UK D8 Xenon with 30w bulb? # of Lumen?

[Luky]

So I just got back from a week of diving in Cozumel and decided that I need a better dive light after a couple of night dives. I was using a Princeton-tech Torrent Xenon with 8 AA cells/115 lumen and it was OK. Just kind of a narrow beam. My Buddy was using an old UK 400 (4 D cell rechargeable Nicad pack) that had a much better spread and seemed slightly brighter when freshly charged, but was only lasting about 50min before it would really dim.

He picked up a dusty used (but never been in the water) UK HID 100 light the other day that I found on craigslist for $125. He is really happy with it so far (now we need to dive with it).

So I was looking at the UK website and like the D8 Xenon with a 367 lumen rating and see they also have a 30w bulb for it. (going for $55 at Leisurepro + $18 for the bulb)

I sent a email to UK today asking about the Lumen output of the 30w bulb with the rechargeable kit (I would just get 8 rechargeable NiMH D cells as I already have a nice "smart charger" that will do 8 NiMH batteries at once). They sent me a response today that said the 30w bulb/rechargeable kit would put out about 1200 lumen! Does this seem reasonable? Seems crazy bright, but it does use dual bulbs so you can have a low beam/high beam... Is the bulb just going to last like 3 or 4 dives at that output? Is 1200 Lumen possible from this setup?

 

[owl72]

The underwater Kinetics web-site lists the D8 at 367 lumens but it doesn't say whether that is for the 14 watt or the 30 watt bulb (although you would assume they would indicate the output from the higher watt bulb rather than the lower watt bulb). The D8 was their brightest light until they brought out the Light Cannon 100.

I have a UK 800R with a 30W bulb. It is the older model of the D8 and it runs on a rechargeable power pack of 8 D cells. As far as I know the specs are the same as for the D8 except that you can't automatically switch between bulbs. From my experience the UK 800R appears significantly less bright that a UK Light Cannon 100 with a nominal output of 450 lumens. While I realize the HID Light Cannon produces a whiter light that might appear brighter irrespective of the lumens, my 30W UK 800R is definitely not outputting anywhere near 1200 lumens. I would say it's probably closer to the 367 claimed on the web-site.

 

[gcbryan]

I'm sure the listed lumen rating is for the 14 watt bulb so I'm also sure the 30 watt is much brighter...but 1200 sounds a bit much but perhaps not. Maybe Xenon bulbs get more efficient with additional power.

This is a big light however and 30 watts is a real battery drainer. You can get something bright and a lot more efficient and smaller in size if you go to led's.

 

[owl72]

Well I suppose the 30W bulb could produce 1200 lumens. However, lumens are not the whole story...

I agree with the previous poster that halogen lights are not very efficient and I certainly wouldn't buy another one. Running this light on full power you will be lucky to get two dives out of it and it is very bulky and heavy. IMHO it's better to have a smaller light that you actually take with you than a large light that you are tempted to leave behind because it's such an inconvenience (I did not take my UK800R on my last trip to Mexico because I was worried about exceeding my baggage limit).

Also, although this light may produce a ton of lumens it is not as white a light as that produced by HID or LEDs. I found a site that said that a 10W HID will look almost as bright as a 55W halogen even though the halogen produces more lumens. This was my experience when comparing my 30W UK800R to a Light Cannon, the Light Cannon appeared much brighter underwater even though, apparently, it produces only a little over 1/3 the lumens of the 30W halogen.

I hope that helps. Good luck finding a light that works for you!