# GMC 3MCP Twin Spotlight



## mvyrmnd (Nov 3, 2009)

I just won this for $34...

Suggestions on what to do to it?


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## TOQ (Nov 3, 2009)

If it were me I'd mount it on the hood of my GMC pickumup truck and use it to blind anyone who cut in front of me on the freeway. But I own a Ford pickumup truck so instead I use my 15 million CP one eyed Cyclops to accomplish the same thing...........Ha! Nice light there. For sure you can find a use for it as 3 million CP is not something to sneeze at. How's things down there in the land of Oz? Been many years since my feet touched that great ground................

Light me up Scotty............Terry


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## BVH (Nov 3, 2009)

I don't think there's enough room in there for 2 "slim" 35 watt ballasts plus the battery but if there were, that's what I'd do. Second option would be to obtain a couple 130 Watt Halogen bulbs to make one bright Incan! How many AmpHours is the battery? That's nice looking light!


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## Patriot (Nov 3, 2009)

That's the old Vector design that sold at Target and Automotive stores for about $49. I think it's too small to do much with. I think the stock SLA's total 4.5Ah and they're running two 12V 55 watt bulbs. 

You could maybe build a safe cell pack for it or li-po packs if you're familiar with them, then install a pair of 100W-130W bulbs depending on what potted bulb options there are. Depending on what the light looks like inside it might not be too difficult.


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## mvyrmnd (Nov 3, 2009)

Patriot said:


> That's the old Vector design that sold at Target and Automotive stores for about $49. I think it's too small to do much with. I think the stock SLA's total 4.5Ah and they're running two 12V 55 watt bulbs.
> 
> You could maybe build a safe cell pack for it or li-po packs if you're familiar with them, then install a pair of 100W-130W bulbs depending on what potted bulb options there are. Depending on what the light looks like inside it might not be too difficult.



GMC have a track record of building other companys tools as soon as the patents expire.

According to the manual, there's 2x6V 6ah batteries (one in the top, one in the base) and 2x100W H3 bulbs.

Maybe the best way to start would be to see if a 12V SLA would fit in the base, leaving the top empty and ready for some ballasts!

Link to the manual ---> http://www.gmcompany.com/download/products/VEC120-AU_IM_ED9.pdf


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## BVH (Nov 3, 2009)

6 AH would be enough to strike one HID bulb at a time (2nd one after 1st starting cycle is over) and run them both for......I'm guessing 20 - 30 minutes. The stock twin Vector 7 AH SLA will run both my 80 Watt Fatboys at the same time. It will strike them one right after the other but I don't do that to protect the poor thing! Never have done a full run time test. Guessing maybe 12 - 15 minutes?


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## mvyrmnd (Nov 3, 2009)

BVH said:


> 6 AH would be enough to strike one HID bulb at a time (2nd one after 1st starting cycle is over) and run them both for......I'm guessing 20 - 30 minutes. The stock twin Vector 7 AH SLA will run both my 80 Watt Fatboys at the same time. It will strike them one right after the other but I don't do that to protect the poor thing! Never have done a full run time test. Guessing maybe 12 - 15 minutes?


I have a 7ah 12V SLA from a failed UPS sitting at work. If I can make it fit in the base, then we're singing!


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## Patriot (Nov 3, 2009)

That would be great if the 7A 12V would fit in the base. I used to own one made by Vector and can say that it would be an awfully tight fit. The other thing that I'll be interested in seeing is the bulb depth. An H4 or H7 bulb for example will protrude way too far into the reflector to the point of touching the inside of the lens. You'll have to figure out a way of spacing them off the reflector base somehow which makes me wonder if that will leave room for a pair of ballasts. I suppose that if you had to you could always mount one on top or at the back of the body.


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## BlueBeam22 (Nov 3, 2009)

I have the Vector brand 3MCP twin beam (which is pretty much the same as what you got), and it is a very impressive light. It has incredible throw and output just with its stock bulbs. I am very satisfied with its performance just with the 100W H3 halogens, but I'm sure it would be absolutely amazing upgraded to HID. The reflector on this light is very reflective and high quality.


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## mvyrmnd (Nov 3, 2009)

As far as the length of the HID bulbs go, the H3 fit bulb I put in Petrov45 (https://www.candlepowerforums.com/threads/247357) was negligibly longer than the H3 halogen that came out. So much so I've had zero issues focusing the light, and have had none of the artifact issues that many of you have had. I even still have the ceramic protector on the return wire. Unless this one (which is in the mail - I haven't see it in the metal yet) has an extremely shallow reflector, I could use the same kit and hopefully still have no issues.

For now, though, the first thing I'm doing is replacing the 100W's with 130W's, and saving for a twin HID kit.


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## LumenHound (Nov 4, 2009)

What about adding an extra 2.4-3.6 volts to the original battery by wiring a high current booster battery pack in series with the LSA's? You could use a second switch (SPDT) to add or bypass the booster pack at will.


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## mvyrmnd (Nov 4, 2009)

LumenHound said:


> What about adding an extra 2.4-3.6 volts to the original battery by wiring a high current booster battery pack in series with the LSA's? You could use a second switch (SPDT) to add or bypass the booster pack at will.


If I did that, would it work to supply the 9v at 8 or so amps that would be enough to run a 55w ballast?

I'm guessing that even if it worked, the runtime wouldn't be fantastic with both HID's running.


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## Norm (Nov 4, 2009)

mvyrmnd said:


> Maybe the best way to start would be to see if a 12V SLA would fit in the base, leaving the top empty and ready for some ballasts!


That bottom section is a lot smaller than a 7Ah 12V SLA, I have a similar light and there's no spare room for anything other than the standard bits.

You may be able to mount the ballast externally, but IMHO it's not the best host to start mucking around with. The reflectors are quite small and as I said not too much room inside.

If anyone is interested I have one old add here price $25.
PM me 
Norm


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## LumenHound (Nov 4, 2009)

mvyrmnd said:


> If I did that, would it work to supply the 9v at 8 or so amps that would be enough to run a 55w ballast?
> 
> I'm guessing that even if it worked, the runtime wouldn't be fantastic with both HID's running.


Your thinking HID. I'm thinking overdriven incan.

The pictures in the owner's manual tell me you would have to mount both HID ballasts externally which could be done but wouldn't exactly be an elegant solution. 

I was thinking that you could easily fit some high discharge AA NiMH cells on one or both sides of the top battery and it would then give you a "Turbo" mode. How long you could run on Turbo would depend on the size of the boost battery pack you go with. 

Have a look at the last chart in this May 2005 post. It shows the large increase in lux of 4 different 12 volt bulbs as voltage is increased up to 15 volts. 

You can find 8, 10, and 15 amp discharge graphs for the above cells close to the bottom of this post.

Think how bright the pair of your 100 watt bulbs would be driven at 14.5-15.0 volts.


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## mvyrmnd (Nov 4, 2009)

LumenHound said:


> Your thinking HID. I'm thinking overdriven incan.
> 
> The pictures in the owner's manual tell me you would have to mount both HID ballasts externally which could be done but wouldn't exactly be an elegant solution.
> 
> ...



Ahh!

Now that's a cool idea!

The light has a slide switch to choose between single and dual mode.

I could re-wire it so that it becomes Dual and Turbo Mode!

If I could get a couple of 2AA holders and slip them down either side of the top SLA, It might work.

I quickly looked over the Thor's Hammer thread - He's using a booster circuit. Would I need that? Or could I just wire them up in series?

If they were in series, would I not be shoving 12V into the NIMH's?


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## mvyrmnd (Nov 5, 2009)

I received the light today... will take 24 hours to charge, so no beamshots for now...

I bought a pair of 130W H3's to put in it, but noticed something - the stock 100W bulbs have the filament running vertically ie. pointing out from the reflector

The new 130W's have the filament running horizontally.

What difference will this make to the beam pattern and throw?


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## LumenHound (Nov 6, 2009)

With those horizontal filaments you will see a bit of an hour glass shape of increased brightness in the spill of the beam with the center of the hour glass being the hot spot. If you can install the bulbs so that the filaments are level with the horizon you'll get some extra brightness left and right of the hot spot. 

This can be handy if your lighting up something in a wide open area.


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## LumenHound (Nov 6, 2009)

mvyrmnd said:


> Ahh!
> 
> Now that's a cool idea!
> 
> ...


I came across the idea in a 2006 post about LarryK doing it to his 15 million candlepower THOR spotlight.
I'd leave the 3 position slide switch alone and install a separate single pole double throw rocker switch for the turbo mode selector. 

If you were going to use battery carriers they would have to have the ability to handle 15 to 20 amps of current. It would be easier to solder 3 tabbed high current cells in series and install a charging plug for the pack on the back of the spotlight. 
A low cost smart charger could be used to keep the boost pack topped up.

I'd wire the boost pack up like shown in the diagram.


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## mvyrmnd (Nov 6, 2009)

Looks like it's time to make a trip to jaycar...

Thanks LumenHound!


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## [email protected] (Nov 21, 2009)




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## mvyrmnd (Nov 22, 2009)

[email protected] said:


>


Yeah, I haven't got to this one yet...


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## [email protected] (Nov 22, 2009)

That's okay... I've got plenty of time & popcorn


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## mvyrmnd (Nov 24, 2009)

Rather than use extra batteries, and 2 chargers and a whole load of wiring... how about a 15v boost circuit - along these lines http://www.maxim-ic.com/appnotes.cfm/an_pk/3843.

Granted it'd have to be able to handle a lot more than 0.5A, but it might be an option, if a more powerful version exists.


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## LumenHound (Nov 24, 2009)

There are Pulse Width Modulation halogen headlight voltage boosters being sold in countries that have cracked down on illegal HID conversions but the problem I see with these units is that they are only designed to overdrive a regular 12V 55 watt bulb up to about 75-80 watts or so. 
They wouldn't work for your application because they just can't handle the current your bulbs would be drawing when you overdrive them to 200 watts each. 
I doubt they would fit inside your spotlight housing. 

A single switch, a charging plug, and 3 smallish high current cells that you know will fit inside your spotlight will get the job done with the fewest hassles.

I'm a real fan of the K.I.S.S. modding method and batteries and a switch is about as K.I.S.S. as it gets.


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## Isthereanybodyoutthere (Nov 24, 2009)

Hmm how about leaving one bulp stock 
And the other converted to hid ,,maybe a 55wat or more 
then you would have the stock for instant light(no warm up)
And the HID for longer run time 

the original batteries could be used and a slim ballast wouldnt look bad on the outside , if inside wasnt possible


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## mvyrmnd (Nov 24, 2009)

As much as the overdriven incan idea interests me, I'd really love to make this thing HID.

A friend of mine has said he could fabricate a new base that could accommodate a larger 12V SLA, leaving the top completely free for ballasts.

I'm torn....


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