EverCool Variable Voltage Mod

[givesuhe11]

Thanks willyb for clarifying what I meant by "piggyback"


And post #233 has pics with the resistors shown. Thought that was obvious, my bad.

 

[bigblue30]

Budjiman1,

You might still be able to edit the post and change the pot to 200 ohms.

 

[WillyB]

Thanks willyb for clarifying what I meant by "piggyback"

And post #233 has pics with the resistors shown. Thought that was obvious, my bad.

Many folks are doing this for the first time, using 'official' and search-able terms will help them understand exactly what is being done or needed.

Although many don't care, they just want to start selling some hacked together versions.

And folks needing help to trouble shoot problems need to provide lotsa details and what specific tests they have already tried.

 

[VV Vapster]

well i got me some 200 ohm pots on order, and went to rat shack and got some 220 ohm resistors, so I should have this thing workin by next weekend! thanks all for the help! I really appreciate it!

 

[Yellowman1972]

I have been lurking for awhile and loved the performance of this chip. I followed your instructions Bigblue and BAM!!! they sent me 2!! I am looking for an enclosure that is not a battery box, just on the look for somthin a little sexier ya know? At this point I am probably gonna go the wood route seeing as how it seems to be the easiest at this point, wanted to incorporate a usb in for recharge purposes but may be biting off more than I can chew. will let you know how it turns out either way I will be victorious or it will be a fail of epic proportions. Thanks again blue for taking the time and holding everyones hand who happens to be a little less than tech savvy. I am sure if it succeeds it will be due to your awesome wiring diagrams and easy instructions

 

[bigblue30]

I have been lurking for awhile and loved the performance of this chip. I followed your instructions Bigblue and BAM!!! they sent me 2!! I am looking for an enclosure that is not a battery box, just on the look for somthin a little sexier ya know? At this point I am probably gonna go the wood route seeing as how it seems to be the easiest at this point, wanted to incorporate a usb in for recharge purposes but may be biting off more than I can chew. will let you know how it turns out either way I will be victorious or it will be a fail of epic proportions. Thanks again blue for taking the time and holding everyones hand who happens to be a little less than tech savvy. I am sure if it succeeds it will be due to your awesome wiring diagrams and easy instructions

I would love to see an Evercool made of wood. Please take pictures when you are done. If I can help let me know.

 

[Gizmo362]

This is my first attempt to make a Wood EverCool. I added a plug for a wallwort and/or Auto Lighter.
I also used a 500 Ohm Pot to get down to around 2.5 Volts for LR attys.

 

[givesuhe11]

Bigblue (or anyone else)... educate me... what other caps could be used? I just got a boxload of electonic parts and gizmos... hundreds of assorted caps... resistors... switches... led's... etc... if you were to "over-engineer" this what would be a better cap to use, 220uf 16v... 100uf 35v... and tons of others. Can SMD caps and resistors be used? I also got some usb chargers and chargers out of PCC boxes from blu ecig and volcano ecig boxes, I'm going to try and incorporate these into the mod too. I have an 8 point slider switch too... gonna try it with set resistors preset voltages. 24volt to 12volt converter... people in an electric wheelchair could vape with an evercool passthrough plugged in... cool!!

 

[theECB]

This is my first attempt to make a Wood EverCool. I added a plug for a wallwort and/or Auto Lighter.
I also used a 500 Ohm Pot to get down to around 2.5 Volts for LR attys.
View attachment 23858View attachment 23857

Wow! That is awesome looking. Very well done. Wood is just so classy!

 

[Gizmo362]

Thanks ECB. I am trying to make this one next. It is turning out to be a pain because my fingers are a bit too large for the delicate woodwork. I'm shooting for 3/4" thick X 1 7/8" wide X 3" tall X 1/16" walls. It might have to be a one of a kind.

 

[theECB]

Gizmo, I think all of my wood ones are a "one of a kind". I am working on a teak wood 5v box at the moment. I typically go real heavy on the glue and then just sand it all down afterwards. So, is the black stripe a different wood? It's a very nice design. I would love to see the finished project when you fingers finally finish that delicate work!

 

[Gizmo362]

The stripe is Walnut like the top and bottom. Other is Maple. That's what I have in stock to work with. I formed the basic cut out for the body and found it very thin for every day use. I might have to go to 3/32 for the body thickness.

 

[dsy5]

The blue POT will turn forever, but will only adjust resistance within a certain range of the screw. I'm not sure of the number of turns to adjust over the entire range, but it's probably around 30-40 turns.

These pots are normally known as '10 turn pots', thus the entire range is within 10 turns. There are some pots that will go 15 turns, but they are rare and the specs should state this.

 

[dsy5]

don't know if anyone has mentioned this, but the current draw on this mod is slightly under an amp at 5.5 volts, with an input of 12 volts (I further modified this mod to allow me to select 12 Vin, from a wall transformer or car power port, or battery powered using a SPDT switch). Interestingly, current increases as Vin drops, increasing to almost 2 amps as you approach the Vout min.

Confused the hell out of me for quite some time, and ended up doing some research; turns out, ohm's law only applies to linear devices, and since the switching regulator is NOT linear, ohm's law does not apply.

What you need to understand here is that you are implying the current that is sourced, that is from the battery, and not what is consumed by the atty.

It is true that a switching regulator uses a pulse width modulation to achieve its desired voltage output.

That means that it can draw different currents for different voltage inputs, which is not true ohms law. Depending on the input voltage used, it could therefore achieve better battery life by drawing less current from a higher battery voltage.

A good point for making a dual or quad-series battery box.

 

[Gizmo362]

I can ony talk about my VVPV performance in my actual use. I find that there is no discernable difference between using fresh 3.7V batteries in series and a 12 volt car battery and wallwort. The performance (Vapor production and throat hit) is the same until my batterys drop below the minimum voltage input. Then the unit just stops working. (Time to change out the batteries.) I do have a question about the forward battery dropping below the protection circuit low voltage level before the rear battery. I notice at the last end of the batteries charge I can see, with my volt meter, that the front battery takes a long time to recover it's voltage value compared to the rear battery. I assume that the rear battery (nearest to the negative side) is supplying electrons to the forward battery to replenish the differential. Of course my batterys are a year old and probably should be replaced. (Mr. CheapScate) Also, when charging the spent batteries, one usually finishes charging before the other. Any opinions about this subject of "batteries in series" is muchly appreciated. Thanks. Gizmo PS: By the way....This is the greatest Home built mod that is on the ECF web site by far... Nuf said.

 

[WillyB]

I can ony talk about my VVPV performance in my actual use. I find that there is no discernable difference between using fresh 3.7V batteries in series and a 12 volt car battery and wallwort. The performance (Vapor production and throat hit) is the same until my batterys drop below the minimum voltage input. Then the unit just stops working. (Time to change out the batteries.) I do have a question about the forward battery dropping below the protection circuit low voltage level before the rear battery...

I agree, the input Vin, as long it's above the threshold needed for your Vout seems to be all that matters.

The minimum input voltage is 4.5 V or (VO/0.83) V, whichever is greater

That the top batt takes a heaver hit is pretty much a given. Some folks recommend rotating the cells, top/bottom, so as to age both batteries equally over time.

I do have a question about the forward battery dropping below the protection circuit low voltage level

Well what does your meter say? Is the top cell being 'tripped'? A tripped cell will read 0V.

 

[Gizmo362]

I had a battery that read 0V and threw it away, thinking that it was finished. Was that mybad??

 

[dsy5]

I find that there is no discernable difference between using fresh 3.7V batteries in series and a 12 volt car battery and wallwort. The performance (Vapor production and throat hit) is the same until my batterys drop below the minimum voltage input.

That would be correct since the output voltage to the atty is always the same. Hence a voltage regulator. The only real difference is that the current supplied by the battery is more likely higher than the current supplied by the wall-wart.

And of course, the unit will die when your battery falls below the required voltage needed to run the voltage regulator. (This is a design factor of the regulator).

Indeed, when running batteries in series, the front-most battery does take a bigger hit - not sure what the scientific explanation for it is, but maybe it has to do with chemistry of the battery? Anyway as previously stated, mark your batteries and regularly swap their positions to maintain the relative life span of both.

 

[dsy5]

I had a battery that read 0V and threw it away, thinking that it was finished. Was that mybad??

Probably not. Even a protected battery should not be allowed to over-discharge. It just ruins the battery by causing lithium depostis to form within the cells - in essence, choking the battery. It is a good idea not to let the batteries fall to 2.4 - 2.6 volts, the usual cuttoff of a protected cell. I would not run the unit to shutoff, but rather check the status with a volt meter occasionally, until you determine the period of usage that gets you to that point and then just change prior to reaching that point.

I may experiment with a IC comnparator to monitor the batteries voltage output and light an LED when a specific limit is reached.

 

[o4_srt]

I may experiment with a IC comnparator to monitor the batteries voltage output and light an LED when a specific limit is reached.

keep us posted, I was thinking about doing the same thing but have not gotten around to it. Still perfecting a capacitive touch sensor