I am a flashlight disaster Part II - More Information, soldering advice needed.

belomeclone

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Oct 13, 2009
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Background: I bought a TLE-300M-EX. I intended to put it in a 2D Maglite, powered by 6AA batteries running in serial. It doesn't work.

Batteries have enough power, other TLE-300M EX's have been run on 6AA batteries, etc. Now, the new information is that the TLE-300M EX works. It does work.

The battery holders are these:
http://kaidomain.com/ProductDetails.aspx?ProductId=2723

They are not perfect. The metal contacts on the end and the positive nipple are both too small. Is this the most likely cause of the issue? How simple would it be to improve? What would I use, exactly? Should I go buy one of those 20 dollar custom made 6AA-2D fitters on the marketplace instead?

I mean, what else could it be? The drop in itself works. It would have to be the contacts not connecting. Am I right in isolating the problem, at least?
 

Rej

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Hi Belomeclone.... did you try the suggestion by one of the reviewers of that battery tray at KD;

"Weaknesses:Build quality is not great. Smaller in diameter than a D Cell. I needed to put some solder on the end as the positive bump would not make contact in a Maglite 2D without it."

??
 

PapaLumen

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Yep unless its the switch, but it worked ok before right?

I'd guess its the positive end not making connection. IE the end nearest the head.

You could buy some neodymium magnets on ebay for cpl of bucks and pop one on the positive end or if you can remove the switch from the light then you can hold the battery holder against it and you should see why its not making contact. There are some ridges around the switch postive contact which can be filed/sanded down to gain a few more mm.
Or if your buddy with the multimeter has a soldering iron you could get him to add a blob of solder to the positive contact.

Switch removal - http://www.youtube.com/watch?v=LbADsdkBLFA No need to take the switch apart, you just want to see the bottom of it where the positive end of your battery holder touches it (or not in your case).
 

old4570

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Yeah , there is a small contact spring in there ...
Take a look [ switch body-plug ] for the + contact point for the batteries ...
Sometimes there a little set in [ recessed ] ....

And if you very carefully stretch it out , you may solve your problem ..
Use great care though , as its very easily pulled out .
And getting it back in , could be problematic . [ at the very least ]
 

Mr Happy

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I mean, what else could it be? The drop in itself works. It would have to be the contacts not connecting. Am I right in isolating the problem, at least?
Yes, I think so. Now I see the details, I have exactly the same battery holders from KD, and I remember they didn't work in my Maglite either. The problem is the spring at the positive end of the light. It is recessed inside a hole and will not make contact unless the battery has a tall positive button. Basically a design defect in the Maglite.

What I did is to stretch the spring, but I don't recommend this unless you know how to completely disassemble a Maglite into every tiny piece and then and put it back together again. Just pulling on the contact spring will yank it out of the hole and then you're screwed.

Raising the bump on top of the battery holder seems better. Maybe a small magnet, maybe a blob of solder. Either might work.
 

belomeclone

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The coil at the end of the Maglite, does it need to make contact with the metal on the cell holder as well?

What else is strange is the batteries work in my other Maglite, but it is an older one, and it may be designed differently.
 

Mr Happy

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The coil at the end of the Maglite, does it need to make contact with the metal on the cell holder as well?

What else is strange is the batteries work in my other Maglite, but it is an older one, and it may be designed differently.
Yes, the spring needs to make electrical contact. On my Maglite I needed to bend the spring like this to help it connect:

springt.jpg
 

belomeclone

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Oct 13, 2009
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Yes, the spring needs to make electrical contact. On my Maglite I needed to bend the spring like this to help it connect:

springt.jpg

Thanks for the picture!

Call me noob, but, what function does the spring have? I am not well versed in these things yet...
 

Eismagier

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Call me noob, but, what function does the spring have? I am not well versed in these things yet...
The spring has the double function of keeping the batteries in place and completing the circuit by connecting the negative end of the battery to the case. The current (power) actually passes through the metal body of the light.
 

belomeclone

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The spring has the double function of keeping the batteries in place and completing the circuit by connecting the negative end of the battery to the case. The current (power) actually passes through the metal body of the light.

I figured that was the case from my testing in the previous topic. Is that a common design with flashlights?
 

Mr Happy

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I figured that was the case from my testing in the previous topic. Is that a common design with flashlights?
Yes, springs are always used for battery contacts (*) since they help to provide constant force against the battery terminals. If they are not spiral springs like the one shown they are flat springs like the ones seen on battery chargers. If the flashlight body is made of plastic then metal strips conduct the electricity from the spring to the other end of the light.

(*) Unless they are clips as with 9 V batteries, or screw terminals as with car batteries.
 
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