

One of the reasons civilian vehicles us 12 volt systems is to reduce the danger to an ignorant owner from death due to electrocution, yes according to the FCC 30 volts can kill. So now someone is thinking those Tazer guns the police have use thousands of volts (and only occasionally kill) how could 30 volts be dangerous? Once more I’ll use a FCC figure; they say one tenth of an amp can cause death. All of this is not to say you can’t hurt yourself with 12 volts however the likelihood of death is greatly reduced (the FCC figures come from the Amateur radio element 2 exam).

Also, 24 volt mandatory NATO slave receptacle for jump starting any NATO vehicle

[David Dunn]

The civilian verson of the Pinzgauer are 24v also.

Only a very few of the 716/18s are 12v, And sourcing some of those parts are even more difficult.

The key electrical component of a Pinz are only available in 24v... starter motor, alternator ...(fuel pump is mechanical)... A 24v winch is only a little more expensive than a 12 v. Light bulbs are readily available ( except for some of the new "techno gadgety" ).

As Jim said, to have alternators and starters rewound or sourced are cost prohibited.

Even on 12v military vehicles, sourcing components that were made over 30 years ago are drying up, and cost are rising.

And to bring the wrath of some ( like I haven't seen that before ), a percentage of MV owners ( not just Pinz) don't/didn't have a clue to the special needs of them, and just shouldn't have bought them.

Spandit... I have 2 Sankey and 2 Supacat trailers that I solely run 24v bulbs in.... even when towed by a 12v vehicle..... if light bulbs were your only problem, you should be grinning from ear to ear.

To repeat Ed, the basic rule of electricity is: volts x amps = watts. On "most" items, watts are the same, so when volts double, ampere is cut in half. I've seen some items that when they were made in another voltage, their power draw went up

[spandit]

David,

Aren't the bulbs a bit dim on a 12V vehicle?
That's not the only problem with the Sankey - needs a bit of welding but at least it should fit behind the Pinz nicely!

[David Dunn]

Yes the 24v lamps are a bit dim on 12v, but still aren't any worse that the stock 710/12 taillamps are on 24v . That is why so many Pinz owners opt to change to some othet rear lamps.
To further my reason for fitting my MV trailers with 24v bulbs :
1) It doesn't mather what vehicle I plug into, the bulbs will work ( if you try the reverse, they'll glow bright for a few moments before popping),
2) All my tow vehicles are are bigger/wider than the trailers and the tail lamps are much more visible/brighter than even the correct bulbs in a Mk2 Sankey ( the Supacat trailers and my Mk3 Sankey have large tail lamps already).
3) And as you are quite aware of, Everytime you pop a lense off a Sankey, you hope and pray you don't break the lense or socket .

My case of tow vehicles / trailers is unusual with 4 variant of vehicle plugs ( 9 vehicles) and 3 different trailer plugs ( 7 trailers), but keep a simple adapter setup to allow any cross use of the trailers. Only 2 trailers have 12v bulbs in them, and that is they will never be towed with anything but one of 3 12v vehicles.

I also imagine that the rear lamps on your Pinz and Sankey ( if a Mk2) have been changed for seperate brake , turn lamps , as require over there. The Swiss 710/12 have combined turn/brake lamps.

the Sankey fits beautifully behind a Pinz

As it does a Supacat

or a Vampire


I have yet to find something it doesn't fit nicely behind.
... note to self... gotta find the pic of the Sankey behind the Toyota Highlander Hybrid !

[audiocontr]

What is that last vehicle?

[David Dunn]

What is that last vehicle?

A Land Rover 101Fc Vampire.

1 of 18 made during the Cold War for listening and following East German and Soviet troop movements.
The masts extends 21m (68 3/4 ft) plus the 15 ft it stands vertically ( collapsed)..... then add the antenna on top of that

I estimated this at a mere 72 ft.