still need help... driving me crazy

[Christopher Gomez]

hey guys so ive watched every youtube video and idk what is going on i do get the ohm law stuff but i guess not so much so let me ask you some things and tell me if this makes sense.

BUILD
Smoktech pro M50 50 watts
Kanger subtank .5 ohm RTA
Vaporfi Rocket tank 1.8 ohm
Sony vtc4 18650 30 amp
spacejam ejuice 50/50 (i think)

I have a smoktech pro50. It only has mech mode or wattage mode. If I know my resistance of the coil but don't know the voltage how do I know what to apply in the wattage mode. now if i cant use variable voltage i cant know the sweet spot?! is there a formula to find out what voltage is needed for a coil (resistance) so i know i wont burn it out on the first hit. if i test shoot in watts it will tell me the volts but im still not sure to tell how many watts my coil can handle. I have a kanger subtank rta .5 ohm coil with a Sony vtc4 battery 30 amp. Also maybe a stupid question but if it's a 4.2 v battery why does my voltage on the mods screen go to 9.9 volts when tested at 50 watts. 

 

[Rob.Gee]

watts = volts x volts / ohms.
so the reason it is showing a higher volts when vaping at 50 watts is because it takes more that 4.2 volts to get to 50 watts with the ohms you are using. so with a .5 ohm coil to get 50 watts you will need to using 10 volts. 10 x 10 / .5 = 50. and some devices read ohms, volts and watts slightly incorrectly. hope that helps.

 

[Christopher Gomez]

watts = volts x volts / ohms.
so the reason it is showing a higher volts when vaping at 50 watts is because it takes more that 4.2 volts to get to 50 watts with the ohms you are using. so with a .5 ohm coil to get 50 watts you will need to using 10 volts. 10 x 10 / .5 = 50. and some devices read ohms, volts and watts slightly incorrectly. hope that helps.

ok but how is it reading 9.9 volts when the battery is only 4.2 unless its because of the type of coil and resistance. it cant be that off. shouldnt it be saying it cant fire because theres not enough power. also i have a vaporfi rocket kit that is variable voltage only. the max is 4.8 volts. now if i put that same tank which is 1.8 ohms on my smoktech 50 watt and guess the wattage till i see 4.6 voltage on the lcd it taste completely different and get more vapor. do you know why that is?

 

[emily n portland]

The electronics make it able to generate more than 4.2v. I don't know how, I can't tell you how my tv works either. Magic?

A mechanical can only pull the current charge of the battery. No electronics, no magic.
There's some very smart people around, would should me around shortly to explain the magic.
I have no interest in dispelling the illusion myself.

 

[InTheShade]

watts = volts x volts / ohms.
so the reason it is showing a higher volts when vaping at 50 watts is because it takes more that 4.2 volts to get to 50 watts with the ohms you are using. so with a .5 ohm coil to get 50 watts you will need to using 10 volts. 10 x 10 / .5 = 50. and some devices read ohms, volts and watts slightly incorrectly. hope that helps.

At 50 watts on a 0.5ohm coil your device will be pushing 5 volts. Your formula was right, your math was off 5*5 / .5=50 watts

As for knowing ohms law in order to find the sweet spot OP, you don't really need to. Just start at the lower end of the scale and work your way up.

There's no need for math or charts, just let your taste tell you what you prefer.

Once you figure out a benchmark (say you prefer a 25 watts vape with a certain type and resistance coil) you can use that as your starting point.

Start low, increase until the vape is good.

It's rare to blow a coil anyway, usually the worst that can happen when applying too much power to a coil is a dry hit. By starting low and working up, you minimize the risk of blowing anything.

 

[RamShot Rowdy]

ok but how is it reading 9.9 volts when the battery is only 4.2 unless its because of the type of coil and resistance. it cant be that off. shouldnt it be saying it cant fire because theres not enough power. also i have a vaporfi rocket kit that is variable voltage only. the max is 4.8 volts. now if i put that same tank which is 1.8 ohms on my smoktech 50 watt and guess the wattage till i see 4.6 voltage on the lcd it taste completely different and get more vapor. do you know why that is?

The electronics look at the resistance of your atomizer and calculate how much voltage to apply to produce the 50 watts. It's reading 9.9 volts because that's how much voltage its putting to the atomizer, with your 0.5 1.8 ohm load, to produce 50 watts of power.

EDIT: I copied the math error from the previous post, I now assume you were using the 1.8 ohm at 50 watts when it was putting out 9.9 volts.

9.9 x 9.9 / 1.8 = 54 watts.

So how does it produce 9.9 volts from a 4.2 volt battery? It's using some sort of voltage step-up technology. There are various ways electronically to do it, and I'm not smart enough to understand them exactly. One thing remains constant though, Power In = Power Out, so if the device is putting out 50 watts of power to the atomizer, the the battery has to provide 50 watts of power to the device. Since the battery provides lower voltage than the device is supplying to the atomizer, the battery is having more current drawn from it than the atomizer is drawing from the device. It's kind of a trade off type of deal, the electronics can provide more voltage than the battery, but in turn the battery has to provide more current than the electronics can.

I hope that's right and makes sense.

 

[Rob.Gee]

ok but how is it reading 9.9 volts when the battery is only 4.2 unless its because of the type of coil and resistance. it cant be that off. shouldnt it be saying it cant fire because theres not enough power. also i have a vaporfi rocket kit that is variable voltage only. the max is 4.8 volts. now if i put that same tank which is 1.8 ohms on my smoktech 50 watt and guess the wattage till i see 4.6 voltage on the lcd it taste completely different and get more vapor. do you know why that is?

At 50 watts on a 0.5ohm coil your device will be pushing 5 volts. Your formula was right, your math was off 5*5 / .5=50 watts

As for knowing ohms law in order to find the sweet spot OP, you don't really need to. Just start at the lower end of the scale and work your way up.

There's no need for math or charts, just let your taste tell you what you prefer.

Once you figure out a benchmark (say you prefer a 25 watts vape with a certain type and resistance coil) you can use that as your starting point.

Start low, increase until the vape is good.

It's rare to blow a coil anyway, usually the worst that can happen when applying too much power to a coil is a dry hit. By starting low and working up, you minimize the risk of blowing anything.

Actually my math and formula were both correct I just didn't use the correct formula when doing the math! My bad haha