My 901 is now USB powered. woot

[Bastage]

I thought the idea for the Janty was cool with a USB plug and manual switch...but I didn't see anything like that for the 901 mini. One of the batteries in my kit was a little tough to activate (the auto switch was not sensitive enough) so I said what the hell..gutted it and went on an engineering rampage. I set out to make this thing work like the kissbox, with external power and a switch. I was tired of charging battery after battery, while I'm sitting at home e-smoking.. why not hook it to the PC, that's just one less thing to worry about wearing out. The performance on a full battery is so much better than when it's dying, I figured with the solid input of USB it would always perform well. I'm usually where a desktop or laptop computer is handy, so USB is probably the best source, not to mention it's perfect for the requirements as far as power source to the ecig. The stock battery puts out 5v, .7 of it is eaten by the LED so 4.3v goes to the atomizer. When I hooked the USB up to the ecig I eliminated the LED, so there's a little more juice flowing to the atomizer. Seems to be performing great with the additional .7v. I hooked an in-line switch to the positive lead from the USB source. I took the switch from an old crappy USB headset because of it's small size and short profile. Now I can manually "prime" the atomizer before I take a hit with the push of a button. The performance of this thing is excellent now, and no stinkin' battery to fiddle with. I've since made a few cosmetic changes and it looks good now, but here you can see the process as I was building it. Pretty simple actually. The hardest part was punching out the battery and existing electronics. I ended up using a small long nail to get the circuit board out of the bottom piece (right below the gold battery connector) After that, a little soldering of some wires and she's good to go!

Cost: FREE

Everything I needed was just laying around. This project was completely FREE for me to do, and only took a few hours. All it takes is a few little parts and a good imagination. If anyone here is interested in me doing a write-up on how to do the mod, I could draw up some diagrams showing you what to do.

-Jeremy

[jigtg]

Cons:
-you might blow up your usb port since it draws way more current than allowed
-it heats more increasing possible health risks while reducing atomizer life as well

See home made battery . If you want to drop voltage search for 1n4007 and see my post there. 3-3.5v would probably be enough since pc power supply can deliver lots of current without voltage dropping.

Oh and this is the "official" version of the story. Many chinese gizmos steal power from usb without negotiating or anything.

[Bastage]

Cons:
-you might blow up your usb port since it draws way more current than allowed
-it heats more increasing possible health risks while reducing atomizer life as well

See home made battery . If you want to drop voltage search for 1n4007 and see my post there.

I can easily drop the voltage with a simple divider circuit, or adding an LED to drop the difference - but you're only talking .7v higher than what the battery normally puts to the atomizer. It is likely that batteries without LEDs put out 5v to the atomizer as well. I highly doubt that equates to any kind of health risk. The Janty USB doesn't seem to have a problem with blowing ports, and this atomizer is smaller and probably uses less current than the Janty. I'm running it off a $10 USB hub. If it blows a port or something I'll be sure to update everyone but I'm running 7 USB devices off my PC right now, and smoking away on the 901 with no problem. The atomizer doesn't get any hotter than it does on battery power. If I start having any kind of problems I'll make a dongle that drops the voltage down a little...but so far so good.

[jigtg]

I can easily drop the voltage with a simple divider circuit, or adding an LED to drop the difference - but you're only talking .7v higher than what the battery normally puts to the atomizer. It is likely that batteries without LEDs put out 5v to the atomizer as well. I highly doubt that equates to any kind of health risk. The Janty USB doesn't seem to have a problem with blowing ports, and this atomizer is smaller and probably uses less current than the Janty. I'm running it off a $10 USB hub. If it blows a port or something I'll be sure to update everyone but I'm running 7 USB devices off my PC right now, and smoking away on the 901 with no problem. The atomizer doesn't get any hotter than it does on battery power. If I start having any kind of problems I'll make a dongle that drops the voltage down a little...but so far so good.

I don't really get what you mean with these voltage dividers and leds dropping voltage. e-cig atomizer draws at least 0.5 amp current and standard led can handle 20mA. Standard resistors are 1/4 watt so they would blow up to ashes at 0.5 amp if used as voltage divider. You have some transistor there driving the atomizer?

All e-cigs I have seen use 3.6-3.7 nominal voltage li-ion batteries.
Even if dse901 would use 5v battery that voltage would drop loads on when atomizing. std atomizer has 3.2 ohm coil so 5^2/3.2 so it would produce 7.8125 watts and that is over two times I have seen on any other device I've seen. Can you check the atomizer coil resistance?

Janty usb would have to have 8.5 ohm atomizer coil to pull out 2.9412 watts from 5 volts(5^2/8.5 = 2.9412). 5/8.5 = 0.58824 so even that pulls more current from usb bus than allowed.

Contrary to belief, minis do not really draw less power. In fact most of them are more agressive burners.

[Bastage]

An LED is a diode and it drops 700mv. If you have a 5v source and only need to supply 3.75v to the device, you put 2 series resistors in the curcuit so that the voltage is divided however you want depending on the resistance values you choose for the circuit

R1 / R1+R2 X Vin
15k/20k x 5 = 3.75, and you pull your source at R1.

If you need to support devices that draw more current just work out the values for a parallel circuit that can support the current draw required by the device, or use higher capacity resistors.

That said... I'm powering the atomizer directly with USB +5 with nothing but a pushbutton switch, and it's working perfectly.

[Bastage]

Jig, if you are doubting this works... just try it yourself. I just used it for 2 hours. It performs as good or better than a brand new battery and there is no degredation in performance the whole time, and more importantly no overheating - barely warm the whole time I was using it. Every hit is consistant and strong. I'll post a video of it in action if you want to see it.

[trog100]

i love home improvements.. well done..

just some corrections.. the little lithium 08440 cell dosnt put out five volts.. fresh off charge its about 4.2 volts.. this drops down to 2.7-ish volts before the battery cuts off.. so your normal e cig is being powered somewhere between 4.2 and 2.7 volts.. a real five volts is little too much for the atomizer..

it will also draw too much from the PC usb socket.. a usb socket is rated at .5 amp max..

try using a powered hub.. or a simple Y lead connected to two usb sockets.. this takes the load of the one socket..

if your atomizer works better but dies a bit quicker.. so what.. the gains are worth it.. just be careful u dont blow your usb socket.. they might have overload protection built in thye might not.. the Y lead is the standard way of powering things one usb socket aint up to doing..

the normal safe charge voltage for a lithium 3.6/3.7 cell is 4.2 volts.. the low cut off point is 2.7 volts.. the cell should be kept between these two figures..

they aint a safe technology..

trog

[Bastage]

If it starts running hot, or has any kind of problems I'll deal with it. Running it off the hub is working just fine.

[trog100]

running off a powered hub will work fine.. running direct of a usb socket might not.. to be honest a PC isnt even needed.. any 1 amp four volt supply will power an e cig..

trog

[Bastage]

running off a powered hub will work fine.. running direct of a usb socket might not.. to be honest a PC isnt even needed.. any 1 amp four volt supply will power an e cig..

trog

Actually I plugged it directly into my PC and it works fine. I went with USB because it's much more convenient than a wall plug. I havent done any long term stuff because I just made it, but if it was going to break I it probably would have done it by now. Those USB mini-fridges pull almost 1 amp and they sell those all day long