Help with Cree LED 12v Power Supply

Illuminating the Abyss.
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SVSeeker
Posts: 8
Joined: Dec 3rd, 2013, 12:26 pm

Help with Cree LED 12v Power Supply

Post by SVSeeker »

How do we power 4 - High Power LEDs - White Warm White, 3000K 2932lm, 800mA, 80CRI - from 11-13v Lipos?

Choose it for the size, lums, CRI, and Lum/Watt ratio. It will be easy to build a watertight housing for each like a small flash light (torch) so that the reflector cone and angle of the light can be adjusted to best suite the cameras.

http://www.mouser.com/ProductDetail/Cre ... %2FKfvcExV

--Doug
Project Page: http://www.submarineboat.com/Streamlined_Mini_ROV.htm
Sunktwice
Posts: 24
Joined: Nov 24th, 2013, 5:05 am
Location: "Sunny" England

Re: Help with Cree LED 12v Power Supply

Post by Sunktwice »

Hi, TBH - not exactly sure of the question your asking ?
Do you need to know how to wire them up, or the "best" method for turning them on/off ? if you'll be using LiPo batteries, you need to pay special attention to the discharge rate and draw from the LEDs -if you drain the LiPos past their nominal lower cell Ve they REALLY don't like it.
SVSeeker
Posts: 8
Joined: Dec 3rd, 2013, 12:26 pm

Re: Help with Cree LED 12v Power Supply

Post by SVSeeker »

Thanks, we figured it out. The question we were trying to ask is how to we supply power to these LED's and the answer is a constant current LED driver. A friend pointed us to eBay where there are several Cree LED arrays complete with 12v DC input drivers available. We have picked the 100 watt units and now have them. I saw spots for an hour after powering it up. 10,000 lumens is awesome. We got some reflector shields too that work great for focusing it into a beam.

http://www.submarineboat.com/images/Str ... driver.JPG

Has anyone tried Cree high powered LED's in seawater without anything more than potting the connections? Any advice there?
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TigerShark
Posts: 108
Joined: Jan 7th, 2014, 2:43 pm
Location: Washington State

Re: Help with Cree LED 12v Power Supply

Post by TigerShark »

Deal Extreme (dx.com)has a great selection of Cree LED's, drivers and special lenses designed for them. I use two 5W LED's with diffusor lenses which really seem to provide a nice even light in the front of the ROV. I haven't dived with them yet so we shall see how they look underwater. The drivers are 6-18v I believe.
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Billrose
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Joined: Jan 19th, 2014, 1:07 am
Location: Ancient Greece

Re: Help with Cree LED 12v Power Supply

Post by Billrose »

I know this may sound silly, even a bit bonkers. But you can have tooo Much light! the camera will 'see' in its own light visual range. In water the refraction is different to air.

For example driving a car in snow with full headlight creates a blinding 'back-scatter' of reflecting light from the snow back towards your eyes. The same thing for the rov cameras, particles will 'back-scatter' the light into the camera.

Therefore if you can control the brightness / or dim the power to the lights this will help.
OR... Direct the light in a off set pattern to illuminate the general area. Rather than a full beam.

(A quick 'Bodge' Tape over part of the light with electrical tape, as a quick fix.)
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