Does an early recharge count as a full cycle on a battery?

[bushmaster]

I asked this question some months ago and received a few relatively unsure(no, not you Gil) answers.
If I decide to go out on the town and have changed my battery within the last couple hours(AW IMR 18650), but choose to change again to a fresh one in anticipation of a long, eventful evening, I'll then place an only slightly discharged battery back on the charger,right?
Will this recharge count as one of the 500 or so recycles that my battery is allotted or since it is only a partial discharge and recharge, does it count as 1/2 of a cycle or?????
I do this all the time placing only slightly discharged batteries on the charger and would very much like to know if its good or bad for the batteries.
Little help here from someone who knows.?

 

[tybin]

i'm not someone who knows

i'm going for the 1.2 cycle count though!

 

[Mvgratz]

I posted the question directly to Mr Andrew Wong (AW) for you buddy. He for sure knows the answer since he makes them...(When he posts and answer, I'll repost it here for you.)

AW's LiIon Batteries Sales Thread *Part 12*

 

[bushmaster]

You are a good dude, Mike. Thanks
What I said is no BS, I've wondered about this question for a long time--it'll be nice to have a real answer

 

[Big Hitter]

If you sleep for 24 hours straight will you live a day longer ????

Thats the question I wan't to have answered !!

But the battery answer will be useful as well

 

[mkp]

I've wondered that, too; thanks for asking the question out loud, Roger, and thank you Mike for taking it to the source.

 

[kyaku]

Thanks for asking and I hope we get a good answer. I've been wondering too.
It would be so nice to go ahead and recharge when you're think it's getting close instead of wondering if it would shorten the life of the battery.

 

[ltrainer]

I found this article that seems to indicate to me that a battery that is charged when 40% used equals 4/10ths of one charge , not one full charge:

Depth Of Discharge (DOD)

At a given temperature and discharge rate, the amount of active chemicals transformed with each charge - discharge cycle will be proportional to the depth of discharge.

The relation between the cycle life and the depth of discharge appears to be logarithmic as shown in the graph below. In other words, the number of cycles yielded by a battery goes up exponentially the shallower the DOD. This holds for most cell chemistries.

(The curve just looks like a logarithmic curve however. It is actually a reciprocal curve drawn on logarithmic paper).



Depth of Discharge vs Cycle Life

The above graph was constructed for a Lead acid battery, but with different scaling factors, it is typical for all cell chemistries including Lithium-ion. This is because battery life depends on the total energy throughput that the active chemicals can tolerate. Ignoring other ageing effects, the total energy throughput is fixed so that one cycle of 100% DOD is roughly equivalent to 2 cycles at 50% DOD and 10 cycles at 10% DOD and 100 cycles at 1% DOD. See also Cycle Life which shows how cell performance diminishes due to deterioration of the active chemicals as the battery ages.



There are important lessons here both for designers and users. By restricting the possible DOD in the application, the designer can dramatically improve the cycle life of the product. Similarly the user can get a much longer life out of the battery by using cells with a capacity slightly more than required or by topping the battery up before it becomes completely discharged. For cells used for "microcycle" applications (small current discharge and charging pulses) a cycle life of 300,000 to 500,000 cycles is common.

This informations was found here: http://www.mpoweruk.com/life.htm#dod

 

[Mvgratz]

I posted the question directly to Mr Andrew Wong (AW) for you buddy. He for sure knows the answer since he makes them...(When he posts and answer, I'll repost it here for you.)

AW's LiIon Batteries Sales Thread *Part 12*

Andrew Wong's answer Rodger....

"Mvgratz : Shallow cycles don't count as a full cycle. In fact, shallow cycles will extend the cycle / life of the cell than full cycle use."
AW's LiIon Batteries Sales Thread *Part 12*

 

[Beans]

Woo Hoo! So if I keep charging my batts early they'll live forever! Great news!

 

[mkp]

Andrew Wong's answer Rodger....

"Mvgratz : Shallow cycles don't count as a full cycle. In fact, shallow cycles will extend the cycle / life of the cell than full cycle use."
AW's LiIon Batteries Sales Thread *Part 12*

Yay! Topping off is *good*...way cool!

Thanks for asking Mr. Wong, Mike.

 

[Big Hitter]

No wonder mine last so long ... I'm getting confused with all these REOs around and I never remember which one I changed.
I'm sure I've put a fresh batt in and changed it an hour later a few times

Better safe than sorry.

 

[Mvgratz]

I've started "checking" my batts with a meter when I feel they are "dropping off"...turns out right at 4 volts even is when I swap mine out. Love that fresh 4.2v vape! (Now to have it confirmed its not BAD for the batts is just icing on the cake!)

 

[Anemone]

Thank you for posting this topic. I was wondering also!

 

[SammyT]

this is great news. I only have 2 batts, and if I am at home I swap them at 4v. otherwise they might get used to about 3.8.

 

[Mvgratz]

this is great news. I only have 2 batts, and if I am at home I swap them at 4v. otherwise they might get used to about 3.8.

I'd defintley get at least one or two more if funds permit... I have 9 18650's in rotation atm between 3 of my reos.

 

[TMellow]

Thanks for that question! That cleared up an old wives tale about it burning out the battery sooner.

 

[Mvgratz]

Lithium Ions do not develop "memory effects" like NI-MH rechargeable batteries...

 

[Skeeter T]

Lithium Ions do not develop "memory effects" like NI-MH rechargeable batteries...

Mike, ya done good. But hold on folks ... we may not have solved the matter. Batteries age whether in use or not. What does aging do to the voltage and/or amperage? Things wear out. As we age our bodies don't have the stamina and endurance it use to have. Our output decreases. What happens to a body when it's kept at a peek energy level for a very long time? So, although shallow cycling increases the life, does it have an ill affect in some other way

Ted

 

[Mvgratz]

Mike, ya done good. But hold on folks ... we may not have solved the matter. Batteries age whether in use or not. What does aging do to the voltage and/or amperage? Things wear out. As we age our bodies don't have the stamina and endurance it use to have. Our output decreases. What happens to a body when it's kept at a peek energy level for a very long time? So, although shallow cycling increases the life, does it have an ill affect in some other way

Ted

Batteries never stay around long enough for me to worry about how old they are. If I get a years use out of them I'm happy... Here is an excellant source for many answers...
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

Service life

The rechargeable battery has a relatively short service life and ages even if not in use. In consumer products, the 3- to 5-year lifespan is satisfactory. This is not acceptable for larger batteries in industry, and makers of the hybrid and electric vehicles guarantee their batteries for 8 to 10 years. The fuel cell delivers 2,000 to 5,000 hours of service and, depending on temperature, large stationary batteries are good for 5 to 20 years.


Simple Guidelines for Charging Lithium-based Batteries
• A portable device should be turned off while charging. This allows the battery to reach the threshold voltage unhindered and reflects the correct saturation current responsible to terminate the charge. A parasitic load confuses the charger.

• Charge at a moderate temperature. Do not charge below freezing.

• Lithium-ion does not need to be fully charged; a partial charge is better.

• Chargers use different methods for “ready” indication. The light signal may not always indicate a full charge.

• Discontinue using charger and/or battery if the battery gets excessively warm.
• Before prolonged storage, apply some charge to bring the pack to about half charge.

• Over-discharged batteries can be “boosted” to life again. Discard pack if the voltage does not rise to a normal level within a minute while on boost.

In Bold above is the main indicator that I use to guage when its time to discontinue use of a battery. Also if performance dramatically starts deteriorating...