18650 Li-Ion Battery Recharging - Page 1
Forum section: electronics / general

author: SgtRock
author_rank: Unknown
timestamp: April 18, 2012, 04:38:16 am
content: Greetings EEVBees:--I have a new Cree Led flashlight that came with a 3200mAH battery (see attached picture, below) which is marked:"Rechargeable Battery with Re/Discharging Protection Circuit.I plan to get an extra battery. The flashlight came with a small single cell charger. I have no idea what method the charger uses to determine when a full charge is reached. I can easily get batteries of up to 5000mAH.--I suspect (but am not sure) that the Charger charges until the Battery signals a full charge, and the quits charging and changes the LED from red to green to indicate it is done. Can anyone tell me if that is correct.There is a great satisfaction in building good tools for other people to use.Freeman Dyson 1923 -Best RegardsClear Ether

author: IanB
author_rank: Super Contributor
timestamp: April 18, 2012, 05:59:20 am
content: That charger and that battery look kind of scary. I really don't think I have seen or heard of that brand before, so it's hard to know what kind of safety or adherence to proper charging algorithms it has.Here is a link to a "good" charger that I personally would be much happier using:http://www.candlepowerforums.com/vb/showthread.php?321423-Review-of-Measurement-on-Xtar-WP2-II-chargerThere are other choices out there, but the above one does quite well in testing and does not cost a fortune. The Pila IBC is perhaps the best regarded of them, but costs more.As for batteries I really doubt you can find them up to 5000 mAh. Around 3200 mAh is close to the limit for an 18650 cell. Anything labeled with 5000 mAh has been rather optimistically and falsely inflated for marketing purposes. People who make such claims are probably not selling a quality product.You will find a few recommendations on CPF for good brands of 18650 for lights, among them being Redilast, AW or Callies Kustoms.

author: kripton2035
author_rank: Super Contributor
timestamp: April 18, 2012, 07:57:49 am
content: I used to buy some batteries from differents sellers on ebay or china...the capacity they claim is more than double of the reality ...may be if you charge them at C/1000 they have the claimed capacity but I don't have time to test this !!and effectively the max you can find on a 18650 is around 3200mAH, never more ...

author: amyk
author_rank: Super Contributor
timestamp: April 18, 2012, 10:34:22 am
content: 3200mAh would be available in the best of the best 18650s, not a generic no-name brand. Expect it to be around the 2000mAh around range.http://lygte-info.dk/review/batteries2012/Common18650Summary%20UK.htmlThe best way to ensure your charger is working safely is to monitor the voltage across the battery with a DMM. It should never exceed 4.20 +/- 0.05v.

author: metalphreak
author_rank: Frequent Contributor
timestamp: April 18, 2012, 05:58:39 pm
content: Most of the good chargers use a CC.CV method.starts withConstant Current - charges at 500mA or whatever its set to until the cell voltage reaches 4.20Vswitches toConstant Voltage - Holds the cell at 4.20V until the charge current drops below a certain threshold, and then indicates a full charge. Threshold is usually something like 5-10% of the constant current setting.