Difference between revisions of "Lithium Ion Charger"

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I have a bunch of 18650 lithium cells laying around, empty, but no means of charging them. So lets build a small battery charger to charge them.

−

The purpose is to make a small charger that I can use with any Lithium Ion cell to charge. The 18650 cells that I have are 2700mAh cells, and charging at just under 500mA takes about 6.5 hours to charge a single cell form empty to full. This is not a good solution to charge big cells, but it gets the job done. Maybe in the future I will make a ~~fster~~ charger for those cells.

+

The purpose is to make a small charger that I can use with any Lithium Ion cell to charge. The 18650 cells that I have are 2700mAh cells, and charging at just under 500mA takes about 6.5 hours to charge a single cell form empty to full. This is not a good solution to charge big cells, but it gets the job done. Maybe in the future I will make a faster charger for those cells.

==Specifications==

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==Hardware and Schematic==

'''BOM'''

−

*[http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en024903|Microchip MCP73831]

+

*[http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en024903 Microchip MCP73831]

*1K Resistor x2

*2.2K Resistor

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*PCB

−

And here is the schematic. This schematic is basically taken straight from the datasheet, with the exception of the Status LEDs. The Status pin is tristate when not charging, Low when charging, and High when fully charged. This circuit shows both leds on when no battery is present, Red (LED1) when charging and Green (LED2) when fully charged.

+

And here is the schematic. This schematic is basically taken straight from the datasheet, with the exception of the Status LEDs. The Status pin is tristate when not charging, Low when charging, and High when fully charged. This circuit shows both leds on when no battery is present, Red (LED1) when charging and Green (LED2) when fully charged. The 2.2KOhm resistor sets how fast the charger charges. A value of 2.2KOhm will give just under 500mA charge. Higher value means slower charge. Th minimum value according to the datasheet is 2.0KOhm which will give 500mA charging current.

[[File:LionSchematic.jpg|left]]

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==Results==

−

That is it. Nothing more needs to be done. Tested and it works.

+

That is it. Nothing more needs to be done. Tested and it works. Charged a 280mAh cell in 45min. The 2700mAh cells take forever to charge (6-7 hours) but it works.

−

Here ~~is my~~ charger front and back.

+

Here are photos of the charger front and back.

[[File:LIONSmallFront.jpg|left|300px]]

[[File:LIONSmallBack.jpg|right|300px]]

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Difference between revisions of "Lithium Ion Charger"

From Francois Louw

Revision as of 07:23, 4 January 2014

@@ Line 10: / Line 10: @@
 I have a bunch of 18650 lithium cells laying around, empty, but no means of charging them. So lets build a small battery charger to charge them.
-The purpose is to make a small charger that I can use with any Lithium Ion cell to charge. The 18650 cells that I have are 2700mAh cells, and charging at just under 500mA takes about 6.5 hours to charge a single cell form empty to full. This is not a good solution to charge big cells, but it gets the job done. Maybe in the future I will make a fster charger for those cells.
+The purpose is to make a small charger that I can use with any Lithium Ion cell to charge. The 18650 cells that I have are 2700mAh cells, and charging at just under 500mA takes about 6.5 hours to charge a single cell form empty to full. This is not a good solution to charge big cells, but it gets the job done. Maybe in the future I will make a faster charger for those cells.
 ==Specifications==
@@ Line 21: / Line 21: @@
 ==Hardware and Schematic==
 '''BOM'''
-*[http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en024903|Microchip MCP73831]
+*[http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en024903 Microchip MCP73831]
 *1K Resistor x2
 *2.2K Resistor
@@ Line 29: / Line 29: @@
 *PCB
-And here is the schematic. This schematic is basically taken straight from the datasheet, with the exception of the Status LEDs. The Status pin is tristate when not charging, Low when charging, and High when fully charged. This circuit shows both leds on when no battery is present, Red (LED1) when charging and Green (LED2) when fully charged.
+And here is the schematic. This schematic is basically taken straight from the datasheet, with the exception of the Status LEDs. The Status pin is tristate when not charging, Low when charging, and High when fully charged. This circuit shows both leds on when no battery is present, Red (LED1) when charging and Green (LED2) when fully charged. The 2.2KOhm resistor sets how fast the charger charges. A value of 2.2KOhm will give just under 500mA charge. Higher value means slower charge. Th minimum value according to the datasheet is 2.0KOhm which will give 500mA charging current.
 [[File:LionSchematic.jpg|left]]
@@ Line 37: / Line 37: @@
 ==Results==
-That is it. Nothing more needs to be done. Tested and it works.
+That is it. Nothing more needs to be done. Tested and it works. Charged a 280mAh cell in 45min. The 2700mAh cells take forever to charge (6-7 hours) but it works.
-Here is my charger front and back.
+Here are photos of the charger front and back.
 [[File:LIONSmallFront.jpg|left|300px]]
 [[File:LIONSmallBack.jpg|right|300px]]