Yet Another Lamp Thread

[potholer]

If you just wanted to see what a flood beam on a P7 was like, I have a little box I knocked up a while ago to play around with that has a P7 with a gentle forward bias (basically giving a fairly smooth spread without the extreme side-light), and second P7 with an incredibly rough spot beam (which probably wouldn't be much use for video work).
One LED runs at once, at something like 2Amps (3/4 of the P7's maximum drive current)
Runs off 4xAA NiMH cells, for around an hour.

I'm not using it at the moment, so if you wanted to get some idea of the amount/quality of light, I'm happy to lend it to you for a while.
It's not waterproof, though that could be improved with some silicone sealant, but it is fairly robust.
PM me if you're interested.

 

[Cave_Troll]

OP was after a dual purpose lamp and mine also get used on open water dives so the ability to easily switch them on and off without increasing the risk of the lamp flooding is a plus for me.

the problem with "twist on/off" is that if you unscrew them to turn them off at depth and then come up, the reducing pressure can cause the front to come off a bit more and then water can get in.
Fine, but with rechargable batteries and LEDs simply don't turn the light off until you're out of the water.
lights with switches have to have pretty much the same set up but also have a switch. this would seem to double the potential failure points

 

[DaveR]

Footleg, I've just fitted one of these;http://www.ultraleds.co.uk/leds-seoul-cool-white-spot-mr16-bulb-lumen-p-1630.html in a dive light. About as bright as a 20w dichroic, but much whiter. Next project is to build a fliming light using two or three of these (there is also a wide angle version rather than this spot beam) powered by 12v NiMh fitted in a small Otterbox like this http://www.pcmus.com/Dive-Photos/Dive-Light-DIY-SCUBA.htm#canister
Not tested the LED dive light yet (got the bulb today) but looks good in a dark room!
Should get to play with it at CHECC this weekend. 8)
Cheers,
Dave

 

[footleg]

That looks like a really interesting possibility. Does it really only draw 3W at 12V? If so that should run on AA NiMH batteries for hours!

P.S. Sorry if that was you I completely ignored in Bernies last Sunday. I was feeling a bit broken after surveying in Rowten passage the previous day and then staying up with students in a caving hut too late in the night! Only occurred to me later that it might have been you behind me in the queue.

 

[footleg]

These wide angle warm white, 15W equivalents look promising too (for video lighting). Only ?7.49 each so could put several in a box for the cost of one of those P4 based bulbs. And only draw 150mA each.

http://www.ultraleds.co.uk/ultra-bright-mr11-acdc-warm-white-bulb-p-1460.html