If a mag d switch gets over loaded what part is going to fail first?
Yup. Bob nailed it!
Do you have pics of this?
I crammed that 5 x q5 module into my mag and think I need to mod the switch. I dont know how many amps they generally pull from 2 18650’s……
My plan was to actually run the positive past the switch with a wire and use the switch to control the negative thus eliminating the set screw as a ground but still using to to hole the switch in place. Is there any reason why I can’t do this. The reason I want to switch the negative side is to easily turn on and off a voltage monitor.
Are you trying to get ground through the body? Because that's a real pain! Fought like hell to get ground from the body on a Mag mod I did. It's easiest to get ground off that set screw. (I ended up soldering my ground wire to that c-ring near the head after sanding the groove to get good contact.)
Someone around here also posted of their struggle trying to use the body of the Mag for ground. Can't remember if it's oldbobk or Old-Lumens, or someone else.
-Garry
You can certainly use the switch as a negative if you want to. The problem with grounding is there aren’t many spots to find ground in the top section of a mag. I finally went to drilling a hole thru the body and using a screw, so I get good ground every time. I do it just below the threads, so the head covers it up… But, if you are using the switch as a ground, then just simply run a wire from one side of the switch, to the metal tab the screw is in and use that for a ground, since it’s already ground. Then it goes thru the switch and to your led.