Charging Li-ion circuit

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Cyirxrc6vec

Joined Aug 31, 2020
1
Hi, I made a circuit that charge Li-ion battery. When I simulated it, I found something strange; the time for charging was too short. I made it with 'LTspiceXVII' and here's my circuit's diagram and the graph, also I uploaded the 'Li-ion bat file'.
So, would you like to help me if you don't mind??

circuit.pngcircuit.pngcharging_graph.pngcircuit.pngcharging_graph.png

(If the libraries are not working, here's full library. Replace \Documents\LTspiceXVII\lib folder to this. And the Li-ion battery files are in "\ZZZ\miscellaneous\Li-Ion_Batt"
download the file here : http://bordodynov.ltwiki.org/lib.zip )
 

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Audioguru again

Joined Oct 21, 2019
1,908
www.batteryuniversity and semiconductor companies that make lithium battery charger ICs say that a lithium battery is far from a full charge when its voltage reaches 4.20V. The battery is supposed to remain connected to 4.20V until its charging current drops to a low amount and then it is fully charged and should be disconnected from the charger.
 

ericgibbs

Joined Jan 29, 2010
10,767
hi C6,
I see R1 the maximum current limiter, but as post #2 explains, you need to add low current charge sensing in order to stop the charge, when fully charged.

E
 

Alec_t

Joined Sep 17, 2013
11,640
How much charging current do you need? According to Fig 10 of the datasheet, trying to draw more than about 500mA from the LM317 with a 6V supply voltage will result in the IC having less than its rated dropout voltage between input and output.
 
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