Are any of the DX P7 lamps waterproofable?

[OS74]

There is a heap of variants of P7-lamps at DX but only the "ugly light" (sku.29069) is supposed to be dive-proof.

I have made my own reed-mosfet relay that I have used with success with a broken-off head from this lamp (i tried to unscrew the head but shredded the tube) sku.12060

I urgently needed a light for a dive trip, and simply put the whole thing into another big dive torch, with a strong magnet on a velcro sleeve to switch the lamp. It still works but is really-really ugly.

So,

1. Is there any of the P7 lamps on DX that could be sealed by replacing o-rings at lens, top cap and bottom cap? (I am planning to weld the tail-cap shut and use my reed-relay solution)
The 2 variants I ordered just had a flimsy o-ring either on the outside of the front-lens or behind it "sealing" directly against the threads, which would not work under pressure.


2. About the "ugly light": Does it have a good o-ring seal-solution at the lens? Can the tail-cap be screwed directly to the head? (I'm thinking of a canister conversion of this light)

Cheers

 

[Caseman2]

If you are doing anything other than lighting up a white wall I would stay away from DX. I have bought a few from there and they work great.

But I wouldnt go diving with them or use them for anything important that I would NEED light for. If im out fishing and my DX drop-in dies "OH well". It will not ruin my night or anything.

 

[gcbryan]

There is a heap of variants of P7-lamps at DX but only the "ugly light" (sku.29069) is supposed to be dive-proof.

I have made my own reed-mosfet relay that I have used with success with a broken-off head from this lamp (i tried to unscrew the head but shredded the tube) sku.12060

I urgently needed a light for a dive trip, and simply put the whole thing into another big dive torch, with a strong magnet on a velcro sleeve to switch the lamp. It still works but is really-really ugly.

So,

1. Is there any of the P7 lamps on DX that could be sealed by replacing o-rings at lens, top cap and bottom cap? (I am planning to weld the tail-cap shut and use my reed-relay solution)
The 2 variants I ordered just had a flimsy o-ring either on the outside of the front-lens or behind it "sealing" directly against the threads, which would not work under pressure.


2. About the "ugly light": Does it have a good o-ring seal-solution at the lens? Can the tail-cap be screwed directly to the head? (I'm thinking of a canister conversion of this light)

Cheers

I'll answer 2. first. It's got a good o-ring solution at the lens compared to the others at DX. After fixing a spring that was too long which was keeping the lens o-ring from fully compressing I've had no problems.

I can't answer the other part of 2. as I've not had the body/head connection apart.

Regarding making your MTE P7 light dive worthy...I'd say yes and no. First of all I don't understand why you would weld the tail cap shut...how would you change batteries?

I have taken a DX non-diving light and with a few modifications have taken it to 100fsw without leaking. I wouldn't consider such a light to be as robust as one designed as a dive light but if the price is right and you aren't going to ruin a dive vacation you can do it.

I haven't taken a MTE P7 apart but I assume it's more or less like the Romisen RC-K4 that I converted.

If it leaks it will be through the front. I removed the flimsy o-ring that was in a groove in the head and used marine grade clear silicone sealant to fill the groove. I put some on the edges of the glass lens. Before I screwed everything back together I put some on the threads as well.

Regarding the tail cap. Take the clicky switch out and fill in the hole with marine grade epoxy. You don't need to weld it. There is a small o-ring there I would imagine and the threads are fine and deep. It doesn't leak most likely. I am even able to use this as a twisty on/off switch. You are using a magnetic switch so it's even less likely to leak there.

Just test it in the water before you put in the electronics.

 

[OS74]

Well I suppose there is no such thing as a free lunch then, you get what you pay for ;-)

Regarding making your MTE P7 light dive worthy...I'd say yes and no. First of all I don't understand why you would weld the tail cap shut...how would you change batteries?

I was unclear, I meant, keeping the tail cap, but removing the switch and weld the hole shut afterwards, thus getting a, hopefully, waterproof tail cap.

If it leaks it will be through the front. I removed the flimsy o-ring that was in a groove in the head and used marine grade clear silicone sealant to fill the groove. I put some on the edges of the glass lens. Before I screwed everything back together I put some on the threads as well.

I suppose the silicone option would work with all MTE lamps, I might try that too. Are you using this lam regularly?

However, it would be nice if there was lamp-body at DX that would be possible to modify to a proper o-ring sealed option as a platform for DIY modifications. Any DX lamps that are that good (I suppose W200 & W300 are)

 

[gcbryan]

Yes, the one's that are sold as dive lights...the ugly light, W200 and W300 have proper lens o-ring designs.

The ugly light does it with a ledge that supports the sealing o-ring. It compresses as you screw down a bezel and the lens compresses the o-ring.

The W200 uses a press fit so there is an outer o-ring to help hold the lens in. There is an o-ring behind the lens to keep water out (compresses) and in some models there is one around the lens as well. It's also just a two piece design...no tail opening.

I've had the modified Romisen on several dives but since it's only 100 lumens I don't take it along often. Just for testing purposes. I only paid $16 for it and bought it to use as a test platform.

An o-ring that compresses would be better but unless a light is designed from the beginning for an o-ring in the correct position it's hard to retro fit something like that.

Silicone works to a point but I wouldn't want to take it much beyond 100 fsw. I wouldn't spend a lot of money for a light that I had to rely on this method either. It seals up to a point but you probably fail at some deeper depth since there is no compression going on. It's actually not that hard to make a light dive proof to 100 fsw. It's just not as robust as a properly designed dive light.

Since you can get the ugly light for $95 in either the MC-E or P7 configuration you're better off either using that as is or using it to modify.Keep in mind it also have reed or hall effect sensors and a magnetic rotating switch.

The MTE light only uses one 18650 whereas the ugly light uses two. I don't know at what current the MTE light is driven but I'm pretty sure the ugly light is brighter.

 

[DaYerk]

@OS74

I would start with a W200. It`s a cheap and good quality base for a dureable tiny divelight.

The W300 is a totally different concept and much more difficult to mod. The only benefit is the room for a bigger more efficient reflector. But there is a lot of machining to do.

Using this lights stock is no option.

Nevertheless, the ugly light is the cheapest way to a P7.

 

[Dennis]

I have a couple of the ugly lights which I made serviceable by double checking all the O-rings, applying a bit of silicone grease, and then loctiting the crap out of the top bezel ring and the bezel next to the magnetic switch. I also put obvious witness marks so I know if the ring is loosening. You can also trim the main contact spring just to make sure everything is OK. I also ground down the teeth to smooth edges instead of somewhat sharp.

Also, people have had issues with the stock batteries giving fluctuating power at depth, order another set of Soshine's or Trustfires from DX at the same time. Just get the "most expensive" ones they have and you should be good. I got good AW batteries from US distributors but they are twice the price at like $10 each.

We also carry stock Intova LED lights as backups.

Dennis.

 

[OS74]

The ugly light does have some sort of driver driving the LED to a maximum 1500mA according to the DX-site.

Has anyone verified this? Could it be modified to give the 2,8A the P7 should have for maximum effect, or can you suggest a replacement?

Like these drivers:
http://www.dealextreme.com/details.dx/sku.20330
http://www.dealextreme.com/details.dx/sku.20329

The difference in light is not massive, but should be clearly visible; from about 1:1.7 in luminous flux according to datasheet

 

[gcbryan]

The ugly light does have some sort of driver driving the LED to a maximum 1500mA according to the DX-site.

Has anyone verified this? Could it be modified to give the 2,8A the P7 should have for maximum effect, or can you suggest a replacement?

Like these drivers:
http://www.dealextreme.com/details.dx/sku.20330
http://www.dealextreme.com/details.dx/sku.20329

The difference in light is not massive, but should be clearly visible; from about 1:1.7 in luminous flux according to datasheet

I'm guessing they did that for run time. The MC-E version of the ugly light has the same driver and is fully driven at 1.500mA since it is wired 2S2P and driven at 7.2 V or something like that.

The P7 isn't wired like that so it must be under driven (unless I'm missing something) but it already has a runtime of 2 hours or less. I don't think you would want to reduce that in a dive light.

 

[OS74]

I'm guessing they did that for run time. The MC-E version of the ugly light has the same driver and is fully driven at 1.500mA since it is wired 2S2P and driven at 7.2 V or something like that.

The P7 isn't wired like that so it must be under driven (unless I'm missing something) but it already has a runtime of 2 hours or less. I don't think you would want to reduce that in a dive light.

But hang on, if they really are using the same driver for both, the P7 version might be really inefficient.

For driving the MC-E it is fine with just a linear driver, but a P7 driver using a power source of about 8V to drive the current through a forward voltage of about 4V, there should really be a step-down driver. Otherwise the energy of one of those batteries is practically wasted.

Anyone here that can confirm the P7 version driver type?

Cheers

 

[DaYerk]

I think it`s only the ususal DX cut and paste problem.

 

[OS74]

I think it`s only the usual DX cut and paste problem.

He he, very ugly in deed. So if you do have the P7 version of the divelight, you may very well run it with one battery instead of two as it would not make any difference in runtime.

Anyone here with experience of the DX P7 drivers I linked above, are they decent in efficiency? The comments on the DX site mentions that id does not quite get 2.8Ah which should be acceptable if it is otherwise ok.

Cheers

 

[gcbryan]

I'm sure your assumptions are not correct. The P7 dive light runs longer than it would given your scenario. Gavin on here has the P7 and might be able to address your concerns with more specifics.

 

[OS74]

I'm sure your assumptions are not correct. The P7 dive light runs longer than I would given your scenario. Gavin on here has the P7 and might be able to address your concerns with more specifics.

Yes, it would be interesting to know what circuit they use for this one. I can't belive they would use same.