Mech mods: voltages

[sonicbomb]

Can I .... in here and ask for a dummy's definition of heat flux? I've read some stuff but it is not clicking in my head. I mean, I know it is a measure of watts per (surface?) area, but I'm not sure what that means in practice. Thanks!

It describes the relationship between heat and surface area, I don't know how to break down the specifics of how it's calculated. If you are using steam-engine it acts as a guide to how hot the coil will be. Some people like a hot vape, some cooler. It also helps you to model your coils potential vapor production.
Imagine a coil of only three wraps but carrying a large wattage, it's going to be very hot with relatively little surface area. It's going to scorch your lungs and not produce a lot of vapor.
Now imagine a coil using the same guage wire but 14 wraps. With the same wattage or even higher the coil will be cooler, but as it has much larger surface area it has the potential to produce more vapor without the scorch.

Read the first post of this thread. It's long, but well worth the read and should help you understand the relationship between surface area and heat how it pertains to vaping.

 

[Layzee Vaper]

The heat flux gives you a good indication of how hot the coil will be, the higher the number the hotter the coil will be. Different wire types and thickness's will run at different temperatures at the same resistance values.

Steam engine will also give you a heat capacity value, this is a measure of how long the wire will take to heat up and cool down. The higher the number the longer it will take for the coil to heat up.

In general thinner wires will run hotter and heat up faster than thicker wires at the same resistance values.

With a mech you have to work within the battery limits and you will find that certain wire types and sizes work best at different resistance values.

Its a matter of trying to find the right balance between surface area of the coil, temperature of the coil, and how long the coil takes to heat up. When you add different airflow, juices and personal preferences it's a bit of a learning curve. However once you find your sweet spot, you are rewarded with a very reliable vape.

 

[sawlight]

Glad to see you asking questions, and listening to solid advice so far!
A mech mod is only as safe as the space between your ears! Keep that in mind, and you'll do fine!
As Soncbomb showed, watts is a function of amps and voltage, amps is a function of load (Ohm's, resistance) and voltage. All of these factors create and add to the other factors to calculate the others.
I've never used steam engine, I've got a couple of coil apps on my phone, I don't use them either, I'm bad. I've done enough coils, and mainly just use 26awg Kanthal, that I've got a pretty good idea what it's going to be when I start, then I check it on an ohm meter.
Also keep in mind, as I haven't seen this mentioned yet, as you add coils, the resistance drops. Two coils it drops by half, three coils in thirds, four in fourths and so on. Keep that as you build. Say you want to run a quad coil and want an end result of .5 ohms, you will need to build four coils at 2 ohms each to get that. Does that make sense? A dual coil, you'd build two 1 ohm coils to get .5 ohms.
Then THE MOST IMPORTANT FACT!!!! Know your battery, know your batteries! If you build a setup and use a 20amp battery for it, then one day decide to use a 15amp battery, you better make sure the build is within the safe limits of all the batteries you plan to use. I also like to allow around a 20% safety margin, as batteries get old they can't carry the same load as when they were new. This is just CYA.
A single battery mech is the only place I'd tell you to start. I'm old school. I remember back when we had stacked battery mods, and I remember why we got away from them! I remember all the warnings that used to be on this site about their use, and recommended not use! It REALLY SCARES me to see all these new members picking them back up!
To use a dual battery mech, you MUST keep the batteries in matched pairs, you MUST drain and charge them in pairs and even then, there's still no garuntee one isn't going to go bad and blow. I'm not a big fan if you can't tell!
Start with high, 1.2 or so ohm builds, get comfortable building them and making them work, then start going lower. That high you aren't stressing any battery if you have a problem. Then once you get there regularly, go lower, but always know the limits of the battery, and stay withing them!
I hope this helps some.

 

[Spazmelda]

It describes the relationship between heat and surface area, I don't know how to break down the specifics of how it's calculated. If you are using steam-engine it acts as a guide to how hot the coil will be. Some people like a hot vape, some cooler. It also helps you to model your coils potential vapor production.
Imagine a coil of only three wraps but carrying a large wattage, it's going to be very hot with relatively little surface area. It's going to scorch your lungs and not produce a lot of vapor.
Now imagine a coil using the same guage wire but 14 wraps. With the same wattage or even higher the coil will be cooler, but as it has much larger surface area it has the potential to produce more vapor without the scorch.

Read the first post of this thread. It's long, but well worth the read and should help you understand the relationship between surface area and heat how it pertains to vaping.

Excellent! Thanks so much, that cleared a lot of things up for me.

 

[bwh79]

What determines the wattages? Is the volts set to a specific level, on each of the different mods or are they all the same?

Since I haven't seen it mentioned (or maybe it was and I just missed it), the voltage depends on your battery's charge state. It is not "set" to anything in particular -- that's what differentiates a "regulated" device from a mechanical or "unregulated" one. There is no regulation of, or control over, the voltage at all. It just is what it is, at any particular moment, and it will change from one moment to the next. The device is basically just a battery holder and a mechanical switch to complete the circuit. There is nothing else going on in between. No circuitry, no safeties. It just dumps raw battery power into the atomizer, whatever that happens to be. And "what that happens to be" will be around 4.2v at full charge, and then gradually decreasing as the battery charge depletes, down to around 3.5-3.7v when you will probably want to change or charge the battery.

 

[EdT586]

I = V/R
W = I x V

Wattage is determined by your coil build as well

 

[edyle]

Wow! I'm nearly getting there
I found on some tutorials that, on a noisy cricket, it is recommended to build around about 3-6 ohms. I just understood from that, it is not a good idea to go "super" low on any unregulated mod eg. Cherry bomber v2 or hex ohm

using numbers that are ten times higher or lower in your calculations can be hazardous to your health.

 

[edyle]

So, is this right?
On mech mods. depending on what coils you build and what ohms it's readings. The ohms determines what current it's drawing ? What determines the wattages? Is the volts set to a specific level, on each of the different mods or are they all the same?
Is there any differences from using dual 18650 and a single 18650, considering the batteries were the same?

I've done some studying on the ohms law, still I thought, by understanding it using an unregulated mod as an example (I've not purchased any btw) I'll be able to get a clearer picture. I've read some answers posted by other members on another part of the forum. Hmm...

1: Yes. With a mech, the ohms determines what current is drawn.

2: watts = volts x volts / ohms

3: on a mech the voltage is the voltage of the battery. nominally 3.7 volts.

4: two batteries can deliver twice as much power as one.

5: most mods nowadays show everything on the screen, so just paying more attention to the numbers on the screen will help you understand ohms law.

 

[Tivaliman]

using numbers that are ten times higher or lower in your calculations can be hazardous to your health.

Oops! Mistakes. I meant to write inbetween .3 ohms and .6 ohms *note: I didn't place the .point!