P channel MOSFET to disconnect a load

Thread Starter

Lagom

Joined Feb 8, 2019
19
Thanks, I'm waiting for a NDP6020P to see how that goes.

If you don't mind two more questions:

1. Why (with the existing "sort of working" P channel MOSFET) does - when the PV solar panel is suddenly illuminated - the LED go out near instantly, while - when the PV solar panel is suddenly blacked out - the LED comes on very gradually? Is this a "typical MOSFET thing", or because the current one is the wrong kind?

2. Why does, when I insert a 1k or 10k resistor between gate and source (pull-up resistor), the voltage not goe to full in broad daylight? I have meanwhile read that one should use a pull-up resistor between gate and source in my kind of high-side set-up. What am I not understanding there?

Much appreciated!
 

Thread Starter

Lagom

Joined Feb 8, 2019
19
All right, the NDP6020P arrived.

I put that one into the circuit instead and now it works as intended. Only in late evening, the LED comes on and goes off already in the very early morning. The P-channel MOSFET does not heat up detectably at all.

Yes, the PV solar panel's output voltage does not decay linearly.

I may now up the charger from 500mA to 1A charging as per Adafruit's instructions and use a 10,000mAh Li-Poly battery for full lumen output over 7 hours.

Thank you all for your advice!
 

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