I am working on making my own "mod" for an e-cigaret (A mod is the device that controls when and how much the coil is heated up to)
I have read a lot about it during the last couple of days, so i have a few different ways to drive it, each with their own ups and downs. Here is what i have learned so far.
- Simple to build
- No power wasted
- No safety features (No current limit, other than the coil)
- No power regulation
- No wasted power
- Able to regulate current, but not fully
- Coil will get full current, no matter what the mod is set to, just not all the time while firing
- Able to fully regulate current
- Potentially lots of wasted power
- Lots of heat generated in the wrong place (MOSFET)
I want to note the schematics are very simplified, of course additional components are needed in order to have a functional design.
I am most inclined to use the PWM apprach, but the fact that i cant measure current directly with a shunt puts me a little off.
Anyhow, here is my questions:
- Is there a way to smooth the current running through the MOSFET so i can measure current with a shunt?
- I have two 18650 batteries in series in order to achieve high enough voltage to drive my coil at the wanted power level (110W in this case), but one cell is limited at 25A in its datasheet, that means i can pull 25A at 7,4V nominal voltage, right?
- Is there another way to drive the coil that i dont know about, where there is smooth current to the coil and minimal power loss in the switch component?