switchtesting , (june13th2015:additional test by MRsDNF in post#44)

Flashlight Modding and DIY Parts
17

The only switches I have killed have been some very junky stock switches that did not handle 10A. Ive never had an Omten switch fail in the 10-12A range. I have not gone higher on those switches. But I believe others have run them at around 15A.

Im curious to see the difference between the two omten switches in this test.

In my latest hot rod build, I have made my own "twisty switch". It should be good for lots and lots of amps, and then some.. I would not trust a typical Omten switch for what Im putting together.. J)

18

10A results. After four hours all three switches work fine. Over the small Omten there is a somewhat higher voltage variance in the end, but nothing I worry about. As said the small switch warms up more, but that does not seem to lead to failure yet. Of course for critical applications, like single li-ion cell lights it is nicer to have the larger switch because it causes a smaller voltage drop. In fact when using the small Omten at 10A the variance upon different clicks can be as high as 0.05V and that could be visible in the output of the light, or lead to a bit shorter period the driver stays in regulation.

What surpises me is that the voltage increase is not lineair with the current, it lags a bit behind, so the resistance decreases a bit when current increases (or because the temperature increases), which is good for the performance. Another thing that is good for the performance: as you can see with almost all 10 click voltage series, the first value is low compared to the average, it is the voltage reading before the first click, it means that if you leave the switch alone the resitance decreases somewhat over time.

Small Omten 10A begin : 54 56 70 59 57 62 60 55 59 55 mV

10A 1.5hrs: 39 62 54 64 61 68 51 56 60 63 mV

10A 4hrs : 55 73 79 100 92 62 52 49 93 51 mV

Large Omten 10A begin : 34 39 42 35 39 50 40 54 54 58 mV

10A 1.5hrs: 37 70 38 47 40 49 68 80 60 43 mV

10A 4hrs : 34 46 51 53 81 88 59 50 54 52 mV

6A ebay sw. 10A begin : 19 18 18 18 20 22 20 22 20 18 mV

10A 1.5hrs: 15 16 16 19 17 18 18 24 20 27 mV

10A 4hrs : 20 24 38 41 20 20 19 20 19 19 mV

All three switches make it to the 16A test! It has to wait a bit because my girldriend hates the sound of the fans, makes her think of bad airco days .

I can't help noticing that making a high amp switch is cheap and easy: a plastic housing with ballpoint click-mechanism, three pieces of metal, a spring. I can't comment much on the type of metal used, but these good performing Omten switches are not exactly using the metal with the best conductance.

19

Are you not sure that it is not the first comment that your girlfriend wants the testing stopped though you did clarify by saying they weren't very hot.

Sometimes I wonder about members here. Orsm testing, still, by the way. Thanks again.

20

She says that she still loves me, I think mostly despite of the hobby even though I did give her a flashlight two years ago (and she refused any more flashlights ever since, glad it was the good old Fenix E01 and not some crappy Ultrafire )

21

16A started:

.....and after 10 minutes: 1 switch down. No, wrong, it was the larger Omten , electrical connection lost and it does not click anymore. oh, and something funny happened to the housing :

Two to go:

It was mounted in the middle, perhaps the two outer switches have some profit from heatsinking through the copper wires? Or the mounting of the small switch provides some extra heat path? Or just bad luck, the next switch would survive better.

22

There's not much wrong with the switch, just some plastic deformation caused it to fail.

23

The heat would of been caused by a bad connection in the switch. is there any arcing on the contacts?

I would say your testing is working pretty good. Maybe testing on a batch of ten is next in order.

24

Ah, (language barrier), now I see your comment . ..Eehm, she wasn't there when I did that. (Shhhh, don't tell her, she still thinks that this hobby is just some innocent man thing)

25

no arcing that I can see, it must have been pure the heat caused by the resistance over the whole metal part of the switch, i measured somewhere above that the metal used is not the best conductive kind (it looks like the disc has a nice silver coating though):

26

I stopped the 16A test after 2 hours because nothing much was happenening, I got bored, and I want to go to bed. The small Omten switch ran hot, but still works fine and so does the 6A ebay switch although the resistance seems to have gone up a little.

Here's the last voltage numbers of the two remaining switches:

Small Omten 16A begin: 73 101 125 92 95 91 145 106 93 100 mV

16A 1.5hrs: 70 113 110 80 132 81 115 77 92 104 mV

6A ebay sw. 16A begin: 26 29 37 27 29 29 33 37 31 40 mV

16A 1.5hrs: 34 51 54 47 45 37 40 42 35 38 mV

I did not expect the switches to work so well. Perhaps the Mcclicky and the Judco(Tofty) switch have a lower resistance (can someone measure that for me?, I'm curious about that), but it is not that these switches fail easily. My ideas on these switches: they eventually fail from heating up, and they get rid of the heat via the leads. If the heat can travel a short distance from the leads to a flashlight body (thick solder blobs all the way to where the leads go into the switch and the leads in direct contact with the aluminium, and such) the switch may well perform even better than in this test where the heat must directly dissipate into the air.

Hope you liked these tests, good night :-)

27

There is but I could not measure the resistance in the Tofty switch with any of my DMM.

28

A DMM, when measuring resistance, uses a small constant current and then measures the voltage (that is what I think it does). When the resistance is very low the voltage is below what the DMM can measure. The way to go with very low resistances is use a much larger current than your DMM does (like more than 1 amp, or 16 :evil: ) and then the voltage is measurable, and the resistance can be calculated.

29

Thanks for doing these test.

I’ve had 3 switches fail recently. One at 3.04 amps, one a 4.8 amps and one at 5.1 amps. These switches were not Omten but generic switches in different lights. They all failed by dimming to barely visable light or going completely off.

It appears that the Omten are much better switches, I have 6 Omten 250v 1.5 amps switches on the way with full confidence in their ability thanks to your test.

30

Thank you for soing these tests. Sure must have been boring though. So much more thank you :-)

31

I'd like to see tests with the same currents but pwm-ed?Because constant current does nothing to switch,except generating heat,but maybe fast pulsating (for ex. 1khz pwm) current cause some additional "electrical wear" damage?I'm just guessing.

32

I think the set-up would still work with this resistor load and a FET-driver, so it must be doable. Say PWM causes more wear, it also means less heat because it is used to make lower modes. What would be more damaging (rhetorical question)?

I'm not going to do any more switchtesting this month (holidays, a nice mod in the planning), so there's plenty of time to think of other switch-tests worth doing :-)

33

Do you think the first switch passed along its heat to the second switch which in turn acted as a heat sink for the third switch?

34

I had a McClicky fail in an odd way, nothing wrong with the contacts but the light wouldn’t turn OFF. The spring inside the switch collapsed from the heat at just over 10A and wouldn’t press the components to cycle through the ballpoint mechanism. Hence, the light stayed on.

I have a cheap looking switch in my Sinner Ti that is Yanguo or something like that, it’s taking 9A to an MT-G2 ok so far. I worry about it, as it would take the same or one almost exactly like it to replace as there’s little room in the tail cap.

Thanks for the extensive testing and lip sacrifice, means a lot to a great many of us. Tell you girlfriend there’s thousands depending on your results and you’re doing it for the team. :wink:

35

Thanks for the test, the omten switches really are good. I have the 5pack of the small switches from cnqg they are cheap, reliable and have low resistance. They are only rated for 1A but don’t have problems with 5A. I also measured the voltage over the switch but in the mV range I don’t trust the DMM to get a absolute value but I always test it at 5A and if the resistance is below 100mV I let it stock and if it’s more I put one of the cheap omten in it.
The ebay switch seems to be a lot better but on the other side 60mV more or less is not the world, some tailcaps from eswitch lights have more resistance.

Before I got the switches from cnqg I often opened the stockswitches and tinned all the metal parts that helped often but was a lot of work. The switches which have only one contact on the side and one on the back are the worst because the current paths is through the spring…

36

Given the resistance in the nickel plated tabs I think you may be right about the copper wires at either end providing a sink for the outer two switches. The design of the failed switch looks good with no current through the spring(usual failure point of cheap switches) so maybe another test with the failed type at one of the outer positions and one of the others in the middle. See which switch survives that handicap best.