BradR sir can't find the post, but will break it down for you in a different way.
This is simply an example, the numbers mentioned here are therotical. Now that that disclaimer is out of the way. You have a 310mah battery, it's c rating is 9. That means it can pull 2.79 amps max without issue. What mah means is at what current the battery can run at for an hour before death. This means you can run it a .32a for an hour before dying. Technicallt this translates to the battery has 19.2a of power inside it. So on a cool cart at 3.3ohms at 3.9v you're pulling 1.18a. That's 16:15 of total run time theortically. We know these aren't regulated so it will be pulling more amps at full charge, less later on, just going with a mid ranged number. Now let's go with a 1.5ohm carto. We'll use 3.8v for the baseline number. 2.53 amps. That's 7 and a half minutes theortically. Now the missing factor in all this is what extra power might be lost to the led or to the dual coils themselves. Just like how a 1200w power supply with a 90% efficiency rating is actually pulling 1320w from the wall, dual coils can pull more amperage than what they're rated for by ohms. So when you factor that in with an led, all of a sudden that 7:30 of total run time, might be shortened to 6:15 of run time.