12v direct drive led options

[Tac Gunner]

Hi guys new to modding lights and I recently picked up a large "15,000,000" candle power spot light for 10 bucks. It doesn't work and may need either a battery or new bulb, it currently has an H3 or H4 headlight bulb in it. What I was thinking about was putting 2 MTG2s on Noctigons in it and direct driving them off the 12v battery it has. The reflector is about 12 inches diameter and 4 inches deep so I was thinking I should be able to get pretty good throw out of it with the mtgs plus have a large amount of lumens. I know XML2s would probably throw better but I didn't know if they would stand being direct driven at 12v. On the other hand though, I wasn't sure if the MTG2s could be driven like that either. Simply put I am looking for an led that can be run at 12v and produce 1,000+ lumens, preferably more than that. I know the new automotive headlight bulbs that are led use either MTG2s or a CXA15 but I wasn't sure if they had a driver that modified the voltage or not.
Thanks in advance,
Tac Gunner

 

[Conte]

Hmm, nobody has chimed in.

The problem is, you need a lot of cooling. The noctogon alone about not do.
The MT-G2 running that hard would need to be attached to a rather larger heatsink to sustain output.

Most LED systems have some sort of driver. It typically limits the current to keep it in spec, or throttles is down to control the heat.
It's one of the reason you see a lot of XML type lights at the hardware stores only rated for a puny 200-400 lumens, cause the cheap light couldn't handle the heat so they just run it weak.

Your best bet would probably be to use one of those ready made automotive dropins you mentioned.
I saw H3 options on ebay.

 

[Tac Gunner]

I knew cooling would be an issue so I was going to put the led on a chunk of aluminum and run it for short times but now I'm thinking of just putting in a prebuilt auto headlight bulb. With enough heatsink and limiting the amount of time used, could you direct drive an MTG2?

 

[Conte]

Sure. I don't see why not.
What are you going to use it for?

 

[Tac Gunner]

It will be in a large spot light I will use when coon hunting and checking the fields. Just short bursts here and there. Which voltage mtg2 would I need? 6v, 9v, or 36v?

 

[Conte]

A pair of 6v like you said for 12v supply.

What does this thing have for a battery. I would confirm the battery health first, if you need a new battery then that will change things, maybe even allow better options.

Some of those crappy spotlights, it's the battery that goes, not the bulb.
Half the H3 bulbs I have in my inventory were working pulls from dead spotlights.
They used SLA batteries that people often don't maintain properly and they die prematurely.

 

[Tac Gunner]

I have confirmed the bulb is good and pretty sure there is a break in the wires between the battery and bulb as I put jumper wires to a good battery and got nothing. Not sure if the SLA battery is good or not but based on what the guy told me I bought it from I doubt its good. What battery do you think for a replacement?

 

[bushwhacked]

Depending on the reflector shape an led may not work at all to make a decent beam. You could try mounting a temporary xml inside first just to check the beam profile. You could get away with just taking out the reflector and holding the star in with a low current.

If everything looks ok and you want to proceed just use 18650 batteries in a carrier the same size as your 12v battery. This won't be as anemic as any 12v you'd be using.

 

[Conte]

18650? Nah, with the space he probably has I would go 26650s.

Question is if the bulb is bright enough to do the job he needs it to do, and if he'll use it often enough to spare that expense.

I think that would be my next step, figure out what is wrong with it, what it'll take to make it work, then asses from there.


Upgrading the battery from this point could get tricky as you would be assembling a pack and would have to factor in balancing.

 

[Illum]

Some of those crappy spotlights, it's the battery that goes, not the bulb.
Half the H3 bulbs I have in my inventory were working pulls from dead spotlights.
They used SLA batteries that people often don't maintain properly and they die prematurely.

its not that people don't maintain them properly... they were doomed since design. It doesn't take an engineer to realize a 55W lamp running on a 12V 5AH battery is not a good combination. If anything its downright stupid

 

[Conte]

Well I got a good run out of one I had a long time ago but I was very diligent about charging it right away and keeping it topped up.

 

[Tac Gunner]

Haven't really had time to work on this project but for the time being I am going to run the 9003 bulb it has and hard wire it with a plug for a cigarette outlet in my truck

 

[Conte]

Haven't really had time to work on this project but for the time being I am going to run the 9003 bulb it has and hard wire it with a plug for a cigarette outlet in my truck

Oh there you go.
That's what I ended up doing with mine when the battery did finally die.

 

[Tac Gunner]

So battery aside, if I just wire the mtg2 straight to 12v I should be ok and not blow the diode correct? Which voltage should I get the mtg in, 6v, 9v, or 36v? I have gotten the light to work just fine with the 9003 and while it has artifacts in the beam, it produces a good tight beam

 

[hannu]

its hard to get the right led for a reflector thats designed fore h3/h4, but why not i hid ?
35w is ok whit hid and it fits the reflector
i am waiting fore som hid kits , this time whit fast start

led's are current driven, but thera are a lot of easy led drivers , but the led is the one thing that is specyfieng the current

 

[Tac Gunner]

I was worried about the heat with an hid set up. The housing and lens are plastic and the only heat sinking is the thin pot metal reflector. But with limited run time I guess it would be ok.

 

[Conte]

I've played with HID, running an LED is going to be more a heat problem that HID I figure.

IF whatever this light is can handle the heat of a hot burning halogen, it should be able to handle the HID I figure.

Int Outdoor just started stocking an MT-G2 driver that can run off 12v. It only pushes 2.4a to the LED but that's quite a bit of output with the MT-G2, and it'll also run significantly cooler.

Meanwhile, if you want throw, it's going to be hard to get with LED unless the reflector is designed for it.

YOu might fluke out, or if your craft enough to align it just right, but otherwise, especially with the MT-G2, your beam is going to spread out quite a bit more.

 

[Illum]

Int Outdoor just started stocking an MT-G2 driver that can run off 12v. It only pushes 2.4a to the LED but that's quite a bit of output with the MT-G2, and it'll also run significantly cooler.

Interesting concept , but the HID reflector is designed to collimate an axial light source, using a single point light source such as an LED you might get a funny output. I say might because it had not occurred to me to try this

 

[Tac Gunner]

Ok so maybe I should experiment with what I have parts wise and get a rough idea before I commit to one build

 

[Conte]

I converted one of those lights to hid even. Worked really well, but I didn't have a battery for it. Rigged it to an external, or car lighter plug.