Would this work to control voltage in an e-cig

[Lagger]

Sorry I dont have enough posts to post other than newbie section, but I was wondering if this could work?

I cant post links yet so please bear with me. Its call an "adjustable regulator pulse width PWM DC motor speed controller switch 6v-28v 3a" and its found on ebay.
The specs are as follows:
Specification:

• Input Voltage: DC6V - 28V
• Sustained current: 3A
• PWM Duty Cycle:5% -100%
• PWM Frequency:21khz
• Material: PCB + Electronic components
• Size (L*W*H): 50 x 29 x 16mm / 1.97"x 1.14"x 0.63"(approx)
• Cable length: Approx 200 mm / 7.88"

The specs say nothing about the voltage out range and im defiantly no expert. So im wondering if you guys think it might work? Im looking at this mode here
e-cigarette-forum.com/forum/battery-mods/121826-very-easy-vv-mod-w-switching-regulator.html and trying to replicate it in some fashion but having an dial thats not attached to the PCB.

Alright, thoughts please.

 

[rondasherrill]

It probably could, but it's pretty huge for just the electronics. This would give you the same end result, in a much smaller package without any question of it working: http://www.e-cigarette-forum.com/forum/modding-forum/191607-easy-okr-t-vv-mod.html

 

[Lagger]

Yes, I saw that mod. Without divulging to much. Im more interested in aesthetically please cases, then assembling internals. Although, that mod would be easy to slap a digital voltage meter display on and would make for a rather sweet combo.

 

[rondasherrill]

Yes, I saw that mod. Without divulging to much. Im more interested in aesthetically please cases, then assembling internals. Although, that mod would be easy to slap a digital voltage meter display on and would make for a rather sweet combo.

Boom: Battery Voltage Indicator

Otherwise... I assume this is the one you are talking about: Adjustable Regulator Pulse Width PWM DC Motor Speed Controller Switch 6V 28V 3A | eBay

You could always try it out. Worst case scenario is it doesn't work and you are only out $3.79.

 

[Lagger]

Check this one its cheaper and no PIA pins sticking out of it ebay.com/itm/321434371155?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

[Lagger]

I think your right about the internals on that one though, I didnt think it out enough. Thous with batteries will be quite large.

 

[rondasherrill]

Check this one its cheaper and no PIA pins sticking out of it ebay.com/itm/321434371155?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Nice. That'll work just fine. Most people like the one I posted because the pins make it easier to work with.

 

[Izan]

Stacked batteries, 21Khz PMW and a 3 amp limit....
A Kick 2 is a better choice.

Be safe
I

 

[Joltas]

Sounds tricky...

 

[rusirius]

Sorry I dont have enough posts to post other than newbie section, but I was wondering if this could work?

I cant post links yet so please bear with me. Its call an "adjustable regulator pulse width PWM DC motor speed controller switch 6v-28v 3a" and its found on ebay.
The specs are as follows:
Specification:

• Input Voltage: DC6V - 28V
• Sustained current: 3A
• PWM Duty Cycle:5% -100%
• PWM Frequency:21khz
• Material: PCB + Electronic components
• Size (L*W*H): 50 x 29 x 16mm / 1.97"x 1.14"x 0.63"(approx)
• Cable length: Approx 200 mm / 7.88"

The specs say nothing about the voltage out range and im defiantly no expert. So im wondering if you guys think it might work? Im looking at this mode here
e-cigarette-forum.com/forum/battery-mods/121826-very-easy-vv-mod-w-switching-regulator.html and trying to replicate it in some fashion but having an dial thats not attached to the PCB.

Alright, thoughts please.

The output voltage is "technically" going to be whatever the input voltage is... It's using pulse width modulation... Are you familiar with an o-scope? Think about the beam moving across the screen...

Now let's say you are feeding this with stacked batteries... we'll call it 7.4 volts...

That means at the "lowest" setting you're going to get nothing... 0 volts.... the scope beam is sitting right dead on the 0 line....

Now let's say you turn it up to exactly the half way point... what you'll see is this....


----+.....+----+.....+----+
.....|___|......|___|......|___

So 50 percent of the time it is outputting 7.4 volts and 50 percent of the time it's outputting 0 volts...

If you set it for 1/4 of the way up... 25% of the time it's outputting 7.4 volts, and 75% of the time it's outputting 0 volts...

3/4 of the way up... 75% of the time it's outputting 7.4 volts, and 25% of the time it's outputting 0 volts...

Get the picture?

But notice the frequency? 21khz... That means this is happening 21,000 times for second... Very fast... Which means a resistance circuit like an e-cig coil isn't going to really "turn on and off" at 7.4 volts... Instead it's essentially going to average it out....

So at 100% on it's going to be running 7.4 volts...

at 50% on it's going to be running LIKE it was getting a solid 3.7 volts...

at 25% it's going to be running LIKE it was getting a solid 1.85 volts....

at 75% it's going to be running LIKE it was getting a solid 5.55 volts...

So would it work? Sure, but you would be better off driving it with a dc to dc off a single battery instead of stacked batteries in my opinion... Use a dc to dc to generate your max voltage, let's say 6v... then feed that output to the pwm circuit...

However... couple of caveats to note...
first, PWM CAN be noisy... driving something like a coil at that frequency could generate sound waves... Not sure it would, just saying the potential is there...

second, it's maximum sustained current is 3a...That means a maximum of 4.5 watts on a .5 ohm coil... 9 watts on a 1 ohm coil.... 13.5 watts on a 1.5 ohm coil... That's not great...

Now alternatively you could always use the output of this pwm to feed a fast switching MOSfet that can handle more current, at least with a decent heatsink, etc... But my guess is by this point we're getting out of the realm of what you're comfortable with....

 

[rondasherrill]

But notice the frequency? 21khz... That means this is happening 21,000 times for second... Very fast... Which means a resistance circuit like an e-cig coil isn't going to really "turn on and off" at 7.4 volts... Instead it's essentially going to average it out....

So at 100% on it's going to be running 7.4 volts...

at 50% on it's going to be running LIKE it was getting a solid 3.7 volts...

at 25% it's going to be running LIKE it was getting a solid 1.85 volts....

at 75% it's going to be running LIKE it was getting a solid 5.55 volts...

So would it work? Sure, but you would be better off driving it with a dc to dc off a single battery instead of stacked batteries in my opinion... Use a dc to dc to generate your max voltage, let's say 6v... then feed that output to the pwm circuit...

However... couple of caveats to note...
first, PWM CAN be noisy... driving something like a coil at that frequency could generate sound waves... Not sure it would, just saying the potential is there...

second, it's maximum sustained current is 3a...That means a maximum of 4.5 watts on a .5 ohm coil... 9 watts on a 1 ohm coil.... 13.5 watts on a 1.5 ohm coil... That's not great...

Now alternatively you could always use the output of this pwm to feed a fast switching MOSfet that can handle more current, at least with a decent heatsink, etc... But my guess is by this point we're getting out of the realm of what you're comfortable with....

Mostly accurate, with a couple of notes to add:
1. 21KHz is probably okay. The Vamo and other mods like that use a 33Hz chip(notably called a rattlesnake chip). This would be significantly better than that. That having been said, my only comparison against the rattlesnake chip is the Provari, which uses an 800MHz chip and provides an almost perfectly smooth output on an oscilloscope.

2. 3A is PLENTY for almost anyone not interested in subohming or using multiple coils, although those might be something the OP will want to account for.

That having been said, DC-DC would provide a better output overall, like you said.

 

[rusirius]

Mostly accurate, with a couple of notes to add:
1. 21KHz is probably okay. The Vamo and other mods like that use a 33Hz chip(notably called a rattlesnake chip). This would be significantly better than that. That having been said, my only comparison against the rattlesnake chip is the Provari, which uses an 800MHz chip and provides an almost perfectly smooth output on an oscilloscope.

2. 3A is PLENTY for almost anyone not interested in subohming or using multiple coils, although those might be something the OP will want to account for.

That having been said, DC-DC would provide a better output overall, like you said.

1) Yes, you wouldn't get an annoying buzz I don't think, but even though 21khz is outside the normal range of hearing, remember that you're feeding a coil, and with all the harmonics that will be generated it's possible you could hear it... Don't get me wrong, it's not going to be like a Provari, but it all just depends, it could make a rather high pitched annoying sound, at the very least it could possibly drive your dog crazy...

2) I don't entirely agree with this. as stated even on a 1.5 ohm coil you're only talking about 13.5 watts... On my kayfuns I generally run a 1.5 ohm coil at 15-17 watts... Above the 3A limit this chip has and that's not what I would consider extreme by any means of the imagination... Most cheaper tube mods run up to 15 watts and generally go to at least 4A. Plus with this being a homebrew device I doubt the OP is going to go to the trouble of using a microcontroller or anything to control (and therefore limit) the output, meaning it would be very easy to exceed that 3A without really giving it much though... Let's just say it's being fed with 6volts... The minimum this circuit can apparently use... That means it would be able to fire a MINIMUM 2 ohm coil safely (turned to 100%) He mentions having a "dial"... So to me you'd have to account for the possibility of it running "wide open" even if you didn't intend to... and a 1.9 ohm coil wide open would exceed the 3A limit at 6 volts...

 

[Lagger]

The output voltage is "technically" going to be whatever the input voltage is... It's using pulse width modulation... Are you familiar with an o-scope? Think about the beam moving across the screen...

Now let's say you are feeding this with stacked batteries... we'll call it 7.4 volts...

That means at the "lowest" setting you're going to get nothing... 0 volts.... the scope beam is sitting right dead on the 0 line....

Now let's say you turn it up to exactly the half way point... what you'll see is this....


----+.....+----+.....+----+
.....|___|......|___|......|___

So 50 percent of the time it is outputting 7.4 volts and 50 percent of the time it's outputting 0 volts...

If you set it for 1/4 of the way up... 25% of the time it's outputting 7.4 volts, and 75% of the time it's outputting 0 volts...

3/4 of the way up... 75% of the time it's outputting 7.4 volts, and 25% of the time it's outputting 0 volts...

Get the picture?

But notice the frequency? 21khz... That means this is happening 21,000 times for second... Very fast... Which means a resistance circuit like an e-cig coil isn't going to really "turn on and off" at 7.4 volts... Instead it's essentially going to average it out....

So at 100% on it's going to be running 7.4 volts...

at 50% on it's going to be running LIKE it was getting a solid 3.7 volts...

at 25% it's going to be running LIKE it was getting a solid 1.85 volts....

at 75% it's going to be running LIKE it was getting a solid 5.55 volts...

So would it work? Sure, but you would be better off driving it with a dc to dc off a single battery instead of stacked batteries in my opinion... Use a dc to dc to generate your max voltage, let's say 6v... then feed that output to the pwm circuit...

However... couple of caveats to note...
first, PWM CAN be noisy... driving something like a coil at that frequency could generate sound waves... Not sure it would, just saying the potential is there...

second, it's maximum sustained current is 3a...That means a maximum of 4.5 watts on a .5 ohm coil... 9 watts on a 1 ohm coil.... 13.5 watts on a 1.5 ohm coil... That's not great...

Now alternatively you could always use the output of this pwm to feed a fast switching MOSfet that can handle more current, at least with a decent heatsink, etc... But my guess is by this point we're getting out of the realm of what you're comfortable with....

Thanks for the incredibly detailed explanation. I think I should reread my Forrest Mims books again.

What Im looking for really is "plug n play" . Yes, I know that willl offend some of you. But im not into sodering many PCBs, my interests lay else where. Well plug n play is really second, safety is number one here. Lemme do some re reading of several books and a few more mods on this site and Ill get back at yall.

 

[Lagger]

1) Yes, you wouldn't get an annoying buzz I don't think, but even though 21khz is outside the normal range of hearing, remember that you're feeding a coil, and with all the harmonics that will be generated it's possible you could hear it... Don't get me wrong, it's not going to be like a Provari, but it all just depends, it could make a rather high pitched annoying sound, at the very least it could possibly drive your dog crazy...

2) I don't entirely agree with this. as stated even on a 1.5 ohm coil you're only talking about 13.5 watts... On my kayfuns I generally run a 1.5 ohm coil at 15-17 watts... Above the 3A limit this chip has and that's not what I would consider extreme by any means of the imagination... Most cheaper tube mods run up to 15 watts and generally go to at least 4A. Plus with this being a homebrew device I doubt the OP is going to go to the trouble of using a microcontroller or anything to control (and therefore limit) the output, meaning it would be very easy to exceed that 3A without really giving it much though... Let's just say it's being fed with 6volts... The minimum this circuit can apparently use... That means it would be able to fire a MINIMUM 2 ohm coil safely (turned to 100%) He mentions having a "dial"... So to me you'd have to account for the possibility of it running "wide open" even if you didn't intend to... and a 1.9 ohm coil wide open would exceed the 3A limit at 6 volts...

I think your right I do need to set a limit on the output.

All the boards ive been looking at dont have any "safety" features built in. There would be a way the end user could potentially hurt themselves.

It may just be simpler to design my own rather than try to modify some of these premade china boards. Thanks for your input rusirius, you really got the wheels spinning there.

 

[rusirius]

I think your right I do need to set a limit on the output.

All the boards ive been looking at dont have any "safety" features built in. There would be a way the end user could potentially hurt themselves.

It may just be simpler to design my own rather than try to modify some of these premade china boards. Thanks for your input rusirius, you really got the wheels spinning there.

Glad I could help... Can you share some details on exactly what you're trying to accomplish?

If you're simply looking for a "plug and play" board to build your own box mod, why not just buy one of the premade chips like Yihi puts out? The SX350 is an excellent device.

On the other hand, if you're doing it because you want something very specific, or want a particular feature, then your best bet really would be to get a microcontroller (I've always been a huge fan of the Atmel's myself... You can get a pretty respectable microcontroller in a ridiculously small package (especially if you surface mount) and can program it to do anything you want. You can't drive a coil directly off a controller since the current is too high for it to sink, but a small driver mosfet could be used that could sink pretty much as much current as you wanted depending on size and heat sink. The only other consideration would be the DC boost portion, making sure it could handle an appropriate amount of current.

The advantage would be being able to do anything you wanted... It's easy to interface to a small serial driven LCD and drive that from the Atmel, then you can have a menu system to change any settings you want, any features, etc... Not to mention you can then program in any limits, etc...

But then we have to circle back to the first part... Why go through all this work to replicate something already out there and available? I don't know how much design or prototyping you've done, but honestly, even surface mounting you'll never get as small and compact of a package as these premade boards. It's "cool" to make your own, I totally get that, I used to have a homemade LED sign hanging in my office that I could stream information to via bluetooth... It was "cool" and kinda self satisfying that it was something I whipped up in a weekend just for fun.... So if that's the reason, then yeah, I totally get it.... but truly if you're just looking for plug and play, the premade boards are really the only way to go... In my opinion...

 

[Lagger]

I didn't know there was premade options out there until after trying to find more plug n play options. I read quite a bit and I was seeing things like dna30 or things similar and I was thinking it was some sort of slang that I didn't understand yet.

I have found a few premades that I might be sourcing but Im going to read up on yours suggestions first. I am really excited to see some premade options out there, American made, that will fill my needs.

I have no interest in being liable for hodge podge circuits that I might or might not of constructed correctly. I dont want to be responsible for someone having a battery blow up in there face. Financially that would be devastating but the guilt would be worse.

Yes, the sense of accomplishment of making something completely from scratch can not be rivaled. Although, thats not my interest in this subject. Thats why, in my free time, I do wood working. There is nothing like take a few pieces of wood; building something useful and beautiful that will stay around for years.

As for what I am doing. Well Ill only say this, 3D printing. There are way to many smarties on this board to be completely forth coming.

I do appreciate every ones input, ya'll have been very insightful.

 

[rusirius]

I didn't know there was premade options out there until after trying to find more plug n play options. I read quite a bit and I was seeing things like dna30 or things similar and I was thinking it was some sort of slang that I didn't understand yet.

I have found a few premades that I might be sourcing but Im going to read up on yours suggestions first. I am really excited to see some premade options out there, American made, that will fill my needs.

I have no interest in being liable for hodge podge circuits that I might or might not of constructed correctly. I dont want to be responsible for someone having a battery blow up in there face. Financially that would be devastating but the guilt would be worse.

Yes, the sense of accomplishment of making something completely from scratch can not be rivaled. Although, thats not my interest in this subject. Thats why, in my free time, I do wood working. There is nothing like take a few pieces of wood; building something useful and beautiful that will stay around for years.

As for what I am doing. Well Ill only say this, 3D printing. There are way to many smarties on this board to be completely forth coming.

I do appreciate every ones input, ya'll have been very insightful.

Yes, there are a few premade options out there... yihi is generally one of the most used and best... the dna20 and 30 are available as well... not sure of other options... not sure that any of them are us made...

I know what you mean about woodworking. My father could craft anything... It was like he could look at a few scraps of wood and see anything and everything they could be turned in to.

3D printing is truly amazing. to be able to prototype or even produce something so quickly is just amazing. It's always been a fascinating subject for me... Even to the point of a few crappy step-motor driven versions I played around with making myself...Controlled and interfaced to via an Atmel ATMEGA168. Never did get one working as well as I'd have liked, but it was still a blast trying!