when you purchase the heater it comes with a small info booklet which explains all about the heater in there it mentions about the heater giving off smoke for a while then it goes away. also I wouldnt recommened anything under 5000mah 3s if you want to use the 12v model also get a low voltage monitor soldered on to stop the lipo dropping to low. I have a ttached a pic it gives off an alarm when drops below 9volts and has three different colored lights to indicated what voltage your battery is at. cheers