one 24volt alternator modification, m1010

Winter has lifted here in the Pacific north west. I have been replacing and repairing parts on my m1010 as needed. When I initially acquired the vehicle I noticed a modification to the electrical system had been done. From what I understand the mod had been conducted by the military. The system has worked without failure for the past two years. I would like to begin working on the electrical system, replacing and updating parts specifically in the charging components. Im wondering if anyone is familiar with the modification that had been done? It's one 24 volt alternator charging both batteries. It utilizes the duvac, wires appear to have been cut near the duvac as well as near the alt. Any help or direction would be greatly appreciated. I'll post pictures as well.

Are you sure that is a 24v alternator?

How are the batteries wired?

edit: i googled the part number on your alt and it does appear to be a 24v unit.

That does not appear to be the original DUVAC. If you can get a part number from the blue box, it would be easier to figure out what it's capabilities are.

. Lavarok thank you for your response. I'm positive that it's a 24 volt alt. The batteries are wired in series. The duvac is getting 24 volts on the entering terminal and 12 volts at the exiting terminal. Attached is a photo of the duvac model number

That is funny, my M1010 has only 1 24V alternator, but it doesn't look like yours..its huge...like double the length but I cant find a duvak on mine anywhere.
Maybe the changed them to 1 alt for the extra power load due to the box in the back.
I can get some pics today and post here if anyone has any input.

That is a replacement DUVAC made by sure power. Sounds like it is working, so you have a 12v source to charge the front battery and provide 12v power as needed to equipment.

After reviewing your photos again, I dont see any issue except for the red wires left hanging in the engine compartment. Those "hot" ends can be problematic when they ground out.

If the system is working, I would run with it. No point fixing something that isn't broken. You have an updated DUVAC II which provides 25A of 12v power. If that is enough for you, then no need to change anything. It is basically a small battery equalizer.

When the photo's were taken the batteries were not in place. That's why the cables were left hanging. I'm in the middle of a good sized tear down and rebuild. I appreciate everyone's response.

I'm getting ready to do the same thing to my M1010. Going to take it apart, repaint, treat any issues, and put it back together for a final coat of Gillespie.

Good luck!

I'm on the fence right now. I have researched and read many debates over the 12 volt conversion. I understand the benefits of 24volt starter. I'm considering the conversion for the the reason of survival. This vehicle is becoming a backcountry camper, specifically for the winter seasons. In my mind the 12 volt conversion would allow the duvac to be removed (there would no longer be a concern of failure there). In an emergency situation a 12 volt system appears to be more manageable. Like I said I'm on the fence. This is why I would like to understand the mod that was done to my vehicle.

The rear heater and ac have been removed, I no longer need the 24 volts for that.

leisman7 said:

This is why I would like to understand the mod that was done to my vehicle.

Click to expand...

A simplified line drawing for your current charging system looks like this.



If your not using the rear AC and other 24v items (surgical light, focus lights, etc), then converting to 12v would a viable option for your truck. In the end, its all about what your trying to achieve and what works best for you.

Solenoids are available to switch battery wiring for this particular scenario. 12v charging system but 24v starting system. Be aware they are $200+ depending on what amperage you are looking for. This may be a good option for those looking to do a 12v conversion while retaining the 24v starter.

http://www.zafr.com/trucktcom/parallel_sw.htm

http://www.texasindustrialelectric.com/T_114_12_series_parallel_switch.asp

Skinny said:

Solenoids are available to switch battery wiring for this particular scenario. 12v charging system but 24v starting system. Be aware they are $200+ depending on what amperage you are looking for. This may be a good option for those looking to do a 12v conversion while retaining the 24v starter.

Click to expand...

Sounds like a great way to complicate what should be a simple system. Part time 12v, part time 24v. Great way to move that RELIABILITY meter way down into the red zone.



Just because a thing CAN be done does not mean that it SHOULD be done.

Lavarok, thanks for the diagram. Please correct me if I'm wrong. Conducting a 12volt conversion in the diagram you have drawn would be a matter of connecting the two positives at the duvac, removing the duvac, wire the batteries in parallel, replace the 24volt, and replace the starter?

Read through this thread and especially post 11. ChevyC60 did the dual one wire 12V alts similar to what the standard CUCV has. The system is extremely simple, super dependable and maintains all of the 12/24V capabilities. Mark did his a little different but yet just as effective. The M1010 ChevyC60 did is mine now and there is never an issue with the charging system.

http://www.steelsoldiers.com/showthread.php?101135-M1010-DUVAC-Removal-Plan-quot-B-quot&highlight=

Can't be any worse that the stock 12/24v system.

Recovry4x4 said:

Read through this thread and especially post 11. ChevyC60 did the dual one wire 12V alts similar to what the standard CUCV has. The system is extremely simple, super dependable and maintains all of the 12/24V capabilities. Mark did his a little different but yet just as effective. The M1010 ChevyC60 did is mine now and there is never an issue with the charging system.

Click to expand...

Where is your link?

leisman7 said:

Lavarok, thanks for the diagram. Please correct me if I'm wrong. Conducting a 12volt conversion in the diagram you have drawn would be a matter of connecting the two positives at the duvac, removing the duvac, wire the batteries in parallel, replace the 24volt, and replace the starter?

Click to expand...

If I were to convert your truck to 12v, I would:

1. remove Duvac II and all wires attached.
2. remove 24v alt and replace with 12v alt using existing wires
3. replace 24v starter with 12v starter (starter relay circuit should be ok as-is - maybe do doghead relay mod to be safe)
4. move the wire from batteries to 12v bus and instead terminate it on the 24v bus, so you have a jumper from original 24v bus to 12v bus
5. wire batteries in parallel using the original 24V bus (now really 12v) for the positive connection

I think that about covers it.

lavarok said:

Where is your link?



If I were to convert your truck to 12v, I would:

1. remove Duvac II and all wires attached.
2. remove 24v alt and replace with 12v alt using existing wires
3. replace 24v starter with 12v starter (starter relay circuit should be ok as-is - maybe do doghead relay mod to be safe)
4. move the wire from batteries to 12v bus and instead terminate it on the 24v bus, so you have a jumper from original 24v bus to 12v bus
5. wire batteries in parallel using the original 24V bus (now really 12v) for the positive connection

I think that about covers it.

Click to expand...

Lavarak thanks for the reply, I
appologize I'm a visual
learner. I'm not understanding step 4? I have also completed dogheads modification.

the wire i am talking about is marked with the two red arrows.

Anybody got a 24 volt alternator they want to sell or know of a source there-of The newer the better. Must fit into a M1009 (passenger side pos). I converted my 86 to 12 volts (used a gear reduced starter...works great). Now I have some 24 vdc radios I want to power. I don't want to use a 12 to 24 volt converter...one more weak link, etc