Charging rate/speed

[seaside]

Hi guys.

I heard I supposed to charge my Li-ions at 1C or less charging rate for safety and preserving cell life, but I am not sure what's going to happen if I charge that with over 1C rate.

For instance, if I would like to charge 880mAH 16350 with 1A.... Most 16340 is about 550mAH even if it's lable says over 800mAH. Thus, it's going to be about little less than 2C charging rate. This may shorten useful battery life tough, does that really be hugh impact on battery life? Will this cause explosion/fire or anything dangerous like that?

 

[Mr Happy]

Hi guys.

I heard I supposed to charge my Li-ions at 1C or less charging rate for safety and preserving cell life, but I am not sure what's going to happen if I charge that with over 1C rate.

For instance, if I would like to charge 880mAH 16350 with 1A.... Most 16340 is about 550mAH even if it's lable says over 800mAH. Thus, it's going to be about little less than 2C charging rate. This may shorten useful battery life tough, does that really be hugh impact on battery life? Will this cause explosion/fire or anything dangerous like that?

(ITYM "of course", not "of cause" BTW.)

You will likely find you "can't" charge Li-ion cells at a rate faster than 1C. What you will find is that the voltage will rise much more quickly to the maximum of 4.2 V, and then you (or the charger) must reduce the current so as not to exceed the permitted voltage.

It all averages out so that when you try to increase the charging current you find a law of diminishing returns and there is not much to be gained.

As for safety, I believe it can cause faster cell wear if higher than recommended charging currents are used, but I don't know how serious that is. People do seem to get away with it.

 

[rizky_p]

agreed, you can try to charge your li-ion with 2C charging current but soon the charger will have to drop the current as it reaches CV stage and you will get a less-then-full pack with higher charging current because of the 1/10C termination uses by most charger. I recommend you to charge with 1C or less, li-ion is not Nimh where you can fast charge the battery with CC until it gets full.

Things get different with emoli though, since they have much lower IR you can basically charge them with much higher current without droping much of the charging current when CV stage are met. those are just my observation over the years of using/charging different kind of battery chemistry using hobby charger.

dont charge normal lithium with higher than 1C it just doesnt work like that, not to mention the risk involved :poof:

 

[VidPro]

depends more on how the charger works.
Which is actually what they both said TOO :-)

when the cell is low, and there are many chemicals ready to convert over to the other side, you can hit it pretty hard, YET when the cell is fuller and many of the chemicals already have "converted" over to thier other state, you need to slow down.
different chargers can have a 1A rate, and yet act completly different, due to the chosen method of charge and termination and all (the charge alogrythm).
so, HOW is at least as important as how much :-)

then also there is a max rate for acceptance of the charge, (about the 1C) where the li-ion will change in resistance or something, going loose when you hit it TOO hard, not sure how that works. because of that, a TOO high rate could really Damage the battery itself, even IF there is all kinds of chemicals ready to convert, even IF the charger then cools out its rate.
pulse charging doesnt have THAT issue untill the charge rate is Much higher.
some cell items are Designed to handle higher charge rates, but even they arent "Fast" relative to how you can pound some ni-cds and stuff.

any safety issues come up when the extra power is converted to heat instead of charge, which is what will happen if the rate is to high, heating up the battery internally, that will depend on how the battery reacts, its age & resistance and all, how it aged, how its built , its quality etc. any instant death of the battery issues would come up if it Gassed out because the rate was to high.

seeing the lineup of HOW many of the li-ion chargers are working, i would say that MOST of them, it would be a BAD idea. seeing how long a crappy li-ion lasts ALREADY, i would say treating it really nice even if its Possible to charge it harshly is a good idea.