You need to learn this easy formula for determining watts based on volts and resistance (ohms), because most juices vape best at around 8-10 watts with a single coil cartomizer.
Volts x volts / ohms = watts.
If you have a 3.7V PV, you want a low resistance single coil cartomizer/atomizer, usually a 1.5.
So: 3.7 x 3.7 / 1.5 = 9.12 watts.
If you run a dual coil at 9.12 watts, each coil gets only half of that = no good. Flavors will be muted, vapor production will be just OK. The coils need to be at a proper temperature to fully vaporize the juice and bring out the flavor.