12 or 24 volt system

[timmobo]

I’ve got an 6.2 diesel ‘86 CUCV, that had a 24 volt system. I didn’t know much about the system and had a family friend make it a 12 volt system…but I don’t think he put in a 12 volt starter. I’m not sure exactly what he did. It seems that all he did was change the wiring so that only 12 volts goes to the starter, so now it always sounds low on charge when starting. Instead of buying a new starter I wondered about just changing the wiring on the batteries to be in series but wanted to confirm what else I should check so that if I wire the batteries in series I don’t fry something.

 

[Barrman]

Don’t do anything else until you can verify what has been done, what parts are actually on the truck and how they are are connected.

 

[timmobo]

Don’t do anything else until you can verify what has been done, what parts are actually on the truck and how they are are connected.

Any ideas as to how I verify what’s been done?

 

[Wreckclues]

Can you disconnect the starter and attach a multitester to confirm the voltage? If it is indeed 12volts I wonder if a 12VDC to 24DC Boost converter regulator would work.
Something like this;
12-24V Premium Quality Starter Solenoid Triple Stage Series-Parallel Magnetic

 

[87cr250r]

The starter has a nameplate that will tell you the voltage.

The 24v starter will not roll the engine on 12v.

 

[Finnegan1008]

Not trying to be a jerk but I suggest you study up on this by reading through the many existing threads on the subject.

this is because you likely wont get a shortcut answer and even if you did, you need to understand the basics of the wiring system on these trucks before any advice would be useful.

The good news is the system is actually extremely Simple and after a bit of homework you will understand what you have going on.

 

[timmobo]

Not trying to be a jerk but I suggest you study up on this by reading through the many existing threads on the subject.

this is because you likely wont get a shortcut answer and even if you did, you need to understand the basics of the wiring system on these trucks before any advice would be useful.

The good news is the system is actually extremely Simple and after a bit of homework you will understand what you have going on.

Apparently, my research skills aren’t as good as yours. I hunted through trying to find threads on this, but didn’t find anything that seemed particularly straightforward. There is no question there’s plenty of homework. I have to do to understand everything that’s going on with this truck. But thanks for the advice.

 

[Finnegan1008]

Apparently, my research skills aren’t as good as yours. I hunted through trying to find threads on this, but didn’t find anything that seemed particularly straightforward. There is no question there’s plenty of homework. I have to do to understand everything that’s going on with this truck. But thanks for the advice.

I found these pretty helpful when I began un- hacking my wiring (still a work in progress)

all of these live in the “helpful CUCV threads” tab in the CUCV forum. That page has 99% of what there is to know about these trucks.

CUCV - Starter Circuit

Read the first few pages of Chapter 2 of the TM 9-2320-289-34 tech manual to learn how to read the wiring diagrams and how the wires are labeled for the diagrams Lets trace the stock starting circuit: 1 - 24v comes off the 24v Positive terminal block via the red fusible link 1 RED-2Z 2 - A...

www.steelsoldiers.com

CUCV Alternator Isolated Ground Therory of Operation

Sometimes we take things for granted. We assume everyone can wrap their head around the concept of the isolated ground circuit and the associated battery wiring. Warthog had asked a fellow member Amphi for his input of the isolated ground circuit and he conducted an experiment. Here is his...

www.steelsoldiers.com

GP Resistor Bank Bypass

I just completed a 12v bypass on my M1009. The military system was running fine since I started driving it in June, but I felt it would be insurance to run AC60G's and I'm planning an Air Conditioning Install this winter as I live in the deep south. So eventually the entire 24v system will...

www.steelsoldiers.com

CUCV Wiring Diagram color (except M1010)

CUCV Wiring Diagrams color (except M1010) I've been working on these, hope they'll help someone. If there needs to be any correction just let me know. I corrected two with warthog's help... Corrected Charging Circuits 09/29/2011

www.steelsoldiers.com

CUCV - Rosscommon 24v to 12v Conversion

There is a company called Rosscommon Equipment Center that has been retrofitting MVs to fire fighting usages for years. http://www.roscommonequipmentcenter.com One of their conversions was to change out the CUCVs (not the M1010s) 24v electrical system to a more standard 12v system. This...

www.steelsoldiers.com

 

[Finnegan1008]

Also this dude (Rocknus urban camouflage) put out some awesome content. I would watch every CUCV related video he did starting with “CUCV classroom”

I assume he’s a member?

https://m.youtube.com/playlist?list=PLEhhfKFkDsGTHR1GJ8MkWA9xDif0PlSfz

 

[nyoffroad]

I'd be spending some time with the "family friend" and find out exactly what he did and carefully ask him why he did it.
The stock system is a good system, a bit odd but it has lasted all this time. Personally I'd go back to the 24v starter as it uses only half the amps of a 12v system. I've had both, 2 civvie 6.2 12volt system and many CUCV 24v system, I had more trouble with the 12v. ones than the 24v.
Why? Some of the problems were from temp sensors/glow plug controllers and some was because of burnt up starters due to high amperage.

 

[85CUCVtom]

My M1009 was converted to 12v by the previous owner and I honestly wish it wasn't. The 24v system is pretty simple.

Your first step is to figure out what exactly was changed on on the starting and charging system. Figure that out then go from there.

 

[NVAM998]

Not hijacking but I have a M998 that is stock 24 V and was reading the TM 9-2320-280-20-1 for fluids capacity and noticed on page 1-32 that the starter voltage is listed as 12 V. The batteries are in series so the truck isn't a 12 V system. Did they actually use a 12 V starter figuring running it on 24 V would make it spin more better? Do they have a giant series resistor to drop the voltage to the starter? I haven't actually measured the voltage as it works fine but it did make me curious.

 

[Finnegan1008]

Not sure about what the TM says but It should be a special 24v starter that is running on 24v.