Understanding Parallel vs Vartiable Voltage

[Jimi Mack]

Let me ask, does a parallel box mod basically give you double the time vaping? If I have a box mod running 2 14500 batteries parallel and I normally get 4-5 hours out of a single 14500, I should see 8-9 hours of vaping from this unit on two 14500 batteries.

Now If I have a box mod set up with 2 14500 as a VV, I do not see such an increased time in vaping. If the VV was used mostly between 4.5 to 5V, and I normally get 4-5 hours out of a 14500 what should I see out of a VV in vaping time then?

These electronic math figures have always driven me crazy and I am still not getting it on how to figure these numbers out. Any simple explanation is appreciated.

 

[makasin]

Exactly. When you wire batteries in parallel, you get the same voltage (or if they are different ones, somewhere in between) and double the current capacity aka double vaping time.
Wiring in series (aka stacking) doubles the voltage, while keeping the capacity the same (if u stack 2 3V batts that have 900mah, youll have a 6V 900mah batt effectively). This wont necessarily give you more vaping time if u stick with the same atomizer (but will prolly make it heat up twice as fast so u dont need to hold the button as long), but if you put a higher resistance (aka High Voltage atomizer), youll see more vaping time.

 

[makasin]

youll probably get decreased vaping time compared to parallel using the VV method, but if you got a higher resistance atomizer, you can make it last longer.
With the VV, the vaping time will not be exactly easy to calculate, because you will be going between the max voltage of the two series batteries, and also there will be some loss in the voltage regulator chip (albeit small).

 

[Jimi Mack]

Thanks for the info, I am trying to decide between getting a VV box mod or a parallel. 3.7 normally is fine for me but at times I feel a little bit more. I was wondering, if I set up a VV with 2 14500's and just use it at 3.7 and then maybe a 4.5 once in a while, would that give better battery life as compared to running it all the time a say 5V?

 

[markfm]

Normally, in a VV device with two batteries stacked in series, the max voltage is always there, available, so I expect you would be better by switching to higher resistance atties or cartos, allowing you to use the higher available voltage rather than drawing more current.

Say your normal sweet spot is a 2.6 ohm carto on a 3.7 ohm device. 3.7*3.7/2.6 = 5.3W of power, obtained by using 3.7/2.6 = 1.42 amps of current. Well, if you have a variable voltage device, stacked 3V batteries, for the same power try a 3.5 ohm carto. If you run the VV at 4.3V, then 4.3*4.3/3.5 = 5.3W [same power], but only drawing 4.3/3.5 = 1.23 amps. You are drawing 13% less current. When you want a bit more kick, you crank the voltage up a bit, say 5V -- that gets you to 7.1W, but you are using just 1.43A.