First Mod Attempt.... couple of questions.

[LFC]

Hello All,
Have been planning to have a go at my first mod since before Christmas, ordered a few bits and pieces, then the holidays took over but now I am ready to get stuck in but I have a few questions I am hoping you can help me with.

I had ordered a few of the 18650 boxes here - eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices - with a plan to do a dual 18650 VV.

I also ordered some of these on a whim - eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices - and of course they do not fit in the top section of the battery case but I have decided to use them to make a few practice devices instead then get ones that fit, or use separate components once I've figured out what the hell I am doing

My questions are - I plan to cut one of the 18650 boxes, basically to get the battery section, then stick that into a project box then mount the LM2596 module and a volt meter in the box as well. But the 18650 box is parallel and I will need to make it series for variable voltage, correct? How do I do that?

And secondly, and this one is a tad embarrassing, I got a vv schematic off another thread (list of mod convertors for newbs) which looks simple enough even for me, but after looking at the schematic, and my LM2596 board, I wasn't sure how the voltage would be altered? Is it done with the little screw on top of the blue module? If so, do you guys usually add something to that to make it easier to adjust without a screwdriver, or have I missed the point altogether and do I need some sort of switch or dial to adjust the voltage? And if so where would that figure in to the schematic?

Sorry this post got a little long... I have a little vari-volt box I traded with another member for, but it is difficult to see the components inside and to get them to correspond to what I am trying to do...

I really appreciate any input you may be able to offer so I do not lose any body parts wiring this thing up incorrectly!!

 

[Sicarius]

Q1 - Change the wiring so that the negative of the top battery goes to the positive of the bottom battery (or install the second battery backward)
Q2 - The blue module is a variable resistor and you will need a screwdriver to change the output voltage

 

[LFC]

Excellent Sicarius, thank you very much... A page of question and answered in two sentences I thought about reversing one of the batteries, but it seemed too simple so I just wanted to check.

I'll get to work on this in the morning.

Much appreciated, I am sure I'll have more questions as I go along

 

[Quigsworth]

Hey LFC, welcome to modding...

Stop!...those are nice boxes, don't hack them up just to make a batt holder for another box...you'll regret it later. Just hit a RS and pick up a "C" or "D" cell el cheapo batt holder and scavenge the contacts out of it, they're $1.50 ea. toss the rest away if you want...physically holding batts in is where you need to be creative...if you can think of a new ingenious method, I can't wait to see it...

That stupid little screw on the pot (blue thing with the screw on top) has been the point of frustration for everyone that's used that module (myself included)...if you come up with something good, post it, please...

I keep thinking about de-soldering that pot and going to a remote mounted wheeled trimmer but it has a pretty wide resistance band, I haven't toyed around with it yet, maybe someone has done this already???

best of luck on your build, peeps here are ready and willing to help...

 

[LFC]

You are right, they are nice boxes..... I'll try and think of another method to hold them.

Thanks for the help.

 

[LFC]

Well, a day of playing around with this and it will not work for me no matter what I try

I have wired it all, soldered it, tested, nothing, took the volt meter out of the loop, tested again, nothing, changed board and resoldered everything, no fire.....

Not really sure what to try next.... basically I now have the schematic above completed, but getting no output at the 510 connection, hoping someone can help?

Thanks in advance.

 

[notsmoking]

This may be a dump question, but did you solder the other end of your battery connectors together? You need to do that to complete that part of the circuit.... just asking because you do not show that in your drawing.

 

[LFC]

Well, it was a couple of little silly things that I hadn't done correctly... I looked at a different schematic from Mamu and realized that I had not added a jumper wire between the other end of the batteries

Also I had wired the 510 connector incorrectly, I just attached the 2 leads to it instead of the red to the post and the black to the case. So, after rectifying those issues it will fire the atty just great.

I added the voltage meter back in to the loop again but it is just flashing up a single digit, looks like 8, quite bright in here and hard to see, but the atty does not fire when the volt meter engages. Perhaps I have connected the wrong pins? I have my black negative out connected to pin 1S - and the red positive out to pin 2S, is this right?

Thanks.

 

[LFC]

You got it notsmoking Just posted again and then saw your reply....

 

[notsmoking]

I am not sure on the pinout.... but I think that it might be pin 3.... but try a test first before you solder it

 

[notsmoking]

opps yes you were right sorry... I was thinking of a different one...it should work the way you have it.

 

[LFC]

Wired the red to pin 3 and it gives a readout now, but always 4.7v, no matter what I do with the voltage dial.... I went back and read the info on the Madvapes site, were I bought the meter, and it says it may not work with some switching devices, which I think the LM2596 is, so it may be that issue....

Many thanks for your responses.

 

[Quigsworth]

If it's the meter off MV hold it so you're looking at the face of the meter and the pins are pointing down...the neg goes to the 1st pin (furtherst left), the pos goes to the pin right next to it the rest aren't used...I usually cut them off

Sent from my Transformer TF101 using Tapatalk

 

[LFC]

Thanks guys. I think when I had connected it first time to the 1st and second pins the dial was turned way up and with a carto on it was just throwing an error code. Tested it holding the wires to it and dialed it down and works like a champ now. The box is finished and I'm really glad I tried a 'fugly' version first time to work out the kinks and see what problems I'd encounter. It's not pretty, but it works and that's the main thing

Will make the 18650 box from China next, but a few other things to do first....

Thanks again, your help was invaluable.

 

[jhonutz]

to make series connected from that box: cut 1 coil and solder to a single + plate from middle of box, and you have series connected batts

 

[Quigsworth]

...I'm really glad I tried a 'fugly' version first time to work out the kinks and see what problems I'd encounter. It's not pretty, but it works and that's the main thing

I don't call them "fugly" versions...I use terms like "proof of concept" or "pre-beta"...it just sounds way cooler and like I have even the slightest clue what I'm doing

So come on, show us some pics...

 

[iamtopher34]

I left the springs on the bottom just on one i put some some thin metal so the positive would make contact works great.
All so will that vv board fit? I have it on the way from China right now i had to use the big square one in mine for now

But i cut the corners off so the button could fit

hope this helped

 

[LFC]

Mine was the same as the one in the battery bay in your first pic Topher.... I was wondering if the square one would fit in the china 18650 box, I guess you just proved it would... is there a smaller one out there? I was also wondering how to get a switch in there too with the square board, nice work! What connection is that? The only ones I have at the moment are the standard gold 510 ones from Madvapes and they don't seem to like solder and are long, yours seems to have a nice short profile.

 

[iamtopher34]

Its a shorty 510 with nut or something like that madvapes has them but are kinda expensive i got mine at myvaporstore.com or goodprophets
to make room for the push button i cut the corners off that had the big silver holes this mod took all of 5-10min to make