Does speed of charging affect li ion battery life, performance, etc? The other day it took my nitecore D2 charger about 5 hours or so to charge one 18650. Later that day I charged my Bosch compact drill li ion pack (which looks like 3x 18650s) on it’s “30 minute” charger. So it charged 3 18650s in—you guessed it—30 minutes. I did not have a way to test capacity. Is that healthy for a battery to be charged that quickly? If there’s no problem with fast charging, why don’t we see more of it with chargers and flashlights.
Separate note. I wish my LT1 charged quicker. (How much would usb-c to usb-c improve this?)
High amp chargers are expensive and "rapid chargers" must be high amp. Nitecore chargers in general are cheap, least cheap in terms of highest rated amp charging, they are generally overpriced in the retail market - you pay for the nice packaging, etc.
The 20R normal charge rate is 1 amp (2 hours) while the rapid charge rate is 4 amps (30 mins). The datasheet doesn't get specific about the rapid charge rate effecting the battery's lifetime and performance, least that I could find. Usually it detracts from the overall effective lifetime. Batteries lose capacity and add resistance over time, so all depends how fast or slow the degradation occurs at.
They say in the datasheet:
7.10 Cycle life With standard charge and maximum continuous discharge. Capacity after 250cycles, Capacity ≥ 1,200mAh (60% of the nominal capacity at 25℃)
So, how does it perform using rapid charge? They don't seem to say, but guaranteed it's gonna be worse.
Yes. There are many factors involved, but generally there is a nominal charge rate. On a made up 3000mah battery, let’s say 0.5C and the cell is rated for 400 cycles before its capacity drops to 80% of new. So this 3000mah cell can have a nominal charge rate of 1.5 amp and get 400 cycles (from 2.5v to 4.2v) before it losses 20% of the rated capacity.
Then it might have a maximum charge rate of 1C, 3 amps in this example, and it might only get 250 cycles before it reaches 80% capacity from new.
It may also have a “max cycle life” charge rate of 0.75A. It might give 500 cycles to 80% capacity.
The same goes for discharge. If you subject this 3000mah cell to 10 amp discharges all the time it will loose capacity faster than if you discharge it at 3 amp all the time.
Basically the more stress you put it under charging or discharging the faster the capacity will drop.
With power tools you might see a case where they are optimized for a fast charge. They may have a lower voltage limit of 3.0v and an upper limit of 4.0v. This allows the battery to charge quicker since your only using the constant current phase of li-ion charging. The constant voltage phase at the end from 4.0v to 4.2v is very slow. (I say 4.0v as the transition point, but it can be slightly higher or lower)
So your Bosch is probably using a high drain cell to handle the high charging current and also limiting the max voltage to get that 30 minute recharge time. They may even set the low voltage limit higher to maybe 3.5v. They prioritize the charging speed over cycle life because that is what most people prefer.
Also note that generally smaller capacity cells can recharge faster than high capacity ones.
Nitecore D2 is only 0.5 amp per cell. Very slow.
I use a Miboxer C4-12 that can do 3A x 4. I like to charge fast so I can do other things.
At work, not home. But I don't program lights/modded lights with NarsilM anymore - use my special version of Anduril now .
I swore at one point I'll never flash firmware again where I can't calibrate voltage and temp from the UI, so now that I modified Anduril to calibrate voltage, and extend temp range, and display a simple version #, I'm pretty happy with it as a NarsilM replacement.