SL4 eLed as Back-up Light

[giles45shop]

I was wondering if anyone is using the SL4 eLED as a back-up light? I'm eventually going to try cavern, and I currently have an SL4 as my play-around light for daytime dives. I like the idea of an LED light, and it seems several of the popular back-ups use the SL4 head (either normal or LED).

I've read lots about how the twist-on switch and non-over-driven bulb are the prime reasons to pick a Scout or Photon Torpedo, but I'm of fairly short torso and the 2C length of the SL4 fits better on my HOG harness. Also, I do have my doubts about the real difference in reliability between the twist on and a simple switch like the SL4.

So, is anyone using the SL4 eLED as a back-up?

Thanks,

John

 

[Rev. Blade]

I have a halogen SL4 that sometimes serves as a backup, sometimes as a primary (depending on conditions.) I bought it after renting one on a night dive (on a trip before I travelled with lights, because I hadn't planned to do a night dive) I figured that if dive shops use them as rentals, they must be pretty reliable. (Mine has been.) The standard SL4 has a nice tight beam, so I sometimes use it on daytime dives, if I don't feel like carrying my HID.

I have a few LED lights (but not the SL4 LED). The Princeton Tec is a great light for night dives (but big), because of the bright wide beam. It's also been a good light for small caves and tight wrecks. The brightness drops off quickly after about 20' - 30' (because it spreads quickly). I have a Princeton Tec XL LED, which is quite compact (4 AA batteries), and puts out a useful amount of light. It uses about 1/10 as much power, so it's good for about 1/2 as far as the Shockwave LED. I also use a Princeton Tec Attitude LED. It uses 4 AAA batteries, and is extremely compact. It puts out plenty of light to read gauges, but very little light for navigating. I keep one a the bottome of a BC pocket as my "better than nuthin'" third light.

I'd expect the SL4 LED, to be between the Shockwave and XL LED lights.

 

[jtivat]

It is a nice light and great main or backup if your not doing overheads, the main problem is the switch and single o-ring seal.

 

[Dive-aholic]

I use SL4s as backups for all dives, night and caves. They strap nicely on my hog harness shoulder straps. I'd recommend the halogen lights. As the battery power drains, you see the change in the intensity of the light and know if it's going to go out on you. You don't have that warning with LEDs. When the battery gets to a certain level, the light goes out. I've taken my SL4s on over 100 dives with no issues. JT, what's your issue with the switch and o-ring?

 

[Mark Vlahos]

When I first started cave diving I had one SL4 and one SL6. I used them as backup lights. I am tall so the length of the SL6 did not present any difficulties fitting on my Hogarthian harness.

I liked the lights generally but had some problems with accidentally turning on the switch. I simply turned the light over so the switch part was more toward my back and this problem was solved.

Several months later the switch on the SL4 failed. The failure was not a leak, but rather the switch was ON in almost every position, there was a small OFF spot between what would normally have been the OFF and ON positions. This made the light unusable as a backup light for cave diving. I purchased an LED twist on light made by Sartek and was quite happy.

Recently I went on a cave dive with my SL6, and the Sartek as backup lights and the SL6 suffered a similar type of switch faliure except it now had two OFF positions and only a small ON position that required me to hold the switch with my hand to get it to work about half the time. This failure was discovered back in the cave during a planned primary light failure drill. I was extremely unimpressed and at my first opportunity purchased a Photon torpedo with the LED module option.

The LED light module that is used with the Photon Torpedo is exactly the same one that is used on the SL4 eLED. I like the light output of my new backup, but I am glad to be rid of the rest of the SL4 and SL6.

Mark Vlahos

 

[Spratman]

I currently use the SL4 halogens and have had them recommended as backup lights for caving. I like the switch on them better than the twist type, because most of the twist type that I've used and have experienced diving with others, is that they will light under pressure and hose the batteries.

I use them on wreck dives while I'm gathering shekels for a HID. Works great but the only problem is that they have a fairly narrow beam.

Having said that, caving is a different matter. So, many will opt for different backup lighting systems. If you are a non-caver, this light will do the trick! I've had mine for two years without any problems.

 

[Hoosier]

UK SL-4 is a proven design and quality. Many other manufactures are using UK SL4 parts. But, it isn't a slim design on a hog harness. . That is only issue I have.

 

[bperrybap]

I use SL4s as backups for all dives, night and caves. They strap nicely on my hog harness shoulder straps. I'd recommend the halogen lights. As the battery power drains, you see the change in the intensity of the light and know if it's going to go out on you. You don't have that warning with LEDs. When the battery gets to a certain level, the light goes out. I've taken my SL4s on over 100 dives with no issues. JT, what's your issue with the switch and o-ring?

While LEDs do normally have a cut off voltage, below which
they can turn off without warning, UK LED lights do not exhibit
this behavior. The UK lights use a switching power technology that
ensures a fairly constant brightness all the way through
the battery life. When the voltage level of the battery reaches
a certain point, the circuit cuts the power output way back
to about 10% of normal. In this mode the LED can still
put out some amount of light which is easily enough to read
gauges and see in very low light conditions.
This low level mode can be used for up to a few days.

So while you don't have the obvious reduced light intensity
as an indicator with the UK LED lights, the UK LED lights
don't just shut off like some of the others.

This low voltage power down capability is also great for rechargeable batteries.
Rechargeable batteries tend to give off lots of hydrogen when
the voltage is low and under high current loads such as lights.
This hydrogen load can cause the light to explode underwater.
My wife has had an Ikelite (non LED light) explode underwater
during a dive when it had NiHh batteries in it and the batteries got low near the end of an over an hour dive.

I'm a purely a recreational diver so I don't know or understand
the light needs for extreme conditions such as caverns etc,
but I prefer LED lights for their battery life and bulb reliability.
(No bulb to fail). My wife has borrowed one of my LED lights
more than once because of some issue with her light.

Because of the switching powersupply and low voltage
powerdown mode of the UK LED lights, I really like and prefer
them over other LED lights.

--- bill

 

[CompuDude]

It is a nice light and great main or backup if your not doing overheads, the main problem is the switch and single o-ring seal.

So... you don't like the Halcyon Scout lights, either? (No switch, but unless something changed recently, I was under the impression they don't have a double o-ring seal...and that was one reason why the photon torpedos were so popular.)

 

[giles45shop]

Thanks for all the replies! Sounds like there are some people that use them, so I wouldn't be the only one out there. I'll probably pick up an eLed one to go with my regular SL4. Like others, I'm saving my $ for a HID cannister light.

John