night.hoodie
Enlightened
I am curious about the need or purpose of Li-ion break in for brand new cells. I am quoting below the some comments/replies from the only two posts I could find at CPF concerning the idea of breaking in new Li-ion, and since they are older threads, and considering all the new chems, I feel an updated thread and comments is not a terrible idea.
ICR LiCo is getting less popular, but now IMR LiMn and INR LiMnNi and also hybrids are becoming popular, also LiFePO4.
Do the experts feel the same way as before, considering new chems and ridiculous capacities?
Take the example of a single new cell, whatever chem. Let's treat this new cell like it is royalty, and forget for a moment it only cost $5-$10, so is not deserving of our time and attention. How do we pamper this cell and ready it for heavy current use? Do we break it in with several (how many?) full capacity high current discharge cycles? Do we rest it for as long as it was in use? Do we charge it slow, and as it approaches termination, increase the charge to faster and higher current?
How do we make a new cell intended for high current discharge as happy as it can be, and last through as many recharge cycles as possible? By giving up the top 10% of charge, and the bottom half, and using the middle-ish of its capacity only? Or top it off, rest it, and take it to the bottom?
Can any achievable and recognizable advantage be had to treating new cells differently for a number of cycles? Any difference of treatment recommended with different chemistry or capacities (low vs. high)?
Or just don't worry about it?! Gamble away the $5-$10/cell on danger may care, and let loose, and just be happy?
Thanks, guys!
from 2006:
from 2013:
ICR LiCo is getting less popular, but now IMR LiMn and INR LiMnNi and also hybrids are becoming popular, also LiFePO4.
Do the experts feel the same way as before, considering new chems and ridiculous capacities?
Take the example of a single new cell, whatever chem. Let's treat this new cell like it is royalty, and forget for a moment it only cost $5-$10, so is not deserving of our time and attention. How do we pamper this cell and ready it for heavy current use? Do we break it in with several (how many?) full capacity high current discharge cycles? Do we rest it for as long as it was in use? Do we charge it slow, and as it approaches termination, increase the charge to faster and higher current?
How do we make a new cell intended for high current discharge as happy as it can be, and last through as many recharge cycles as possible? By giving up the top 10% of charge, and the bottom half, and using the middle-ish of its capacity only? Or top it off, rest it, and take it to the bottom?
Can any achievable and recognizable advantage be had to treating new cells differently for a number of cycles? Any difference of treatment recommended with different chemistry or capacities (low vs. high)?
Or just don't worry about it?! Gamble away the $5-$10/cell on danger may care, and let loose, and just be happy?
Thanks, guys!
from 2006:
Hello Leef,
It can be beneficial to do a few 1C cycles on Li-Ion cells if you plan to use them in heavy current draw applications, however they are usually ready to go without needing a forming charge or break in.
4.2 volts is fully charged, 3.8 volts is good for storage and is what new cells come charged to. It sounds like your 3.8 volt cells did not charge.
Tom
from 2013:
Hi all,
I'm about to be delivered my new ebike, fitted with the Bosch engine and the new 400 Wh battery. The user manual doesn't deal with a "break-in" process to be followed when the battery is new.
I've searched CPF/Flashlight Electronics - Batteries included, but found nothing about Li-Ion break-in, unlike NiMH break-in which is dealt with in many threads.
A Google search gave me two very different recommendations:
- According to this page: it is recommended that you perform a "break-in" cycle consisting of three discharge/charge cycles to allow your batteries to reach optimum performance. This involves three complete discharges and three complete recharges.
- Whereas according to the Battery Break-in Process section on this page: It is recommended to perform 5 to 10 cycles of low discharges followed by full charges. A low discharge would be drawing 1-3 AH or riding 2-5 miles without heavy loads. Since the cells will discharge at different rates, the first cell to reach the minimum voltage will trigger the detection circuit in the BMS, which shuts off power. The range will be low and the customer thinks they have a bad pack. By doing short cycles the cells have a chance to equalize and not get far out of balance. The BMS has a balancing circuit, but it does not have the ability to bring up a cell that is much lower than the others. They have to be kept within a certain range of each other. In addition, leaving the pack on the charger over night gives the BMS time to equalize the cells.
Who is correct? Three full cycles, or 5 to 10 "very partial discharges + full charge" cycles?
Generally you do not need to do break in on LiIon batteries, but some battery meters need a few cycles to calibrate the reading.
That is some wisdom that was valid for old types of batteries, not for LiIon.
Today you are seeing 3 different types of rechargeable batteries: Lead acid, NiMH and LiIon, the first two can benefit from some break in, but not LiIon.
There is a few things you can do to get the longest lifetime from LiIon batteries:
Do not leave the battery in a hot place.
If you run the battery down, recharge it immediately.
If you are putting the bike away for the winter, discharge the battery to half charge, before storing it in a cool place.
To learn more about batteries I can recommend: http://batteryuniversity.com/
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