Before you tell me that the question has already been asked, only similar things have been asked.
I need to power a Raspberry Pi with some electrical equipment attached to it. The Pi needs to run for at least 48 hours and I need at least 2V and 900mAh to be used for the other equipment. The device must be portable, so it doesn’t have to weigh too much. I thought about using more than one power source and somehow merge them together (for example using rechargeable Li-on batteries and a solar panel).
What would be the best way to accomplish it?
EDIT: I should be able to see how much power is left.
You say you need “at least 2V” for other equipment. Does that mean the other devices require 2V or have a variable input voltage? The Pi runs off 5V, so if your other devices can use 5V also that would be easier. If you know exactly what else you would like to power, please add details to the question (the design would be easier that way).
Sep 14 ’14 at 16:11
The power isn’t variable, it needs 2V to run, but this current isn’t always needed, it’s only needed when a certain thing happens.
Sep 14 ’14 at 16:16
Add to your 2 V load at 1800 mWh the power consumption of the RPi. Find a good guess on that at RPi@SE. Given the amount the RPi consumes (20 to 45 Wh a day) your load seems to be negligible for your power supply. So the most simple solution would be to pick a suitable power supply for the RPi and use a switching step down regulator to provide the 2 V.
(Depending on the application the RPi might not be best suited for a portable solution.)
I honestly thought that the raspberry pi would use more than just 45 Wh a day. Guess I was wrong 🙂
Sep 14 ’14 at 16:25
How would I check the power left? Are there chips that measure the voltage and send back an analog input with it?
Sep 14 ’14 at 16:32