Variable Voltage Evercool Copper Mod

[breaktru]

Variable voltage Copper mod. 3.6volts to 6.14volts with (2) 3.7v 18350 1200mah UltraFire batteries (7.4v).
http://breaktru.com/smf/index.php/topic,170.0.html
PV on far right:

On the bottom of the tube I cut a right angle grove to lock the cap in place.
I cut a 1/4" of tubing for battery stop. See diagram: http://breaktru.com/images/copper_mod.jpg

I used a 96% efficient switched regulator: http://focus.ti.com/lit/ds/symlink/ptr08100w.pdf

3 amp CK switch - 200 ohm variable resistor in series w/ 220 ohm resistor.
(2) 100uf - 10v Tantalum caps

Collar used to lock top of batteries from moving

Pressed collar in place with a socket

Low end voltage

Sweet spot voltage

High end voltage

Your fixed resistor will set your max voltage for the PTR08100W
With the pot zeroed out, the fixed resistor gave me a max voltage of 6.1volts

 

[Skyway]

Very nice!
Is that meter from the 80's? lol
Dont need to fix what aint broken.

 

[breaktru]

Very nice!
Is that meter from the 80's? lol
Dont need to fix what aint broken.

Very Good Skyway. You got that right. I have checked it's accuracy against New Flukes and it's still spot on.

If you stare at the meter long enough you could almost hear:
Jefferson Starship - "Jane"
The Smithereens - "Elaine"
Boston - "Amanda"
Toto - "Rosanna"
Toni Basil - "Mickey"

 

[Rockproof]

Sweet. This has to be next for me.

 

[breaktru]

Parts Layout:

 

[Skyway]

First of all breaktru, thank you for making that simple diagram. It allowed me to kind of understand the diagram that is listed on the pdf file. I have one question and maybe I bought my Tekkeon sooner than I should have. In order to make a full VV I would need to start at the 7.4v and not the 5.2v that the tekkeon gives. I am going to be making a mod real soon that I want VV. I personally will probably only use it for 4.2v or whatever my sweet spot of 10.3 watts is. I love the fact of having a regulated voltage. I think it is the most important thing about all of this. I want to get away from the ups and downs of the voltages of my 3.7v batteries. I have mine coming in the mail this week from TI. Will using non tantalum caps make that much of a difference? I could not find any tantalum's in my searches but I did find other makers with the same specs.
The other question I have is where would I wire something like a charging unit up like this one from madvapes? USB CHARGER I am going to take it apart and use it in conjunction with all the other circuitry. I am guessing I can just attach it to the outer most pos and neg of the batteries which would be in series. This would bypass the function of the regulator but still work to charge the batteries I am hoping. It is my suspicion that I am thinking too simply and it would entail more. That is why I am asking before I start messing around. Can two 3.7v batteries in series, effectively 7.4v be able to be charged in this fashion? I know the Tekkeon can do it but it has a controller card that has some functions that I am not familiar with.

 

[WillyB]

.... I personally will probably only use it for 4.2v or whatever my sweet spot of 10.3 watts is. I love the fact of having a regulated voltage. I think it is the most important thing about all of this. I want to get away from the ups and downs of the voltages of my 3.7v batteries. I have mine coming in the mail this week from TI. Will using non tantalum caps make that much of a difference? I could not find any tantalum's in my searches but I did find other makers with the same specs.


The other question I have is where would I wire something like a charging unit up like this one from madvapes? USB CHARGER I am going to take it apart and use it in conjunction with all the other circuitry. I am guessing I can just attach it to the outer most pos and neg of the batteries which would be in series. This would bypass the function of the regulator but still work to charge the batteries I am hoping.

Well hopefully you will make it VV. There is no magic, universal watts number. As atties age the conversion of theoretical watts to actual heat/temperature changes. One of the benefits of VV is how old, tired atties can get a second wind by just tweaking the volts a bit and very often different eliquids respond better at different volts/watts even with the same atty.

I could not find any tantalum's in my searches but I did find other makers with the same specs.

If you glance at the datasheet TI's actual cap specs can be quite confusing, much more that just uF and voltage, and frankly well beyond my understanding. It may not matter though. But here's an example of the requirements.

The main considerations when selecting input capacitors are the RMS ripple current rating, temperature stability, and maintaining less than 100 mΩ of equivalent series resistance (ESR).

Regular tantalum capacitors are not recommended for the input bus. These capacitors require a recommended minimum voltage rating of 2 × (maximum dc voltage + ac ripple). This is standard practice to ensure reliability.

No tantalum capacitors were found to have voltage ratings sufficient to meet this requirement.

For folks who have the room these Panasonics are on TI's recommended list for both input/output. Cheap too.

EEU-FC1V181 Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded

As to using that charger it won't work for charging cells in series.

 

[breaktru]

I purposely didn't respond to Skyway because I knew WillyB would come to the rescue with intelligent answers. Nice Willy. In the spec sheet, the preferred cap is the electrolytic. Yes it is cheaper too. I went with the Tantalum because of the limited space in a tube mod. I will try the electrolytic in my next mod. Bought a ton of parts from several vendors. Maybe a box mod with a dial or slide variable, a (BQ2052 - Primary Lithium Gas Gauge W/High-Speed 1-Wire (HDQ) Interface, 3 Prgmable LED Patterns BQ2052SN-A515), going to use the control pin for a micro switch, volt meter and what ever I can think of. Going to try to squeeze it into the smallest possible box.
Don't know if I can use the Gas Gauge but it would be so cool to know how much capacity is left in the battery if it works for this type of situation. I believe it is rated for up too 1200mah which would be perfect for the UltraFire 18350, 1200mah, providing it will work with 2 bats in series.

Update: Looking at my photos above, the electrolytic would probably fit.

 

[Skyway]

Thanks for all the info. I am sorry if I may have taken something away from your thread breaktru. It did not dawn on me until I came back to the thread that I might have been doing a little thread jacking. Sorry if I stepped on your toes. I have another idea and I will bring it up in a different thread.
Again, excellent work!

 

[breaktru]

No Skyway, this is what this forum is all about. Questions and answers. It's all related to the building of the v.v. mod.

 

[Skyway]

 

[WillyB]

Folks actually paying should note the 6A version is a good choice.

PTR08060WVD from Texas Instruments | Arrow Electronics Online Component Sales

 

[breaktru]

Nice find WillyB,
A side by side spec scan shows almost no difference than the 08100. It's physically 0.082" thinner, Overload threshold Reset Autorecovery is 10A instead of 16A (so what, who cares) and testing was at 4 amps instead of 6 amps. again (so what, who cares).
And for $7.77, it's a great buy. Thank you WillyB.