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stockcropper/Solar Charger/Solar Sailer.md

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+E = 1/2 C V^2
+
+10x 2.7V 500F capacitors
+35 x 60mm
+500F:
+-> E(14V) = 36 kJ
+-> E(10V) = 25 kJ
+-> E(14-10V) = 11 kJ
+
+
+
+
+16 x 27 mm
+
+
+12V x 20A = 240 W
+say a 4 second tug
+that's 1 kJ
+E = 1/2 C (Vf^2 - Vi^2)
+C = 2 E / (Vf^2 - Vi^2) = `2 * 1k / (14^2-10^2)` = 20 F
+So we're talking super-cap range
+
+A 9ah battery is like $22
+
+https://www.digikey.com/en/products/detail/abracon-llc/AHCR-S04R0SA227Q/23018981
+$7.20
+220F - max storage is 1.76 kJ
+
+https://www.digikey.com/en/products/detail/abracon-llc/AHCR-S04R0SA127Q/23018999
+$5.17
+100F - max storage is .80 kJ
+
+oh but these all have peak currents of like 10A
+and what do you do after dark
+and on and on
+
+just put a damn battery on it and move on to the next problem
+
+
+
+PWM vs MPPT chargers
+- MPPT are up to 30% more efficient, especially in lower light
+- PWM are simpler
+- Both need a microcontroller I guess
+
+
+https://www.instructables.com/DIY-1kW-MPPT-Solar-Charge-Controller/
+https://github.com/opensolarproject/OSPController/wiki
+https://www.arduined.eu/arduino-solar-charge-controller/
+https://hackaday.io/project/159708-arduino-pwm-solar-charge-controller
+http://www.andrewwhyman.com/blog/electronics/arduino-pwm-charge-controller/
+https://web.archive.org/web/20161023034412/http://256.uk/?page_id=23
+![[MPPTschematic.jpg]]
+
+https://www.solorb.com/elect/solarcirc/scc3/index.html
+
+
+how to drive an IRF4905 - should be able to replace BC337 with 2N3904 (but how are those BJTs not a short?)
+https://forum.arduino.cc/t/automotive-pwm-control-of-p-channel-mosfet-irf4905-as-high-side-switch/434372/93
+![[a5f9f8ce1c919c81156c09ffb5a3e5eed443ef58.gif]]
+
+
+https://www.instructables.com/ARDUINO-SOLAR-CHARGE-CONTROLLER-Version-20/
+
+
+https://github.com/gameinstance/switcharger
+
+![[getnt29x2jjg7gb9.png]]