Li-Ion batteries can be safely charged up to 2C (two times the rated capacity of the battery), but ideally should be charged at 1C or lower. So if you go below the rated capacity of the battery, then you will be perfectly fine, it just may take a while to charge the battery.
For example, say you have a 900mAh battery and a charger which outputs 4.2v @ 150mA. Well, it will take you roughly 6 hours to charge the fully depleted 900mAh battery, but it will not be dangerous (unless it trickle charges and doesn't terminate the charge once the battery reaches around 4.15 - 4.2v charge, which is a big no-no for any Li-Ion charger).
Now say you have a charger that has an output of 4.2v @ 1000mA and you are trying to charge a 150mAh battery, well that is VERY bad and should NEVER be done.
A good rule of thumb is simply sticking to 1C or lower. If you battery has 900mAh, then as long as the charger has 900mA, or less, charge rate @ 4.2v, then you will be fine. This is also a good idea since many Li-Ion manufacturers exaggerate their mAh ratings (*cough*Ultrafire*cough*Trustfire*cough*) . For example, many 900mAh 14500 Ultrafire/Trustfire batteries are actually between 500-750mAh. Only a few Li-Ion suppliers/manufacturers actually state the real numbers, like AW for example.
Maximum lithium ion battery charge rating is not 2C
I used to think maximum charge rates for all lithium ion batteries was at least 1C, but I found out a little while back this is not true. IMR generally range from about 1.5C to 4C AFAIK, so if you want to really rapid charge one you have to look it up. But hybrids and ICR can go as low as 0.4C max AFAIK, so again if you want to really rapid charge one you have to look it up. I don't know at what point of overcharge rate a battery will start to heat up, but I strongly suspect charging a 0.5C max charge battery at 2C would be a very exciting experience involving flame and possibly explosions.
Originally Posted by ITPython
I checked a few common batteries used in vaping and listed the charge ratings with references below.
Panasonic CGR18650CH 2250mAh Hybrid IMR Li-Mn: Max charging rate - 2.15 Amps (0.95C)
Panasonic NCR18650PD 2900 mAh Hybrid Li-ion: Rapid Charging current: 1.35A (0.46C) I have seen one instance of a max charging current for this at 1450mA (0.5C)
Panasonic High Drain NCR18650PF Hybrid 2900mAh li-ion: Max. charge current: 1.5A (0.52C)
Panasonic NCR18650A 3100mAh Protected Li-ion: Max charging rate - 3.1 Amps (1C)
Last edited by Ryedan; 10-27-2013 at 10:48 PM.
Last edited by Ryedan; 10-27-2013 at 11:09 PM.
Reason: Kant spel
Thought you might appreciate that. Sounds like a date. Dog's packing his toys.
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