Thoughts on a 24V Ex Mod?

[Burlsube]

I'm thinking about pulling the trigger on my first Series. I found a great Ex Nato truck. Everything looks great - new chassis, well maintained etc. The only thing holding me back is the 24v electrical system...

Does any one have any experience with the 24v system.

I understand that the electrical bits are 1) more expensive 2) harder to source. Is there anything else to consider? How about conversion back to 12V?

[roverlandpark]

It all depends on your comfort level. There are several great threads on the Ex-Military Land Rover Form (emlra.org). From what I understand, the biggest challenges with maintenance are the spark plugs, alternator, and distributor. They're expensive if something goes a miss and you'll probably need to order them from a UK supplier. Lights can be sourced locally as big rigs are 24v. On a plus side, the 24V stuff comes up a lot on e-bay.co.uk because other people convert them to 12V. I personally would keep it original. On the other hand, if you want to convert, it's pretty straight forward. Check with the emlra forum or give Les at RN a call. If memory serves, he converted a Lightweight years ago from 24V to 12V.

[disco2hse]

Mine is ex-army 24V FFR. Things like starter and alternator might give you some grief but things such as plugs, etc. are 12V. I am assuming you are referring to a V8? You should find that there is a 24->12V converter for the ignition system. Does it have points or is it electronic? What kind of dizzy does it have? Is it EFI or carby?

On mine the alternator died so I replaced it with a 24V Bosch truck alternator. The original behemoth was provided to charge three 24V battery banks and since I am not using all of them the split charge system was not required, therefore I went to something that is much lighter weight. The starter also died and this was quite hard to find and reasonably expensive compared with a 12V version, but still about the same price as most late model model starters on newer vehicles, so comparisons with pricing are not always accurate.

The converter died a while back so I dumped it and replaced it with a 12V Petronix Flamethrower II low resistance coil and electronic Ignitor II module. That means no ballast resistor requiring a drop to the normal 6V coil. This is running from one of the batteries and to protect the two batteries I have put in a charge equaliser.

Lights are all 24V and cost about twice as much as 12V lights, so ummm $4 instead of $2 for the park lights. Big deal huh. Apart from that you will find the wiring is a lot heavy grade to handle the large amperage (30A fuses which cost about 50 cents each). Gauges should never have to be replaced but if they do there are plenty on the second hand market.

If you want a stereo or communications radio then use a voltage converter from the main power feed. Get a 15A minimum one that can soak up spikes, and make certain it is fused. Don't run it from one of the batteries otherwise it will cause the main battery to sulphate and boil the secondary one.

If you want to use LEDs, say as spotties, you will find most are 24/12V and are priced much the same as standard 12V units.

Anything else?

[Burlsube]

Thanks for the info. Aside from the ignition bits does anything else 12v in a 24v truck?

[JimCT]

It can be a big plus to have a waterproof and sealed ignition system.

[scott]

Thanks for the info. Aside from the ignition bits does anything else 12v in a 24v truck?

Lucas canned smoke but the 24v loom takes twice as much, or maybe it's half as much...

[Terrys]

The primary reason the MOD trucks were wired for 24 volts was because all modern day military radio equipment is intended to run on 24 volts, to save weight in the radios.
I've never been a big proponant in changing them to 12 volt, but it's done regularly. Problem is most conversions are done half way. The proper way to go about it is to repace the entire wiring harness, as the military harness is very complicated in lighting, charging and radio circiuts
All auto electric shops are capable in rewinding starters and alternators of 24 volts. The wiring is ample to carry heavier loads than that used in 12 volt trucks. Generally speaking, a 24 volt system that hasn't been bodged is more reliable. Bulbs are not difficlt to source in the least. They also start better in the winter.

[SeriesShorty]

I HAD a 24v FFR Series. I loved how waterproof everything was, the 24v components are stout as heck, the generator put out enough to light a small city, and it would start in cold weather like no ones business. The down fall was my truck had shielded ignition components so I couldn't even find spark plugs easily, and definately not cheaply. I tried to do the half-way conversion using a 24v-12v converter wired only into the ignition so I could keep all of my other 24v goodies. It was flakey, unpredictable, and left me stranded a LOT. Headlight bulbs are NOT easy to find, luckily a fellow board member sent me one he had. It was pretty reliable the first year I had it, but when I had my first component failure I just didn't have enough technical knowledge to diagnose it properly, and parts are too expensive to just go replacing on a whim hoping you'll fix it.

A not-so-gentle nudge from the Rover Gods left me stranded after a small section of my wiring harness melted down and left me gasping for air out of my smoke filled cabin as I jumped outta my truck into a VERY bad section of St. Louis. That was just the right push to make the full switch to 12v. Not having any desire for a concourse restoration, I've also swapped to parts that I can find locally without scouring the internet and waiting on shipping. Napa is my friend.

I've spent the last 11 months (I've just been taking it slow, time off for bad weather, etc.) yanking all the old radio wiring, the original harness, relays, 24v components, etc. I've built my own harness, got rid of the junk I didn't want, and was able to easily add lots of cool 12v accessories. I now have 12v power outlets, Hellas up front, a rear work lamp, a CB, and my center seat which held two batteries will now be a cubby box for the important things...like holding my 32ounce Pepsi. ;) I'm REAL close to finishing but the abnormally hot summer has left me sitting inside staring at my truck through the window. I hope to have it finished by September.

Some folks love the 24v and have no problems so I don't want to turn you off from it. It just takes a little tech savvy than I had at the time. But I've learned a lot from the experience regardless.

Good luck with your search and welcome to the board!

[Burlsube]

Can you use non sheilded 12v plugs? Ill like the idea of conversion. I'll probably undertake it after i get I put in the over drive and get a few other things sorted out. Did you need to get new guages too?

[disco2hse]

Lucas canned smoke but the 24v loom takes twice as much, or maybe it's half as much...

Half as much and flows twice as fast. Makes for some interesting sparks when things don't go as planned. :P

[disco2hse]

Thanks for the info. Aside from the ignition bits does anything else 12v in a 24v truck?

Nope. That's about it. And some of the 101 Forward Controls also had 24V coils which are next to impossible to source now (there's a company in the Netherlands I believe that still manufacture them new for the military).



I HAD a 24v FFR Series. I loved how waterproof everything was, the 24v components are stout as heck, the generator put out enough to light a small city, and it would start in cold weather like no ones business. The down fall was my truck had shielded ignition components so I couldn't even find spark plugs easily, and definately not cheaply. I tried to do the half-way conversion using a 24v-12v converter wired only into the ignition so I could keep all of my other 24v goodies. It was flakey, unpredictable, and left me stranded a LOT. Headlight bulbs are NOT easy to find, luckily a fellow board member sent me one he had. It was pretty reliable the first year I had it, but when I had my first component failure I just didn't have enough technical knowledge to diagnose it properly, and parts are too expensive to just go replacing on a whim hoping you'll fix it.

That alternator. I still have the old one (just waiting for the price of copper to come up again :D ). You'd be amazed at how much power the thing sucks out from the engine though. A smaller one does just as well.

Our military replaced the OEM shielded gear with Mallory components. No more points, all electronic and on the later ones they started using marinised distributors too. Plugs are standard NGKs. Very :cool: I have since replaced that with Pertronix (less prone to nastinesses).

A lot of the electronic switch gear you can use from the marine trade. Lots of larger vessels are 24V. Also, you should find that Hella make all the correct bulbs in 24V, even the little peanut bulbs for the brake and diff lock warning lights.

I know what you mean about the converter business. I had similar issues and had to be towed (ignominiously) from the middle of the bush. Damn my right leg was sore - it's amazing how much you have to rely on engine braking off-road. That's why I now take the feed from one of the batteries and use the charge equaliser. The Mallory system is also known for failing and when mine did I dumped it.

A number of people around here have done the same as you and not regretted it. However there is no real shortage of 24V components though.


I've spent the last 11 months (I've just been taking it slow, time off for bad weather, etc.) yanking all the old radio wiring, the original harness, relays, 24v components, etc. I've built my own harness, got rid of the junk I didn't want, and was able to easily add lots of cool 12v accessories. I now have 12v power outlets, Hellas up front, a rear work lamp, a CB, and my center seat which held two batteries will now be a cubby box for the important things...like holding my 32ounce Pepsi. ;)

I have thought of doing the same. I really want to get rid of the split charge diode because I reckon that's where a number of the spikes are coming from in the circuit. It is old technology and very inefficient, however it is bullet proof and not sensitive to rough treatment compared with the newer alternatives.

Of course if one wants to convert to 12V all that is required is to change the starter, alternator, gauges, wiper and fan motors and rewire the coil and ignition. The rest of the harness can be left in place and even the 24V bulbs can be used (they will be dimmer that's all).