Why Batteries Function Better with Their Dedicated Chargers?

C/3 or 0.33C is certainly safe, but seems to be rather conservative. Most sources I’ve seen recommend 0.5C as a safe charging rate.

All properly designed Li-Ion chargers will automatically and gradually reduce charging rate toward the end of the charge cycle when they switch from Constant Current (CC) phase to Constant Voltage (CV) phase. This is to prevent over-voltage situations.

All EVs, like Tesla, also do this. Charging up to about 80% is fairly quick. The last 20% takes a long time. Plus, it’s actually bad to charge li-ion cells all the way to 100% - high voltage puts extra stress on the cell. I typically charge my cells to about 70-80, including my phone, unless I just really have to have 100 capacity available to me.


here is a charger that can do both LiIon and Eneloop

you do not have to tell it what charge rate to use (but you can), it is smart enough to charge safely, automatically.

here is a review:
suggest just scroll past all the test pictures, to the conclusion at the very end…

usually the ‘automatic’ ones are just slow

like 100ma default for a 2200 mah battery, would take all day

they do have to reduce current at the end but bigger capacity cells can have more current before that phase

smaller ones may end up over-voltage if the charge is too fast

i have one tiny worn out 16340 that ends up at 4.7V on the lowest current i have, 300 ma


charging to 80% is still slow if you are way under the max current the cell COULD take

or if you do not monitor temperature


Sounds like its internal resistance is extremely high now and should be headed for a recycle bin. :slight_smile:

yeah probably

it;s old and cheap

….didnt know about th HJK site. Round cell charger index
Wished I’d known before I bought my charger a month ago :slight_smile:

….just noticed the “sticky” in the charger category.

This one I bought for several euros almost a decade ago but it was a standalone charger. Is it similar to chargers that come in clamshell packages with included batteries?

It takes almost half of a day to charge batteries. It acts strange sometimes because some channels have indicator that either does not turn on. Or turns on but emits a dim light. When I rotate the battery the light turns on fully. You can see it in this video: https://streamable.com/zhj7nv

Are you referring to chargers that plug into wall’s receptacle directly? Those branded chargers for their respective batteries like Panasonic, Duracell and my Camelion? With 100mAh it would take 22 hours to charge 2200mAh battery?

Another question. Are there chargers that come with or without batteries that are as easy to use as plugging them into wall’s receptacle without requiring any knowledge but are almost as smart as universal charger to take care of batteries automatically? This one I would need for someone who just wants easy to use optimal charging that charges withing 4-5 hours without wearing out batteries. I assume that these wall chargers are only for NiMH and NiCads but are not for charging lithium-ions?

usually the default currents are pretty low, for safety

2200mah / 100 ma would be 22 hours - at least

the “C” (capacity) is 2200mah, 100mah is 1/22C

BU-409: Charging Lithium-ion - Battery University
https://batteryuniversity.com › article › bu-409-chargin…

The advised charge rate of an Energy Cell is between 0.5C and 1C; the complete charge time is about 2–3 hours
that would be 1100 to 2200 mA


your assumption is mistaken. The charger I linked you to will do all of those, automatically.

Try to let go of the idea that certain brands of batteries need certain brands of chargers. That is not correct. Chargers do not care what brand the battery is.

they can distinguish battery type, easily

what they cannot do is, figure out the capacity of a li-ion

and without knowing that, they can only guess the right charge rate

you are right, brand does not matter

what i was thinking more about was, internal chargers, where the [internal] charger knows what battery comes with the light
there, the charge rate can be matched to the cell


I refered to different chargers this time. Not universal chargers with separate power adapter. I refered to wall chargers without display that have retractable, (although not always) prongs that you plug in directly to receptacle.

I saw them usually sold with batteries of the same brand. Mine is Camelion but I wanted something close to universal smart charger without additional power adapter that charges more optimally causing less wearout for batteries. But these kind if chargers are made to charge Ni-MH and Ni-Cd batteries as far as I noticed.

Which Nitecore do you use often? UM4 model seems like a good choice at the moment. I understand that after purchasing you need to verify authenticity through code obtained from manufacturer’s website in order to start using the charger?

It comes with USB cable and requires USB wall plug to connect to. I don’t know if I need to buy special USB wall plug for it that is offered as accessory. It states 5V 2A and 9V 2A 18W in its input. I happen to have the following 2:

- Input 0.15A

- Output slot #1 5V 2A

  • Output slot #2 5V 1A

- Input 150mAh (same as 0.15A I guess)

  • Output 5V 1A

As to 18W none of the 2 above mention it. Regarding 9V 2A it is probably for high density lithium ions or rectangular 9V rechargeable battery? Can it charge 18650 lithium ion with 5V 2A?

Sounds like your charger is broken. All li-ion chargers in good working order should be using 4.2V as the charge voltage. In the CC stage the current is limited which will limit the voltage to the cell. Once the charge current is at or below the current limit then the cell will get the full 4.2V (CV stage) while the current slowly drops off as the cell slowly gets to 4.2V

No matter the battery condition/age, if the end cell voltage is at 4.3V or above then that charger should be retired and not used.

probably, lets assume a 3000mAh 18650 battery

it is not very good for the battery to be fast charged at 2A in 1.5 hours
better to use the 1A slot, and charge in 3 hours

lower charge rates are needed for lower capacity batteries, for example 14500 battery with 1000mAh capacity should not be charged at 2A in 30 minutes. It will get hot, and that will degrade the life…

look for a charge rate that takes 4 hours… that would mean a charge rate of 250mA… would charge the 1000mAh 14500 battery in 4 hours.

neither slot on your 2 slot charger starts low enough for the 14500 battery… look up the name and model, and see what battery Sizes, it says it is capable of charging. My guess is it says 18650, and does not say 14500…

nothing is really low enough for cheap 16340 cells though

real capacity can be like 500mah