|
|
Charger for Li-Ion batteries
I was working on flashlight project, witch will use 3x parallel 18650 type Li-Ion batteries, and i needed a charger for it, so here it is! ;)
It is build around LM2576 switching regulator IC1, IC2 (i used MCP6042) is used for max current limiting and for "end of charge" indication. Red - when charging and Green - when charge current drops bellow ~100mA. R8 sets the final charge voltage, R9 sets max charge current. D3 is for reverse polarity protection (also BY550 or SB540 or else).
After i draw the board, i realized, that the charger will draw some current from batteries, when power is disconnected from charger. So i added a relay. I didn't want to add a diode on output, because, i think, the regulation would decrease. If you plan to use it as standalone, (not integrated, like me) you can omit the relay.
Here is the board, i designed it to fit in 150W halogen spotlight case.
If someone is interested - here are Eagle project files: Schematic and BoardAnd here it is mounted in flashlight
|
|
