What to look for in a flash light

[HantsDiver]

A cheap one from eBay. Too many to list but all I've used seem to work fine. My personal favourite is old faithful a £3 plastic number in fetching yellow that has now completed 12 dives and is still on the original batteries put in two years ago. I carry three torches all under £30. If you get a inexpensive torch you won't be gutted if you lose it and would be less inclined to go after it if you did. The most expensive torche I have cost £28 and is a monster 18000 lumens and works very well. Good luck with whatever you purchase.

No it's not.

 

[soggybadger]

No it's not.

Sold as that powerful and how would I know otherwise?

 

[HantsDiver]

Sold as that powerful and how would I know otherwise?

You wouldn't. I was simply stating that there is no way they can make a torch with that output for that amount of money. My car is supposed to do 54mpg on a run according to bmw. It doesn't do that either. Companies lie to get us to spend our money.

 

[soggybadger]

You wouldn't. I was simply stating that there is no way they can make a torch with that output for that amount of money. My car is supposed to do 54mpg on a run according to bmw. It doesn't do that either. Companies lie to get us to spend our money.

I see. You actually KNOW bugger all and are guessing about an item you have never seen just because you BELIEVE you understand the global torch market inside and out. Well done.

 

[HantsDiver]

I see. You actually KNOW bugger all and are guessing about an item you have never seen just because you BELIEVE you understand the global torch market inside and out. Well done.

Is this the torch? Waterproof 100m 18000Lm 9x CREE XM-L2 LED Diving Flashlight Torch

 

[soggybadger]

Is this the torch? Waterproof 100m 18000Lm 9x CREE XM-L2 LED Diving Flashlight Torch

Nope. I do have one similar to that but you are short on led's by 6

 

[HantsDiver]

Nope. I do have one similar to that but you are short on led's by 6

Which one do you have then?

 

[soggybadger]

Which one do you have then?

I have Several including one like you posted but that is more like 3000 and has a very white beam. Loads of backscatter in bad viz. The big one is advertised as 18000 to something like 25000 so I took its power as the lowest given rating. Its a Chinese wingwang or summat. I'll post a pic when I get back from work on Saturday. The best cheapo I have used so far was a little red aluminium number that cost £6 and was plenty powerful enough for poking around in crevices.

 

[tbone1004]

15xml's will not produce 18000 lumen on that small of a battery.

being optimistic, 18000 lumen with an xml will pull 150watts. 6x 18650's at 3400mah, and 100% usage have about 75wh. 30 minute burn time.

relatively easy way to figure out how much light you are actually getting on average
put light in a bucket of water, turned on, with fresh batteries, time it until it shuts off.
However many minutes it burns/60 to get burn hours.
watt hours of pack *this is probably going to be theoretical since a lot of mfg's don't quote their actual burn.
watt hours of pack multiplied by the burn time in hours gives you average watt draw. Multiply that by 110 ish and that will give you the average light output with an LED light using Cree XML's

in the case of the Big Blue AL1200NP, they claim 1200 umens, for 2 hours, on a single 18650.
18650's have a max of 3400mah, or 3.4ah at 3.7v, which is 12.6 wh.
12.6wh/2hours-6.3watts draw on average throughout the burn.
6.3*120=756 lumens.
That's optimistic numbers, realistically you are only going to be able to get 10wh out of the battery, and there is going to be on average a 90% efficiency, so the real number is about 540 lumen out the front on average for the burn. Big Blue doesn't use a constant output driver, so that's just the average number, but you can see how doing your homework says that the specs that they claim are not possible with the technology they use, and not feasible or practical with todays technology

 

[BDSC]

Just bought this. Looks interesting. Big Blue CF1200P 1200 Lumens LED Light

A whole bunch of my friends dive these as their every day light and love them. Very well made with rechargeable battery and adjustable beam. You won't be disappointed.