Hi
An EVOD 650 mAh is a fixed voltage, not a variable voltage, correct? I'm going to answer this as if it is.
A 1.8Ω coil will work fine on a 650 mAh battery, although you might notice the charge won't last as long. "Might" because it's pretty subtle and a 650 mAh doest last that long anyway.
When you say two coil, my guess is that you mean dual coil. While it could work on your battery, you won't experience the full effect. Dual coils really suck up the amps and the juice. They aren't designed to be used with a fixed voltage battery.