MEP003A glow plug conversion to 12Volt

[MusgroveM]

I seeing that the 24V glow plugs are getting harder and harder to find. I understand that there is a civilian version that requires 11Volts. I called Wellman (Diesel Rx) today and they no longer make the 24Volt glow plugs. Has anybody tried to convert their glow plug system to a 12Volt system? There has to be some sort of voltage dropping device that will take in 24V and put out 12V. Maybe a transformer, a voltage regulator, or a resistor that drops the voltage.

 

[epitts]

Welcome Lurker: I do know the CUCV has a resistor pack that steps 24 down to 12 volts for the glow plugs. However it can cause a cascade failure if you have some plugs fail by boost volts to what remains. So it can be done but not by me! But most convert it over to 12 volts.

 

[doghead]

http://www.parttarget.com/2920-01-040-0308_2920010400308_CH49.html

http://www.amazon.com/Champion-CH49-Cummins-Diesel-Engines/sim/B0060RLGAK/2

 

[doghead]

A site search for CH49, brings up 4 results.

 

[doghead]

Pitts, notice what forum this is in.

 

[epitts]

I did, I was trying to answering his question with what I knew. And the CH49 is the intake heater not the glow plugs as he ask about. The glow plug part number is 333-0107 as per the TM.

 

[MusgroveM]

I guess I should have been more specific. I'm wanting to replace the CH42 glow plugs, not the CH49 intake warmers. The CH49's are already 12V and still fairly prevelent.

 

[Jimc]

I emailed diesel rx a month ago and they said they were going to produce them again. They are currently sourcing raw materials and would be avail in about 3 months. The ch42 plus are still being made as far as i know. Rockauto and racemart have them at a decent price.

 

[MusgroveM]

Thanks Guys,

I did find a couple places that have them. Rockauto's sight says 6 remaining and are reasonably priced . Championsparkplugs.com has them as well reasonable priced. Racemart has them all beat. (Thanks Jim). The other sights that do have them say "limited aviability" and want over $25ea for them. If Wellman is going to start making them again then I'm not going to worry, so much, about aviability.
NSN 2920-00-106-1817
Champion CH42
Champion CHA182
Onan 333-0104
Wellman 6A843G042 or 6A843G024K

You guys are the best!

 

[Jimc]

I hope wellman wasnt just blowing smoke because i do like thise plugs much better than the champion. Not sure why. They just seem better quality plus they come with the copper gasket.

 

[MusgroveM]

I got the CH42's at O'Reilly's auto parts for $13.50. They had to special order them, but I got um.

 

[johnray13]

I seeing that the 24V glow plugs are getting harder and harder to find. I understand that there is a civilian version that requires 11Volts. I called Wellman (Diesel Rx) today and they no longer make the 24Volt glow plugs. Has anybody tried to convert their glow plug system to a 12Volt system? There has to be some sort of voltage dropping device that will take in 24V and put out 12V. Maybe a transformer, a voltage regulator, or a resistor that drops the voltage.

For around $20 you could add one of these.
I wonder how many amps the (head) glow plugs draw?

http://www.auto-gadget.com/index.php?route=product/product&product_id=20385

 

[Triple Jim]

My experience with very cheap DC-DC converters is not good. This one might be fine though...

 

[steelypip]

If you're talking about doing a 12V glow plug conversion on an MEP-002/003, I wouldn't bother with a DC/DC converter. Just add up the resistances of all the 12V stuff in the circuit and then put in a dropping resistor to get rated current with B+ = 24V. Plain old V=IR stuff.

An even easier route if you're willing to accept the single point of failure would be to just wire two 12V glow plugs in series, so you'd have one glow plug circuit for an MEP002 and two for an MEP-003A. That would be the route I would go with.

 

[johnray13]

I thought about that but couldn't figure out how to do it since they use the threads for ground. How would you series them?

I also looked at resistors. That converter is just a sexy little black box with resistors on a heat sink. I don't think I could make one for much less than $20

 

[Triple Jim]

As long as 24V glow plugs are available, the simplest thing to do is keep using them. Demand will keep them available, as well. Then if they really do get scarce, the system could be redesigned to use dropping resistors or a DC-DC converter to change over. Simple is reliable. A $21 Chinese DC-DC converter, which has a lot more electronics in it than some resistors, is not something I want on my 003A when there's an outage.

Here are some more thoughts:

I measured my glow plugs' current consumption, and it's about 4.5 amps each, which is 108 watts. Assuming the two intake heaters are about the same, that's 6 x 108 = 648 watts total. At 24 volts, this is about 27 amps. If you convert the four glow plugs to 12v and leave the two intake heaters in series, and assume a 100% efficient DC-DC converter, the 24V battery will still be supplying 27A, but you'll be up to 45 amps to the glow plugs/heaters, so you'll probably need to rewire the whole preheat circuit, possibly changing to a bigger relay.

If you use dropping resistors on four 12V 108W glow plugs instead of a DC-DC converter, the total current will still be 45A, but now you'll be drawing 45A from the battery because the two 108W intake heaters in series will draw 9A, and each glow plug and resistor combination will draw 9A. This is because a 12V 108W glow plug requires a current of 9A instead of the 4.5A current of a 24V 108W glow plug.

To answer your question about putting 12V glow plugs in series, it would not be easy, as you pointed out.

 

[johnray13]

I agree the Chinese converter leaves a lot to be desired. I also agree that as long as the 24v glow plugs are available, it's a no brainer to keep using them. But, they are getting harder to find. Unless we keep spares on hand (I don't have any-even though I know I should) a back up plan is always a good idea.

So this got me thinking. Since 12v plugs are widely available (not so sure about the 7/16x20 thread), how about running a circuit from just one battery to the plugs. You could use an auxiliary momentary switch, or if you want to keep the existing panel switch, use the 24 volt glow plug circuit to close a relay for a 12 volt battery connection-glow plug circuit. That would still allow for 24 volts to the manifold heaters.

That keeps it simple with not much of a chance for failure.

John

 

[Triple Jim]

Yes, that would work. I'd hesitate to do it that way, but if you swapped batteries once or twice a year, you'd probably avoid any unequal charging problems. In my case, I'm 55 years old, so I just have to get through another 25 or so before I won't care any more. If I got a complete spare set of stock glow plugs, I'm pretty sure it would take me to that point. The younger guys here might need two sets if they run their generators a lot.

The Chinese converter you showed really isn't an option, since its output would power only one of the four 12V 9A glow plugs.

 

[billypop]

I know this is an old post. but............ I was wondering that since most are using two 12 v batteries, could you convert the plugs to 12v, run a circuit (12v) to the plugs, add a switch and heat em up from that switch. Thoughts................?????

 

[glcaines]

I routinely see the 24V glow plugs on Ebay. Over the years I have purchased quite a few spare glow plugs when I see them for sale at a cheap price. However, I have the original glow plugs that came in my MEP003A when I got it in 2009 from GL. It had just come back from Iraq. I have not had a single glow plug fail in over 11 years of fairly heavy use. Several years ago, I pulled all of the glow plugs and looked at them, intending to replace them with new ones. They were in very good condition, so I re-installed them.