20A VV Bottom Feeder Rises From The Ashes

[Alexander Mundy]

You are more than likely aware that I built a VV Reo Grand with a 20A VV buck converter but couldn't figure out how to get the battery power required inside it to fully power it safely.
I found 1 possibility (maybe) with a 3S LiPo pack but I decided I would rather have LiFePo4 or IMR batteries due to their more inherent safety.
So it was either chop up the VV Grand and expand it's size or start with a different form factor.
Some of you will have a sigh of relief that I just couldn't bring myself to cut up the VV Grand.

Surfing the ECF one day early this month someone (wish I could find that post to give proper credit) said they had some of these coming to see what they could do with them.

Then again I saw someone mention this power bank on another forum and I decided to purchase one.

Then I saw shortyjacobs had one he is making into a dna mod.

http://www.e-cigarette-forum.com/fo...china-dna20-mod-hopefully-4.html#post11600644

Many thanks shorty for taking photos and measurements while I awaited mine.

Got vapemail today.

Both the power bank and the Orbtronic SX30 2100mah 30A IMR's I had ordered for this project.

I pried off the top like shorty said he did and here is the insides.

And with the USB sub board removed which has a tiny amount of glue and pulls out relatively easy.

I gently pried the top part of the button over the plastic pins holding it in place like so.

Then pried it up and in with a small screwdriver like so and it popped right out.

Thanks to shorty I knew that after the 3 small screws were removed there was still a solder connection under the bottom cover that held the main board in.

The triangle vinyl like cover peeled right off exposing the solder connection.

Unsoldering the connection let the battery springs and negative connector spike to the main board loose and allowed the battery holder to come free from the top where the electronics are.

Lifting the main board out revealed the full cavernous space available in the top section.

No problem housing the 20A VV board with lots of space for extras.

Grabbed a DNA20D just to see what it would fit like and still lots of room left over.

This thing couldn't have been made to hold a 6ml bottle any better.

The 2 things that I would like to improve are the resiliency of the case and the fact the battery cover is only held in place by 3 small tabs.

Next I will see what the best ergonomics are for fire button, switches, potentiometers, voltage display, and atty connector, but that's all the time I have for tonight.

 

[pdib]

Git to work, Mundy! I wanna see more!






(and hang in there!)

 

[Alexander Mundy]

Been working at what pays the bills grasshopper!
Got about an hour tonight to contemplate.

Think I will have one battery up and one down.
That will allow a connection at the bottom between the batteries with + and - of the 2S combination at the top.

Took the button and removed the spike from the backside and carved a bowl to match the button on a tactile switch.

That should allow me to make a mount (with a little creativity) that will hold it in place with a replacement longer screw that holds the battery section to the top.
Shown here with a wire where the longer screw will go.

Also fiddled around in the junk pile and found that an original Pro Tank base has Ego threads and an old Ego battery connector has a small ledge past the threads.

Put together they will clamp onto a plate with a hole the size of the Ego thread and give a 510 connection with a catch cup.

Made a hole in the original top and put them in for a mock up.
Like shorty I will replace the plastic top with something sturdier.

This seems to be about the best configuration for the set up.

Although I will have to squonk with a finger instead of my thumb which is what I am used to.

The wife is impatiently waiting for me to go upstairs now, so...........

 

[shortyjacobs]

Cool stuff - I've been in a haze of holidays and my own mod, hadn't looked around the forum to see what others were doing until now. I like the bottom feeder idea!

 

[Alexander Mundy]

Thanks shorty, glad to see you got yours going and great job BTW!
Do you have any concerns about breakage if you drop yours?
I am a natural born klutz and was thinking maybe carbon fiber cloth and resin like I used to do for model airplane wing reinforcement?

 

[shortyjacobs]

Thanks shorty, glad to see you got yours going and great job BTW!
Do you have any concerns about breakage if you drop yours?
I am a natural born klutz and was thinking maybe carbon fiber cloth and resin like I used to do for model airplane wing reinforcement?

Never really thought about breakage. I guess I'm just hoping I don't drop it....I've crashed a few mech mods to the ground recently, but I attribute that to the tall/skinny footprint and the fact that they tip over easy.

I was trying to come up with a way to class it up a bit - the white/grey color scheme doesn't do much for me, but I don't know if it'll just look crappier. Was thinking of just doing the white body in gloss or flat black instead.

BTW, what's that 20A VV chip you have there? Pretty nice small package. Gonna do a display, or just fly blind?

 

[Alexander Mundy]

Got a .28" (LED height) 3 digit voltage display I am hoping to incorporate.

Next one is going to have a microprocessor.
I am thinking about ordering this module, but it is a little too big for this enclosure.

https://www.sparkfun.com/products/11315

It has a graphics processor with some user memory and limited I/O.
Wouldn't take too much in the way of external support to use for our purposes.
Don't know what possessed them to use Dallas 1 wire though.

 

[negrete35]

I just gotta say that I really admire you guys that can take chips/modules that weren't specifically designed and labeled for use in creating powerhouse mods. I can slap together a nice little DNA 20 mod thanks to Evolv and a few members here. But doing what you're doing is just awesome.

Sent from my SAMSUNG-SGH-I537 using Tapatalk

 

[Alexander Mundy]

A little progress.

Took a small slider switch I found in one of my old goodies organizer

Took it apart and enlarged the slider hole in the middle so the tactile switch would fit in the slot and using a cutoff in the rotary tool I cut of most of the sides leaving 2 tabs to fold over the tactile switch.

Took two 2-56 blind nuts from the flight box and cut the spikes off, ground the height down to the same height as the little walls beside the existing switch insert, and trimmed the sides so they would clear the little walls when mated with the switch holder holes.

Found 2 allen head 2-56 machine screws in the flight box and cut them to length so they would mate through the switch holder holes without protruding.

Here is the combination mocked up to test that the tactile switch works ok with the original button.

Put a little JB weld on the blind nuts and the spots where they land and clamped in place making sure the button still worked.

Removed the clamp the next morning and amazingly enough (with my usual bad luck) it works great.

Changed my mind on connector and took an old Ego top cap and cut the 510 part in 2 places to make a nut to hold a 510 to Ego adapter to the top plate.
This will allow more space inside and the Protank base can be threaded onto the Ego threads from outside or removed independent of the plate mounting.

Found a scrap of sheet metal in the garage left over from the supercharged fuel injected VW Bug project and cut it to a tight fit using the original top cover as a template.

Also decided I would use the little Ego 5 click board powered by one battery as a switch interface to the VV board fire pin.
This will allow 5 click on and off and I believe should inhibit firing if that battery gets low.

That's all for now.

 

[vccy118]

Amazing work man! The display will be a ..... to program...

 

[Alexander Mundy]

I assume you are talking about the uoled module I mentioned for the next project.
It is a little to big to incorporate into this case with 2 X 18650 & bottom feed bottle.
It also needs a little external support in the way of voltage regulation and additional I/O circuitry.
Programming doesn't look too bad, especially if Dallas 1 wire interface support chips are used.

This one will only have voltage display (if that fits).
Progress very slow due to heavy work load.
Got to try to get to the job site now.
Hope I don't end up off the road due to this round of snow coming down.

 

[Alexander Mundy]

Got about an hour tonight to play!
(Been working 14 to 16 hours a day 7 days a week)

Unsoldered the UVT020A0X3-SRZ module and soldered new wires on:

BTW, I don't think I posted in this thread just how small this thing is:

Took the 5 click Ego board and removed the LEDs & switch and soldered wires to the board for remote use:

Also soldered to the B+ and B- and the gate of the output mosfet:

The UVT020A0X3-SRZ module takes negative logic for the enable pin.
In other words, you normally put a pull up resistor from the on/off pin to V+ so the on/off pin is pulled up above 2V to cause an off condition.
Then a switch or digital logic pulls it down to below 2 volts to cause an on condition.
Using the output of the Ego board would be just the opposite.
I tested the board and it has a 4K7 pull up resistor for the mosfet gate and the processor pulls the gate down to turn the mosfet on.
This pull up resistor is more than sufficient and the processor can sink more than enough to pull the UVT020A0X3-SRZ module on/off pin low.
Key here though is that the Ego board would not be able to take 2 series batteries and would go poof.
I mocked up the setup and powered the Ego from just the battery tied to the negative of the UVT020A0X3-SRZ module and then tied the 2nd battery to go on to the UVT020A0X3-SRZ module V+.
This in theory should allow the Ego board pull up resistor to pull the on/off pin of the UVT020A0X3-SRZ module above the 2V threshold to disable it and the Ego board processor to pull it down to enable it using the gate drive from the Ego board and the Ego board only sees one battery so it is happy and the UVT020A0X3-SRZ module sees both batteries in series.
The proverbial smoke test showed that theory worked and pressing the button enables the output and letting go disables it.
Clicking 5 times disables the button till you click 5 times again.
Holding the button for about 10 seconds disables the output until the button is released and pressed again.
I took the LED from the USB board I removed from the battery housing originally and the Ego board fires it just fine so I will use it as an indicator light.
Bed time now.

 

[shortyjacobs]

Nice update! Looks like lots of delicate soldering work.

 

[Alexander Mundy]

Got a short amount of time to play this afternoon.

Took a .28" 3 digit LED 0-100V voltage display and examined it.
The adjustment pot on the board was causing variations in reading so I decided to make my own resistor divider network to replace it.
Also, since I wont need over 10V, I decided to make it a 0-9.99V display with the new voltage divider network.
This will allow for readings to the 1/100th +- 2 digits instead of to the 1/10th +- 2 digits.
(The whole concept for this mod involves being able to output low voltages of around 1 volt at high amperage's so the improved display accuracy is a plus)
I also was going to move the decimal point, but upon examination of the LED module itself found it is a multiplexed common cathode unit with the 3 decimal points common on the anode side of the matrix so it cant be done with hardware changes.
I dug into the resistor bag and found 22k resistors to get close to the original value since the proper adjustment was 21K / 24K on the pot.
Found 1 that was 21K and 1 that was 23K so I decided to use them.
Removed the pot and bypassed the input resistor network.
Installed the resistors in series so I would have a center tap to feed that was close to the pot settings.
Using a decade box I found that I needed 3K515 for the input resistance to the center tap to be exactly calibrated.
Dug and found a 3K8 resistor that was a little low at 3K75.
Dug and found a 47K resistor that paralleled with it measured 3K52 which was the closest combination I could come up with.
Installed them and I am well within 1 digit of accuracy.

Modified display and an untainted one:

Reading 4.203V:

Then it occurred to me that while I cant move the decimal point I am not using any of the other 2 decimal points anyway so I can eliminate it.
Traced it down with the scope and found that at the left edge of the board there is a through hole that connects the decimal point common to the dropping resistor from the processor and drilled it out so the 2 sides of the board no longer connected that trace.

Voila, no decimal point:

Also decided not to use the LED output of the Ego board because I can use the voltage display as my indicator by feeding its power from the Ego board output, so I added a wire to the Ego output and removed the wires to the LED output then after making sure it worked properly potted the whole board in hot glue to provide some resistance from Eliquid getting on it.

That's all the time I have for today.

 

[Plinkk]

That thing is looking great man I can not wait to see the finished product..

 

[Alexander Mundy]

Well, not finished yet, but functional.
I have been working 12 to 14 hours 7 days a week so it is hard to find time.
Still need to install mounting for the top (but it fits pretty tight like it is) and finish the outside.

Displaying the combined battery voltage:

Displaying the output voltage:

Where the bottle, potentiometers, display switch, and fuses ended up:
(BTW, the black just sanded right off the front of the display)

The guts inside the top:

If I do this one again I will use different potentiometers and in a different location.
When I started cutting for them I didn't pay attention to the room that was going to be taken up by the bottle and had to make due.

 

[pdib]

SWEET!!!!

 

[Alexander Mundy]

Yea, but the sweet part is that mod sitting beside it.

 

[Alexander Mundy]

Well, something unexpected happened.
I am (was) using the battery closest to the negative side to power the ego board from a common connection between them.
I didn't think of the ramifications if that battery wasn't in and the other was.
It puts a reverse polarity on the ego board and bricks it!
Removed it and hooked the switch directly to the converter with a pull up resistor.
Vapes the same, but my 5 click, low voltage cut out, and timeout are missing now.
Will have to ponder that mistake and how I might make another ego board work.
First inclination was a simple diode in series with the power to the ego, but the ego would shut down .7V early so not good.
Second is a Zener and resistor to use the ego from the series battery voltage, but that would have a parasitic power draw and the voltage cut out wouldn't work.
Third is a small voltage regulator, but that would take up more space and increase the count of things that could go bad and ditto on voltage cut out.
Fourth, and maybe best, is a voltage divider hooked to the series batteries. Small parasitic draw, but voltage cut out would work and be a function of the average of the batteries.
Next version should have a custom micro to do these functions, but time is not something I have in abundance.

 

[pdib]

Awwwwwww, nuppin'