How to save battery on a double coil RDA.

[sandwiches]

hi guys I have a nuke RDA that needs two coils by default. But when used on my evic vtc mini I have to crank up the watts to 30 to get a satisfactory vape and it eats my battery way too fast. It reads 0.3 ohms by the way.

So instead of using two coils, i used one coil at 1.1 ohms, but still I have to crank up the watts to 25.

Contrast this with my sub tank mini which I get a nice vape at about 9 watts at 0.6 ohms.

Is there something I can do to make my nuke RDA require less watts to heat up faster?

Thanks.

 

[MVP]

Hey Sandwiches,

I'm kinda new into vaping, but I thought I'd at least give it a go to answering your question.

First thing, what battery are you using? If you have a lowers Mah your battery will not last as long.

What wire are you using? If you use like clapton coils, it is going to take longer to get the coils going and drain your battery faster.

Only last thing I could think of is to just get your ohms higher, by more wraps and a bigger diameter.

regardless 25 watts seems really low to me, and haven't heard of many people going below 25 watts.
Thanks, MVP

 

[Moueix]

hi guys I have a nuke RDA that needs two coils by default. But when used on my evic vtc mini I have to crank up the watts to 30 to get a satisfactory vape and it eats my battery way too fast. It reads 0.3 ohms by the way.

So instead of using two coils, i used one coil at 1.1 ohms, but still I have to crank up the watts to 25.

Contrast this with my sub tank mini which I get a nice vape at about 9 watts at 0.6 ohms.

Is there something I can do to make my nuke RDA require less watts to heat up faster?

Thanks.

Absolutely! Get your self some 32 gauge wire. It is much higher resistance per foot (or inch, or whatevs). The easiest thing to do is use the Battery Drain feature on Steam Engine calculator, but I want to help you visualize the WHY too, so here is the calc:

http://www.steam-engine.org/batt.asp

Now the why. It is easier to understand if we talk about water instead of electrons. Your battery is a bucket. It holds X amount of "water". Your coil is a hose. You are going to put water through it. Pressure in the hose is the resistance. SO.. You want your water to last as long as possible. Use the thinnest possible hose. It takes much less water to fill it and create the pressure. The LONGER the hose is, the more resistance it will have also, to how fast the water flows. Resistance is heat to an electron.

 

[Moueix]

Forum is pissing me off with the "not allowed to post" nonsense.. where were we...

So the longer, and thinner, that your coils are, the more resistance you will have. The more resistance, the longer your battery will last to produce the same amount of "pressure" or heat.

OK, from Steam Engine, here is your RDA with 24ga coils at .3ohms. a 7/8 wrap on each coil with a 2.5mm diameter to achieve .3 ohms dual. Making some assumptions, but it's all the same. Look at the heat flux you get for your 50w. 184 mW/mm^2. That is how hot your coil gets. Look at the heat capacity below that. That is the mass of your coil. So how long it is going to take to REACH that temp, and how long to cool down. SMALLER is much better.



Now here is the same setup, but with 32ga wire: 1.7 ohms. Take a look at how much heat 50W produces! WAY too much. Same amount of juice from your batt as the other setup though, so no power savings, but LOTS more heat. We don't need all that. Lets try to get the same heat after I show you this.



Now lets get back to the same heat with the 32ga, that you had with the 24 ga. That 187 mW/mm^2. Look! We gotta turn that sucker down to 18 watts to get there! So MUCH less drain on your battery. AND, as an extra, you onliy have a heat capacity of 7.9 instead of 55, meaning your coil will heat MUCH faster, and cool much faster too. A better vape, by far!




Now if you go play with these numbers in the Battery Drain feature on Steam Engine, you will find that with this 1.7 ohm setup with 32ga wire, you will get 3X as many 5 second draws as you were getting with the 24ga setup at the exact same amount of heat! You'll get a lil less vapor, because you don't have as much SURFACE AREA with the smaller coil, but it will be well worth 3X the battery life. Take a lil longer pull, and get the same vapor, and at least double the battery life.

 

[sandwiches]

Thanks guys so much for the replies. I got a much clearer picture now.

 

[sandwiches]

Ive been playing around with the website. And I realise despite the same resistance, different awg will affect the heat flux which is something I never noticed.

 

[Moueix]

Ive been playing around with the website. And I realise despite the same resistance, different awg will affect the heat flux which is something I never noticed.

I love the much thinner wire, like 32ga.
Many do not, and I think it is because it is much more fragile, and difficult to work with. When you re-wick a 32ga coil, you have to be more careful to not de-form the shape.
Another advantage of the 32ga vs. 24 or 26, is it is thinner, so you can fit MANY more wraps in the same diameter deck. So getting 1+ ohm builds, even with dual coils, is quite possible.

 

[ej1024]

28 gauge 10 wraps dual coil 2.5 id
That should come out ..3ohms 15 watts will fire these badboys
Goodluck


VAPE IT

 

[rolf 2]

hi guys I have a nuke RDA that needs two coils by default. But when used on my evic vtc mini I have to crank up the watts to 30 to get a satisfactory vape and it eats my battery way too fast. It reads 0.3 ohms by the way.

So instead of using two coils, i used one coil at 1.1 ohms, but still I have to crank up the watts to 25.

Contrast this with my sub tank mini which I get a nice vape at about 9 watts at 0.6 ohms.

Is there something I can do to make my nuke RDA require less watts to heat up faster?

Thanks.

what do you mean duel coils by default ?
I am using the boreas with a single coil , at 14 watts !
2.5 mm kanthal 28 g 7 wraps , about 1.2 to 1.5 range. or even one of my favs a four strand 34 kanthal.twisted .
which is a little harder to rewick (more flimsy )
the boreas is the big boys atty . don't let that detur you . what I did to vape low watts is a made an insert from silicone putty, which cuts down the chamber and also closes the opposite air hole . works like a champ !
the silicone is food safe and high temp . now the large juice capacity and long battery life ..nice flavor to !
here is what I mean

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