DIR Backup - LED vs Tungsten

GLOC · December 18th, 2005, 09:20 PM

As I understand it, backup lights need to have 3 C-cells to be considered DIR but something like the Lenser Frogman which is powered by 4 x AA is not DIR (or so I believe). Why?

I understand the rational that for a backup light you need to have good battery life hence the 3 C-cells, but if the Lenser has 50h battery life with 4 x AA cells, surely this is longer than 3 C-cells on a tungsten bulb (5.5-6 hours quoted). The Lenser is measured as 1.25W & 33 Lumens, whereas the Scout and Photon Torpedo are both 5.5W but I have not been able to find the lumens (the important number) and so a direct comparison cannot be made as the shape of the reflector has a lot to do with the final light output.

So, what is the 'real' definition of a backup light, is it based on brightness, battery life, or some other thinking?

Thanks

Gareth

Rob Dobson · December 18th, 2005, 10:41 PM

The cynics out there might suggest that if George sold the Frogman it would be DIR...

Having seen non-LED Scouts in the water I think they're pants and I'd rather have the Frogman any day. The Frogman is only rated to something like 60m so that might be restriction to some - but not me. *Just yet*.

*Clare Gledhill* · December 18th, 2005, 10:49 PM

I think (although I would be grateful if he would clarify) that Howard Payne had one of these - and the shiney twist on/off was almost impossible to turn with cold hands in gloves....

If I'm thinking of the wrong light - apologies.

Anyway backup lights - by George....

Backup Lights
( by George Irvine )
I am not sure what a Scout is in the first place, unless it is the Halcyon light that looks like the old Oceanics, and I carry three of them on dives where I might have to deco in the dark ( 3rd one in pocket for that purpose).

At one time we carried a second small primary with a 35 watt bulb and nicads to back up the old 5 hour halogens, but we have been running 13 hour lights ever since then and no second primary.

The backup lights have a few basic rules : they must not be used for anything but backup ( hence the segregated 3rd light), they must have a focused beam good enough for your dive buddies to see you signal mixed in with their primaries ( assuming dive buddies who are paying attention), they must have no switches, they must have replaceable batteries, they must be of a voltage that matches battery and bulb, not overdriven so they don't blow when you need them most, they must be three c cell in line with a twist on bezel, they must have a straight attachment point, they must be stowed DIR, they must be deployed properly, and they must tested and voltage checked before the dive.

I know you guys all like to talk about stuff, and I know that everyone likes to reinvent the wheel, complicate things, make their mark, etc etc, but the best bet is to do what I did all along - go to the pros and find out what they do and why, and save yourself the bs. Backup lights are serious things, and I can tell you serious stories of very serious uses of them in situations where any CF would have been a death sentence.

lizardland · December 19th, 2005, 03:12 PM

The three c-cell requirement came about because the Scouts originally were tubes of delrin threaded to use UK SL4 heads. The SL4 was designed to take 4 c-cells and it was believed that using same head on scouts but underpowering it with only 3 cells would make it less likely to burn out when switching it on. Using 3 c-cells has no value on its own as a rule, it is dependant on the bulb.

LEDs need to be powered by the right voltage or they do not work, they are not like incandescent bulbs. They also have no risk of burning out when you switch them on so underpowering them is not an issue.

**Howard Payne** · December 19th, 2005, 07:35 PM

Clare is annoyingly right as usual. She took one look at my LED Lenser which is a crackin little backup light with a great tight beam pattern and promptly told me you won't be able to turn it on or off underwater in gloves. She was absolutely right. They also unscrew to turn them on (ie: go too far and you flood it - unlikely but possible) I've got a snoopy loop round the head now to solve the grip problem and that mod works very nicely, but it's in the departure lounge

. As a recreational sport diving light - I reckon they're perfect. The LED Lenser chip is 1.5w which is incredibly bright - the Heser b/up lights are 3w apparently which must be not far off a Salvo! LED is def. the way forward on backup lights, the battery life, colour temp and brightness is in a different league to conventional bulbs.
I shall be meeting up with the Eva Braun of the Dive Nazi's again in the new year so that she can laugh at some more of my equipment

*Clare Gledhill* · December 19th, 2005, 08:58 PM

Quote: (Originally Posted by Howard Payne)

I shall be meeting up with the Eva Braun of the Dive Nazi's again in the new year so that she can laugh at some more of my equipment

You sure you don't want to rephrase that

daz · December 19th, 2005, 09:05 PM

Quote: (Originally Posted by Gledders)

Quote: (Originally Posted by Howard Payne)

I shall be meeting up with the Eva Braun of the Dive Nazi's again in the new year so that she can laugh at some more of my equipment

You sure you don't want to rephrase that

IIRC that's exactly what happened with Chasey at the back of the boat isn't it?

Daz

*Clare Gledhill* · December 19th, 2005, 09:28 PM

Life...

So much piss to take...

So little time

Divbum · December 19th, 2005, 10:29 PM

Quote: (Originally Posted by lizardland)

The three c-cell requirement came about because the Scouts originally were tubes of delrin threaded to use UK SL4 heads. The SL4 was designed to take 4 c-cells and it was believed that using same head on scouts but underpowering it with only 3 cells would make it less likely to burn out when switching it on. Using 3 c-cells has no value on its own as a rule, it is dependant on the bulb.

LEDs need to be powered by the right voltage or they do not work, they are not like incandescent bulbs. They also have no risk of burning out when you switch them on so underpowering them is not an issue.

The SL4 was over powering the bulb - making its life end prematurely - but they were bright. The 3-c cells is suposed to be proper voltage.
SL4 also had a switch which failed a bit.

**Howard Payne** · December 20th, 2005, 12:24 PM

I don't want to rephrase it at all!:D

December 18th, 2005, 09:20 PM	#1 (permalink)
GLOC(Offline) Moderator Join Date: Nov 2005 Location: Fleet, Hants Posts: 1,953	DIR Backup - LED vs Tungsten As I understand it, backup lights need to have 3 C-cells to be considered DIR but something like the Lenser Frogman which is powered by 4 x AA is not DIR (or so I believe). Why? I understand the rational that for a backup light you need to have good battery life hence the 3 C-cells, but if the Lenser has 50h battery life with 4 x AA cells, surely this is longer than 3 C-cells on a tungsten bulb (5.5-6 hours quoted). The Lenser is measured as 1.25W & 33 Lumens, whereas the Scout and Photon Torpedo are both 5.5W but I have not been able to find the lumens (the important number) and so a direct comparison cannot be made as the shape of the reflector has a lot to do with the final light output. So, what is the 'real' definition of a backup light, is it based on brightness, battery life, or some other thinking? Thanks Gareth

December 18th, 2005, 10:49 PM	#3 (permalink)
Clare Gledhill(Offline) GUE Instructor Site Admin Pacman Champion! Join Date: Nov 2005 Location: UK Posts: 1,540	I think (although I would be grateful if he would clarify) that Howard Payne had one of these - and the shiney twist on/off was almost impossible to turn with cold hands in gloves.... If I'm thinking of the wrong light - apologies. Anyway backup lights - by George.... Backup Lights ( by George Irvine ) I am not sure what a Scout is in the first place, unless it is the Halcyon light that looks like the old Oceanics, and I carry three of them on dives where I might have to deco in the dark ( 3rd one in pocket for that purpose). At one time we carried a second small primary with a 35 watt bulb and nicads to back up the old 5 hour halogens, but we have been running 13 hour lights ever since then and no second primary. The backup lights have a few basic rules : they must not be used for anything but backup ( hence the segregated 3rd light), they must have a focused beam good enough for your dive buddies to see you signal mixed in with their primaries ( assuming dive buddies who are paying attention), they must have no switches, they must have replaceable batteries, they must be of a voltage that matches battery and bulb, not overdriven so they don't blow when you need them most, they must be three c cell in line with a twist on bezel, they must have a straight attachment point, they must be stowed DIR, they must be deployed properly, and they must tested and voltage checked before the dive. I know you guys all like to talk about stuff, and I know that everyone likes to reinvent the wheel, complicate things, make their mark, etc etc, but the best bet is to do what I did all along - go to the pros and find out what they do and why, and save yourself the bs. Backup lights are serious things, and I can tell you serious stories of very serious uses of them in situations where any CF would have been a death sentence. __________________ Clare . "Keep away from people who try to belittle your ambitions....Small people always do that, but the really great make you feel that you too can become great." Interested in DIR dive training? Always happy to chat/answer questions so get in touch via PM or visit www.dirdiver.co.uk

December 19th, 2005, 08:58 PM	#6 (permalink)
Clare Gledhill(Offline) GUE Instructor Site Admin Pacman Champion! Join Date: Nov 2005 Location: UK Posts: 1,540	Quote: (Originally Posted by Howard Payne) I shall be meeting up with the Eva Braun of the Dive Nazi's again in the new year so that she can laugh at some more of my equipment You sure you don't want to rephrase that __________________ Clare . "Keep away from people who try to belittle your ambitions....Small people always do that, but the really great make you feel that you too can become great." Interested in DIR dive training? Always happy to chat/answer questions so get in touch via PM or visit www.dirdiver.co.uk

December 19th, 2005, 09:28 PM	#8 (permalink)
Clare Gledhill(Offline) GUE Instructor Site Admin Pacman Champion! Join Date: Nov 2005 Location: UK Posts: 1,540	Life... So much piss to take... So little time __________________ Clare . "Keep away from people who try to belittle your ambitions....Small people always do that, but the really great make you feel that you too can become great." Interested in DIR dive training? Always happy to chat/answer questions so get in touch via PM or visit www.dirdiver.co.uk

December 19th, 2005, 10:29 PM	#9 (permalink)
Divbum(Offline) "It's always an adventure..." Join Date: Nov 2005 Location: Midwest Posts: 30	Quote: (Originally Posted by lizardland) The three c-cell requirement came about because the Scouts originally were tubes of delrin threaded to use UK SL4 heads. The SL4 was designed to take 4 c-cells and it was believed that using same head on scouts but underpowering it with only 3 cells would make it less likely to burn out when switching it on. Using 3 c-cells has no value on its own as a rule, it is dependant on the bulb. LEDs need to be powered by the right voltage or they do not work, they are not like incandescent bulbs. They also have no risk of burning out when you switch them on so underpowering them is not an issue. The SL4 was over powering the bulb - making its life end prematurely - but they were bright. The 3-c cells is suposed to be proper voltage. SL4 also had a switch which failed a bit. __________________ Safe Diving, Greg www.shipwreckadventures.com 815.378.8152

December 18th, 2005, 10:41 PM	#2 (permalink)
Rob Dobson (Online) Chillin' with the ninjas Join Date: Nov 2005 Location: Oxford Posts: 536	The cynics out there might suggest that if George sold the Frogman it would be DIR... Having seen non-LED Scouts in the water I think they're pants and I'd rather have the Frogman any day. The Frogman is only rated to something like 60m so that might be restriction to some - but not me. Just yet.

December 19th, 2005, 03:12 PM	#4 (permalink)
lizardland(Offline) LCS Join Date: Nov 2005 Location: Evidently Chickentown Posts: 591	The three c-cell requirement came about because the Scouts originally were tubes of delrin threaded to use UK SL4 heads. The SL4 was designed to take 4 c-cells and it was believed that using same head on scouts but underpowering it with only 3 cells would make it less likely to burn out when switching it on. Using 3 c-cells has no value on its own as a rule, it is dependant on the bulb. LEDs need to be powered by the right voltage or they do not work, they are not like incandescent bulbs. They also have no risk of burning out when you switch them on so underpowering them is not an issue.

December 19th, 2005, 07:35 PM	#5 (permalink)
Howard Payne (Online) Strokey Dokily Doo Join Date: Nov 2005 Location: London Posts: 1,202	Clare is annoyingly right as usual. She took one look at my LED Lenser which is a crackin little backup light with a great tight beam pattern and promptly told me you won't be able to turn it on or off underwater in gloves. She was absolutely right. They also unscrew to turn them on (ie: go too far and you flood it - unlikely but possible) I've got a snoopy loop round the head now to solve the grip problem and that mod works very nicely, but it's in the departure lounge . As a recreational sport diving light - I reckon they're perfect. The LED Lenser chip is 1.5w which is incredibly bright - the Heser b/up lights are 3w apparently which must be not far off a Salvo! LED is def. the way forward on backup lights, the battery life, colour temp and brightness is in a different league to conventional bulbs. I shall be meeting up with the Eva Braun of the Dive Nazi's again in the new year so that she can laugh at some more of my equipment

December 19th, 2005, 09:05 PM	#7 (permalink)
daz(Offline) "Don't worry I'm approved" Join Date: Nov 2005 Location: Bristol Posts: 209	Quote: (Originally Posted by Gledders) Quote: (Originally Posted by Howard Payne) I shall be meeting up with the Eva Braun of the Dive Nazi's again in the new year so that she can laugh at some more of my equipment You sure you don't want to rephrase that IIRC that's exactly what happened with Chasey at the back of the boat isn't it? Daz

December 20th, 2005, 12:24 PM	#10 (permalink)
Howard Payne (Online) Strokey Dokily Doo Join Date: Nov 2005 Location: London Posts: 1,202	I don't want to rephrase it at all!:D