Why USB???

[mykanix]

I have seen a wonderful array of ideas and mod builds on this forum. One concept that has been keeping me wondering is why usb for a passthrough? I have only a select few ports for ipod, jump drive, charger, etc. I have also noticed many suggestions for using a dedicated hub or wall adapter. I have built 4 very simple mods using various boxes, switch, atty connector (make your own from madvapes tutorial) and cell phone ac power supplies. The best results I have seen in performance is using a 4.5v @ 1000mah power supply. At first I wanted a usb passthrough but now I am wondering if you have to plug it in why go usb???

Has any one put together one of these super simple mods?

 

[MrPuff]

Well one thing is usb gives you a easy 5v, no regulators, no resistors, heck no battery period. No need to charge. Never dies. There are pluses that weigh against the negatives.

 

[mykanix]

Well one thing is usb gives you a easy 5v, no regulators, no resistors, heck no battery period. No need to charge. Never dies. There are pluses that weigh against the negatives.

Thanks for the input. I understand the benefits of usb I just don't see any difference in using an ac power supply instead. Any pros or cons???

 

[CartHeadMod]

USB gives you plenty of power...I only need to recharge every three to four months....

 

[Dave Rickey]

I actually have a 5.2V, 2.5A wallwart from an old Linksys router that I spliced to have a USB socket so I could use it with the rest of my stuff interchangeably. "Why USB" essentially comes down to the fact that it works (although theoretically capped at 0.5A, most computer PSU's can feed 2.1-2.5A on that rail), and it makes a good enough standard to build around. USB wall-warts and automobile adapters are easy to find, and there are lots of devices that can charge a Li-Ion or Li-Poly cell off a mini-B connection to act as starting points for a mod.

If not USB, we'd have to choose from among the couple of dozen different power terminators used by various power supplies. USB isn't necessarily superior to any of those on technical grounds (and inferior on some grounds), but it's good enough and it caught traction early with the USB pass-throughs from the chinese manufacturers.

--Dave

 

[kristin]

One nice thing about USB on the PT is that it's easy to use with a USB car adapter. Plugging in a PT in the car with AC would be trickier. I take my PT on the road and love it!

 

[NatureBoy]

It's also the most readily available in terms of accessories such as the mentioned above car adapters, as well as rechargeable battery packs for on the go power, hubs, wall adapters, etc. Look up USB battery packs and you find a whole bunch of them you can build mods with. Ready made cables, sockets, adapters, etc. etc.

Can't really say the same for any other useful voltage range.

 

[mykanix]

One nice thing about USB on the PT is that it's easy to use with a USB car adapter. Plugging in a PT in the car with AC would be trickier. I take my PT on the road and love it!

I can definitely see the benefits of using one on the go! I have an hour commute to work each day and for the trip maybe usb would be the way to go. I already have griffin usb accessories for other things. My ac wall power supply mods are great for stationary use.

I have only attempted to make one USB PT with little luck. I wired up black and red to atty connector with a switch. Plugged it into a wall adapter and pressed the button. The voltage just surged/pulsated for a second on-second off-second on-second off and so on.....I know that most use batteries with their pt mods. Is that necessary to help regulate things???

 

[Dave Rickey]

You need something that can supply enough current to heat the atty. That's between 1.0 and 2.5A, depending on the exact atomizer (a 510, for example, will run towards the high end, while an 801 towards the low). Many wall-warts designed to trickle charge a phone or MP3 player will only provide 0.5A (500mA). The plug-in transformer for a powered USB hub will typically provide 2.1-2.5A. It gets more confusing because many low-rated supplies are capable of putting out much higher currents for short periods without being obviously damaged.

A battery-mediated USB passthrough (especially one with a Li-Polymer flatpack like the DigiPower or Lenmar PPUMINI, which can handle much higher discharge rates) gets around a lot of that by only drawing a 100mA or 500mA trickle to charge the battery, which supplies the high amperage surge current for the atomizer.

Just to confuse it more, it's becoming more and more common to make "Big battery" mods with integrated USB-cable charging circuits ("Fistpacks"), so that they become their own USB passthrough. And the PPUMINI is in an odd middle ground, with enough capacity for a few hours of vaping, but not enough for all-day operation like the true "Big Bat" mods built around an 18650 or similar.

Confused yet? Basically, although it is *possible* to make "Direct Drive" USB passthroughs that work directly off the power supply for the USB (or the PC), it's gone out of favor because of the risks to the hardware (overloading a thousand-dollar PC to avoid buying a $25 eCig PS is bad economics) and the greater utility of integrating charging circuits into the mods, so you can charge when juice is available and keep vaping on the same device when it isn't.

--Dave