I'm rather new to circuits & DIY electronics, but am thoroughly enjoying tinkering with my new RaspberryPi and assorted components. I'm trying to power the device using a few simple solar panels I stripped from cheap LED lawn lights from Menards.
I've combined three 2V solar units in series to output 6V total. The RasPi (B+ model) device needs 5V @ 800mA (including some components I've added). While I expect steady, consistent lighting (will be inside under relatively bright fluorescent lights, but I haven't gotten to measure their luminosity or anything yet), I believe the solar panels can only put out a couple hundred mA.
I have a couple old Samsung Galaxy batteries, which put out 3.7V, 1650mAh. My thought is that a charged battery (or perhaps two in parallel) could provide sufficient current, while the solar panel could keep the voltage in the circuit high enough. But my understanding of the intricacies of circuits (especially many elements in combination) is really limited, so I'm not sure this is possible.
My hope is this: Fully charged, two Samsung batteries in parallel could provide 3300mAh at 3.7V, which could supply the RasPi's needed 800mA for just over 4 hours. But the voltage is too low, so I hope I could "combine" the battery's current with the solar panel's 6V voltage supply "upstream" of the RaspberryPi.
I also know that using the solar to charge the battery is a whole other question, given the RasPi's power needs. Even without any load, at 1650mAh, each battery would take 11 hours to charge, or 22 for both! So I'm not too concerned about that just yet. But I'm curious for now to see what's possible with the pieces I've got.
Thanks in advance for any help or advice! Let me know if I can clear up or expound on anything I said.
I'm not entirely certain whether they address my questions, but I'm working on it.