Need help with 2 flashlights

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Vincent.hannah
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Need help with 2 flashlights

Hello all,

I have been a forum member for a while but I am not sure if I have ever posted. 10 years ago in high school I started making my own flashlights to hunt with. Over the years I have made plenty for myself and gifts for others around Christmas time. I have always been successful and it honestly hasn’t ever been too hard, some solder here some there and your in business. I just got stuff to build 4 lights, 2 small 1×18650 lights and 2 big 2×26650 lights. I have the 18650 lights complete and they work great. But my bigger lights are both having the same problem- they come on but extremely dim maybe 2 lumens.

One of the lights is a convoy l6 body with a crew 70.2 and a MTN FET 30 mm driver (designed for the l6 body). It turns on extremely dim but doesn’t program at all following the programming rules. It will flash out its voltage and that is the only thing I can get it to do. I have made sure it has a good ground and I even took a ground wire from the negative on battery to the body to make sure it wasn’t the tail cap.

The second light is a uf-1405 with a cree xpl-2 and a mtn-maxlp hp 5.5A buck driver. It does the same exact thing- dim light. This driver has 4 modes the standard configuration. I have also taken a ground from the negative to the body to check the tail cap and same thing.

They both have thermal paste under the led, both have good solder to the led (cant pry the wire off with a screwdriver and light pressure) and both have retaining rings on driver installed. I was thinking the driver was bad on the first light I did but now the second is dong the same exact thing. Both have new charged batteries.

Any ideas guys? Any easy tests? I cant for the life of me figure them out. I do have a cheap electrical tester but I can’t text amps with it.

Correllux
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On your XHP70 did you happen to buy one/the mcpcb for 12v operation instead of 6v? That emitter can go either way. Did you flow the emitters yourself? Did that one ever light up brightly and then get stubborn with the dimness?

I don’t have a suggestion for the zoomie but if you can share photos maybe that could help. And the cells are definitely known good and can carry some current, yes? I’m sure Richard still tests everything before shipping out but maybe there’s a possibility he got some bad chips or inductors or something.

Vincent.hannah
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I just checked my bill and it says 6v. Is there any way to check the mcpcb? Both were already flowed onto mcpcb’s. One may have got bright at first, I did think that it was better the first time I turned it on. But it definitely wasn’t full power (at least I don’t think). I can put some pictures up when I get a chance to take some. Thanks for the help.

Correllux
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If it’s 12v it’s usually printed on there, easily visible (except for Kaidomain’s boards last I looked). I just looked at what Richard is offering and it looks like the boards he’s selling for the 12v use an additional component to jump the traces…does the same thing just a little different than other boards’ layout. So if you got it from him you have two clear indicators of 12v. Once the emitter is mounted you can’t really see the pad layout or the gaps between the pads…if you can tilt it up or remove it you could have a look, and you can see the typical pad layout design by looking up the boards…12v looks like kind of a fat Z with two smaller rectangular pads while the 6v one big rectangle in the middle and either smaller pairs on the sides or sometimes continuous ones.

Obviously if you were trying to feed 8v to a 12v emitter you wouldn’t get much light…that was my first thought. On whether it was bright and then went dim…made me wonder if the direct fet drive could possibly have killed it. These are really strong emitter and if memory serves they were taking 12-15 amps with no problem (voltage going up accordingly with the higher current) so I wouldn’t imagine that 26650 cells would open up enough to zap the emitter, but that was a thought. And then of course if the cells couldn’t handle the direct drive they’d fall on their face and things would start to get hot, current and output would diminish quickly, but after a rest should be able to make it fire up bright again.

Dunno. Pics might help a little.

Oh, also…these cells are normal, right, not protected cells? What cells are you using?

Vincent.hannah
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These are protected cells. Shouldn’t be a problem though until it actually starts drawing a lot of current correct? I am making one of the lights for a present and I hate giving away unprotected cells. Most people don’t even care to know the difference let alone pay enough attention to not kill them all the way. I know being an FET driver it could trip the protection circuit but it shouldn’t until it’s actually drawing enough current to do so. I know You can set the max draw so I was basically going to set it to where it’s max is not going to trip the battery.

I get your thinking that 6 bs 12 volt wouldn’t put out as much power but it should still put out some correct? I can look at the led that’s how dim these things are.

Also, how do I post pictures on a phone?

Rexlion
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Pictures would have to be uploaded to a photo hosting site, then linked to via the ‘insert image’ dropdown menu.

== We save the planet from darkness ==

Correllux
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Might search to see someone’s bench test for that emitter but the data sheet suggests that it needs a minimum of 10v or a little more to even light up but the stated minimum to get any appreciable current flowing is above 11v. I really don’t know how the protection circuits would act here since I think most are geared toward the typical 2-6 volt range for components….soooo, if you did indeed have a 12v on there then yes, that’d be a problem. The driver doesn’t have any way to boost voltage up to where it needs to be, so it’s an instant under-voltage situation and whether or not the emitter can even light up just depends on how little it needs to respond.

If you have the 6v emitter/board that you expected then I’m not sure what’s going on without some more info or a peek. Do you have any unprotected cells that you could test with? You could even use 18650 cells to do this. Depends on the added circuit but better protection these days can (grudgingly) deliver 10 amps…6 or 8 amps is more common. But again, if that were the case you’d expect some bright-bright light on fet until the protection circuit dumbed it back down and that should be repeatable behavior.

I use this site for sharing photos here – very simple host, just upload/drag and it’ll give you direct links that you can use. Not a feature rich site like imgur and such but it always works and it’s quick. Have to use the buttons in the reply box if you want those photos to be embedded/visible in the post.

https://postimages.org/

Vincent.hannah
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https://postimg.cc/gallery/B8VM3nV

That didn’t seem to work. I’ll try again. Also, this isn’t as many pictures as I would like to send. This is what I had on my phone I’m currently not at home.

Vincent.hannah
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Vincent.hannah
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Last seen: 1 week 10 hours ago
Joined: 07/01/2014 - 21:32
Posts: 17
Location: Utah