Variable voltage question.

[basementcat]

So I have a question as to exactly what's needed for variable voltage. I am researching making my first mod. I am looking like something similar to the voltage regulator on the little sister mod. Anyone know what they are using? Need something similar or smaller that would do that trick. Looking for 3.7-7 or at least 6v max. Parts list please. Thanx.

 

[basementcat]

Anyone? I really wanna get together parts for my first mod.

 

[basementcat]

Soooo ive searched all over and can't come up with what potentiometer would be needed. I know it would need a 7v regulator but dunno what specs are required for the variable resistor. Any help would be appreciated.

 

[misterD]

dont know what its used on the lil sister but this thread might help you a bit
http://www.e-cigarette-forum.com/forum/battery-mods/102419-adjustable-voltage-box-mod.html

 

[WillyB]

Soooo ive searched all over and can't come up with what potentiometer would be needed. I know it would need a 7v regulator but dunno what specs are required for the variable resistor. Any help would be appreciated.

Don't know what makes you think you need a 7V regulator per se, but of late these forums have been littered with VV mods and guides, of various skill levels and complexity. Using a TI UCC283 or 383 there are many, many options when it comes to pots depending on what components you use, how you choose to wire it and what voltage range you want. Single turn, 15 turn, 25 turn. 5kΩ, 10kΩ, 100kΩ, 200kΩ etc.

 

[basementcat]

I have limited electronics knowledge. Just wanna make a compact variable voltage mod. 0-7 volts preferred. Have been looking at regulators and pots but am still lost a little. Dunno what specs are required to make sure the thing doesn't melt or just fry on power up. I have been looking at the ti site and have found a few that I think are useable but still new to all this. Looking for something compact with a small knob for adjustment.

 

[5cardstud]

Ebay has allot of adjustable voltage circuits for less than $10.00 that are built already. I just ordered this one.

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[basementcat]

Looking for something small to possibly work in a 2 aaa box. Might be impossible but still searching.

 

[5cardstud]

Here is the one I'm using in my box mod. 3A Adjustable step down switching voltage regulator

 

[mrgodai]

I think the OP wants to build little sister himself, which is just this mod http://www.e-cigarette-forum.com/forum/battery-mods/77007-3-minute-lighter-mod.html

with a variable voltage.

the problem is to build a variable circuit small enough to fit into the lighter casing

http://www.boxmods.net/components/com_virtuemart/shop_image/product/DSCF2613.JPG

i think it can be done with surface mounting capacitors/resistors, just not sure about the exact parts.

If anyone got a little sister and willing to take it apart for the part numbers, please share!



OP, you can also try to build Fistpack V2, which is close to what you wanted.
https://docs.google.com/Doc?docid=0AXdaMZo4FKMVZGhqdnE4YnNfNDNjN2Q0cHBoZg&hl=en
but be warned, the parts will cost you as much as a little sister, if not more.

 

[CloudBurst]

Would this work?
Mini LM2596 DC-DC Step Down Adjustable Power Supply - eBay (item 230522096039 end time Oct-05-10 07:50:01 PDT)

 

[WillyB]

Would this work?
Mini LM2596 DC-DC Step Down Adjustable Power Supply - eBay (item 230522096039 end time Oct-05-10 07:50:01 PDT)

From the specs:

* Input voltage: 4.5-36V
* Output Voltage: 1.25-32V (adjustable)
* Output current: rated current 2A, maximum 3A (need to add heat sink), if the output power greater than 15W, combined heat sink is proposed.
* Conversion efficiency: Up to 92% (output voltage higher, the higher the efficiency)
* Switching Frequency: 150KHz
* Minimum dropdown voltage:2V

All good till the 'Minimum dropdown voltage'. In a nut shell it sounds like you'll need 7V to get 5V output, for a 5V vaper that sounds like about 15 minutes of vape time.

Compare that to most TI regs which will provide 5V till the batts hit 5.5V. Big difference.

 

[basementcat]

Yeah I'm trying to build a cheap cmaller variable mod comparable to the LS. Just can't afford 65 bux for one when the parts are prolly about 20 bucks if not less.

 

[BuzzKill]

copy it , everybody else does LMAO !
Lm317-t smal ltrim pot maybe 1 k , get the data sheet

 

[WillyB]

Yeah I'm trying to build a cheap cmaller variable mod comparable to the LS. Just can't afford 65 bux for one when the parts are prolly about 20 bucks if not less.

Why bother, 10440's are crap batteries. They are rated at a max discharge of about 500mA each. A Joye 510 @5V will want about 2.3A which will be stressing the hell out of 10440's as they struggle to provide over 2 times what their puny size can handle. And those regulators (assuming its an LDO) generate a lot of heat, they need some air space and a heat sink is a good idea too. They shouldn't be crammed into that tiny area with the atty connector, which also gets quite hot at higher volts, and plays hell with that thin plastic that's supposed to support it (it melts, distorts and loosens).

A 3AA box with two 14500's will give you the room you need and hours more vape time.

You have to decide if you want a cute under built toy or a solid performing mod.