Easy OKR-T VV mod

[mamu]

Thanks for sharing the wiring diagram bstedh. I built a mod with this module and it provides a great consistent vape.

And Cape was right - this module doesn't require the min 2v in/out difference.

But I am concerned that the batts go below a safe voltage without the regulator cutting it off. I'm using 14500 AW IMR batts and I really don't like them going below 3v, or 6.5v combined. Is there a simple fix to make this a safer setup so the regulator will cut off when the batts voltage get to around 6.5v?

 

[CapeCAD]

But I am concerned that the batts go below a safe voltage without the regulator cutting it off. I'm using 14500 AW IMR batts and I really don't like them going below 3v, or 6.5v combined. Is there a simple fix to make this a safer setup so the regulator will cut off when the batts voltage get to around 6.5v?

A zener diode and resistor on the enable pin is all that you need for UVLO. I posted a diagram on this thread, but resistor value and zener value should be verified for your requirment.

 

[WillyB]

Well some credit should go to the very modest CapeCad who was first to use this chip back in 8-2010 in a mod and again in another in January.

 

[bstedh]

Well some credit should go to the very modest CapeCad who was first to use this chip back in 8-2010 in a mod and again in another in January.

Absolutely Positively...

This chip was recommended to me when I was working on my VVeller.

Here are some referenced past posts.
http://www.e-cigarette-forum.com/forum/battery-mods/70282-adjustable-voltage.html

http://www.e-cigarette-forum.com/forum/battery-mods/149524-5v-regulator.html

http://www.e-cigarette-forum.com/forum/battery-mods/115033-my-synchronous-buck-mod-591-6-0v-95-efficiency-7v-input.html#post1752420

http://www.e-cigarette-forum.com/forum/battery-mods/152392-coolgate-variable-voltage-mod.html

http://www.e-cigarette-forum.com/forum/battery-mods/170173-need-help-vv-box-mod.html

 

[SurvivorMcGyver]

Glad you took the leap Mamu nice unit -- the proof is in the puddin'

 

[bstedh]

Thanks for sharing the wiring diagram bstedh. I built a mod with this module and it provides a great consistent vape.

And Cape was right - this module doesn't require the min 2v in/out difference.

But I am concerned that the batts go below a safe voltage without the regulator cutting it off. I'm using 14500 AW IMR batts and I really don't like them going below 3v, or 6.5v combined. Is there a simple fix to make this a safer setup so the regulator will cut off when the batts voltage get to around 6.5v?

I had the same question.
CapeCad had a modification to my circuit with a zener to keep it from activating below 6V. Right now I just rotate the batteries every now and then and check the voltage every couple of hours.
http://www.e-cigarette-forum.com/forum/battery-mods/193434-low-voltage-cut-out.html

 

[mamu]

A zener diode and resistor on the enable pin is all that you need for UVLO. I posted a diagram on this thread, but resistor value and zener value should be verified for your requirment.

Thanks for the tip Cape. I'm surprised this module can take the batts as low as 2.55v and not shut itself off, especially with me vaping at 5.5v. I did notice though that the hit was weak, so I should at least pay attention to when the hit drops off.

In some of my mods that had the room for it, I added a LM431 shunt regulator as a batt status monitor. Of course it doesn't shut the regulator off, but it does let you know if your batts' voltage is greater than 6.5v. If the LED lights, batts' voltage is greater than 6.5v. If the LED doesn't light, the batts' voltage is less than 6.5v. At least it lets you know when it's time to charge the batts.

Here's how I wired it in the mod (I used a separate small tactile switch for it, but I guess you could also wire it to the atty switch):

For 6.5 volt indicator:
R1 = 3.3K ohms
R2 = 2K ohms
R3 = 500 ohms
R4 = 500 ohms

 

[bstedh]

To save space you can accomplish the same thing with just a zener, resistor, and LED.

Never mind =] I see you are doing that over in the other thread.

 

[Rockproof]

bstedh,

I just wired one of these together with the exact parts you referenced in your thread starter. Thanks for the diagram.

Question...The range I am getting off of the voltage is 4.32v lowest and 7.77v highest. What did I do wrong?

 

[bstedh]

Check the ohms across both the resistor and POT. At the lowest setting you should be getting around 200ohms If it is less than that the voltage will be higher than 6V. You can check the resistance against the chart I have posted in the thread to cross reference what voltages you should get at what resistance. Also another thing to check is the resistance of the POT across it's entire range. I had one that had intermittent shorts and opens.

My first guess would be that your resistor and POT are wired in parallel instead of series giving lower resistance but that is just a guess.

 

[Bdbodger]

I have a question . I have a flashlight that uses 3AAA batteries in a circular battery holder . I was thinking of using 3 10440 350 mAH batteries and the OKR-T/6-W12-C that would be 3.7v X 3 or 11.1v how do I decide what resistance I need or is this not a good idea .

 

[unloaded]

You should package the parts and sell them as little kits.

Instead of the pot could I use dipswitches, rotary switch or similar with resistors to select specific voltages? I can't see needing more than 3 or 4 settings or changing them often. Are there setups already going like this? I'm behind the curve on all this but trying to catch up.

peace.
unloaded

 

[bstedh]

I have a question . I have a flashlight that uses 3AAA batteries in a circular battery holder . I was thinking of using 3 10440 350 mAH batteries and the OKR-T/6-W12-C that would be 3.7v X 3 or 11.1v how do I decide what resistance I need or is this not a good idea .

Everything stays the same as long as your supply voltage does not exceed the ratting of the regulator. Take a look at the data sheet. I think the max voltage for the okr is 12V but I don't remember for certain. Also you want to use the batteries full charge voltage when calculating as they will hit 4.2V off of the charger.

I'm not positive however if you would use the unloaded voltage or loaded voltage when worrying about the maximum voltage.

 

[bstedh]

You should package the parts and sell them as little kits.

Instead of the pot could I use dipswitches, rotary switch or similar with resistors to select specific voltages? I can't see needing more than 3 or 4 settings or changing them often. Are there setups already going like this? I'm behind the curve on all this but trying to catch up.

peace.
unloaded

Na, The parts that don't come on the board are what allow you modify it to your specific need and preference.

"Unloaded" Voltage -- Ha ha.. =]

 

[unloaded]

Well, cigs aren't the first bad habit I've had to quit. If you'd known me 15yrs ago "Loaded" would have been a better name for me 8)

 

[Bdbodger]

Everything stays the same as long as your supply voltage does not exceed the ratting of the regulator. Take a look at the data sheet. I think the max voltage for the okr is 12V but I don't remember for certain. Also you want to use the batteries full charge voltage when calculating as they will hit 4.2V off of the charger.

I'm not positive however if you would use the unloaded voltage or loaded voltage when worrying about the maximum voltage.

4.5-14 Vdc input voltage range so I should be ok . Thanks

 

[Bdbodger]

Any updates on your design ? I seen the other thread about adding a resistor and zener diode to the control pin . What about caps have you given any more thought to using them ? I see Mamu has a new mod that uses the OKR-T/6-W12-C and mentions using input and output caps .

http://www.e-cigarette-forum.com/forum/battery-mods/201297-presenting-merlin.html

 

[bstedh]

Any updates on your design ? I seen the other thread about adding a resistor and zener diode to the control pin . What about caps have you given any more thought to using them ? I see Mamu has a new mod that uses the OKR-T/6-W12-C and mentions using input and output caps .

http://www.e-cigarette-forum.com/forum/battery-mods/201297-presenting-merlin.html

I have had too many irons in the fire to play around with the VV lately. Still working on my future VV plans. Caps are not needed but you could add one on the input side to smooth out the draw on the battery to hopefully extend it's usable life but I doubt it would make a huge difference. The output has no need as an atty could care less if there is a ripple in the voltage. The only time you may need one on the output is if the ripple is bad enough that your small voltage meter won't work on it but other posts say that they work fine with the OKR.

 

[Animeguy]

Oh man....my vv is broken I think. I don't know what is wrong. I rebuilt it 3 times now and it keeps telling me 6.88 volts. I most the pot on one side and it says 6.88. Other side, 6.88. In the middle 6.88. The resistor is at .200? I think its right cuz all the new ones have that value. Any idea whats going on? Please I need this vv working soon. I have 1 more complete set to make another OKR-T. This not the only one. I tried building a new one and it is doing the same thing. I figured I ask here before I waste a 3rd set of okr build.

 

[CapeCAD]

Resistor should be 218 ohms minimum, .200 is too low.