Yet another M1010 Charging Issues :(

[chevymike]

Hi guys,

Okay, so I have been reading SS for the last month (well before I got my M1010) and know there are a number of issues with the DUVAC system and charging on 1010's in general. There seems to be a number of different solutions on removing this troublesome system. Also a lot of reference to TM's for troubleshooting.

So today, after gettting both batteries charged up (holding 12.8 volts after 24 hours from being charged), removed all the connections from the DUVAC system and cleaned them. Put some dielectric grease on them during reconnection. It does have the "orange" wire conversion and the battery voltage is the same at the battery and at the end of the orange wire at the DUVAC. Zero voltage drop so my connections should be good.

Here is what is happening. When running, I am getting 27.4 volts across the two batteries and from the output post on the lower alternator. When I check the voltage at the front battery, I am only getting 10.4-11 volts when running. I get this same voltage at the upper alternator output post. I know this is not right and it should be the mid 13 to low 14 volt range.

Now the question I can't seem to find easily answered (as the TM's want you to test the alternators off the vehicle) is, what voltage should I be seeing on the upper alternator output post? Should it be closer to 28 volts or 14 volts when running?

I have also checked all the fuses on the fuse block (test light) and get power to all of them depending on ignition switch or master switch setting. I checked this as I had found others running into weird issues when some of those fuses were blown.

I ran out of daylight and couldn't check to make sure the 3 diodes by the DUVAC are working.

Sorry this is long winded but I really wanted to make sure that it is known that I have been testing/reading/checking everything I can come across and not just posting up without doing my homework.

Thanks for your help and hope someone knows what the upper alternator output is.

 

[chevymike]

Anyone??? Getting ready to start at it again and really need to know what the upper alternator output should be at the output post.

I think I might have a bad alternator but no one open on Sunday can test a 28 volt one.

 

[markg]

Anyone??? Getting ready to start at it again and really need to know what the upper alternator output should be at the output post.

I think I might have a bad alternator but no one open on Sunday can test a 28 volt one.

i own a 1010 and went through similar problems. your top alternator charges the front battery, its not charging. you have checked the fuses. with the truck running measure voltage across the back battery alone, what is it? what is the front? both alternators have 6 screws for the removal of the regulator, i think default is the medium position. move the top one around between low-high and see if there is change. there is also an adjustment on the duvac unit, i couldnt make it do much, its a small pot on the front of the unit covered by rtv. sounds to me like the top alt is not energizing. i doubt that its bad. let us know what happens. thanks, mark

 

[chevymike]

Okay, more testing and to answer markg questions. I checked all the fuses yesterday and I get power thru all of them (used a test light and checked both sides of the fuse).

Rear battery alone = 14.8 volts, both batteries = 27.4 volts. I did pull the regulator and found it was on the medium position so I moved it to the high. Now the front battery is running at 12.2 volts set at high and in the meduim spot, 11.4.

I checked all three diodes over by the DUVAC and they all tested good. I pull them and cleaned all the plugs.

I tried the adjustment on the DUVAC and turning it a 1/4 turn either way made zero change in the voltage.

Again, at the actual output posts on the upper alternator, I am only seeing about 11 volts.

The only idea I haven't tried, which I read about here, is switching the front and rear leads on the DUVAC but from what I read, if the upper alternator is not working, this will not correct the problem either.

Thinking the alt or regulator is bad but again, have no way of testing it. If the top alt is not energizing, is there a way to "rig" this so I can see if the alt is working?

Thoughts, ideas, fire bomb???

 

[markg]

i had the same symptoms as you when i got my truck, i had high 15.2 out of the back and 12.2 out of the front battery when running. it seems the higher the voltage gets on the back the lower it gets on the front. my problem was the fuse that runs the gages. i dont know the connection but when i found the bad fuse and replaced it the front battery came up to 13.9 and the back was at 14.2. close to where it should be. my truck only has 7800 miles , i know the duvac system has given people a lot of trouble, enough that they gave up and switched out the blue box. when the weather gets better here i can get out and do some more tests if you havent got it whipped by then. thanks, mark

 

[chevymike]

Yeah, I think it might have been one of your posts that mentioned the fuse for the gauges, hence why I checked all of the fuses. I specifically pulled that one and doubled checked it with a meter and used a test light on all the others. I had even thought the Gen lights might be the problem if burnt out but after more reading I realized that 1010's don't use the Gen lights (dumb IMHO).

Honestly I am seriously looking to rip all the 24 volt stuff out since I have zero need for it. It already had the 12 volt GP relay swap done. I am not looking for a "restored" MV but bought this to do a full on 4x4 camper out of it. My wife and I do some very remote wheeling/camping where we can be 50-100 miles from the nearest anything, let alone a parts supply store. The real likelihood of us finding a replacement 12 volt item (starter, alt, etc.) in the middle of nowhere is greatly higher than any 24 volt part.

I was hoping this system would work for a little while so I can focus on other parts of my build up but I said if I ever need to replace an alternator, I was going 12 volt. As it is, I have been researching a TON on J-180 mount alternators (which is what the stock 1010 style is) and there are a ton of them out there. Some outputs all the way up to 320 amps! Even brushless ones. The J-180 mount is about the most common style and the nice thing about these larger alts, they put out way more current at idle than any of the "standard" 12 volt alts you typically find. My ultimate plans are for dual 12 volt alts and 4 batteries in two battery banks.

If anyone wants to follow along with my build, it will be documented at Expedition Portal New Build; 1984 Chevy CUCV M1010 4x4 Ambulance - Expedition Portal Forum

Well if anyone has any ideas on testing the upper alt, to verify its bad or not, post on up before I rip it all out. I guess if I do rip it all out, I'll have some spare parts to sell for those who want to keep things stock.

 

[Ambulancechser]

the alts should have the same output voltage...roughly 28 volts.(they're both 24 volt alts)

the problem likely involves the way the charging system works...the upper alt does not charge all the time...it's switched.the switch assembly (for want of a better description) is a switching diode box that should be mounted just behind the duvac...the duvac is likely not the problem.

the diode assembly senses front battery voltage,and excites the field on the top alt when battery voltage is low,thus allowing it to charge.when the battery reaches full voltage,the field is switched off. the front battery charges in pulses.i believe (it's been some time) that the charge interval,with fully charged battery's is around 30 seconds.apply your volt meter to the top output terminals,load the charging system (turn on evry light and fan/blower you have)and wait at least 5 minutes.if there is no change in output,the diode switch is likely fried (mine was).a further test would be to simply switch alternators top to bottom.that will tell you if the top alt is not charging.

i had this exact same problem...my solution was to remove one alt,and use a battery equalizer.ran flawless after that.your correct that there's a ton of j-180 mount alternators out there.i'm also switching to 12 volts.

your expo' build is where i'm heading with mine...i'm starting with a cummins/5 speed conversion,camper stuff to follow.it's been a terribly long time since i posted on this board...but i still lurk.here's some pics...cheers.

 

[chevymike]

Thanks for confirming what I thought I should be getting at the actual alt terminal. 10-11 volts is definitely not right for a 28 volt alt (per the regulator marking).

Nice looking rig!!! What size lift and tires are on that beast? I have been looking at engine/trans swaps too but for now will focus on making what I have reliable and get the camper built. If I have to pull alts to swap and test, I might as well replace them with 12 volt ones.

I considered going with a battery equalizer but with the cost of it just to keep the 24 volt starting system, in the long run it seems better to switch to 12 volts. Living in SoCal, I am not worried about temps below 20* as we don't typically camp in these temps. I can see the need for sub zero temp areas.

Love to see what else you have going on your build.

 

[lavarok]

If you want to keep the AC, you have to keep 24v.

Best bet is to remove the duvac and install a battery equalizer. You can find sure power 52208 or 52210 units on ebay for decent prices. I've also heard good things about Vanner.

 

[chevymike]

Not really concerned with the A/C in the box since we don't do desert camping in the summer. I am actually thinking I will use the factory compressor and use something like Vintage Air to put A/C in the cab, where we might need it more (most of our camping is fall thru spring). I am looking at different options for heating too so not too worried about the rear heater.

My biggest concern with an equalizer is load capacity and reliability in wash board environment off roading. I am placing all my 12 volt systems onto a "magic box" versus a standard alt/battery system. If that box dies, it takes all my 12 systems with it. I WON'T find a replacement in some small town USA. For a vehicle that spends all it's time on paved roads, I might be swayed into this system but when you start thinking of trails like Mojave Road or El Camino Del Diablo, I just don't get a good feeling about this system.

Since it doesn't seem like there is much more I can test for, the 24 volt system is history. I'll likely be ordering 12 volt stuff this week. Luckily my best friend does auto electrical installs all day long with his company, doing police, emerancy and support type rigs so this conversion will be done right, no hack jobs.

 

[lavarok]

If you dont plan to use the box AC, then you have a great idea of reusing the compressor for a cab AC setup. Smart.

Good luck with your conversion. I'd be interesting in any of the stock parts as you progress, including the AC unit.

EDIT: I think your truck would rattle apart before a solid state battery equalizer would be affected. But I do understand your reasons for moving to 12v.

EDIT2: For the record, you would not loose all your 12v systems if the battery equalizer happened to fail and was wired to "equalize" and not just "convert". You would still have one battery providing a 12v power source.

 

[chevymike]

If you dont plan to use the box AC, then you have a great idea of reusing the compressor for a cab AC setup. Smart.

Good luck with your conversion. I'd be interesting in any of the stock parts as you progress, including the AC unit.

EDIT: I think your truck would rattle apart before a solid state battery equalizer would be affected. But I do understand your reasons for moving to 12v.

EDIT2: For the record, you would not loose all your 12v systems if the battery equalizer happened to fail and was wired to "equalize" and not just "convert". You would still have one battery providing a 12v power source.

I will very likely have a LOT of parts off of this. Most everything in the box, including the rear doors is likely getting removed/replaced. The big challenge would be cost of shipping... unless you came out to sunny SoCal to pick them up.

On your Edit2, I am not quite sure I understand how this would work. Please explain this. If the equalizer failed, what would charge the 12 volt system? I am not sure I follow but if a failed equalizer would not leave me stranded after a couple days of it failing, then I might consider this. If the 12 volt system just runs until the front battery dies, then that would not work. Definitely curious on this.

Thanks again for the advice and help.

 

[lavarok]

Hi,

Yes shipping for the big items may pose a problem unless packed on a pallet and sent truck freight. I'll look at options. The small items I'd definitely take. Door handle hardware, door hinges, ac components, alternators, etc. Alot of this stuff could be packed in flat rate boxes.

As for my edit above, forgive the ambiguity. You would loose 12v charging. I mentioned the wiring of the equalizer as the Sure Power I used could be used to supply 12v for equalizing (charging 12v) or just to convert 24v to 12v as needed. If wired as a converter, no 12v output would be available if the equalizer failed. If wired as an equalizer, the 12v draw could still occur on the front battery as needed. The equalizer is basically doing what the duvac could never get right. The symptoms you have now would be about the same if the equalizer were to fail.


Given your scenario as stated above (post 10), I think your idea with 12v high amp alternators will work fine. It sounds like the better option for you.

 

[chevymike]

Thanks Ian for the info. Given everything and our needs, I think the 12 volt conversion is the way to go in the long run. Cry now and not later. Sure don't want to be in the middle of nowhere and have the equalizer die and strand us.

As I remove stuff, I'll let you know and we can work something out. Definitely won't just be throwing away things.

 

[chevymike]

Okay, it had been done. Ordered a Leece Neville 4860JB, 200 amp 12 volt alt and 12 volt starter (all new parts). This will be a great starting point and then if the need/want to add a second alt, I can order another one and put it parallel to add redundancy to the system.

I will document this conversion so if anyone else want to do it this way, they will know how.

 

[Monkeyboyarmy]

Why not try to put the 12 volt alternator on top to charge the front battery and leave the bottom alternator to charge both batteries.The top alternator will act as the eualizer.That way you would not have to change any of the starting orglow plug stuff. I just put a Leece Neville from a M915 (without the 12-24 transformer) on top and it seems to be working well. Just an idea. BTW, I am looking for parts to.

 

[chevymike]

The glow plug stuff was already converted to run via the 12 volt system before I got it. At this point the only thing really running 24 volts is the starter and I ordered that with the new alt. That will be an easy item to take care of.

I'll post up parts availability as I remove stuff.

 

[docfarmall]

Thanks for the insite

 

[tomc]

Chevymike,

Did you ever put up a list of parts available from the box? Need all litter straps as well as a set of cushions.

 

[bo911miller]

Why not try to put the 12 volt alternator on top to charge the front battery and leave the bottom alternator to charge both batteries.The top alternator will act as the eualizer.That way you would not have to change any of the starting orglow plug stuff. I just put a Leece Neville from a M915 (without the 12-24 transformer) on top and it seems to be working well. Just an idea. BTW, I am looking for parts to.

How would you wire this? Would this be with the duvac intact?