Using a cheap Chinese bike light as a canister light head?

sucnip

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Dec 14, 2005
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Has anyone considered using a cheap Chinese bike light as a canister light head? Would need a new lens and fill a couple of holes... Would it work??
 

lucca brassi

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Kocevje , Slovenia, Europe
Diving light is ''at least supposed to be'' waterproof at depth.

Personal looking all these posts ... why I would throw away 30-50$ or some maglite and some other similar light and try to made it watertight instead of buying complete prepaired empty lighthead host designed for diving ?

IMO I think cheap china light cost on end far more than starting and of course finishing work as it should be done .
 

sucnip

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Sydney, Australia
Thanks for your thoughts. The appeal of a Chinese bike lights is that for less than $50 you get a set of batteries, led's, optics, a driver (of unknown quality) and a torch head that may or may not be able to be sealed successfully for underwater use. I've asked the question because I've never seen one IRL before.

What's the best option for an empty light head?
 

350xfire

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The problem is finding the O-rings that will seal tight. There are so many sizes out there that it can be a challenge. Can be done but may be a pain to get it to work. Then there is the lens, the light may not have a thick enough one.
 

sharkbite

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Having just bought one of these with the intention of making a canister light.....i can confirm they would be a good starting point...
brighter than a 10W HID.....

Although......seeing as the burn time is around 2-3 hrs with a 26650....and they are a tiny little unit....
i am no longer going to bother...

If this one survives for a while - i'll buy another, to get 4-6 hours total burn time, and not have to carry or maintain an expensive canlight....
 

DIWdiver

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Don't believe the numbers on that site. They claim 1800 lm out of an XM-L, which is just impossible, even at the emitter surface. You can overdrive an XM-L, but you can't get that much light. Just. Not. Possible.
They also claim 2-3 hours on one 26650. Since this is a 4 Ah cell, that suggests a load of 1.3-2A, which would give you less than 800 lm.

The only way to get high brightness and long burn times is to let the light come out of regulation and run a long time at reduced output. More realistically, the light probably produces 800-1000 lm at the emitter, 600-800 OTF, for an hour, then starts dropping. At 3 hours, it's probably 50-100 lm. That's if it has a good regulator in it. If it has a crappy regulator in it (which would be my guess), it's probably something more like 1000 lm (emitter) at switch-on, immediately starts dropping, until it reaches the battery protection voltage at 3 hours and 50 lm.


The numbers presented above represent a highly educated guess as to what the most likely scenarios are. Ultimately, the time vs lm curve can take many shapes, determined by the nature of the driver. But the max lm output is limited by the LED and the optics, and the lm-h output of the light is limited by the W-h rating of the battery, the efficiency of the LED, and the optics. The maximum possible output of an XM-L is currently well under 1800 lm, and the max that's sustainable from a single 4 A-h, 3.7V cell for 2 hours is around 800 lm.
 

emmashi

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Nov 18, 2012
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+1
in order to let the item more interesting, some dealer make fake data. and this flashlight from ebay just have 1 T6 LED, and then I think the most brightness of it is 800 Lm ,not 1800 lumens
 

quics

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Aug 18, 2011
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Hi guys!
I'm new to this forum but tried building a few dive lights before. I Just ordered a triple XM-L light at Kaidomain (http://www.kaidomain.com/product/details.S021404) to make a dive light from it. Done that before with two single xm-l lights mounted next to each other on a goodman handle which worked for one diving vacation but when I tried it a few months later it was broken - I have yet to find out why.
I know the KD light won't have anything near the claimed lumens but if its the same brightness as my previous 2x XM-L light it's more than enough.
I used 2 mm polycarbonate lenses btw. The self made canister houses 2 (4x18650) Battery packs that came with the lights.
Didn't like the narrow beam of the old light. The new triple xm-l should be a bit wider.
regards, phil

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rodex99

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Oct 30, 2010
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I have bought one of these, obviously I do not believe the numbers, and have only had it in the water once to 15m, but nevertheless is bright, fits in a bcd pocket and at that price takes a lot of beating. Spot is a bit too small to my liking to be perfect. If you wanted to do a conversion you can get them cheaper without the batteries and charger.
Rod
 

diveuk

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Oct 26, 2011
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Having just bought one of these with the intention of making a canister light.....i can confirm they would be a good starting point...
brighter than a 10W HID.....

Although......seeing as the burn time is around 2-3 hrs with a 26650....and they are a tiny little unit....
i am no longer going to bother...

If this one survives for a while - i'll buy another, to get 4-6 hours total burn time, and not have to carry or maintain an expensive canlight....

I have also ordered one, not received it yet but I have an old HID umbilicle setup laying around with a good battery pack, my plan is to use this head, put a gland on the rear screw cap and connect the battery pack to it. I do not know if this is feasable though, these run on 3.7 volts and my battery pack is rated at 11.8 volts, will I just burn the emitter and/or circuitry out?
 

sharkbite

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I have also ordered one, not received it yet but I have an old HID umbilicle setup laying around with a good battery pack, my plan is to use this head, put a gland on the rear screw cap and connect the battery pack to it. I do not know if this is feasable though, these run on 3.7 volts and my battery pack is rated at 11.8 volts, will I just burn the emitter and/or circuitry out?

That was what i was going to do as well.....only i was going to make a 3.7v battery pack.....i'm tipping that 11.8v will result in smoke.....having killed a similar cheap
light attempting the same thing......and killed that one with a mere 7.4 volts.....

i was going to use 9 x 2500mAh AA nimh with solder tags to give a theoretical 7500mah at 3.6v and at least 3-4 hours burn.....
but since the supplied 26650 lasts 3 hours anyway (i tested this in the bath!) - as i said - not gunna bother....

Also - to get the cap nice and flat so that a gland will screw into it requires more effort to machine than i am prepared to put in....

Echoing the sentiments of other posters - this light is nowhere near the claims made by the manufacturer for brightness - but -
The spot on this beats my buddies 10w HID.... and two of them will burn longer - just have to swap them halfway through the dive...(if i ever go on a dive that lasts more than 3 hours that is!)

Probably the only advantage a Canister has over this light is that the canister is DIR.....ya can't accidentally lose the light if you drop the head ;-)
 

DIWdiver

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You have to be careful comparing apples to pears. Your 3S3P AA pack would have nominally 24.75 Wh, while the 26650 is nominally 14.8. A good portion of the 3 hours from the 26650 is probably at substantially reduced brightness, while you calculated your burn time at full brightness. Not really the same thing.
 

sharkbite

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You have to be careful comparing apples to pears. Your 3S3P AA pack would have nominally 24.75 Wh, while the 26650 is nominally 14.8. A good portion of the 3 hours from the 26650 is probably at substantially reduced brightness, while you calculated your burn time at full brightness. Not really the same thing.

i don't care much for "woulds" and "Probablies".....

I own one of these units and have used it underwater

....for the type of diving i do - nowhere near caves or wrecks, or anywhere else that actually needs a full burn for 3 hours -
i don't notice the difference.....
for the odd night dive that lasts for 1 hour tops - this torch is more than adequate - and still stomps all over a 10W HID.....(for that first hour at least - haven't been on a double-night dive with it)

It's a great starter for a canlight - and if the OP goes ahead with his plans - best of luck!
Like i originally said - i was going to do it - but the performance of the light as is suits my purpose so im not gunna bother.
 

diveuk

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Oct 26, 2011
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I dive CCR and dive a lot of wrecks, my run times can be 2 to 2.5 hours on occasions so I am looking to get long burn times out of my light.

If my 11.7 volt battery pack will fry this lamp is there anything I can do to prevent this like putting resistors in the power supply or connecting a voltage reg. somewhere in there?????
 

sharkbite

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I dive CCR and dive a lot of wrecks, my run times can be 2 to 2.5 hours on occasions so I am looking to get long burn times out of my light.

If my 11.7 volt battery pack will fry this lamp is there anything I can do to prevent this like putting resistors in the power supply or connecting a voltage reg. somewhere in there?????

You can - but both solutions will waste power....

you could also replace the existing driver with one that can handle 12v.....BUT

this particular light has a driver integral to the housing, and also has an internal set of reed switches so that
it can be switched on and off via a magnet hidden in the black ring near the head (fairly tricky to modify)

i think a simpler solution would be to have your existing battery pack re- wired......

or you could do what i was going to do....make (or get made) a whole new battery pack....
making the 9xnimh solution yourself would cost around AUD$40 and a bit of time with the soldering iron....
and i have found that the chargers from the famous brand of finnish mobile phones work a treat at this voltage!


OR....


you could just buy two of these and when the first one stops working, switch the other one on!
 

diveuk

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Oct 26, 2011
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Probably the only advantage a Canister has over this light is that the canister is DIR.....ya can't accidentally lose the light if you drop the head ;-)[/QUOTE]

It has a nice ring on the endcap to thread a lanyard through.

Received mine in the post this morning, 4 days after ordering a lot quicker than the 10-20 days quoted on E-bay, now in the bath on test, inspected threads and O rings, no swarfe or sharp machining edges on threads, O rings were even greased. So long as it works @ 40-50 mtrs. looks like a good buy for the money it costs, beam looks bright with a reasonably tight spot.

I will update after its first real dive @ the weekend.

If all is well I will purchase another one and use it as a donor for an umbilical mod.
 
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