RDA Dual coil math

[Darth Xibalba]

Just starting out doing builds, if u can call it that, since I use pre built coils. What I was wondering was if there is an equasion or chart that lists what the ohm reading of a build will be when combining two coils. I've been putting in two 0.5 ohm clapton coils and getting like 0.3ohm. Also tried a 0.5 quad coil build and got a 0.13ohm. Just got in some 0.4ohm alien coils to try next. Also does the type of coil factor into the final reading as well?

 

[seek2]

Its cut into 50%. 2 coils so less resistance. Asusming the coils are 100% equal.

No. As long as the coils are equal and both grounded they will be exactly 50% ohm.

 

[Darth Xibalba]

Ok thanks

 

[mindriot]

Also as an aside it is worth noting that the resistance on the prebuilt may not be exact and the length of your legs is playing a part as well. They probably take the ohm rating based on some assumptions about expected leg length in typical use or something like that. So it is correct that two of the same coils will half the resistance compared to one but it is not necessarily the case that you will end up with a build that is exactly half the number printed on your coil packet.

 

[Darth Xibalba]

Also as an aside it is worth noting that the resistance on the prebuilt may not be exact and the length of your legs is playing a part as well. They probably take the ohm rating based on some assumptions about expected leg length in typical use or something like that. So it is correct that two of the same coils will half the resistance compared to one but it is not necessarily the case that you will end up with a build that is exactly half the number printed on your coil packet.

Yeah I've noticed that since I've been using 0.5ohm coils and ending up with like 0.3-0.35ohms. Those alien coils I got are 0.45, not sure if I wanna use those for dual coil builds or not. Maybe in my Buddha V2 or something that has a ton of airflow

 

[bwh79]

What I was wondering was if there is an equasion or chart that lists what the ohm reading of a build will be when combining two coils.

Technically it's:

1 / ((1/coil1) + (1/coil2) + (1/coil3) + ...)

but presuming all coils are identical, then that simplifies to (coil resistance) / (number of coils), so 2 coils is half the resistance of a single coil, quad coils is 1/4 the resistance, etc.

 

[Darth Xibalba]

Technically it's:

1 / ((1/coil1) + (1/coil2) + (1/coil3) + ...)

but presuming all coils are identical, then that simplifies to (coil resistance) / (number of coils), so 2 coils is half the resistance of a single coil, quad coils is 1/4 the resistance, etc.

Yep got it, thanks!

 

[seek2]

Are you taking about the geek vape alien coils?

My package sure did say .5. But a dual coil setup ohmed at .09. When Mike vapes reviewed the tsunami, his dual aliens ohmed at .08.

They must of changed something since there is no way even the whole coil was .5, with the legs.

I tried a few of those geek vape coils. They aren't that good.

You can make your own claptons very easily.

Have yet to try any other pre built coils.

 

[Darth Xibalba]

Are you taking about the geek vape alien coils?

My package sure did say .5. But a dual coil setup ohmed at .09. When Mike vapes reviewed the tsunami, his dual aliens ohmed at .08.

They must of changed something since there is no way even the whole coil was .5, with the legs.

I tried a few of those geek vape coils. They aren't that good.

You can make your own claptons very easily.

Have yet to try any other pre built coils.

Not sure what the brand of the clapton coils are but they've been pretty good so far. The Alien clapton coils I just got are Vapesoon. Haven't tried them out yet