Flat Twist-Switch does not work with my LS2

I just purchased one of the 123 twist-switch tail packs from Arc and discovered that it will not work with my recently-made LS2 (LSH). It screws on just fine, but the light won't come on even when I tighten it down all the way. I have tried it with two different types of batteries, including Duracells, but I get no light at all. The 123 clicker tail pack works fine with both types of batteries.

I emailed Arc but all they said was "No, there's not really anything more you can do." Plenty of folks seem able to the twist-on tail packs with recent LS2s. Can anyone suggest anything for me to try that might make this work?

--Bob Q

Put some foil in the bottom of the twist pack. The little tit sticking up that's supposed to mate with the negative terminal of the battery is probably not making contact with the battery. Let us know how that works out for you.

CM

I will give that a try. I worry about the foil making a high-resistance contact and causing problems with the circuitry. Seems to me that the basic design really ought to have a spring or compression washer in there. Hmmm...

Thanks for the suggestion!

Do some of the twist-switch tails have shorter contacts than others? Think I should take a chance on picking up another one?

--Bob Q

You will need to put something conductive, preferrable something that expands and contracts with pressure between the negative end of the 123 and the bottom of the battery holder. A shortened spring from another flashlight works well for me.

I have found that this issue does vary among different twisty tail packs. You might have better results with another tailpack, but it would be iffy at best.

Putting something conductive behind the battery would be your best bet. I personally use foil and it seems to work. Conductivity could be an issue with foil so the spring idea might be better. I have found with foil, that sometimes the light comes on by itself because the foil can move around and still make contact even with the pack unscrewed. I have to really unscrew the pack quite a lot in order to prevent this. I have gone through 2 batteries rather quickly since using foil.

I am going to look into using a spring or something more solid than foil, perhaps a thin washer.

As much as I hate the extra length created by the clickie pack (you don't get as nice a fit for EDC in your watch pocket), I will probably order one and just use that anyway. I enjoyed the clickie on my LSH Second before I sold it and got my LSH-P /ubbthreads/images/graemlins/smile.gif

put solder dots on your batteries /ubbthreads/images/graemlins/grin.gif

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Rothrandir said:
put solder dots on your batteries /ubbthreads/images/graemlins/grin.gif

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That's a really good idea, provided the heat doesn't adversly affect the battery. Would conductive epoxy work for this?

i have done this on aaa's aa's and d's, didn't <font color="blue">appear</font> to affect anything... /ubbthreads/images/graemlins/icon3.gif i think lithiums should work fine

i don't know much about conductive epoxy, but one would guess it has a much lower electrical conductance.

Why not just put the solder dot on the positive contact, and then you won't have to modify the batteries at all? It should be easy to solder to. Your clickie pack would still work too.

I use a blob of solder on my P-123 twist pack also but I don't put it on the positive contact. I put it on the bottom of the twist pack itself right in the middle of it where it contacts the negative side of the battery. It seems to work perfectly for every brand of battery I've used so far.

Thanks for all the suggestions! Putting something conductive in there does seem to do the trick. I'm going to experiment with a combination of a solder dot and a bit of foam to act as a kind of spring.

--Bob Q

How can you get the solder to stick to the aluminum?

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Sproing said:
I use a blob of solder on my P-123 twist pack also but I don't put it on the positive contact. I put it on the bottom of the twist pack itself right in the middle of it where it contacts the negative side of the battery. It seems to work perfectly for every brand of battery I've used so far.

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I've seen solder that *claims* towork with aluminum, but it worked poorly at best. What kind of solder did you use? I have an early SLS that has a low negative contact, and a bit of solder there would be a sure cure! TIA /ubbthreads/images/graemlins/thumbsup.gif

My 123 battery pack works OK, but you have to twist harder than I like; I've been putting a little solder on the + end of the battery itself, which works perfectly, but is a bit of a nuisance. /ubbthreads/images/graemlins/icon23.gif

Yep, had the same problem over here. Received the replacement flat packs (longer thread) but none worked - even when screwed in all the way. Just added a spring - the type used inside battery holders. Widen the spring base (bend it open) so it fits snugly inside the holder and Viola! Problem solved. Just watch that you do not lose it when changing batteries!

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Gandalf said:
I've seen solder that *claims* towork with aluminum, but it worked poorly at best. What kind of solder did you use? I have an early SLS that has a low negative contact, and a bit of solder there would be a sure cure! TIA /ubbthreads/images/graemlins/thumbsup.gif

My 123 battery pack works OK, but you have to twist harder than I like; I've been putting a little solder on the + end of the battery itself, which works perfectly, but is a bit of a nuisance. /ubbthreads/images/graemlins/icon23.gif

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I wasn't expecting it to stay on either because I have tried before to solder to aluminum without any luck whatsoever. But I decided to try it anyways and it worked! I just cleaned the bottom of the pack with some contact cleaner and applied some flux from a flux pen (which probably did nothing). The solder I used was just electronics solder with a "rosin core" I bought at radio shack. I don't know why it works but its on there really securely and hasn't come off even once.

How do you turn the light off with the spring in there? Do you just use a short enough spring that you can unscrew the tail beyond its reach?

--Bob Q

My version of the Arc still uses the "foam" ring keeping the battery from making contact. The spring basically replaces or elevates the "nib" in the base of the battery holder. Insert the spring and start turning the holder. Shorten the coil if it turns on immediately. As it is now, I require a 1/4 - 1/2 turn to switch it on. It bottoms out after another full turn. The spring is to be long enough to overcome the foam ring when compressed.

is the case of the batterypak bottoming in the head of the light.I am not sure how they are made,I have one on order but it is not here yet,but if it seems the case is to long in relation to the battery would it be possible to shorten the case?

I just tried to solder a dot on my 123 battery and accidently made an indent in it. Now it works beautifully since the egde of the nipple touches the side of the inverted cone I made with the indent on my battery. Just my $.02.

Dan

I recieved my LSH-S today and it would not work with the twist switch tail pak ,it does look like the base of the head is bottoming out on the shoulder of the twist case befor the batt makes contact. I took sheet copper and punched a dimple in it then cut a disc around the dimple, disc diamiter = id of twist case. the disc was a snug friction fit in the case when inserted sideways.After inserting the disc spin the disc flat, I used used a deep socket that would fit freely in the twist case to push the disc to the bottom of the case,I then gave the socket a rap with a wooden mallet. the disc conformed well to the bottom of the twist case and is good and tight it seems to work great now with no need to mod the batteries. /ubbthreads/images/graemlins/smile.gif