5V RIT (Regulator-Ina-Tube)

[candre23]

Here's a potentially lucrative accessory idea for anybody with the tools/ability to pull it off. There are a lot of mods that take an 18650 or 14500 that could be made into HV mods by using two CR2/123A or 14250 batteries respectively. The problem is that even with 3V CR2/123A batteries, you get a 6V vape that is a bit more than many people want. With two 14250s you end up with 7.4V, which is too much for anybody. An AP1084D50 5V 5A regulator is only about 6.5mmx9.7mm. This could easily be fit into a tube the size of a 510 atty with connectors at both ends. For less than $8 in parts (a lot less if you can get atty/battery connectors wholesale) you could build a regulator-ina-tube that could be put between any 3.7V mod and atomizer. With the right batteries, it would now be a 5V mod. At a reasonable price ($25-30), they'd probably fly out the door.

 

[duke118]

Thats what I'm trying to do myself,the problem is the amount of heat the regulator makes.My box regulator lasted about a month of heavy vaping.The best way to go about this is 3.7 volt low resistance atty witch I will try next.

 

[candre23]

the problem is the amount of heat the regulator makes.

What was the current rating of your reg? I'd imagine a 5A rated regulator wouldn't have too much trouble with a ~3A load. Plus, being in an aluminum or copper tube would allow it to dissipate heat better than in a plastic box. Especially if you put a dollop of thermal grease on the back to bridge the gap between the flat regulator and the round tube.

LR attys give you (nearly) the same heat at 3.7V as a regular atty at 5V, but they're only available in 510s right now, and they generally burn up in about a week.

 

[Rocketman]

Does this one have the ability to cut off current when voltage of one of the cells drops to an "unsafe" level? Or is the user supposed to stop sucking when it stops vaping (sounds dumb but the shoe fits some people).
Some regulators will keep conducting and try to put out 5 volts even when input voltage falls. I think this one has a 1.4 volt drop out which would actually be safer than a low dropout regulator with 0.4 volt dropout. With this one anything less than 6.4 volts and the output starts falling off, which the user should notice.

R

 

[yanks21]

Candre, I think you're absolutely right.

I really am surprised there aren't more 5v mods out there as many agree it's the "sweet spot"

Prodigy is going to stop being a 5v device so as of now the only retail mods at 5v are: The Xhaler and The GLV correct?

I know the Joker is coming soon but as of now it's unavailable . . .

 

[candre23]

It's a linear regulator, and it requires that the input be at least 6.4V (at 5A. It's probably a bit lower at 3A), so if one cell dropped out due to the PCB cutting it off, you should get nothing on the output. Unfortunately, there's no way to monitor the batteries individually without a complicated circuit, so although you're relying on the battery PCBs to avoid damage, it's the same story with any 5V regulator.

EDIT: On further inspection, I don't see any mention of a cut off voltage in the spec sheet. However, if one cell drops out, you'd be looking at only about 2.7V (3.7 - 1V drop out @ 3A, but probably even less than that unless your batteries are wildly unbalanced) output. I think anybody would immediately notice the difference between 5V and 2.7V.

I suppose if you wanted to get really fancy about it you could add a 5V LED in parallel with the output. That way, if a cell dropped out, you'd see the LED not lighting up. Kinda defeats the simplicity of the mod though.

 

[Rocketman]

Agree,
Protected cells would protect the vaper from an unsafe unbalanced battery condition.
Would have to be a pair of protected 3.7 volt cells as a pair of 3.0 volt cells would not get to 6.4 volts.
The little bugger does have a pretty high temp coef though. Lets see, 7.4 - 5 = 2.4 volts, maybe 2 amps = 4.8 watts dissipated at a junction TC of 12C per watt=+58C over ambient, + TC of heat sink =??

How warm do you think the little tube would get?
Heat input would be from conduction from atty? and from regulator?
At least hotter than the atty shell by itself.
They have these little press on radial transistor heat sinks that would look absolutely cool on this idea. Anodized in an matching color, and they are pretty cheap.
You may be on to something. Dead atty for case and one connector. Dead battery for the other connector. One off prototype would be cheap.

And warn people not to try this with unprotected cells, because this regulator will keep trying all the way down to 1.5 volts input.
R

A little guess work on thermal effectsjust a guess)
The junction resistance for the smaller of the cases for this regulator is 12C/W
A joye 510 at 5 volts would be at least 2.2 amps, and a pair of 3.7 volt cells would give 7.4 for a while giving a component dissipation of 5.3 watts. If the tube (about 10mm in diameter and 25mm long) was copper then the still air thermal resistance would be about 40C/W. But that would be for continuous heat input. If we assume a 10% duty cycle (about two 3 seconds vapes a minute) then we could use 4C/W (disregarding spreading resistance and heat input from the atty (it does get warm) then we add about 21C. On a warm day, vaping, and holding this in our hands then ambient could be at least 30C.
Our junction temperature would be at least 111C. This is getting pretty close to the 125C specification and we left out some of the heat sources.
Heat kills. Current ratings not withstanding, junction temperature will heat up the device case and let all the smoke out. Once that happens it quits working.
Regulator in a plastic box? Indeed

Does anybody remember the old Pentium 60mhz Cpu (that was a little before the Pentium 4) and the heat sinks that Intel supplied that weren't good enough so they went to forced air?

The Pentium 60 dissipated about 12 watts.
Without the heatsink the CPU would overtemp in about 30 seconds.

486/50 only dissipated 5 watts, but that was before dirt was even invented.

 

[candre23]

I couldn't find any radial heatsinks that would fit on a TO-252 chip and fit inside the tube. Personally, I think a bit of this would work even better, making the whole tube a heat sink and securing the chip in place. Yes, it would get hot, but so do attys. It probably won't get hot enough to burn, but I guess it will take some experimentation to know for sure.

 

[Rocketman]

I couldn't find any radial heatsinks that would fit on a TO-252 chip and fit inside the tube. Personally, I think a bit of this would work even better, making the whole tube a heat sink and securing the chip in place. Yes, it would get hot, but so do attys. It probably won't get hot enough to burn, but I guess it will take some experimentation to know for sure.

No I meant radial heatsink on the outside, part of the Bling aspect.
Tube itself won't be enough. The little chip inside the chip will be 120 degrees F HOTTER than the tube. Then the tube heats up. Gotta get rid of the heat.
I hate to make this sound negative because it's a great idea, please, I don't mean to be. This would be one cool little accessory. Swap batteries, install the regulator tube vape at 5. Strip it back down, swap batteries, vape at 3.7. Universal accessory. Just a few details to work out.

 

[candre23]

The chip does have thermal shutdown protection, so I guess worst-case it would simply stop working until it cooled down a bit. Like I said, some physical experimentation is needed.

 

[Rocketman]

agreed

Another example of "thinking outside the box"

 

[Krythis]

I don't have any commercial mods, but I use a version of the fog log I made that has a 5v regulator from MadeVapes. There a bit of a pain to get set up in the copper pipe, but I'd rather pay 2.29 for a regulator I need to solder in than a atty shaped regulator for ~$20.

 

[candre23]

That's great, but a lot of people do have commercial mods, and there is usually no way to add a regulator to them. This is not so much a project for modders to use in lieu of incorporating a regulator into their designs, but instead a project for a modder to make and sell to people who already have 3.7V mods.

 

[Rocketman]

I don't have any commercial mods, but I use a version of the fog log I made that has a 5v regulator from MadeVapes. There a bit of a pain to get set up in the copper pipe, but I'd rather pay 2.29 for a regulator I need to solder in than a atty shaped regulator for ~$20.

Krythis,
Foglog could easily dissipate the heat from the regulator. Lots of copper for a heat sink.

But the inline atty-reg (with a few of the bugs worked out) would be marketable, especially to the folks that pay $20 for another atty top for their commercial mod. Or the modders that are melting their plastic boxes.

Would probably be the perfect SD accessory. Are there 2 protected batteries that will fit in a SD?

and in order to buy one of these inline regulator you would have to pass an on-line IQ test to see if you were smart enough not to try stacking unprotected cells.

R

 

[candre23]

Would probably be the perfect SD accessory. Are there 2 protected batteries that will fit in a SD?

Not the real SD. Both the MK1 and MK2 use 340mm batteries. There's nothing short enough to get two of them in that space. You could use two protected 14250s in a DSE901 (14500 SD clone) without modification though. Even better, you could stick one of these on a VYPR for what has to be the worlds smallest 5V mod.

 

[WillyB]

Candre, I think you're absolutely right.

I really am surprised there aren't more 5v mods out there as many agree it's the "sweet spot"

Prodigy is going to stop being a 5v device so as of now the only retail mods at 5v are: The Xhaler and The GLV correct?

I know the Joker is coming soon but as of now it's unavailable . . .

If you've noticed the fancy American mods are quite basic. The 5V models you mentioned do not use regulators nor are they even true 5V devices. They just use a resistor to tone down the initial voltage. This voltage is constantly dropping as you vape, while a high quality regulator (like the TI ) will maintain a true 5V during the whole session. But with just a straight through mod (without anything) it turns out if you use a Joye atty and a pair of the 3V Tenergy LiPo's you are vaping at 5.18V right out of the gate anyway.

 

[candre23]

I finally had a chance to test out this part. I think this can work, but it will be a bit trickier than I originally though.

I soldered some wires to the AP1084 and hooked it up to a 2xAA battery box with 2 14500 batteries, and a 3ohm, 20W resistor as a dummy load. With no heat sink, the regulator went into thermal shutdown in 8-10 sec. Not good enough, obviously.

I stuck a small heatsink (about .3x.5in) on it, and that did the trick. Even without any heatsink compound and the chip held on with a twist-tie, I was able to run it for over a minute without it shutting down. Without the heatsink, the voltage would start to drop a second or two before it shut down. With the heatsink, it held steady at 4.94V the whole time.

Here's the tricky bit. The metal plate on the back of the regulator where the heat sink needs to be attached is also the 5V output. That means it needs to be insulated from ground, which means using an old atty tube is pretty much out of the question. You might be able to do it with some plastic spacers between the connectors and the tube. A better idea would be a specially machined, finned tube. You'd get better cooling, and with the inside having a flat surface, you could easily attach the regulator with an electrically insulated heat sink sticky-pad. Any idea how you might go about making an aluminum tube with a cross-section like this?

 

[Sci]

Haven't tested it for heat endurance, but how about painting it with liquid electric tape? What kind of temperatures are you getting?

 

[candre23]

I don't have anything small enough to measure the temp at the back of the reg. The reg shuts down at 150c, so the temp at the back is probably close to that. That plastic dip stuff is a no-go, as it is not thermally conductive. I need the heat to transfer from the chip to the tube to keep it cool enough to be useful.

Just for the hell of it, I stuck the regulator in an old 510 atty tube and squeezed in a bunch of silicone thermal grease. This stuff isn't meant to fill a 1-2mm gap, but it actually worked halfway decently. It ran for about 50 sec before shutting down. I waited 30 sec for it to cool a bit and got another 30 sec before it shut down again. The tube was pretty hot by that point, but I think it would work well enough for all but the most rabid chain-vaper.

I did some poking around to try to find a non-conductive thermal adhesive that didn't cost an arm and a leg for a couple drops worth, and came up with nada. Arctic Silver makes some, but it's just too expensive. I'm thinking of trying some of this stuff instead. It claims to be non-conductive, and I'm hoping the fact that it "contains metal" will allow it to transfer heat somewhat well.

 

[MastiffMike]

Have you seen Tinear's B.O.B. add-on??