Become a Patron!

Help with Low Ohm tube style Mech Building w/2 batteries

P

Palmer1997

Hi, I recently got my hands on an authentic Rogue brass mech, and it came with an extra tube/sleeve to make it a series with 2 batteries.

I know what NOT to build on it so far, as far as battery safety is concerned. I believe I have my ohms down, but I’m definitely mis-understanding something about how 2 batteries in a mech mod work as series.

I have .17 resistance coils on it, which if I do calculations is abouts 20amp and very safe with 1 battery calculation.

When I do the two battery calculation, it says I’m pulling a tick above 40amps, that’s not very good right?Obviously way over the 2 batteries each 30amp rated discharge 18650 s20’s.

The person who built it for me said this was OK in a stacked 18650, and I trust him he has had 10+ years building mechs and such. Was he just comfortable putting this on due to sheer experience making them? It feels safe to use although very very powerful with the extra battery.

Honestly I feel silly that I’m questioning it so hard but I want to understand why this build is not only working so far, no hot batteries, But is safe if it has a 40a load on the batteries when the 2nd battery is added into equation when I stack them?

thanks for reading and putting up with my inexperience! So far I’ve been playing it safe with just single tube no stack, the dual battery is like taking a drag from a jet engine, amazing cloud and flavor but honestly scary to me right now. I’m just getting back into mechs again I’ve had regulated mods forever.
 
hawkwind5usa

hawkwind5usa

Bronze Contributor
Member For 4 Years
Screenshot_20200711-200540_Vape Tool.jpg
Palmer1997 said:
Hi, I recently got my hands on an authentic Rogue brass mech, and it came with an extra tube/sleeve to make it a series with 2 batteries.

I know what NOT to build on it so far, as far as battery safety is concerned. I believe I have my ohms down, but I’m definitely mis-understanding something about how 2 batteries in a mech mod work as series.

I have .17 resistance coils on it, which if I do calculations is abouts 20amp and very safe with 1 battery calculation.

When I do the two battery calculation, it says I’m pulling a tick above 40amps, that’s not very good right?Obviously way over the 2 batteries each 30amp rated discharge 18650 s20’s.

The person who built it for me said this was OK in a stacked 18650, and I trust him he has had 10+ years building mechs and such. Was he just comfortable putting this on due to sheer experience making them? It feels safe to use although very very powerful with the extra battery.

Honestly I feel silly that I’m questioning it so hard but I want to understand why this build is not only working so far, no hot batteries, But is safe if it has a 40a load on the batteries when the 2nd battery is added into equation when I stack them?

thanks for reading and putting up with my inexperience! So far I’ve been playing it safe with just single tube no stack, the dual battery is like taking a drag from a jet engine, amazing cloud and flavor but honestly scary to me right now. I’m just getting back into mechs again I’ve had regulated mods forever.
Click to expand...
Dunno boss. But my calculator says you're making a thermonuclear setup.
 
hawkwind5usa

hawkwind5usa

Bronze Contributor
Member For 4 Years
If your RDA is big enough here's a 80 watt setup I run in my double stacked mech.
Kanthal A-1, 26ga. You need 2 pieces of wire at least 6.5" long to make 2 coils. Do 12 wraps around a 3mm tool. Using the two coils in parallel will give you about .88 ohms. I like a little space between the wraps but you can run this setup without it.
 
~Don~

~Don~

Platinum Contributor
Member For 5 Years
I’d go .28 if you want nice and hot... higher if you want comfy warm.


Sent from my iPhone using Tapatalk
 
Carambrda

Carambrda

Platinum Contributor
ECF Refugee
Member For 5 Years
Seeing as you have enough build space to accommodate it, I suggest that you try 28/36 Ni80 staggered fused claptons at 7.5 wraps 3mm ID dual coil. If you haven't made SFCs before or have trouble making them, just let me know and I'll explain, they are in fact easier to make than regular fused claptons, if you know how.

Personally, I, am vaping on a pair of 20S batteries in a series mech with a 25mm RDA as I'm typing this. It's a .25 ohms dual coil build, 29/36 Ni80 aliens at 6.5 wraps 3mm ID.

29g aliens.jpg

To calculate the amps, volts, and watts (the latter number being equal to the amps multiplied by the volts...), I like to follow a more accurate route because I find that more precisely knowing the watts will allow me to draw a clearer picture of what to expect performance wise. The 20S has a DC internal resistance of .0135 ohms. You can simply add this number to the resistance of your coil build so in my above example of a .25 ohms coil build it means you get a combined resistance of 2 batteries multiplied by .0135 ohms equals .027 ohms, plus .25 ohms equals .277 ohms. That is, not counting the resistance of your mech mod itself, and also assuming the .25 ohms was measured correct. Next, if we apply Ohm's Law, we get 8.4V divided by .277 ohms equals about 1/3 of an amp more than 30 amps. That is, if each one of these 2 batteries is still fully charged to 4.2V. Now let's look at the volts. How big is the voltage sag? Volts equals amps times ohms. So then, we get 30 ⅓ amps times a combined DC internal resistance of .027 ohms equals about .82V total worth of voltage sag and that we have to subtract from the initial 8.4V to know the volts delivered to the RDA, which means we still get about 7.58V. Multiply that by 30 ⅓ amps and get about 229.9 watts. With a pair of alien coils this size, it's all you really need to get good flavor. (And then some.) :)
 
Last edited:
P

Palmer1997

Carambrda said:
Seeing as you have enough build space to accommodate it, I suggest that you try 28/36 Ni80 staggered fused claptons at 7.5 wraps 3mm ID dual coil. If you haven't made SFCs before or have trouble making them, just let me know and I'll explain, they are in fact easier to make than regular fused claptons, if you know how.

Personally, I, am vaping on a pair of 20S batteries in a series mech with a 25mm RDA as I'm typing this. It's a .25 ohms dual coil build, 29/36 Ni80 aliens at 6.5 wraps 3mm ID.

View attachment 164751

To calculate the amps, volts, and watts (the latter number being equal to the amps multiplied by the volts...), I like to follow a more accurate route because I find that more precisely knowing the watts will allow me to draw a clearer picture of what to expect performance wise. The 20S has a DC internal resistance of .0135 ohms. You can simply add this number to the resistance of your coil build so in my above example of a .25 ohms coil build it means you get a combined resistance of 2 batteries multiplied by .0135 ohms equals .027 ohms, plus .25 ohms equals .277 ohms. That is, not counting the resistance of your mech mod itself, and also assuming the .25 ohms was measured correct. Next, if we apply Ohm's Law, we get 8.4V divided by .277 ohms equals about 1/3 of an amp more than 30 amps. That is, if each one of these 2 batteries is still fully charged to 4.2V. Now let's look at the volts. How big is the voltage sag? Volts equals amps times ohms. So then, we get 30 ⅓ amps times a combined DC internal resistance of .027 ohms equals about .82V total worth of voltage sag and that we have to subtract from the initial 8.4V to know the volts delivered to the RDA, which means we still get about 7.58V. Multiply that by 30 ⅓ amps and get about 229.9 watts. With a pair of alien coils this size, it's all you really need to get good flavor. (And then some.) :)
Click to expand...

Awesome reply thank you, that is a mighty wicked setup you have. This is above and beyond what I was looking for, I appreciate you sharing your dank build!
 
You must log in or register to reply here.

VU Sponsors

Top