12v conversion alternator not charging

[k20]

Ok, converted my truck to 12v via the roscommon article. Now the passenger side alternator is hooked up, but its not charging the battery. Now when I bought the truck it had no belts so there is a possibility the alternators were dead, but who knows. Anyway, does anyone know of a 'common' problem or missed step in the conversion that may be causing the alternator not to charge? If it is the alternator gone bad, I would probably swap in a different style (not the isolated ground style that is in there now), does anyone know a p/n for one that would fit the bracketry (I forget what the different styles/sizes are, cs140, etc etc).

Doesnt have to be stock amperage, probably best if it was an upgraded amperage.

Oh and if I pull this off to take to the parts store to get them to test it, is there any specific thing they need to do when they hook it up? (I assume hook something to the ground terminal, but anything else, or can they even use their machine?)

 

[tcg528]

I'm not familiar with the roscommon article, is it on this site, or a different one? I've been having the same problem with a M1009 that I bought. The problem is the Isolated Ground. The design ( Page F-11 in the -20) depicts the isolated ground as the negative terminal of the passenger side alternator going to a capacitor, then the ground. This design, with the capacitor being rated at 12v, blocks 12v and below from reaching the ground. Now, I'm not sure if the capacitor is stock external to the alt or internal, but in order for that alt to have a ground, it would have to produce over 12v.

If the isolated ground is external, you should be able to cut it out of the system and go straight to ground, however, do more research first, as I'm still not that familiar with this type of system.

If the isolated ground is internal, we both need to get new alts. Sorry, I won't have a p/n until I can check it out more.

I plan to take a better look at it tomorrow, weather pending.

Also, do you get the Gen 2 light to go off once you start it? If it goes off, the alt is probably good.

 

[dstang97]

Why not fix it the right way (24). ?

 

[Warthog]

I'm not familiar with the roscommon article

Roscommon Equipment Center

http://www.roscommonequipmentcenter.com/news_notes/nn10.pdf

 

[Warthog]

Ok, converted my truck to 12v via the roscommon article. Now the passenger side alternator is hooked up, but its not charging the battery. Now when I bought the truck it had no belts so there is a possibility the alternators were dead, but who knows. Anyway, does anyone know of a 'common' problem or missed step in the conversion that may be causing the alternator not to charge? If it is the alternator gone bad, I would probably swap in a different style (not the isolated ground style that is in there now), does anyone know a p/n for one that would fit the bracketry (I forget what the different styles/sizes are, cs140, etc etc).

Doesnt have to be stock amperage, probably best if it was an upgraded amperage.

Oh and if I pull this off to take to the parts store to get them to test it, is there any specific thing they need to do when they hook it up? (I assume hook something to the ground terminal, but anything else, or can they even use their machine?)

Which version of the Roscommon conversion did you do? The steps are very straight forward. Did you connect the ground wire from the alternator to the engine?

The alternator cases are DelcoRemy 27SI type 100. Any version will work with this conversion.

Any rebuild shop will be able to test the alternator. If you can find an old-timer or someone who can think for themself at the local parts house they can test they also. But the majority of the time if they can't look it up in the computer they are clueless.

If you still can't find the problem, I would contact Roscommon and ask them.

Just make sure you document what you have done, so when you sell the truck to the next person, they won't post questions on here about their alternators not working and have no idea what they have.

 

[tcg528]

I gotta stop posting at 0100.

Thanks for the link Warthog

dstang97, I can't speak for k20, but I bought my m1009 half-way through a half-assed 12v conversion. The guy before me got rid of the driver side alt and bracket, the slave receptacle, the wiring was just cut instead of redone. Since I got off of Title 10 orders, I've had no luck finding work, and my primary goal is to get the truck up and running before a hard snow hits. Right now, it would cost way too much money and time to convert it back to 24v.

I do have to say I'm impressed with the m1009. I finally needed to charge the batteries last night, after 2 weeks of starting and running on just battery power alone.

 

[CapKrk]

I do have to say I'm impressed with the m1009. I finally needed to charge the batteries last night, after 2 weeks of starting and running on just battery power alone.

Correct me if I'm wrong but unless you were running lights then you only used your battery for starts. Remember, you have no spark plugs.

I have 3 Blazers (one being a bastard 12v) and I will never convert the other two. I bought the 12v "converted" and it's my only PITA. I feel your pain as I can't change it back with the harness all cut up. The TM's work everytime on the other two.

 

[Warthog]

Correct me if I'm wrong but unless you were running lights then you only used your battery for starts. Remember, you have no spark plugs.

You need the batteries for starting and then 12v to energize the fuel cutoff switch on the injector pump.

 

[tcg528]

This is my first diesel, so it's still new and amazing to me how versatile and rugged it is compared to a gasoline engine. I'm aware that it has no spark plugs, and that the only electricity it needs is for the injector pump. I wish I had gone diesel sooner.

 

[CapKrk]

Thanks Warthog.