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Sanity check
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Don Offline
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Post: #1
Sanity check
I'm thinking of building a passthrough to stick a (dedicated) atomiser in the car. Thinking a 510 connector on a stick with a switch and a cable to the power socket basically.

That means it is going to be running off 12-14V - say 13.8 which is often given as the end of charge point for a car battery.

So I want 10 watts or thereabouts. So power=voltage x current - so for 10W we have 10=13.8 x current

So current = 10/13.8 or 725mA

Then voltage = current x resistance so 13.8V = 0.725A x resistance

So resistance of the coil needs to be 13.8V/0.725A = 19 ohms!

Or around ten inches of 0.15mm Kanthal. Going to be fun wrapping that coil!

With 0.3mm it's over a yard of wire!

This seems rather high to me hence the request for a sanity check. Obviously there'll need to be some sort of fuse and switch in there which will add a bit of resistance so the overall coil resistance can be a bit less. But it looks like quite a lot of thin wire will be needed...

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21-01-2014 11:06 AM
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vapejuiceuk (05-24-2016)
Spasmod Offline
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Post: #2
RE: Sanity check
Looks spot on to me Don - you might have to use a dual coil as it's probably going to be fairly large. It'll be interesting how it turns out though and I hope you get it working.

Sensible putting a fuse in there too because if things go wrong using a car batt it can get nasty.
21-01-2014 01:14 PM
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vapejuiceuk (05-24-2016)
18sixfifty Offline
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Post: #3
RE: Sanity check
It's official you are insane. Dodgy lol

You should be able to use some kind of in-line resistor like this 5 volt resistor. I used this one in a 5 volt mod to reduce two 18650's down to 5 volts. I can't remember where I bought these it's been awhile. I also don't know the max voltage it can handle but I'm sure there is something specked out that would do the job. 

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21-01-2014 01:19 PM
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vapejuiceuk (05-24-2016)
Don Offline
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Post: #4
RE: Sanity check
The reason my thinking was running that way was that voltage dropping devices capable of 10-15W aren't that cheap. Which is why I was thinking in dedicated atomiser terms. Given that the fuse on the lighter socket is 40A, I'll definitely be wanting a far smaller fuse (Around 1A) inline.

I could just use some mech mod with a Davide tank on it, or even a dripper but there are times when a dedicated car device could come in handy. Like when the alternative is stinkies from the gas station.

Resistors act more as current limiters than voltage drop devices. On many Chinese devices the resistors seem set to protect the fuse by blowing first....

(21-01-2014 01:14 PM)Spasmod Wrote:  Looks spot on to me Don - you might have to use a dual coil as it's probably going to be fairly large. It'll be interesting how it turns out though and I hope you get it working.

Sensible putting a fuse in there too because if things go wrong using a car batt it can get nasty.
Doesn't a dual coil make it worse - it halves the resistance. Then I'd need two metre long coils

If I up the power to 20W the length becomes more practical but I'd still be stuck with very, very fine wire

Power =13.8 x current
20/13.8=current = 1.45A

Resistance = volts/current or 13.8/1.45 or 9.52 ohms.

With those sort of resistances this is going to be very much a 12V only device - but that's OK as it is intended as a car-only device.

But I'm not sure that I wouldn't need a stick to push my lungs back in when vaping from a 20W device. And that sort of coughing is NOT a good thing at 70mph. Sad
It'd get REALLY interesting on a truck 24V system Angry as that's the sort of colour the atomiser would turn...

TVF tested battery info to be found here

http://www.preventsuicideapp.com

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21-01-2014 01:50 PM
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vapejuiceuk (05-24-2016)
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Post: #5
RE: Sanity check
Yeah you're right - forget I said that Tongue to be honest though Don, you'd be far better of using a voltage regulator to be honest.

These regulators are quite simply awesome - I've used them, they're simply set and forget. You just make a standard coil, tweak the pot to where you like your vape and you're done.

As long as you don't exceed 2 amps (or 3 amps with a heatsink) you can't go wrong.
21-01-2014 02:07 PM
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vapejuiceuk (05-24-2016)
gords1001 Offline
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Post: #6
RE: Sanity check
I was going to suggest one of those lm2526? Voltage regulator boards, stick in a box fixed somewhere, flying lead in cig socket,  four core lead out to handle with momentary and 510 connector.
21-01-2014 02:14 PM
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vapejuiceuk (05-24-2016)
Spasmod Offline
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Post: #7
RE: Sanity check
(21-01-2014 02:14 PM)gords1001 Wrote:  I was going to suggest one of those lm2526? Voltage regulator boards, stick in a box fixed somewhere, flying lead in cig socket,  four core lead out to handle with momentary and 510 connector.
Yep
21-01-2014 02:17 PM
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vapejuiceuk (05-24-2016)
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Post: #8
RE: Sanity check
Or modify a KIS-3r33s . If you lived stateside I could have sent you a couple...
You can get them for dirt cheap, and they are good for 3a bursts. 5v at 3a would be right at your 15w. The inventor of the Genesis atty was a big fan of them and used them quite a bit in his mods


I bought a handful of them in plans of building the vape bay, a VV 3.5" bay device. Could always do like Tivo on BLF did for his cheap PSU, put a couple in parallel, if you are worried about the 3a limit

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21-01-2014 02:21 PM
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vapejuiceuk (05-24-2016)
Don Offline
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Post: #9
RE: Sanity check
Now the regulator idea makes a lot of sense. I see one of those in my future. If it wasn't for the £3 postage I'd have ordered one already. So I'll just have to have a good look around the Stealthvapes set to find other things to add to the order to justify the postage Smile

Atomiser on a stick! Angel

I think I have a dead eGo battery somewhere I can gut (Very much outdoors) for the 510 connector. If I can't find a suitable box round here, I'm not trying. Heatsinks can be torn off old computers of which I have several knocking around. And that's after I took several tons of really old ones to various tips last year.

TVF tested battery info to be found here

http://www.preventsuicideapp.com

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21-01-2014 02:41 PM
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vapejuiceuk (05-24-2016)
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Post: #10
RE: Sanity check
Look for some 5v regulators in those old PCs.

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21-01-2014 02:44 PM
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vapejuiceuk (05-24-2016)
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