Cant turn off AC switch after powering with DC power (newbie)

[Smitiz]

Hello everyone!

I'm very new to this whole universe of solderind and electronics, but I1m eager to create

I have red somewhere that I can use AC switch on DC power, so I did...

I've connected 3 18650 3,7V li-ion batteries in serial way to power a 12V PC fan so it can blow away all the nasty fumes while I solder in the future

I have a small 2 pin AC switch similar to this one
https://dx.com/p/diy-rocker-switch-for-car-vehicle-black-red-11cm-138180
But mine is 3A 250V AC / 6A 125C AC and dosent have wires, just pins.

I've connected the battery pacs black negative wire to the fans black wire.
Soldered the fans red wire to the switches pin (the one closer to the ON state, and soldered the battery pacs red wire to the switches other pin (the one closer to the OFF state).

I have tryed out without soldering, everything worked like a charm, the switch was functionig properly.
But when I soldered the battery to the OFF pin, the fan started and didnt stop untill I desoldered it.. :-/

Any ideas?

 

[magvitron]

the switch might get damaged when soldered on to a circuit. that might be the reason

 

[jpanhalt]

Switch ratings are different for AC and DC. What is your switch's DC rating? DC ratings, when present, are usually much lower than the AC rating, because fusing of the contacts is a much greater problem with DC. It is possible your switch is not rated for DC, or if it is, you exceeded its rating, and the contacts are fused (welded) together.

John

 

[KeepItSimpleStupid]

Always respect the AC/DC ratings. Typically you won't find a sliding contact for DC high current switches. Plating is an issue too. AC needs arc suppression.

Switching 10 mA signals or less gets very problematic. Switching 15 kV signals or 1000 W RF signals are also problematic in much the same way.

 

[Smitiz]

I cant find any Dc data about those switches :-/
I have 1 more of these:
https://www.electro-tech-online.com/custompdfs/2013/03/MFP102_eng_datasheet.pdf

Whould this be a better choice?

 

[Smitiz]

I have tryed it with the switch linked above, it works great, thank you for the help! ^^

 

[KeepItSimpleStupid]

The first line of the datasheet you posted: Contact rating: 30 V DC, 350 mA

That's only 0.35 Amps.

 

[Smitiz]

Could you recommend a switch for me to use with 18650 / 14500 / 16340 batteries?

 

[jpanhalt]

It is not the battery type that matters, it is how much current you are drawing by the fan. Do you know the current rating of your fan? If not, since the fan is not life-critical, I would go with what you have that works until it fails.

For higher currents, for example as used for model airplane motors, the power "switch" is a solid state device, and the mechanical switch is just logic level with almost no current.

John

 

[Smitiz]

Well its a Ball bearing fan, DC 12V, 0,17A

Mod: So its okay for the switch

Could anyone recommend a really simple book like "electronics for dummies"?

 

[jpanhalt]

0.17A means your are well withing the limits of the switch.

Keep cool!

John