Battery Shelf Life
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It is not something that is discussed too often because Li-ion & li-po batteries have a very slow "shelf drain". as compared to battery technology counterparts like the rechargeable ni-cd & ni-mh.
It is something to be concerned about though, because if you let Li-ion & li-po batteries go below their minimum voltage they become useless (something about the battery acids solidifying... dont quote me). roughly < 2.8v and most smart chargers throw errors while trying to charge.
Whereas ni-cd & ni-mh can be charged up from 0.0v. and is actually encouraged to fully drain the nickel based battery before charging to prolong the life (re. battery memory)
i dont know exact numbers. but when i was using Nickel based batteries (6-cell 3200mah packs) i would have to charge them just before a race, because they would loose 20% of their charge over night.
This problem was eliminated when the RC industry recognized Lithium batteries as a safe alternative for on-road racing.
i'll stop babbling now...
It is something to be concerned about though, because if you let Li-ion & li-po batteries go below their minimum voltage they become useless (something about the battery acids solidifying... dont quote me). roughly < 2.8v and most smart chargers throw errors while trying to charge.
Whereas ni-cd & ni-mh can be charged up from 0.0v. and is actually encouraged to fully drain the nickel based battery before charging to prolong the life (re. battery memory)
i dont know exact numbers. but when i was using Nickel based batteries (6-cell 3200mah packs) i would have to charge them just before a race, because they would loose 20% of their charge over night.
This problem was eliminated when the RC industry recognized Lithium batteries as a safe alternative for on-road racing.
i'll stop babbling now...
Probably of most importance is the number of charge/discharge cycles that determine overall life, of which of course these(the AW IMR 26500) had zero cycles on them. Also, i just went through the 11 AW IMR 26500's i had left (and i think i only sold 8 or 10 of those 11) and all read 3.90-3.93 volts. As a comparison, i just tested the AW IMR 18350's and IMR 16340's i got in last thursday and they read around 3.91-3.94, so no worries for those couple of customers who snatched up the last couple of AW IMR 26500's as they are testing just what a new one would.
for reference:
my 4800 mah 7.4V 4-cell pack (2 series-2 parallel) sat on a shelf for 14-15 months and only lost about 600mah... so i'de say, shelf life is a non issue in the e-cig world. unless you throw a drained cell in a drawer and forget about it for 6 months....
but this is just my experience with lithium batteries, which may not perform the same as the AW cells used in out mods.
my 4800 mah 7.4V 4-cell pack (2 series-2 parallel) sat on a shelf for 14-15 months and only lost about 600mah... so i'de say, shelf life is a non issue in the e-cig world. unless you throw a drained cell in a drawer and forget about it for 6 months....
but this is just my experience with lithium batteries, which may not perform the same as the AW cells used in out mods.
From Battery University~
How to Store Batteries
The recommended storage temperature for most batteries is 15°C (59°F); the extreme allowable temperature is –40°C to 50°C (–40°C to 122°F) for most chemistries. While lead acid must always be kept at full charge during storage, nickel- and lithium-based chemistries should be stored at around a 40 percent state-of-charge (SoC). This level minimizes age-related capacity loss while keeping the battery in operating condition and allowing self-discharge.
Finding the 40 percent SoC level is difficult because the open circuit voltage (OCV) of batteries does not lend itself well to state-of-charge estimations. For lack of better methods, voltage is nevertheless used as a rough fuel gauge indicator. The SoC of Li-ion is roughly 50 percent at 3.80V/cell and 40 percent at 3.75V/cell. Allow Li-ion to rest 90 minutes after charge or discharge before taking the voltage reading to get equilibrium.
Primary batteries store well. Alkaline and primary lithium batteries can be stored for 10 years with moderate loss capacity.
How to Store Batteries
The recommended storage temperature for most batteries is 15°C (59°F); the extreme allowable temperature is –40°C to 50°C (–40°C to 122°F) for most chemistries. While lead acid must always be kept at full charge during storage, nickel- and lithium-based chemistries should be stored at around a 40 percent state-of-charge (SoC). This level minimizes age-related capacity loss while keeping the battery in operating condition and allowing self-discharge.
Finding the 40 percent SoC level is difficult because the open circuit voltage (OCV) of batteries does not lend itself well to state-of-charge estimations. For lack of better methods, voltage is nevertheless used as a rough fuel gauge indicator. The SoC of Li-ion is roughly 50 percent at 3.80V/cell and 40 percent at 3.75V/cell. Allow Li-ion to rest 90 minutes after charge or discharge before taking the voltage reading to get equilibrium.
Primary batteries store well. Alkaline and primary lithium batteries can be stored for 10 years with moderate loss capacity.
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