Extending 18650 Li on battery life...

[carl cipriano]

So essentially, in an impossibly ideal situation you'd be charging your batteries to 4.1V, then draining them to like 3.8V and charging them back up. Your battery would likely last years, but obviously that's not practical for any vaper unless you wanna be excessively .... about it.

Actually, I have found that it is not really too difficult to do this - having multiple cells to rotate is definitely a must to be able to do this - one other thing that helps, but this also provides a little confusion, and I am hoping that someone may help to clear up my confusion - when I build a coil that is a little higher in resistance, and set my mod to a higher voltage output, I am able to vape much longer before I reach the 50% or so range and need to rotate out the cell - for example, if I use a coil that is 1.2 OHMS, I have to rotate the cell half-way through the day; however, when I use a coil that is around 2.5 OHMS resistance, and set my mod to discharge the cell at about 4.3 Volts, strangely (to me), the cell lasts all day before reaching that 40 or 50% mark....my question is, even though the cekll is lasting longer during that one day, is doing this reducing lifespan in total?

 

[schatz]

Actually, I have found that it is not really too difficult to do this - having multiple cells to rotate is definitely a must to be able to do this - one other thing that helps, but this also provides a little confusion, and I am hoping that someone may help to clear up my confusion - when I build a coil that is a little higher in resistance, and set my mod to a higher voltage output, I am able to vape much longer before I reach the 50% or so range and need to rotate out the cell - for example, if I use a coil that is 1.2 OHMS, I have to rotate the cell half-way through the day; however, when I use a coil that is around 2.5 OHMS resistance, and set my mod to discharge the cell at about 4.3 Volts, strangely (to me), the cell lasts all day before reaching that 40 or 50% mark....my question is, even though the cekll is lasting longer during that one day, is doing this reducing lifespan in total?

From what I remember from my electronics training in the 80s and what I have read aroun here, the higher your resistance, the lower amps you use. thats why the sub ohmer people go through batteries quicker.

 

[Mooch]

Actually, I have found that it is not really too difficult to do this - having multiple cells to rotate is definitely a must to be able to do this - one other thing that helps, but this also provides a little confusion, and I am hoping that someone may help to clear up my confusion - when I build a coil that is a little higher in resistance, and set my mod to a higher voltage output, I am able to vape much longer before I reach the 50% or so range and need to rotate out the cell - for example, if I use a coil that is 1.2 OHMS, I have to rotate the cell half-way through the day; however, when I use a coil that is around 2.5 OHMS resistance, and set my mod to discharge the cell at about 4.3 Volts, strangely (to me), the cell lasts all day before reaching that 40 or 50% mark....my question is, even though the cekll is lasting longer during that one day, is doing this reducing lifespan in total?

No, that's not reducing the lifespan of your cells. In fact, because you're cells are lasting longer you are drawing less current from them. This allows them to run cooler, which makes them happy. This might only extend their life a little bit, but it definitely doesn't hurt the cells.

What voltage do you run your 1.2 ohm ohm coil at?
If I understand your post correctly, you would need to run it at 2.06V or so to (roughly) equal the current drawn by your 2.5 ohm coil at 4.3V. If you are running the 1.2 ohm coil at higher than 2.06V then you are drawing more current than your 2.5 ohm @ 4.3V build, thus draining the battery faster.

 

[carl cipriano]

No, that's not reducing the lifespan of your cells. In fact, because you're cells are lasting longer you are drawing less current from them. This allows them to run cooler, which makes them happy. This might only extend their life a little bit, but it definitely doesn't hurt the cells.

What voltage do you run your 1.2 ohm ohm coil at?
If I understand your post correctly, you would need to run it at 2.06V or so to (roughly) equal the current drawn by your 2.5 ohm coil at 4.3V. If you are running the 1.2 ohm coil at higher than 2.06V then you are drawing more current than your 2.5 ohm @ 4.3V build, thus draining the battery faster.

Okay, I admit I am a little bit confused by your question. Let me use an example - one that is actually real, not hypothetical. I built a nano coil with 30 guage kanthal wire, and it measures 2.7 OHMS. I have been using it for a few days, and I have been using anywhere from 4.3 to 4.6 volts output on my vamo v5.....which, according to my calculations, translates to roughly 1.6A/and 6.8 watts when I click to 4.3 volts on my mod, and 1.7amps/7.8 watts when I click to 4.6 volts on my mod and fire. When I use a 1.2 ohms coil, I generally need to set my mod to anywhere from 3.3 volts output, which means that my battery is putting out around 2.75 amps and 9 watts, to 3.6 volts output, which translates to about 3 amps and 10.8 watts.....

I found it difficult to understand how my battery ;lasts so much longer when I use a higher resistance coil because logically, I am thinking that if a coil is sort of like a hose with water running through it, then shouldn`t it take MORE energy to run the water through it as the hose is reduced in size? It seems to be the other way around, where as the hose (wire) is bigger, MORE energy is expended.....am I correct in the assumption that as there is less resistance, then the battery makes more cycles through the wire and back again, thus the higher amperage and wattage? I have to do some more research, of course, as battery chemistry is somewhat new to me....

I think I understand what you are saying about running the 1.2 ohm coil at 2.06V....however, currently I only have two APVs, both of which cannot run at lower than 3V.....I have found, through trial and error, that my batteries last the longest when I actually use a 3.5 ohms coil and run it at 4.8V....which draws about 1.4 amps/6.6 watts.....but the taste is not great....the best taste AND the longest I can get my batteries to last come from a 2.5 to 2.8 ohms coil at 4.3 to 4.6 volts......generally, I try to stay below 2 amps and 10 watts.....I hear all this talk about sub ohming and 50 and 100 watt box mods, and although I am definitely going to be purchasing a Kangertech Subox starter kit as soon as I can afford to, I doubt that I will ever run it higher than 10 watts...I just don't see the need, and I want my batteries to last as long as possible. Perhaps I am missing out on some of the fun of blowing massive clouds of vapour, and perhaps I could lower my nicotine content dramatically if I used a sub ohm coil, but I just don't get the appeal.....

Anyway, My question is: when you speak of running a 1.2 ohms coil at 2.06V in order to equal the current drawn by my 2.5 ohms coil at 4.3V, can you explain a little further what you mean, concerning how I would be drawing more current otherwise? Thanks a bunch

 

[Mooch]

Each battery has a "capacity", rated in milliampere-hours mAh), that determines how long the battery will last vaping. It is calculated by the manufacturer by taking the amount of time the cell took to drain and multiplying that by the current used to drain the cell. If the cell took two hours to drain at one amp, it is a (2.0 hours) x (1A) = 2Ah = 2000mAh cell. If it took 1/2 hour to drain at 10 amps, it is a (0.5 hour) x (10A) = 5Ah = 5000mAh cell.

Think of capacity as the size of the tank that your hose is attached to. The diameter of the hose is the resistance. The pressure inside the tank is the voltage. And the amount of water that flows per second is the current.

The larger hose (lower resistance) will always drain the tank faster than the smaller hose (higher resistance) because more water (more current) can flow through the larger hose each second. This assumes that the pressure (voltage) inside the tank always stays the same. This isn't true for an actual battery, battery voltage drops as you use it, but let's assume it's true for now.

We'll use this to determine how long a battery will last with different setups.
Let's use the setup first mentioned in your post. The first setup will be a 2.7 ohm coil with your Vamo set to 4.5V. The other setup will be a 1.2 ohm coil with your Vamo set to 3.3V.

Which will last longer, and why? Let's see what happens if you have a 2000mAh battery. We can calculate how long a battery lasts by using the following equations:

(Voltage) / (Resistance) = Current
(Battery Capacity) / (Current) = Time before battery is drained

Using 2.7 ohm coil...
(4.5V) / (2.7 ohms) = 1.67A
(2000mAh) / (1.67A) = (2000mAh / (1670mA) = 1.20 hours before the battery is drained

Using 1.2 ohm coil...
(3.3V) / (1.2 ohms) = 2.75A
(2000mAh) / (2.75A) = (2000mAh / (2750mA) = 0.73 hours before the battery is drained

Since the lower resistance 1.2 ohm coil draws more current from the battery, it drains it faster. It acts as a larger hose, draining the water tank (battery) faster than the 2.7 ohm "hose".

It all depends on the voltage you have set for each coil resistance though. You could use a higher voltage on the 2.7 ohm coil and a lower voltage on the 1.2 ohm coil and, by doing the equations, you could find that the 2.7 ohm coil drains the battery faster.

But....

If you have the same voltage for both coils, the lower resistance coil will always drain the battery faster. The bigger hose will always drain the tank faster than the smaller hose if the pressure inside the tank is the same.