Ohms, Amps and Volts are interrelated in a complex dance called Ohm's Law. If you change any one of them, the others adjust to compensate. The thing about mechs-- where they differ from regulated mods-- is the voltage is semi-fixed. You always get whatever voltage the battery is supplying at that instant. Now, that voltage varies a bit, depending on the charge state of the battery. At full charge, it will be 4.2 volts on a new battery. By the time it discharges down to "too weak to vape," it will be in the 3.5 volt range. A regulated mod is different from this. It doesn't care what voltage the battery is supplying because it has internal circuitry that takes the battery voltage and increases or reduces it to produce the set watts in accordance with the atomizer resistance. But a mech can't do that. Voltage is what the battery gives you and it can't be changed. So yes, to answer your question, Ohms directly relates to the battery amps on a mech mod. This is not completely true, or rather more complex, on a regulated mod. The VTC4s are 20 amp batteries that can be safely run to 30 amps without danger of a catastrophe-- that's why I like them in mechs-- but doing this damages the battery and reduces it's capacity and its life. VTC4s are, and should be treated like, 20 amp batteries. Now, as to how much amps they will tolerate... that depends on the safety factor you like. I personally like 50%; that is, don't ask a 20 amp battery for more than 10 amps. That's the rule I use on my mechs with VTC4s. At full charge 4.2 volts, this 10 amp maximum works out to be .42 Ohms. However-- yes, another caution, sorry-- ohm meters are not perfectly accurate and batteries are not either. I wouldn't try to build out to .42 Ohms. As I have told you above, .5 Ohms is a good place to shoot for. That way, if you undershoot a bit, or your ohm meter is off a few tenths of an ohm, you're still safe. If you try for a .5 coil, and it works out to be .48, you know that's still within safe limits and you can use it instead of trashing it and starting over. MAh does, in fact, indicate battery life. The more, the longer the battery will last. However, while it isn't important for building and has no safety impact, you should be aware in practice the trade-off for high current is low capacity. That is, a 20 amp battery will have fewer mAh than a 15 amp battery; and a 30 amp battery will have fewer than a 20 amp. The VTC4s you just bought are 20 amp batteries with 2100 mAh. The LG HB6 batteries are honest 30 amp batteries, but they only hold 1500 mAh, which is why vapers don't use them much.
