Rat shack switches

[djamwolfe]

I built my first box mod a few weeks ago, and used one of these switches. I was told here that the .5A limit was too low, but so far they seem to be working fine.
Now the question -- The switch is labeled for .5A at 125v, that means it can handle about 60 watts of power. If I convert that to 3.7V i come up with about 16A of current at 3.7V. Is my math or concept wrong?
Hope to find some answers

Devon

 

[mv2envy]

Your math is correct. It will be fine.

 

[Rocketman]

The switch is labeled for .5A at 125v, that means it can handle about 60 watts of power. If I convert that to 3.7V i come up with about 16A of current at 3.7V. Is my math or concept wrong?
Hope to find some answers

Devon

Think of it this way.

When the switch is closed and conducting, how much voltage does the switch see across the contacts? Hopefully milli volts.When the switch is open the insulation needs to protect you from a 125volt short to not shock you (not a problem for an e-cig).
With 125 volts, switch arcing is more of a problem than at 3.7 volts.

16 amps with a 1/2 amp switch?

Ratings can not be "multiplied" like that. A 0.5 amp 125 volt switch is much better than a tact switch.
For personal use pick a cheap switch you like. If you plan on giving or selling a boxmod to someone else, pick something better.

 

[djamwolfe]

Well even if i use a 1.5ohm atty, I'd still be under 2.5A -- so I feel OK with this switch.

Thanks
Devon

 

[KAC_fenris]

How come I've used this type of switch which has the same specs, but it keeps failing? I usually get mis-fires or delays in firing and almost every other day, they fail (some don't even fire, one actually got stuck and I couldn't press it).

Maybe it's a cheaper version than what Radioshack sells because it's from a local dealer here in the Philippines (we don't have Radioshack anymore over here; they closed shop years ago).

 

[Rocketman]

Take one of your failed switches and open it up.
Look at the little disk that contacts the two pins. The harder you press, the more you damage the switch.
If you don't press hard enough the switch contacts erode.

A positive stop for button force and a spring loaded contact force is more reliable.
Contact size and material will determine longevity with higher currents.
Devon: The Rat Shack switch is much better than the 59 cent switch.
It will probably last you a long time.
I have used both. A reasonable spec for the RS switch would be an amp or two at low voltage DC.
Just not something I would pass on to someone else, unless it included an offer to repair if it failed.

It's a shame that some of our vendors sell stuff with overloaded components.
This didn't used to be much of a problem, but with atty resistances getting lower and mod voltages getting higher reliability switches become more important.