Rocketman

Rocket's 12 volt pass through mod

This is a guide to making a DIY pass through for operation from a cigar lighter in your car, truck, boat, or space ship. This requires some fairly close soldering, a little bit of hand machining with a drill, a file, and a sharp implement. Refer to the tool photo for everything I used to make this. You will also need a small battery or electric drill. A good two part epoxy would be handy. Wiring can be robbed from an old mouse cord, USB cord, or an old phone charger. We really aren’t concerned with resistive losses like we would be with a battery powered mod, so 20 to 24 gage wires are fine.

Many details may seem too simple to bother reading. Fine, if you already know some of this, it will be easier. If you already know ALL of this, you must be bored. This might be a way to breath new life into that dead eGo (or clone) you have lying around, especially if you spend a lot of time on the road (or in the dog house )

The cigar lighter plug and cord.
I have several excess car adapters for old cell phones, and who knows what else. I picked one that was for something that ran @ 12 volts, had a red led, and a fuse. A quick measurement shows the resistance of both the Positive and negative wires to add up to about 1.2 ohms. The small gage wires would not be adequate for a normal pass through but the current through the wires will be about an amp, and the voltage lost due to the resistance of the wires won’t matter in this application. Efficiency of a battery mod is important as the battery has to supply lost power as well as atty power, losing a few percent of the energy doesn’t matter with a car mod (I have a 130 amp alternator), and the Murata converter works more efficiently at a lower voltage generating less heat.

I cut the power cord plug off just behind the metal shell and trimmed the insulation to expose about ¼ inch of the wires. On mine, the red wire was positive, and the black wire was negative. Use your ohm meter to verify the + and – for yours. Leave as much of the molded rubber strain relief intact to protect the cord. I’m going to start out with a 2 amp fuse and hope the inrush current doesn’t blow it.

EGo disassembly.
Put an old steel carto and cone on the eGo and put a bending force to slowly work the connector out of the shell. Go slow and rotate the force around the circumference but try to not enlarge the end of the battery tube. Mine came lose with very little bending and pulling. None of the wires will be needed so just pull everything out the top, including the Li-ion cell. The negative lead of the cell is soldered to the bottom cap. Just pull it out. Trim the leads as short as you can and wrap the cell in some plastic wrap and get rid of it. The end cap knocks out of the tube easily. Remove the ego circuit board and put the plastic carrier, button, board, and center pin in a small container. Lose any one of these parts and you will be taking another eGo apart. Remove the center pin insulator and inspect it for damage.

The circuit board has about a dozen little parts on it that are useless. I used a box cutter blade (standard airline self-defense model) to cut all leads and remove everything on the back side and everything but the switch and LEDs on the front side. Just for fun, use the diode test on your meter to turn the cute little LEDs on. HINT: reverse the leads if they didn’t come on. The switch has 4 solder points. Find two that go to other solder pads that you can get to easily so you don’t have to solder directly to the switch (and melt it). Use your ohmmeter to verify the two points you found actually connect to the switch, and that the switch works. These will be the only two points we will use on this board. Solder a 3 inch piece of wire to each of these points. Test the switch function at the ends of the wires with your ohm meter.

Wiring.
In addition to the two switch wires, we will be soldering two to the power cord, one from the eGo connector shell, and one from the connector center pin. Make them all about 3 inches long. The negative ground wire can be soldered to the connector shell (don’t put it in the way of the board or plastic carrier) or solder to the end cap if you want but leave the center area of the end cap free.

The center pin of my eGo clone did not have a hole, or depression, just a flat surface to solder on. Hold the pin in an alligator clip, so it doesn’t move around and solder a wire to the center pin staying within the diameter of the end of the pin. If solder flows over the edge, trim it back with the razor or file. Inspect the connector insulator and replace it with a carto insulator it you want, now, not later. To reinstall the insulator, put it in the front end with the bevel edge down and push it in with the flat end of a 3/16 drill bit. You can try and bend it and work it in with little dental picks and toothpicks but it was designed just to be pushed in straight. A drop of PG might help lubricate it. Once you see how it is installed, and what holds the pin and insulator in place, maybe you will think twice before twisting and prying around on the center pin to fix a bad connection.

I pushed the end cap back into the tube shell to hold it to drill a ¼ inch hole as centered as possible and filed the edges to chamfer them a little. The rubber end of the power cable was a tight fit. Leave about half the strain relief on the outside. Remove the end cap and epoxy the cord in place. Make a small loop bend in the copper wire, pre-tin all the ends of the wires and solder a 3 inch wire to each power cord lead. Insulate the bare solder connections. I used the outer insulation from the cord I robbed the wires from, but heat shrink tubing would work.

At this point you should have the power cord glued into the end cap, two power wires soldered to that, the center pin with a wire soldered to it and insulator installed in the eGo front connector, a wire to the connector shell, and the switch board with two wires. I think that’s about six wires in total. Put the center pin, switch button, plastic carrier and circuit board in the eGo connector and make sure everything seems to fit. Take a break. You done good so far.

I'll have to remove the negative power lead and put on a longer one. It's not long enough as it is to assembly every thing from the top. Live and learn OK, negative wire replaced. I opened the cigar plug assemble again and put the series diode in there. I just cut the positive circuit run, scraped back some of the green solder mask and soldered a 3.5 amp BYV 28-200 I robbed from a computer power supply. I would suggest leaving a little longer leads on the diode.
and, why not a couple more pics.

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Rocketman

While we waiting on the rest of the parts, lets learn a little about this DC to DC Buck Converter.
Two models that I'm going to experiment with are the 3 amp and 6 amp models made by Murata.
The model numbers are OKR-T3-W12 and OKR-T6-W12. The spec sheets can be downloaded from the Murata site:

http://www.murata-ps.com/data/power/okr-t3-w12.pdf
http://www.murata-ps.com/data/power/okr-t6-w12.pdf

I ordered mine from DigiKey.

Even if some of the information seems like Greek Gobbledy Goop, at least look the spec sheet over.
You might just gleem a little info just looking at the pictures

See if the wiring diagram in photo 5 makes sense. Remember that this is NOT a BOOST converter. It is only useful to convert a higher voltage (like 12 volts) into a lower voltage (like 5 volts). The advantage over a linear regulator is the way that the voltage is converted.

A linear regular for a car application would need the same input current that is drawn by the atty. If you vape at 5 volts with a 2.5 ohm atty, then 2 amps will flow all the way through the circuit. The linear regulator eats up volts, but the series current remains the same. For a 12 volt to 5 volt regulator, 7 volts (at 2 amps) would be lost as heat in the regulator. 14 watts generated as heat would require a substantial heat sink. The input power would be 12 volts X 2 amps for a total input of 24 watts, just to get 10 watts out to vape on.

The Buck converter uses 'magic waves' to convert the 12 volts to 5 volts and generates less than 1 watt of heat for the 5 volt/2 amp example above. The extremely high cost of the Buck converter (over $6 for a 3 amp version) is the reason they aren't used more frequently in e-cig mods.

and the revised schematic. Don't know if it's the best design, but it works.

You folks that want high voltage use the 270 ohm fixed resistor and the 100 ohm trimmer for 3.79 to 4.97 volts.
I used a 330 ohm resistor for a range of 3.34 to 4.17 volts and set it for 4.00 volts out, unloaded.

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Rocketman

PARTS BE HERE, W00T

Got both the 3 Amp and 6 Amp but decided to go with the 3 Amp first. I played around with the pull down resistor and just went with 2200 ohms, and a 330 ohm fixed resistor in series with the 100 ohm trimmer. I could easily fine tune between 3.98 and 4.00 volts, I didn't verify the full range equaled the calculated range but 4 volts was close to the mid point on the trimmer with a 330 ohm fixed resistor.

I took a few photos with the wires, and resistors soldered to the converter. It went together sort of like a puzzle, but was able to get everything mounted to the 5 pins of the converter board. With all the fiddling with it I had to replace the small wires to the switch board with some less stiff.

The swamplady and I have already tried it in the car, and 4 volts (3.98 loaded) seems to fine. I'll post some more after we have vape tested it some more, but so far nothing seems to get hot.

NOTE: I wrapped a layer of heat resistant plastic (cut a piece from a microwave cooking bag) around the board to insulate everything from the eGo shell.

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Rocketman

Digikey part numbers:

6 Amp converter, Murata OKR-T6-W12, DIgikey # 811-2179-ND $8.25
3 Amp converter, Murata OKR-T3-W12, DIgikey # 811-2115-5-ND $6.20
Diode, 3 amp, 1N5401 $0.27
Trimmer, 100 ohm, Digikey # 3306F-101-ND $0.42
Shipping, USPS First Class was $2.39
1/8 watt trim resistors and pull down resistors not included, I already had them.
but they are only about $0.09 each. Maybe a couple of 270, 300, 330, and 3300 ohms.

You could get enough parts to build two of the 3 amp versions for about $17.00,

plus a couple of used cigar lighter power cord and dead eGos.

CountryCarolyn

Nice!!

Rocketman

Thanks, probably be Friday before the rest of the parts get here.


"Driving Down the Freeway Mod" already has a number 1 position

CountryCarolyn

I may attempt something like this with that riva. Not exactly but to give you another idea that I just got from your idea. I wonder if you could make a vv with the tubing and threading??

I ended up getting some vv regulators I don't have the other supplies but heck, the regulators were free, soooo I couldn't pass that up.

Rocketman

This could be done with a Riva, or any one of the eGo type Clones. The DC to DC Buck Converter I'm using takes 7 to 14 volts and drops it to 3 to 6 volts out. It is small enough to fit inside the eGo tube. Batteries won't fit.

A VV battery powered MOD using a linear regulator and two stacked batteries is different. You might be able to use some of the ideas, but you pretty much have to use the exact parts to make this work as described here.

MadVapes has a How-To for a battery VV Mod. Check his site.

Brutus

Love the tutorials Rock. One of these days I am going to get a soldering iron and get busy. I hope you keep it up. Just know that these are not going to waste, and that you always put out vital information; it is always greatly appreciated.

mrwizard

Nice one, Professor.
This project is at the top of my list for the day I ever get some free time again.

Rocketman

Parts came in, first one complete.
and guess what?

It works

more photos posted, and more to come. I looked at the spec sheet, and sketched out the parts, but you just don't realize how small these converters are until you see them in real life (6 amp shown). They even make a 10 amp one the same size as the 6 amp.

I did find out I have no need to go over 4 volts with an eGo Mega Dual Coil.

Figured I stay up since I don't have to go to work in the morning and start another using the 6 amp model. A little different in that I used a pair of 150 ohm resistor, as a 300 ohm fixed trim to hold the 100 ohm trimmer (300 to 400 ohms), and a 5.1Kohm pull down. Notice the 5 pins of the converter are bent in various directions to give me more room.
I set it for 3.85 volts, about 1.1 amps into a 12 volt bulb, and will let it 'cook' for a while. I'm running it off a 12V/5A power supply.
Here's a few pictures to show how the parts can be mounted right on the converter pins.


EDIT: I now recommend a pull down value of 3300 ohms instead of 5100 ohms when operating from a 12 volt supply.

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CigarMan

Rocket, you're truly a gifted man! Nice tutorial, I need to build one of these. I find my sweet spot on the ego duals is around 3.8-4v too, any more is too much.

RY4

Yes, very gifted and talented indeed. Thanks for sharing your wisdom Rocky.

Steampunk

Very nice but one question: how do you get to the trim pot?

Rocketman

Pop the top. But I don't expect to be doing it that often

I posted photos of a second one that might be easier to drill an access hole for the pot.
6 Amp converter.

Rocketman

I've tested the first one of these, and started making the second, and will test vape them between now and our road trip. I think this would be a great mod for someone that spends a lot of time on the road.

I'll set mine for about 4 volts and the swamplady's at about 3.6 volts (she normally vapes an eGo) and I doubt we will have any problems with this converter with the 'lite beer' vaping we do. It's just so neat, it makes you want to go out and sit in the car to vape

I'll be around to answer any questions if someone decides to make one of these (or any of the mods I've posted).

The tutorial is complete, this is the end of meaningful input to this thread.

Let the dibble begin

(kidding)

Rocky

Rocketman

Finished the second 12 volt car mod. This one has a power jack so I can hook it up to a 12V laptop supply and not have to go out to the car to vape it. I also tried to see just how small I could make it. Man, what a dumb idea.

I had a Vgo that bikes had sent me and another eGo connector. So I married those together. I cut the Vgo down to have just enough room for the parts. and put it together, took it apart, put it together, etc. There is no spare room inside. I also drilled a hole in the tube to access the pot and get 3.5 to 4.5 v.


One note about the pull-up resistor. I would recommend 3300 ohms. 5100 ohms give a control pin voltage of 0.51 volts (with 12 volts Vin). It still works but is over the "off" voltage in the specs. I'm not going to pull it apart to change it, but 5100 ohms might be a little to high if you run this off 12volts.

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40bikes

I've got a big blue recycling bin full of crap, I'll see if UPS will deliver it to LA. You do good with garbage,Rocky

Steampunk

I think you should call it the "Rocket Down The Highway" mod...

Rocketman

Not necessary. I go out late at night and rummage through the neighbors trash every Monday night.

Steampunk

Hmmm...ya know, I believe he does!

mrwizard

Martha! That little green man in the daisy dukes is a-goin' thru our trash again!
No, I'm serious.

No! I ain't been drinkin'.
Gimme my camera, quick!

Dang, too late... he's gone in a cloud of vapor again.

No, I told you I ain't been drinkin'!
...well... not much anyways...

RY4

Too funny Dr. Wiz LMAO!

Steampunk

Oh, I reread it. Iat first I thought it said "Green cloud"...

RY4

I'm sure there was probably a green cloud around somewhere. There all over some of the threads here.