How are u guys getting 1-2 days with 2x batteries

[JimKinchloe]

im getting 3-4 hrs per 2x18650 samsung inr on average
1. batteries fully charged to 4.20
2. I put them on charger around 3.65-3.71v
3. I blow through on average 10Mls at 40-50w before they need to go back on charger

Besides the fact that you are running a somewhat extreme setup @ 0.15 to 0.2ohms, you aren't even using half of your batteries life. On a regulated, OR unregulated mod it is safe to discharge the batties down to 3.2 volts. An 18650 is considered to be a 3.7 volt battery not a 4.2v battery. Nominal value is the term used. That is where you are considering them finished and pulling them out though. Consider this discharge chart for an LG HE4 battery:

The area I marked 1 is where you are removing your batteries. The spot marked 2 is where a regulated mod will tell you to change your battery. The drop from 4.2v to 4.0v occurs almost instantly on first use. You are removing your batteries at anywhere from 12 to about 15 minutes of actual discharge. Taking them to 3.2v provides nearly 4 times the life you are using.

So you are burning 10ml using 1/3 to 1/4 of the life of the battery. That would be 30-40ml using the whole usable life. Which on a 2ohm drip atty, would be about 4 days worth of vaping. 2 18650's, 4 days. That's my experience using a drip atty.

If you want to go longer between changes, raise your ohms, lower your watts, and use the whole 1 volt drop of battery life.

 

[Dopefish]

With builds that low in resistance you are going to be pulling quite a bit of power, it's like when I use my .16 ohm anarchy build and the battery drains in about half a day of moderate chain vaping. If you do start to run at a higher resistance, you won't have to crank as many watts out (and in turn lower the amperage of the current flowing through the wire) and you're battery will drain considerably slower. When I vape on my >.25 ohm builds I find that the battery drains significantly slower.

Also, like the poster above me said, you are probably only running your battery down to probably somewhere ~75%, the batteries will drop very quickly from 4.2 volts and then the curve will even out and the voltage will drop much slower.