Hello,
I have been working on a Clas Ohlson "North Light 1531" solar-powered wall light with motion sensor (AS312), which prematurely drains its double 18650 (7.4V) Li-Ion battery.
The PCB is connected to the battery (upper right), the LED light itself (lower right) and the solar panel (lower left). There is also a pot for defining the duration of light during detected motion and a button switch for selecting one of the three modes (or off).
What I'm seeing is a constant 1.5 mA draw even when turned off, which I'm unable to attribute to any of the valid main components.
When turned on in any of the three modes, I see a 4.0 mA draw, even when the LED panel is not lit, either due to daylight or no motion detected. This effectively drains the battery in a couple of weeks.
What I have done so far:
- Removed indicator LED1 and LED2, on both sides of the PIR sensor.
- Desoldered and checked C1 and C2 for partial short and capacitance.
- Desoldered and checked EC1 for partial short and capacitance.
- Disconnected the solar panel.
- Examined the board with an IR camera for identifying components warming up. Even with the light turned off, the 5.1Kohm resistor Ra does get a little warm, but I'm assuming that is due to the current being drawn from somewhere else. Other than that, nothing is visibly warming up.
I'm sorry I don't have a schematic. I'm hoping someone could give me an idea on what to check for next or let me know if you see anything in the design which would make these lights draw this much power constantly.
Any tips are appreciated!
Thanks,
JG