Convoy S21A with TIR - bicycle light: Changing modes and turning itself off - what to do?

[manithree]

@mccririck

@Delta_V

AFAIK, the black and gray have always been rubber buttons, while the colored hosts use metal buttons.

It would appear not.
14.57€ 24% OFF|Grün/lila/orange/rot Convoy S21A mit luminus SST40,orange peel reflektor, 21700 taschenlampe, taschenlampe|Taschenlampen| - AliExpress

I don’t remember every seeing metal buttons on the S21A. My old purple S21A with an Osram emitter has a soft plastic switch cover.

That’s what I remember for S2+ buttons but not the S21A.

[mccririck]

Also if you go to the Convoy Flashlight Store and click on links to “S21 series” or any other general link you get “Sorry, no matches were found for your refined search.”

[Delta_V]

Oops, was thinking of the S2+ for some reason. But the links seem to work fine.

[mccririck]

@Delta_V

Oops, was thinking of the S2+ for some reason. But the links seem to work fine.

Not for me.

[PiercingTheDarkness]

Convoy store is missing parts, noticed that too, but I buy in bulk direct using PayPal, so rarely ever look at AE

[Peppergeo]

Here is Weerapat Kiatdumrong’s answer from youtube about his expierence with the brass pill inside of the S21A.

@Weerapat Kiatdumrong

It unscrew itself even with spring on the driver sir. That’s why I like S21b more than s21a. Even the flashlight with no pill may experience this problem. My Mantaray c8.2, its brass ring that tighten the driver can unscrew itself when riding rough terrain. So it’s important to check carefully. (…)

Thanks for sharing with us, WK!

@manithree

(…) I never had my S21A change modes or had the driver come lose. I’m pretty sure I have over 3k miles of commuting on that light with no problems. Mine is the SST40 version that has a spring on both ends of the battery. It’s been rock solid.

First of all: Hilarious username, Manithree! Made me smile. :laughing: It’s nice to hear this positive review. But I just don’t know why some are working good, others not. Is there anything else special about your S21A? Reflector or TIR? But (gasket+reflector+glass+oring) should be the same length as (TIR+glass+oring)…

@Delta_V

A spring on the driver may stop the pill from unscrewing. The pill is held in place by friction, and the hard impact directly on the driver is generating enough force to overcome the friction force. A spring will spread the impulse out over a longer period of time, resulting in a lower peak force that hopefully won’t exceed the friction force.

Thanks for explaining! A spring on the driver should be more reliable than a solid column. Why is there this solid column in the first place? Higher currents possible? Or any other advantage?

Interestingly inside my Astrolux ST01 is a solid column on the driver side too, but there are two springs on the tailcap side. One is bigger and longer, the second one is smaller and shorter and inside/under the bigger spring. I have used it with a shorter 18650 battery as secondary throwing light on my bike since 2-3 months and it worked as expected. It has an side-switch - so I think the change of modes is probably not done via a short interruption like in tailswitch lights. And it has an integrated shelf. BUT hold-for-off is bad when using it as secondary light that is often turned off and on again.

Regarding the S21A:
It can be my user error, that the S21A has these problems. But I did my best to get it to work properly with all the parts it has at the moment and without major modifications. I don’t know if the unscrewing-of-pill will be really fixed when soldering in a different driver and led. Or switch out the solid column on the existing driver. Maybe it is fixed, maybe not.
Right now it is not working good enough - especially for important rides like commuting. So I think the way for me is just to buy another bike light.

I don’t know if I have motivation to try all the modifications to the S21A at someday in the future and test it as bike light again. Then I will share my findings with you all. Thanks for all your help!

[Delta_V]

Yeah, a brass post will allow for higher currents. Also allows the light to be a bit more compact, since a spring needs a certain amount of space to avoid permanent deformation.

The dual-spring setup is another way to allow higher currents - the longer, thinner spring ensures consistent contact, while the shorter, thicker one has lower resistance and allows for higher currents.

[Peppergeo]

@Funtastic

Yeah, I just copied your link above and didn’t realize.

You’re right. My inital link was leading to the wrong size.
One more question if I try to solder a spring to a spacer and then put it inside while the spring faces towards the driver (with a removed metal column):
If the spring is compressed, is there a risk that the lower and wider parts of the spring are touching parts on the driver. Would this cause problems?

[manithree]

@Peppergeo

@manithree

(…) It’s been rock solid.

First of all: Hilarious username! Made me smile. :laughing:

If you’re talking to me, thanks. You might be the first person (I’ve been using that name online since 1995) that figured it out.

@Peppergeo

It’s nice to hear this positive review. But I just don’t know why some are working good, others not. Is there anything else special about your S21A? Reflector or TIR? But (gasket+reflector+glass+oring) should be the same length as (TIR+glass+oring)…

It’s exactly like Simon shipped it, except that I put some DC-Fix on the lens. It’s an SST-40 with the reflector. I put in thousands of miles bike commuting with S2+s, also, and never had a problem. I even had a mount improperly installed and an S2+ hit asphalt at 25 mph. It got dinged up, but it was still in strobe mode (no bike strobe on it), and didn’t do any permanent damage.

So, I strongly suspect that the lack of spring on the positive end of the battery is the culprit. They’re cheap, and you can never have too many. Maybe you need another one to test the theory.

[Peppergeo]

@manithree

If you’re talking to me, thanks. You might be the first person (I’ve been using that name online since 1995) that figured it out.

Yes, your name manithree. I edited the above post to avoid misunderstandings. I think others also have figured out your name. But I think they never wrote about it.

@manithree

So, I strongly suspect that the lack of spring on the positive end of the battery is the culprit.

Probably you are right… :+1:

[Peppergeo]

I just realised that I have also bought two lighted tailswitches from convoy for the S21A. They lay here in my parts bin and have springs on them. Do these springs also work on the driver side?