Technical Question: Why is it so hard to build a functional dry herb mod for ecigs?

Maybe this is a stupid question, but why is it such a big problem? I don't know much about technology, but i'm thinking since a while, that a simple bimetal trip could keep the herbs from combusting. the same mechanism the iolite and wispr work with, i believe. Can't this be used for an ecig somehow? Another idea would be to program a heating interval, that stops heating from time to time automatically, so that the herb chamber never gets too hot. Might take a lot of time to find such an interval that works with different herbs, but i think that can be done with a lot of temperature measuring.

Maybe someone knows why these things can't work. I'm not an engineer and could never implement such things, so I might be wrong, for sure.

The thermovape Evo is a 510 threaded herb cart that works on a mech mod, but it generates a tremendous amount of heat, so much so that any mod that isn't insulated will get too hot to hold. There is no way around it, it takes a lot of heat energy to vaporize dry herb.

clouded vision said:

There is no way around it, it takes a lot of heat energy to vaporize dry herb.

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That, I think, is the key to the castle. Evolution uses 20 Watts, give or take, and has to build up heat before the hit (not possible except in convection systems). Far past most e-cigs ability.

Physics is against the idea.

OF

Ecig batteries usually cannot provide enough power to vaporize dry herb.

but they manage to combust them?! doesn't make sense to me.

This is the difference between convection/conduction!

The evo is the only one true convection cart but it need a lot of power to get some hits (8 hits with 2Xrcr213a!).

The conductions heating system are more "powerfull" cause herb sits directly onto the heating coil (or around the heating center pin) and can easily burn here to be able to vape a bit the rest of the load and you obtain a black and green abv, and a bad taste!

I tried my evo 6V with my Persei, I put 2xrcr123a into and attached the evo cart with an adaptater it worked really nice but after 2 or 3 hits the Persei top was really warm so i stopped heating process to preserve my Persei!

I think about to use my sr-74 connector between my evo+adapteter and my persei as an insulator...what do you think about this? (my persei is a V2).

mrweed said:

but they manage to combust them?! doesn't make sense to me.

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Think about it. Combustion is fire, once started it generates all the heat it needs to keep going. Making vapor is like boiling water, you need a constant energy input to make it work.

OF

I think temperature regulation is also key. An ecig coil is great for heating up hot and fast but is hard to control the temp, but for a herb vape the maintenance of a specific temperature is much more important. I imagine this would also necessitate more complex hardware/circuitry.

photobooth said:

I think temperature regulation is also key. An ecig coil is great for heating up hot and fast but is hard to control the temp, but for a herb vape the maintenance of a specific temperature is much more important. I imagine this would also necessitate more complex hardware/circuitry.

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Sorta. Remember, probably the best (portable) dry herb vape made, Cera, has a glowing coil..... It's how heat is used I think.

To understand you need to separate heat from temperature. They are different. It's important not to let the temperature of dry herb get much above 400F as combustion is lurking. But to make vapor you'll need a constant input of heat. If you didn't make vapor, the temperature would go up, but as long as you do make vapor the heat causes more vapor, not higher temperatures.

Think about boiling eggs. The water is 212F, any extra heat doesn't change that, it just 'boils faster'. The eggs cook exactly the same since they 'see' a 212F water bath (or less at lower pressures/higher altitudes, which is why a 3 minute egg in Denver is to be approached with caution....). As long as there is water remaining. This is an important concept I think. For instance it's why Cera works so well. Extra heat (drawn from the core) makes extra vapor but doesn't raise the temperature.

Degrees and calories are different animals. Best not to confuse them.

OF

It takes alot of power, as well as large thermal mass, to heat air. Ecigs and concentrate pens just need to use enough energy to heat a little liquid. Vaping bud involved heating the air that will bathe the bud.
The Cera seems to have a working heat exchanger. The Lotus is a torch-powered vape, it seems to have a cutting edge heat exchanger. I look forward to seeing someone couple it with a handheld 30W or 50W heating element. An electric powered Lotus head with a 510 power connector. It can be done.

215z said:

I look forward to seeing someone couple it with a handheld 30W or 50W heating element. An electric powered Lotus head with a 510 power connector. It can be done.

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I would not hold my breath. 510 is just not up to the power. A half of that, at best. Which is why TV went to the larger connector they used on Cera. Even their special built "510" connector line from T1 barely handled the load in 'near ideal' conditions. Like ideas based on "USB Power", there's just not enough to do the job fast.

Log vapes do fine on 8 Watts, but build up working heat over 20 minutes or more. But 8 Watts is about all you can really go looking for from 510s, 15 is about the most any but 'brute force' battery mods deliver?

The only other way around it is to really hammer special batteries like the T1 did to get to 30 (5 Amps at 6 Volts) or Flashvape. MFLB does this as well, with 15 Amps from that poor little NiMH AA cell.

An electric Lotus could be fun. You can probably do it by reshaping the foil cover some by direct heating (run the current directly through it). Doing so on batteries would be a challenge indeed I think.

There's a lot of smart guys working hard on this very idea and coming up dry. The lack of useful vapes on those lines in the market is not for lack of trying.

OF

OF said:

I would not hold my breath. 510 is just not up to the power. A half of that, at best. Which is why TV went to the larger connector they used on Cera. Even their special built "510" connector line from T1 barely handled the load in 'near ideal' conditions. Like ideas based on "USB Power", there's just not enough to do the job fast.

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Hey OF

Not to challenge a man much smarter then myself on this subject, but there are ecig box mods that claim to be capable of hammering 120 watts through a 510 connector. I myself am pushing according my calculations about 70 watts hot off the charger on a single 18650 sony vtc5. (http://3.bp.blogspot.com/-RmyUb0MGpmw/U0bMaE_bmAI/AAAAAAAAUxc/b0-YKaDMoEc/s1600/Capture.JPG)

Is the problem with the 510 connector, that the voltage drop through it causes to much heat to build up in the time we need to do convection vaping?

As I see it (without the lens of an electrical engineering degree) the problem lies more in moving and containing the heat necessary to vape. The cells seem to be gaining quickly in terms of performance 18650's can do 2500 mah with 30 amp continuous discharge and 26650 are even higher....

Puffers said:

As I see it (without the lens of an electrical engineering degree) the problem lies more in moving and containing the heat necessary to vape.

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I get that, I'm just giving you the reason(s) I don't think that's happening. And, face it, it's not happening. Again, lots of guys have and are trying to do this simple job for what is obviously a ready market.

Again, consider FlashVape. You're getting close to the power you want, even if not for long or very reliably. It eats through it's batteries (but does produce lots of vapor fast) but is way past the size most are willing to accept? Or the battery life?

It's at least as much a job to develop the needed power long term on demand as it is to use that power effectively to make vapor.

"If it was simple we'd just have the Janitor do it".

OF

OF said:

I get that, I'm just giving you the reason(s) I don't think that's happening. And, face it, it's not happening. Again, lots of guys have and are trying to do this simple job for what is obviously a ready market.

Again, consider FlashVape. You're getting close to the power you want, even if not for long or very reliably. It eats through it's batteries (but does produce lots of vapor fast) but is way past the size most are willing to accept? Or the battery life?

It's at least as much a job to develop the needed power long term on demand as it is to use that power effectively to make vapor.

"If it was simple we'd just have the Janitor do it".

OF

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Appreciate the feedback and your input as always OF. Just trying to wrap my head better around where your coming from. I work with 480v-24v AC usually and low voltage electronics and their intricacies/fall backs can sometimes be a bit foreign to me.

Puffers said:

Appreciate the feedback and your input as always OF. Just trying to wrap my head better around where your coming from. I work with 480v-24v AC usually and low voltage electronics and their intricacies/fall backs can sometimes be a bit foreign to me.

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Understood.

Perhaps reflecting on 'why 480 Volts?' might help? In general, as we need to do more work (Power, in Watts) we go to higher voltages so we can keep the Current (in Amps) in the reasonable range. We shifted from 6 Volt to 12 Volt cars long ago for this same reason, lower current so smaller wires, saving a little money on each car.

So in our houses (using a few kW) 220 service is fine. A 100 Amps or so is all we want. For the neighborhood, we use (typically) 12kV so many houses on the street can use the feed (through their common step down transformer on a pole somewhere) at some reasonable current. Same deal with the dozens of Watts in such a dream vape. That's significantly above reasonable currents at 3.7 Volts, we need to go to multi cell batteries, fighting a losing battle with all that brings.

I used to work for an outfit that made X-ray machines for cancer treatment. Seriously big, 15 and a half tons on the hoof with all the lead and covers on. A standing joke reply to 'wow, they're big' was "It'll be portable......as soon as we put the handles on".

Same deal, I think. With the state of the art you're going to need a much bigger shirt pocket to put it in.

OF

I think if the Grasshopper pans out that will be the closet thing to an e cig like shape, I would love one exactly shaped like an e cig though...