Time to build a box mod...

[gaffer]

Ok so it is time I do this. I am going to build a simple box mod using a voltage pentameter but I have ZERO idea of what to look for when getting said pentameter. My build is inspired by the beast box mr eliquid is selling so i want to be able to hit near that out put range which is up to 6 or 6.5 amps and it used series 26650 batteries to give high voltage... so what pentameter do i need to get (i would love to do a wattage one but i know that would require a lot more parts and knowledge to get done.

Also is there a simple way to make a cut off so that the device will stop firing at a given battery voltage?

Are there pentameters that will boost a battery voltage as well as just regulate it or does that get into complicated stuff (I assume it does but not totally sure how the pentameter is doing its job)

Thanks guys, I am sure there will be a lot more questions soon.

[CYBORG]

 This could possibly be worth a look
http://www.stealthvape.co.uk/electronic-cigarette-mod-parts

 

[gaffer]

ok so at this point from some research so far i have figured out i think i need:
 
from http://www.digikey.com
1x OKR-T/10-W12 (power supply board)
1x 3352T-201LF (potentiometer)
1x MRS2500C200 FRP00 (200 ohm resistor)

from radio shack or some where else
PCB boards
project box
switch
volt meter
510 connector
wire, solder, and shrink wrap
terminals for batteries if the box I get doesn't have terminals pre installed
LEDs for s's and g's
batteries in what ever flavor i decided.

I ~think~ with this I can push 10 amps/50 watts. I figure if i want to push that much I need to rig with switch up to the power supply board in a way that the power is not being delivered via the board.

To be able to hit realistic voltages with this mod I think I will need to use 2 batteries in series (if I correctly understand how the power supply functions) but I also think the batteries will need to be rated higher than 10 amps to safely hit the full amperage potential). is that right?

[CraigHB]

The best converter to use in my opinion is the OKR-T/10.  It can output up to 10 Amps or 50 Watts, whichever comes first.  Here's a circuit for it at Breaktru's forum.

One of the really nice things about going with series cells and a step-down coverter as opposed to a single cell with a boost converter is that the step-down converter reduces amperge demand from the battery.  DC-DC converters conserve power.

For example, if you want to run an atomizer at 6 Amps and 4.0 V, that's 24 Watts (6A times 4V).  That means input power will be 24 Watts plus about 10% for converter losses.  With input power of 26 Watts and input voltage of 7.4V (nominal), current loading on the battery will be only 3.5 Amps.  This gives you a wide option of battery types.

A couple IMR 18350's could do the job quite nicely.  A couple IMR 18490s could provide more run time without making the mod terribly big.  A couple ICR 18650s can do the job no problem and would provide huge run time.  It would even be possible to use a couple IMR 14500s if you want to minimize size absolutely.  You'd still get a total of 1200mAh with two IMR 14500s which would provide a reasonable amount of run time.  There's just tons of battery options there.

[gaffer]

its members only for the schematic (i will have to register there later)

So with this power supply what protection (if any) are already there? reverse battery protection (if not can I just use a diode in the circuit to provide that), over discharge protection? etc etc?

Yeah I am not sure what batteries I will run yet I kinda want to do 26650s just because but after really looking at the rates I could really just use 2 NCR 18650s and get pretty good battery life... hell I could even use 4 18650s (2 and 2 in series and then those groups in parallel) if i want to be stupid Realistically I think i will end up going with 2 of the Panisonic NCR 18650 3400 mah.

[SamIam]

You'd get some serious run time out of that 

[gaffer]

You'd get some serious run time out of that 

You haven't seen me vape

but in all seriousness I vape 3-5 ml a day between carto tanks and rebuildables so I usually am changing batteries a couple times a day in a cargo tank and maybe once a day on a rebuildable. I know that may not have much on craig lol but there is only one other person I work with that vapes around the same as I do.

[CraigHB]

So with this power supply what protection (if any) are already there? reverse battery protection (if not can I just use a diode in the circuit to provide that), over discharge protection? etc etc?

When you view the schematic you'll see a PTC fuse inline.  That will protect the circuit from reverse polarity.  Also, the fuse will protect the cells from overload and short circuit, but the OKR regulator module also offers protection there.

The one issue you may run into is over-discharge protection.  Since the regulator doesn't cut out until the voltage of each cell is well below 3V, it can be a problem.  Though, you will notice the loss of vaping performance and be able to tell when the cells are getting low. 

One alternative would be to use a protected cell, then you could forgo the fuse.  However, you would not want to use a protected cell smaller than 18650 or you would possibly trip the protection under heavy load.

[CraigHB]

I know that may not have much on craig lol but there is only one other person I work with that vapes around the same as I do.

Yeah, hehe, I vape a *lot*.  I run pretty high power and I vape non-stop when my hands are idle.  I vape at least 10ml a day, but I'm not going to admit an amount.  I actually don't know, I'm afraid to keep track.  In terms of battery consumption, I use around 6Ah a day.  Average would be about a quarter of that.

[gaffer]

wasn't there certain chargers that would not play nice with a protected battery that tripped because it wouldn't push enough power to it to trip it back?

also FYI craig, according to pharmacological standard IIRC there may be cause for concern if you are inhaling more than 10ml of pg or vg a day (10ml of one of them total).

[CraigHB]

wasn't there certain chargers that would not play nice with a protected battery that tripped because it wouldn't push enough power to it to trip it back?

Any multi-charger that has to detect the battery type before initiating the charge cycle will have trouble with a protected battery that has been over-discharged.  The charger has to connect to the cell to sense the type before it can initiate charging.  An over-discharged protected cell has to see charging initiate before the protection will reset allowing a connection to the cell.  Chicken or egg.

also FYI craig, according to pharmacological standard IIRC there may be cause for concern if you are inhaling more than 10ml of pg or vg a day (10ml of one of them total).

Well, I've been vaping like this for over three years and all is well.  I smoked like a fiend too.  Pretty sure I'd be in pretty bad shape about now smoking like I used to.  Was already getting to that point when I started vaping.  My lungs were seriously trashed, but they're pretty good now, probably not as good as if I didn't vape either, but a hell of a lot better than when I smoked.  I'm sure vaping as much as I do is not "good" for me, but smoking that much is definitely worse.  BTW, I vape 60/40 juice so by those standards I can vape 20ml a day.  Pretty sure I'm not over that.