I am looking to make a dog feeding mechanism that will operate regardless of power outages. The main point of this query initially is to figure out how to work with the materials I have (or can get) to store enough power to run a small Arduino or two for a non-predetermined amount of time.
I have a small collapsible solar pack that is 5v 8 watts, made for slow charging phones and stuff camping. I have started experimenting with Super Capacitors and currently have 6, 2.7v 500F Samwah (MH47765) caps. I also have a rather large supply of 18650 Li-Ion batteries.
I am having a problem understanding how to balance charge my supercaps. I am also unsure how to approach power distribution between each segment. I have a small converter that takes 0.9v-5v and outputs 5v at approx 96% efficiency(claimed). I have the necessary parts for a lm2596 5v switching voltage regulator circuit. I may have pre-assembled ones out of china as well as enough to make 7 or 8 more.
Would it be prudent to regulate the voltage or the solar cells to the caps with the small 5v buck converter or better to do that after the caps? if I use the lm2596 it seems like it would be just as good to use the arduino's onboard voltage regulator? The Diodes have have from the lm2596 are 5amp Schottky diodes; are they appropriate for balancing purposes?
The idea of charging two 2.7v caps in series to 5v and then when full, perhaps use a relay to switch to another pair maybe another pair after that. This would maximize power harvesting from the sun. Then once two pairs had charged I could use a relay to put two pairs into a series at 10v making the use of the onboard or lm2596 voltage regulators work, possibly utilizing extra energy to charge some of the li-ion batteries as well?
The system would need to be able to run a real time clock, or could be simplified to work with the sunrise and set. It would need to trigger the feeding mechanism twice a day. So I should have lots of "extra" stored power to pour back into Li-Ion batteries.
I live on an island (Guam) and we get very bad storms and typhoons. The power system on the island is antiquated (WWII Diesel)and we suffer from rolling blackouts frequently and prolonged outages during stormy periods. I goal is to ensure food is provided to two 95lbs (44 Kilograms?) German Shepherds. I have to travel off island for medical and if a bad storm hits the pet sitters may not be able to get to them.
This doesn't talk about the feeding mechanism side of this but I figured one step at a time. I am happy to add this for those who are curious or if anyone thinks it may affect the approach so far, but I am trying (and failing) to keep this shortish.
Any ideas, creative alternatives, or any help understanding my options would be very much appreciated!