Ohms is a measure of electrical resistance. I think 3 ohms is good for the ProVari. You should avoid using low resistance (2 ohms or less) atomizers because they draw more current and will drain your battery faster. Also, you're more likely to get E1 and E2 errors using LR atties on the ProVari, which indicates that you're pulling more current than the ProVari's circuitry can handle.
If you're atty is 3 ohms and you're vaping at 4.5 volts that means you're drawing 4.5/3 = 1.5 amps (current) and vaping at 1.5*4.5 = 6.75 Watts. With a 2 ohm atty you would only need 3.7V to get that much power (3.7/2*3.7 = 6.8 Watts) and you'd be drawing 3.7/2 = 1.85 amps.
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Hmm? I never had any issues with 1.5 or error indications.The 18490 is an 1100 mAh battery I think it can more than handle it since it is well above the required 450 mah for 1.5Ω. It will drain faster than a 2.5Ω but keep in mind, although it is a 3.7 v battery it is made to go up to 6V. I would think using a 3.7 v battery at 6v drains it just as fast or faster.Talk about wattage and amps! (IMO)
Vaader. Although Digs has a point about it draining faster ( Although I dont understand the 1.5 not working thing. ??) you have to figure out what fits you. It all depends on what "best" means for you. performance or battery life.The higher the wattage the higher the performance. Kinda like a muscle car. The faster you drive it, the sooner you run out of gas. Thats why I suggested getting all three Ω ratings.To find out what fits you.I personally wouldn't buy a 69 Selby Mustang Mach I and worry about gas milage.
Case in point. I would never use a 3Ω below 5v. But Thats because I didn't spend all that money on a Provari to go sunday driving. I bought it cuz it performs like a muscle car and I set it to what ever I need to get the most Vapor and flavor out of it that I can and the way to do that is to achieve 7-9 watts. 6.75 is ok but...... 5v x 5v =25 / 3Ω =8.33333333333 wats.8 watts is what we call a sweet spot (warm enough to give you clouds but cool enough to not burn your juice)
I have never had and issue with it not lasting the day either way.Its 1100 mah after all.If for some reason That isn't enough for your particular vaping style, get the 1600mah 18650.
You dont buy a Provari to worry about how much power you are using.Thats what a 1300mah Ego for $80 is for. You buy a Provari to find the perfect voltage to fine tune your atty to its fullest potential!!