Charging...... Lithium-ion batteries (Li-ion)
- Thread starter Warstud
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JHZR2
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Li-ion batteries get maximum cycle life when the batteries are kept in the narrowest state of charge range possible. That usually also means some middle of the road state of charge. Oxidation is more likely to occur at high state of charge, and some protective circuits won't allow charging if a battery discharges (use plus self discharge) too low.
It is important to fully discharge and fully charge from time to time, to help calibrate the algorithms and Management systems. Some batteries also balance cells, and that often needs a pack to be topped up.
I leave my tool batteries partially charged as much as possible. I don't let them go too low, but also don't let them go too high needlessly.
They are best when charging between 40-80%......you have to discharge them completely from time to time just to re-calibrate them.
For a long term storage......leave battery @40%
Depends on how many of them I have.
For my dewalt 20v tools, I have 7 different Li-ion batteries. I could let them run down before recharging. My oldest Dewalt 20V batteries are from 2011 and are working fine.
Other things like floor sweepers, I may top up the charge when I can tell it's running low.
I do believe that all these batteries should be run down from time to time before recharging.
Can a new Li-ion battery be left as is for a long period of time w/o removing it from its original packaging and charging it?
Originally Posted By: demarpaint
Can a new Li-ion battery be left as is for a long period of time w/o removing it from its original packaging and charging it?
Originally Posted By: dishdude
How does cell phone fast charging impact longevity? I have an S7, it's crazy how fast it will charge if you turn that option on. I'm thinking it can't be good for battery health so I try not to use it.
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Originally Posted By: Warstud
Originally Posted By: demarpaint
Can a new Li-ion battery be left as is for a long period of time w/o removing it from its original packaging and charging it?
Originally Posted By: demarpaint
Or is leaving it as new and unused bad for it?
JHZR2
Staff member
Originally Posted By: demarpaint
Can a new Li-ion battery be left as is for a long period of time w/o removing it from its original packaging and charging it?
JHZR2
Staff member
Originally Posted By: demarpaint
Originally Posted By: Warstud
Originally Posted By: demarpaint
Can a new Li-ion battery be left as is for a long period of time w/o removing it from its original packaging and charging it?
Originally Posted By: Warstud
When do you charge your devices that use Li-ion batteries?
Quote:
Don’t charge them too high
Don’t swing them too wide
Keep the temperature low to extend their life.
Just to be clear: These rules are for Li-ion batteries; for phones, laptops, cars etc. Not for other kinds of batteries. And not for every Li-ion battery known either; but the most popular ones.
Originally Posted By: JHZR2
Originally Posted By: demarpaint
Originally Posted By: Warstud
Originally Posted By: demarpaint
Can a new Li-ion battery be left as is for a long period of time w/o removing it from its original packaging and charging it?
I designed a lithium ion battery charger a while back and the two biggest things the customer stressed were to ramp the charging current down in a predictable way as the very accurate peak charging voltage was approached and to help them keep the battery from being charged if it was too hot or too cold (0 to 50C was generally considered to be safe). I had to dramatically change the design late in the game to move the "refresh" voltage up closer to the peak voltage and make that voltage much more accurate...after a charging cycle finally reached the peak voltage and the charging current was completely shut off, the battery could self discharge sitting in the charging cradle or maybe discharge due to a parasitic load. If the refresh voltage level that signaled to start a new charging cycle was not very close to the peak battery voltage, a customer could take the device out of the cradle at just the wrong time and have much less capacity than they would expect.
Lack of deep discharging was not really viewed as an issue by our customers, probably reflecting that we were targeting consumer devices that would have limited lifespans. We would still try to trickle charge a battery with a very low voltage at the start of a cycle (below 2.5V), but this charging would terminate in an accelerated fashion if the battery voltage did not pop up fairly quickly...a lithium ion battery that is still alive should recover from a low voltage very quickly even with a small charging current.
The chemistry was generally viewed as being fairly "easy" except for the critical current rampdown near the peak and the super critical battery temperature concerns...no real memory effect and deep discharging also being of little concern beyond the need to trickle charge down low. Of course, I was not a battery expert and was generally designing to specs that the customer had OKed, but we had some latitude as to how we approached some things.
Originally Posted By: batteryuniversity
Most Li-ions charge to 4.20V/cell, and every reduction in peak charge voltage of 0.10V/cell is said to double the cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 600–1,000 cycles; 4.0V/cell should deliver 1,200–2,000 and 3.90V/cell should provide 2,400–4,000 cycles.
Originally Posted By: batteryuniversity
The largest capacity loss occurs when discharging a fully charged Li-ion to 25 percent. The loss would be higher if fully discharged. Cycling between 85 and 25 percent provides a longer service life than charging to 100 percent and discharging to 50 percent.
Theory/best practice aside, it's not practical for me to stop charging my cells at 85% and stop discharging at 25%, mainly because that would require significant amount of manual intervention.
Li-Ion cells are pretty cheap these days, and even if I only get 300 cycles out of them, based on the way I utilize them, that still means 6+ years of usage for me. 500 cycles would be around 10 years. I really don't mind getting new cells every 6-10 years in exchange for convenience and ability to use 100% of their capacity instead of 60%. Another words, I'm not going to worry about it.
new cells ship at 30-40% for safety and because degredation is slowed way down.
cells i actively use get topped up anytime i use the device more than a few minutes.
spares not in use i keep at less than 50%
as these cell are cheap now i dont worry about them much.
i get so many for free from bricked but otherwise good laptop packs its hard to care.
when you have 8000 of them in a car pack you better baby them.
never below 20% nor above 80%
i am willing to bet that the tesla model s module on my ups will still be ok in 20 years.
i have seen laptop packs 15 years old that were never used have nearly new performing cells even though the bms had bricked it.
worst case with li-ion is high soc and high temp.
this is why they die early in laptops.and nissan leaf.
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