Optimal voltage output usage of battery

[Captain Pegleg]

Hello, for life expectancy (number of charge cycles) of a battery, is there an optimal voltage output? If my mod throttles/ bucks voltage way down, is that easier on a battery? If charging slower is better, then is draining slower better as well? My new tank and mod, kanger subox mini, is drawing 1.8-2.3 volts (7 to 12 watts)
I haven't seen anyone talk about these voltages/wattages but that is not my concern, my concern is if this is harder or gentler on my batteries than higher volts.

 

[Morandir835]

Captain Pegleg even with it throttling down the voltage, it's still pulling full voltage from the battery, just less amperage. Less amperage will prolong the life of a cell, just as using it at or near it's max continuous rating will constantly will shorten it's cycle life. Give you an example using the Sony VCT4's. One I ran at no more than 4 amps of power on a mechanical mod using a coil ranging from 1.1-1.8ohms. The other ran at 12+ amps using a resistance of 0.2-0.4ohms. With proper handling (no deep cycling, CC/CV charging, no over charging, etc.) got 388 charges out of the first battery before losing 25% capacity on it. The second battery though that was constantly ran at higher amperage only lasted 274 charges before losing the same mAh. Long story short, you will prolong the life of your batteries theoretically by using them at lower settings.

 

[Captain Pegleg]

Thank you very much for the excellent and quick reply! I hope to make mine last as long as possible, trying to be frugal/efficient now that I have "the setup."

That is to say, I have Invested, now it's time to reap the benefits of actually saving money over cigarettes got a few months of catching up before I come out ahead, I did quite a bit of "investing" and, investigation lol

 

[Thrasher]

I try to always run batteries well below thier capacity. I have some cells going on 2 years even after several deep discharges.

My findings indicate to me driving batteries hard is much more harmful to longevity then deep discharge.

 

[Mooch]

I try to always run batteries well below thier capacity. I have some cells going on 2 years even after several deep discharges.

My findings indicate to me driving batteries hard is much more harmful to longevity then deep discharge.

Agreed.
Cell aging starts accelerating at about 45°C and really gets going at 70°C-80°C...temperature is the enemy. Cells can be discharged down to 2.5V (typically) every single cycle and still achieve the manufacturer's spec for cycle life. This is how the cells are spec'd in the datasheets.

[edit] I should add that while discharging down to low voltages, in my testing experience, won't affect your cycle life as long as you recharge soon, that assumption was made based on the manufacturer's cycle life estimates. If you only discharge down to something over 3.0V then you can increase cycle life to a number above the manufacturer's specs. Compared to that number, discharging all the way down to the rated cutoff will definitely affect your cycle life. Sorry for any confusion.

 

[Captain Pegleg]

So my goal for longevity would be to pull lower amps, correct? Are there other things that cause too much heat besides fast charging/discharging?

 

[Mooch]

Overvoltage during charging is very bad.
And, of course, high temperature surroundings...hot car, etc.

Of course, at a certain point, you end up compromising your vaping just to extend battery life a bit. Better then to use the (safe) settings that let you enjoy your vape and just get another set of batteries when you need to.

 

[Captain Pegleg]

Overvoltage during charging is very bad.
And, of course, high temperature surroundings...hot car, etc.

Of course, at a certain point, you end up compromising your vaping just to extend battery life a bit. Better then to use the (safe) settings that let you enjoy your vape and just get another set of batteries when you need to.

I'm definitely enjoying a low-amp vape, so win-win for me I haven't gone over 4.2 volts even with my Horizon tank 0.5 ohm, I like very long draws so I keep it cool. Cooooooool. Very long to me is probably just average to someone with bigger lungs, though. Like, 5 seconds, 7 tops.

 

[Ryedan]

Captain Pegleg even with it throttling down the voltage, it's still pulling full voltage from the battery, just less amperage. Less amperage will prolong the life of a cell, just as using it at or near it's max continuous rating will constantly will shorten it's cycle life. Give you an example using the Sony VCT4's. One I ran at no more than 4 amps of power on a mechanical mod using a coil ranging from 1.1-1.8ohms. The other ran at 12+ amps using a resistance of 0.2-0.4ohms. With proper handling (no deep cycling, CC/CV charging, no over charging, etc.) got 388 charges out of the first battery before losing 25% capacity on it. The second battery though that was constantly ran at higher amperage only lasted 274 charges before losing the same mAh. Long story short, you will prolong the life of your batteries theoretically by using them at lower settings.

Great data Sir, thank you

I take pretty good care of my batteries but it's very nice to know what I'm actually doing to them when I push them a bit harder which I sometimes do.

 

[Morandir835]

Mooch sir have had just as many issues with deep cycling killing cells as temp. Doesn't affect them as bad, but still have seen anywhere from 50-120 charges less with deep cycling and keeping the cells in the 35-40°C range max. Running them to 60°C or above has robbed me of as many as 202 charges on some early INR cells (Samsung 20R from 2013. Only got 48 charges before they loss 45% capacity). Temp is worse, but deep cycling is an issue in all my testing.

 

[Mooch]

Mooch sir have had just as many issues with deep cycling killing cells as temp. Doesn't affect them as bad, but still have seen anywhere from 50-120 charges less with deep cycling and keeping the cells in the 35-40°C range max. Running them to 60°C or above has robbed me of as many as 202 charges on some early INR cells (Samsung 20R from 2013. Only got 48 charges before they loss 45% capacity). Temp is worse, but deep cycling is an issue in all my testing.

Interesting! I haven't had results like that with the cells I've tested. Usually I'm within a few percent, if off at all, from the manufacturer's rated cycle life as long as I keep the temperatures within the manufacturer's ratings. I'm only referring to cells from manufacturer's who have published cycle life data. Batteries using unidentified cells, with only the reseller/distributor publishing the specs, always fall short in cycle life in my testing. But, they typically never had a cycle life spec so perhaps asking them to perform as well as other cells was naive.

Just curious...
What voltage levels do you deep cycle to? You had these big drops in cycle life even with cells rated by the manufacturer for that discharge cutoff voltage (and a particular cycle life)? Were you recharging soon after discharge? I ask this last question because I've never had the time (and no client has asked) to quantify the effect of immediate recharge versus, let's say, leaving the cell uncharged overnight.

[edit] hmm...actually, you made me realize that I should amend my earlier post. While I haven't seen an impact on rated cycle life when discharging to a manuf. specs there is definitely an impact on discharging down that far versus discharging to, let's say, only 3.2V-3.4V. You would definitely get an increase in cycle life by doing that and discharging down to a much lower voltage would affect that cycle life.

 

[Mooch]

arrgghhhh...replied instead of editing my post, ignore.

 

[mcclintock]

The converter in a VV/VW mod is highly efficient. There may be a slight increase of losses at the extremes of settings but they are still low enough to be considered more or less constant. If you need 20 watts to the coil and the converter loses 5% then the battery needs put out 21 watts. If the coil is .05 ohms then 20 watts is 1 volt at 20 amps. If the coil is 20 ohms then 20 watts is 20 volts at 1 amp (just for example, since no mods I know of can put out 20 volts). Only if the power (however it is arrived at) is set lower does the battery get drained slower.

In my example of .05 ohms, there will be more losses between the converter and coil, however, which I didn't include. I generally agree with the consensus here that in units of full charges, power levels that elevate temperature is what will reduce your charges. However, a little less will actually make it out of the battery then too per charge, because of resistive losses in the battery cell (basically heating the battery instead of the coil, with the lost power shown as lower battery voltage under load).

 

[Morandir835]

Consider anything under 3.4V deep cycling sir, that's my usual cut off when it's time to charge. Put them on a charger asap- sometimes it's right away, other times it's within 12-15 hours (if they reach that point while at work). Have never noticed a difference in charging right away to waiting, but you've sparked my curiosity. Going to have to test that on my next new set of batts. When I do a cell that is strictly being tested for deep cycling cut off at 3.0-3.08 each time.

 

[Mooch]

Consider anything under 3.4V deep cycling sir, that's my usual cut off when it's time to charge. Put them on a charger asap- sometimes it's right away, other times it's within 12-15 hours (if they reach that point while at work). Have never noticed a difference in charging right away to waiting, but you've sparked my curiosity. Going to have to test that on my next new set of batts. When I do a cell that is strictly being tested for deep cycling cut off at 3.0-3.08 each time.

I'd be very interested in hearing the results!

 

[Morandir835]

Will make sure to message you when I have them sir.