USB mod with pneumatic switch

[Grumpysanta]

As bastage says, 4 batteries is too much, using 3 batteries gives you 3.6 V which is just right for the atomiser. 4 batteries could shorten the life of your atomiser. Also 3 batteries don't weight too much but more batteries could be awkward to carry around. I'm using my Gizmo at home at the moment but I eventually want to be able to carry it in my coat pocket so weight could be a minor issue. If I were going for more that 3 batteries I would certainly be using more than 4 but I would use a simple electronic circuit to maintain a 3.6V output therefore giving a very long battery life. The thing is I really believe in KISS (Keep It Simple Stupid) so 3 batteries again is the easy way out. Checking maplins I have found a very simple and cheap (I love that bit too) auto overload cutout which will autoreset once the overload is taken off. I'm looking at the 1.6A cutout. Think in terms of - what if your cable / atomiser goes short circuit? My external batteries are cheap NI-Cad's which are capable of delivering 4 times their mAh rating, Under short circuit conditions these batteries could attempt to deliver nearly 3 amps. They would get very hot and could explode. a simple auto cutout will stop anything nasty happening. Bastage and other people are using far more expensive NimH batteries some rated at 2800mAh so it would really be a good idea to install an auto cutout.

[aaa]

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[aaa]

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[Bastage]

aaa you are wrong. Too much input voltage will destroy the device. I know you're a professional, but let me give you a quick example in layman terms:

If you have a device that runs on 5v 1000ma, you can plug a 5v 2000ma power brick into it, and it'll only draw half the available current because that's all it needs. Perfectly safe.

If you have a device that runs on 5v 1000ma, you CANNOT plug a 12v 1000ma power brick into it. If you do, you'll blow it up.

[Grumpysanta]

aaa: That device was only ever suggested as a way to protect the batteries. It's cheap, simple and works. And, I'm using a manual switch. I've been vaping happily on three cheap Nicad batteries for days and my atomiser is still working ok. maybe I'm lucky, maybe at 3.6V my atomiser is not overloaded, whatever, it works. if you want to get semi technical use an inline transistor with a zener diode to maintain a constant voltage, that way you can have more batteries. You could go for constant current, you could go for electronic shutdown, dead easy with an inline transistor - short zener so the base goes to ground, or we could just stick with 3 simple batteries and vape.

[dablackanarch]

Hey, Jdrancor! I have a question. When you use the pneumatic switch in the remaining battery casing, do you still experience the auto-cutoff? Because my USB e-cig is manual switched, I don't worry about that. Your idea is great and I'd like to try it but, if I get the auto-cutoff, what's the point. I vape heavy and need that blast I get from letting it roll just a bit longer than most auto-cutoffs do.

[aaa]

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[yo han]

Just finished my 901 USB battery with original switch and LED.
Everything's still working like it should. Now all it needs is a paint job and it's finished.

[madog]

Originally Posted by yo han

Just finished my 901 USB battery with original switch and LED.
Everything's still working like it should. Now all it needs is a paint job and it's finished.

That's beautiful - I would just clear coat it - The silver looks awesome.
What did you find was the easiest way to cut the tubing down?

PS - Don't smoke that analog -

[yo han]

Thanks madog. I always use a mini pipe cutter to cut the tubing.

Just clear coating it would be nice but I rather want it to look the same as the atomizer. And I hope painting it will somewhat disguise the joint in the middle (although it looks far worse on the pic than in real life).