He is telling you to get higher amp discharge batteries because you are currently risking a battery venting in your mod. Your battery is rated for 10 amp discharge. With a 0.2 ohm coil at 3.7 volts, you would be running it at 18 amps, which is 80% more than the battery is rated for. If you are getting 4 volts out of it, you are running it at 20 amps, which is double what it is rated for. If you move up to a battery rated for 20 amps, you are going to be a lot safer. If you plan on building that low, I would just tell you to skip the 20 amp discharge batteries and get some authentic VTC4s from orbtronic and have something rated for 30 amps. Even if the most you ever draw is 20 amps, that still gives you a lot of safety margin.