How to build a vv "passthrough"?

[Colt Peterson]

Hello, I'm hoping to find some guidance, preferably a lot of guidance, in building a variable voltage "passthrough" capable of powering a sub-ohm rda.

I'm not looking for a true passthrough in the sense of something that charges a battery while you vape. I basically just want a soldering iron with a 510 connector, a button to control when it fires, and some way to manage the amount of power that the atomizer receives.

I'm no electrician or engineer, I'm hoping someone can help me figure something out. I spend a lot of time working at my computer and would like to ditch the batteries while I'm not out and about. Thanks!

 

[WarHawk-AVG]

You can buy them pretty cheap

Otherwise you would just need a 510/eGo control head, a push button, some wire...the variable part is going to be difficult, because I think the circuitry even on the USB bypass will still prevent firing from sub-ohm situations

$5.58 Variable Voltage USB Passthrough for E-Cigarette at FastTech - Worldwide Free Shipping

https://www.google.com/#q=diy+usb+passthru+e+cig

Most specifically
https://www.google.com/search?q=diy...te:www.e-cigarette-forum.com&biw=1920&bih=897

 

[AttyPops]

Most PT's run off of USB.
USB is a 5 volt standard.
Most USB connections are amp limited. You can get AC-to-USB adapters (Wall Warts) that have 2 or 3 or more amp output.

However, with sub-ohm stuff, you need a lot of watts. That translates to a lot of amps. Let's say 3.7 volts at 20 watts...that's 5 1/2 amps. No computer USB will supply that (about 1 or 2 amps...it actually varies depending on the standard, the new 3.1 standard is interesting for power).

So you're basically using an external power supply no matter what you do. Then there's the VV part....voltage regulators with enough power dissipation. Now you need to dig into power supply options, connectors, safety, etc and figure it out. Easier to use an external variable DC power supply.

I'd check the modder's section of ECF. Or just use the IMR batteries and an external charger like everyone else. It's portable that way.

So basically, use an external adjustable DC power supply and rig up a connector. You will fry the button if you pass all the current through it though. So you need to figure out power FETs.