How fast does performance decline in unregulated 3.7v devices?

[supremekizzle]

I've heard that with 3.7 unreg. mods and such you'll start off at 3.7 but this will stedily drop. How fast does this happen?

 

[tobarger]

Depends on the battery.
The graph below shows the voltage characteristics of two of the best (currently) 18650 batteries.
The AW 18650 2900mAh and the Redilast 18650 2900mAh.
The 2 Amp curves are most pertinent to PVs since a LR 1.5 Ohm atty at 3.7v is about 2.5 Amp.
I can't think of anything in the PV world that draws anywhere near 5 Amp.

View attachment 30120

The graphs depict a constant 2 or 5 Amp load until the batteries are dead.
With vaping its on off, on off etc.
As far as length of time goes, this would depend on how aggressively you vape.
Either of these batteries should give even an aggressive vaper a full day without a noticeable decline in performance.

 

[cuseguy]

I've heard that with 3.7 unreg. Mods and such you'll start off at 3.7 but this will stedily drop. How fast does this happen?

First off, most 3.7V's come off the charger at 4.15-4.2V, so it actually takes a few hours for you to even get down to the rated 3.7V. As he said, on an 18xxx battery mod, the drop off won't be noticeable for 10+ hours. But some of us don't want to lug around a big battery mod for 3.7V performance if we don't have to. So we try to find a tradeoff between size and performance and usually end up with single batt CR123/16340 or even a 14500 mod. Generally, I get good heavy vaping performance from morning to bedtime on a pair of CR123's, switching them once when I detect it is starting to " limp along", but that depends on many factors obviously. If you don't mind the size of 18650 mods, then you can go all day and night with the right battery. Personally, if I am going to carry an 18xxx mod and I do sometimes, it had better be capable of doing something more than 3.7V! or I'd just rather use something a little smaller like my P-16 or a GLV-2. But we're all different.

 

[cskent]

I've got a couple of unregulated big batt mods that use 18650's. I don't see any noticeable dropoff in vapor production after 24 hours of use. I've also got boxmods that use 14500's which are quite a bit smaller. I have to change batt's after about 10 hours of use with them. The 18650's are 2600 mah, and the 14500's are 900 mah. With the 18650's I've gone 2 days when I forgot to charge and finally thought, hey, I oughta charge this thing. But it was still performing nicely.

 

[Bozzlite]

I have a RoughStack that uses the 18350 900mah batteries. The Batts come off the charger at 4.20 volts and thats when I get optimum performance.

After 4-5 hours of use, performance begins to decline somewhat. I have measured the voltage at that point, and it's usually around 3.80 volts.

By the time the battery gets to 3.7 volts, (6-7 hours) performance is very poor.

Admittedly, TrustFire is not the best performing brand, but I haven't been able to find protected 18350's made by AW or Readilast.