DUVAC internal pictures?

[BushEngineer]

Before you say anything...I know and have done the research on the DUVAC elimination. Not what I want to hear in this thread. This is a science and electronic thread.

Does anyone have a extra DUVAC lying around they could take the cover off and show me the guts? Mine's still on the truck. If no one has one, I'll take mine apart so I can a) see what inside, b) test individual components, and c) decide if it's repairable.

I just figured with all the hate for the DUVAC, surely someone's actually considered what is wrong inside the box. I have a feeling the m1010 worked as intended for a number of years from GM.

Thanks!

 

[dependable]

I recall that when mine failed, dark goo oozed out of it, the kind used in older transformers. That night make breaking one open for a look a little more involved than just getting off the cover.

That points to a transformer failure, I guess.

 

[joshuak]

I have one that your welcome to have, if you pay shipping. Condition is unknown.


Appears to be cast resin type, not sure how to expose internals.

 

[CUCVFAN]

I remember a friend telling me that he spoke to someone who swore it worked as advertised when he had a heavy 24V load, which most hobbyists would not be able to replicate. I have no confirmation of this behavior, but it was what I heard second hand.

 

[BushEngineer]

I appreciate the offer. I'll let ya know.

 

[BushEngineer]

Do u have pics of the labels...specifically the DUVAC. The relay has a label with corresponding patent numbers and from this I can determine true design intent. I have the relay part number and label images. Just need the DUVAC itself. Thanks.

 

[CUCVFAN]

Try my old "fix" of swapping the front and rear (red and orange) wires of the DUVAC and see what you get. It is probably not posted here, but I do have a lot of documentation on this system from back when I had one and dealt with this issue that I will post up, if it helps.

 

[CUCVFAN]

Some DUVAC info

I just converted my old write-up to PDF. Hopefully, it helps. Can't believe it has been 14 years since I wrote this...

 

[gimpyrobb]

Not what your looking for, but a kind of a "work around". Read the last page:



https://www.steelsoldiers.com/showthread.php?154284-CUCV-II-(CUCV2)-Dually/page7&highlight=equalizer

 

[BushEngineer]

CUCVFAN...I was trying to find that...all the old links from the diesel forum were dead.

Gimpy, I'll take a look.

 

[BushEngineer]

CUCVFAN, before I got your informations(thanks so much) I was reading patents(for the sure fire relay(the smaller blue box)) today to understand the design intent. I too initially thought the DUVAC was doing something to only allowing 12V output from 24V input. After studying the Sure Fire patents i found today....thats not the case. So only changing which voltage(low 12v or 24v) is referenced, the alternator does the rest. So running the top alternator in 12V output continuously should be fine with the only drawback being reduced total system 24V output. i have a question...I would say most if not all alternators are always directly connected to the battery on the + terminal. In fact the second alternator(24V) is wired directly to 24V bus and ground...so its hot 24V all the time. I believe the alternator has its own diode built in to prevent back flow. So what is your concern there? And why not bypass the DUVAC and RELAY(little blue box) completely and run a charging wire direction from the top alternator + terminal to the front battery +? Use a keyed 12V source as your field? Like this....http://www.prestolite.com/productinfo/alternators/A0014629JA/A0014629JA_wiring.jpg

 

[BushEngineer]

I posted something 40 minutes ago and it said it will show up after being approved..not sure why.

 

[BushEngineer]

The jist of it was....
i appreciate your info very much. I was studying the Sure Power patents today to try to understand design intent...I too understood that it seems the alternator was capable of the dual voltage(12v or 24v) based on the field value. So why not just wire the top alternator to charge the front battery and eliminate the DUVAC and relay(little blue box)?

http://www.prestolite.com/productinfo/alternators/A0014629JA/A0014629JA_wiring.jpg

 

[gimpyrobb]

Send a pm to a moderator.

 

[joshuak]

Do u have pics of the labels...specifically the DUVAC. The relay has a label with corresponding patent numbers and from this I can determine true design intent. I have the relay part number and label images. Just need the DUVAC itself. Thanks.

Only one label.

 

[BushEngineer]

Thanks man....says right there only needed if your charging two batteries with one alternator.

 

[CUCVFAN]

Yes, that is right. But, to get the 200 amps of 24V power they wanted, and to be able to provide 12V power to run the rest of the truck, they decided to run it with the dual alternator setup and use one of them, along with the DUVAC, to balance the system. Or so they thought...

 

[CUCVFAN]

DUVAC user guide

Here is an old DUVAC user guide, which is pretty good reading for anyone curious about the system. It's not the exact vintage of the CUCV stuff, but the concept is the same.

 

[CUCVFAN]

Orange Wire Kit Instructions

And, here are the "Orange Wire Kit" instructions, including correct battery hookup sequence.

 

[BushEngineer]

And, here are the "Orange Wire Kit" instructions, including correct battery hookup sequence.

So...I tried switching the red and orange wires on the DUVAC. No change.
I also attempted to see if the alternator(if fed 12v directly to the field and outputting directly to the front battery..i.e. bypass the reg and duvac) would supply 14v.
Even with alternator adjusted to the LOW setting still got 15.8V charging on front battery. At least I know the upper alt is working.

I also just saw your orange wire kit post. Appreciate that but I can say mine is not equipped...also seems the -20 TM is updated to show the orange wire kit...no wonder I couldn't find the 3rd diode on the diagram. That all has me wondering if I shouldn't try the orange wire kit to see if the thing starts working.

Otherwise I'm getting ready to swap in a 12V alt in the upper position...thus achieving proper battery balancing while sacrificing a 24V max amperage.