switch tests: KAN-28, update: stock switch UF-1405 in post#12

I ordered these from Fasttech:

..and I got these:

A quick search, this 'KAN-28' appears to be around, Richard (Mtn Electronics) sells it too for about as cheap.

The leads are brass, not much voltage drop over the leads (5mV over the exposed length of one lead at 16A):

Testing:

At 6A, the voltage drop over the switch was between 25mV and 35mV

At 10A, the voltage drop over the switch was between 40mV and 50mV

At 16A, the voltage drop over the switch was between 65mV and 95mV

Like in my switchtesting thread from a year ago (see sigline) the voltage drop varied from click to click. At 6A it was tested for half an hour with multiple clicks every now and then. 10A was tested for an hour. 16A was tested for 40 minutes with several click-sessions. The switch got fairly hot at 16A (1.3W dissipation), but kept on going and did not fail.

The performance looks like it is good, probably close to the Omten that it has replaced (never tested that square Omten but the internals are probably the same as the big round Omten in my other test, that tested similar to this KAN-28)

i see that i ordered the same ones as you did, and also got KAN-28.

Can you post a picture with the other common switches to see the size comparison?

Thanks djozz. Good info as usual.

^ +1

Hope I got this right...

You ordered Omten PBS 101 from FT and instead that you got KAN-28?

Thanks on the test. I am really really thankful but...

Djozz could you please drop generic uniquefire no name kan-28/PBS 101 on test here? I have one that I continuously use almost every day for more than week now with DJOZZ style FET driver (oppan Djozz style ) and ncr18650PF dragging 4.15A(measured with clamp meter) and it seems working just fine.

Thanks!

Yes sure, first on my list for the next hobby-window-of-opportunity :-)

Btw, Fasttech does not mention that the switch is Omten, but the picture shows one.

+1

Did not realize that I received KAN-28 last month from FT until I saw this post.

Hi djozz, noticed quite a few of my newer lights (incl. Convoy) come with white OMTEN PBS1288BDM. Perhaps you could include them in your next test?

I could if I had them. But would you not think that all those Omtens come with the same internals (just scaled down in the small ones), and perform just as well?

Ok, the stock switch in my UF-1405, same shape as the Kan-28 and big Omten, but no markings:

Rigged up:

Note that the leads were very short because they were soldered on a board, so the heatsinking through the copper wires could be a bit better here than in the test of the OP.

And the results: 25-40mV@6A, 35-50mV@10A, 65-95mV@16A. Each current was applied for more than an hour, clicking on and off multiple times with all currents went fine.

This switch behaves no different from the KAN-28 or big Omten switch. Made in the same factory or they copied each other well?

I understand some stock switch failures were recorded in the UF-1405, but at least this one is fine :-)

Thank you so much! :) I think problem can happen in bypassing spring (plenty of UF modders will react WTF :) ), but it can cause failure if we take our soldering iron bit longer on switch PCB + base trying to solder bypass wire or braid. So if we heat a lot sometimes we can even transfer solder over vias to other side of PCB + contact, melting switch plastic, and switch eventually fails cause heating changed structure of material:) happened to me...

Yes, it is very easy to melt a switch, a good idea is to remove the switch when bypassing the spring and then solder it back. I alway make sure that when soldering a switch, both sides of the joint already have solder on them, and then just quickly melt the blobs together.

I can not thank you enough for this. I will certainly not change it any more unless I'll have to.

Most of the switches I’ve come across if not all are simply two plastic parts mated with press fit pins and no glue and can be separated to either examine the internals or alter the leads. Justin showed us how in his example Modding a Judco switch . Without opening up the switch to solder the leads loose, wrapping it in a wet paper towel will help but the most important thing is get in and get out quick with the iron, don’t keep heating and fussing with it. Get extras, figure you’ll need them, and don’t sweat it if you screw up, just do it again until it’s right. If you do melt one then use it to practice on until you’re confident of gaining a good result. Much of successful soldering seems to come from having the confidence to proceed with alacrity.

+1 on pre tinning springs and wires and most anything that requires significant heating to wet to. The only exception I can think of of hand is solder pads with holes where pre tinning either the pad or wire would prevent the wire from fitting.