My 7 XP-G Dive Light

[The Magpie]

Hello folks,

I've been lurking around for a while and asked a few questions and thought I'd share a dive light I created.

It is based on the body of an old 20W halogen I had lying about:

I stripped out the inside and sealed up the old switch which went through the back with silicone.

I wanted new batteries as the old ones were pretty knackered so I got some 4 18650 holders from turbo ferret and decided to use a reed switch with it:

The reed switch I put into a thin carbon tube which was glued to the outside of the battery holders:

I got a mate with a lathe to knock up a tight fitting heat sink and order a 7xp-g R5 board from cutter:

I used one of George's Hyperboost drivers running at 1.2amp, which fitted into a recess on the back of the heat sink:

Connected it all up and grabbed a magnet and sure enough:

Everything went back into the case and I made an elastic strap which goes around the body with a couple of rare earth magnets sown into a pocket to switch it:

Couple of beam shots, first a P7 ugly light for reference then the 7 xp-g, then the beam pattern from the Kathod "6 degree" optic, I know the light floody but I'll be doing quite a bit of filming with it and it'll only be used for night dives so that's fine:

So thanks to everyone who has mostly unwittingly helped me with this build. I'm now planning a 3 P7 maglite based canister light, I think I'm addicted!

 

[gcbryan]

Nice!

So is 1.2A going to each light or is that current divided by 7?

How are the leds wired I guess is what I'm asking..series or parallel?

Nice touch with the reed switch!

 

[The Magpie]

They're in series so each should be getting 1.2amp. To be honest I thought it would be a bit brighter!

The reed works, BUT occasionally it does stick on. It always turns off with a quick shake of the wrist though. I don't think it is the contacts welding, I'm guessing that the batteries are maybe creating some sort of field? Dunno? Better it sticks on than off anyway!

 

[gcbryan]

They're in series so each should be getting 1.2amp. To be honest I thought it would be a bit brighter!

The reed works, BUT occasionally it does stick on. It always turns off with a quick shake of the wrist though. I don't think it is the contacts welding, I'm guessing that the batteries are maybe creating some sort of field? Dunno? Better it sticks on than off anyway!

Isn't that why many people use a relay with a reed switch?

Anyway, yeah with 7 XP-G's fully driven that's a lot of light! Have you tried it out underwater yet?

What is that housing made of...I can't tell from the pictures? As long as it's metal of some sort and can help transfer all that heat out to where the water will take care of it I'll bet it will be even brighter underwater.

 

[The Magpie]

Yep, but I don't know anything about relays or how or use them. Reed is rated to 5amp and it's carrying under 2 so hoped it would be ok. Going to post a thread soon about that as I think I'll need to use one for my can light.

Not used in water yet, far too cold!

Yes it's alloy so heat shouldn't be a problem. The housing starts to get warm after about 1 minute in the air and is quite hot after 2 so heat is transfering from the sink to it well. Not run it for any longer than that!

 

[Codiak]

Nice build, gotta love george's drivers.

It's too bad that turbo ferret is out of business I'd found his site long ago and regret not buying nack then

 

[The Magpie]

Yeh, I got a couple of the last ones, shame he's not doing them anymore. You can get similar holders from here:

http://www.luminousdiy.com/Light Kits and Parts.htm#holders

Though they're not quite as well designed.

 

[Codiak]

Need round, and need 5 per level.
A wooden dowel, 19mm drill bit and a dunk in a nice high temp polymer will do the trick ;-)

 

[HansV]

What kind of lenses are you using? I am thinking of making a similar modification, and I'm wondering what kind of optics I should use.
I will have 5 Cree's(XP-G/XP-E/XR-E). The options are either no lense/width spead, reflectors or lenses like you have.
What is the best option in a diving light? How tight should the beem be? The average sight is normaly 5-10 meters, so it doesn't need to be too tight or reach too long.
I'm doing this for a friend, and don't dive myself. Therefore I need some expert opinion.
Sorry about hijacking this thread, but I thougt this was so related that it was better not to start a new thread.

 

[The Magpie]

As I said in the post, that light uses the "6degree" Kathod optic from Cutter, though it's nothing like 6 degrees.

If you read some thread you'll probably find the general consensus is to use as narrow a beam as possible, as you get problems with backscatter using wide floods, but for me it depends what you're using it for.

If it's for daylight diving to look into dark holes and wrecks, yes, that makes perfect sense. But mine will be used solely at night and so a wider spread is useful as if it's not in the beam you don't see it when it's dark.

Also if it's going to be used for any photography or filming you need a wider spread as a narrow beam will cause images to be over exposed in the middle of the beam.

Look through Pachhorses threads for some ideas, he's a big fan of a light sabre like dive torches.

 

[cesare250495]

Hi to all!
My 2c about reed switch.
With boost boards (like Hyperboost or Maxflex) there's a little peak when you turn the board on due to the fact that you have a switching IC inside. This peak in current lead reed switch sometimes to stay on.

The problem can be solved using a mosfet, a hall sensor and a 47KOhm resistance.
Here some products that I normally use:
MOSFET, P, TO-220 FAIRCHILD SEMICONDUCTOR FQP17P10
SWITCH HALL, SIP-3, 1101 A1101EUA-T

The mosfet has tree pins: source, drain and gate.
Source = V+
Drain = Led out
Gate = control (on/off)

The hall sensor has tree pins too.
+ = battery V+
- = battery V-
Out = out to mosfet Gate

The out of the hall sensor has to be connected directly to Gate of the mosfet.
The 47K resistance has to be connected between mosfet Source and Gate

In this way (and for 5$ cost) you can build a 20A switch
Be careful: for high currents the mosfet needs good cooling
Be careful (2): the (specific) hall sensor reacts ONLY to ONE pole of the control magnet.

Hope this helps....

@Magpie: I've also modified a lot of diving torches. The last one has SIX P7 - 2.8A driven - on board... You can find in the fondali.it forum - "Attrezzature Open Source" section.

 

[TorchBoy]

They're in series so each should be getting 1.2amp. To be honest I thought it would be a bit brighter!

I would have thought so too; the beam looks only slightly different in shape. I thought you could equal a P7 with roughly two XP-Gs run hard enough. Have you measured the current the LEDs are actually getting?