Lets talk safety!!!

Yep, you got it right. If you stay under the safe amperage with theoretical calculations, there should be no problem due to voltage drop. So the actual voltage the battery is putting out will be lower than what you measure with a multimeter because the mod and battery itself have some small internal resistance. Thus, lower amps. Its not as safe when you actually factor in the voltage drop and try to push right up to the amp limit with even lower resistance.

So lets say my battery comes off the charger reading 4.2V and my coil is 0.5 ohms. Theoretically, that is 35 Watts at 8.5 amps. My batteries can handle up to 10A. So in theoretical fantasy land, even that is safe. Now, if you consider that I am getting 0.4V drop at that current draw (its probably considerably more than that with my cheap mechs), I am actually operating at 3.8V, which is only 29W at 7.6A. Lets say I measure my voltage drop and decide to play with fire. I drop my resistance down to 0.4 ohms, and assuming the drop is still the same (it would actually be a bit more), now I am at 9.5A. That's how sensitive it is, 0.1 ohms less and you're pushing the limit.

So be safe, know exactly what the electricity is doing with a decent multimeter, and use theoretical calcs to stay under the battery limitations.

 

I agree you are on the right track bebeau. One thing that is incorrect - a freshly charged battery will run between 4.15 and 4.25 volts. Most chargers will stop charging very close to 4.2. At 4.25 volts and 0.7 ohms, you will be drawing 6.07 amps, a bit over your smaller batteries capacity. A short will make the resistance go down, taking the amps way above what these batteries can handle. This is not safe.

I run a mech mod and AGA T with 0.7 ohm coils drawing the 6.07 amps we already established for these numbers. I use batteries rated for 10 amps and this has been safe for me since February this year. I regularly check battery volts and coil resistance with a multimeter. Vape safe and enjoy!

 

Correct me if i'm wrong but I believe that firing your battery at exactly or a little under it's amp limit will reduce the overall life of your battery.

 

I believe you are correct ST. Actually, pushing a battery to any limit will stress it and shorten it's life. Fast charge, over charging, running to almost empty and running hot all come to mind. It's amazing how few people know this.

 

And users come here wondering why they are only getting 2 hours time on their battery.