Hi, my name is Victor. I'm german but try it in english. I have a solarcell and an TP4056 IC for example. (I know its not good setup). The voltage is termined by IC and the max current by resistor. Althing work (not fine) but "ok". My question is what happens with the 1S 18650 cell with that setup? The CV ist ok. But there is no possibility for CC. What changes with the 18650 for example: Lifetime? Capacity? other difficulty? Is a fluctuating current input so significant for e.g. NCR18650B Cell? Why CC recomend? If you can give me a good link in german or english with researches or information from a producer like panasonic/sony/... would be great. Or if you have do test and could share would be really great. I couldnt found something like that in web. Best regards
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Here are some specs of your cell: https://www.batteryspace.com/prod-specs/NCR18650B.pdf CC is recommended because it has the highest charge speed without hitting a critical limit. The NCR18650B has a maximum charging current of 1625mA. If you limit this current by a ((4.2V-3V)/1.65A) 750mohm resistor, you get a significant lower charging rate. However low charging rate is always good for cycle life but with a limiting resistor, you still have a higher maximum current compared to a CC with the same charge speed, so even if you want to limit current for better cycle life you can have better results with CC instead of a resistor. But in your case, the TP4056 has a CC setting. You can set it over a resistor. Also, you can check the maximum current which the solar cell can deliver. If this current is not higher than the rated charge current, there is no need to limit it afterward.
David W. wrote: > However low > charging rate is always good for cycle life Having a very low charging rate near the cut-off voltage might actually decrease the cycle life..
vwilde wrote: > I'm german but try it in english. Crazy, in a German forum? To understnd the 4056, please look fr this: Youtube-Video "Charging a Lithium 18650 Cell using the TP4056" Der TP4056 startet mit Konstantstrom, wozu sonst hat er wohl den Widerstand? Deine Frage ist ziemlich unklar.
The cell doesn't care if the charge current is variable. The "CC" just means limiting the current so that neither the Charger nor the Cell is outside of its specification. For the cell that usually means 0.5C to get the nominal cycle life.