@Rftop @Backpacker87 - Gentlemen, stumbled onto this thread because Im building a simple Argon based device and want to use solar. I have a small .6W 6v (OC) panel coming and am going to try the reverse bias zener diode regulator with VUSB solar power and a lipo.
Looking at the Argon power consumption, it looks like I’ll need at least 265-odd ma. The panel I have coming cannot do that, but this diode can as it looks like a 1N5341BG can allow up to 765 ma (Izm), if Im interpreting this correctly.
1 - What would you recommend in terms of specs for a bigger panel considering the Argon is more power hungry than a Xenon (RIP)? I will be sleeping this as much as possible between readings, maybe 50 readings a day?
2 - I’d like to confirm you put the zener anode (stripe) on the panel power output (+), and zener cathode on the panel GND, essentially across the panel leads.
3 - Why no resistor? [Edit: There’s no need to drop the voltage further with a small 6V panel] This thread helped
4 - When the lipo charging circuit detects power on the USB pin, if I understand the theory correctly (not an EE) the board will be powered from that source (solar panel). When VIN exceeds zener diode breakdown voltage (Vr >= 3V), the diode will short circuit to ground and the board will use lipo for power. [Edit: I got this all wrong…when reverse biased, the zener voltage Vz = the breakdown voltage Vr, and when the diode begins to conduct (above breakdown), the overall voltage of the circuit is dropped to the breakdown voltage of the diode, 6.2V, minus 0.7?].
4.1 - If there isnt sufficient sunlight, or it’s intermittent, has this resulted in the board resetting / power cycling / browning out, (does the board only switch power sources when it detects 5+V as expected for USB)?
Thanks for taking the time to look through these many questions. Any insight would be appreciated.
[Edit: I found this site helpful to explain zener concepts.]
-RC