How to power the RaspberryPi for more than 7 hours with a single 18650 battery
Get a good 18650 battery by a dealer who knows what he's speaking about (and who has done some test to be able to tell it's not fake batteries).
Maybe I was just unlucky, but the red UltraFire battery I got from eBay was just crap. The good one was a Sanyo/EVVA 3400 Protégé got from PuissanceLed:
Get this 1€ battery charging board, and use this wiring:
- Ready to run for more than 7 hours!
During this test, the SamplerBox software was constantly running (so there was a non-negligible CPU usage), and these devices were connected to the RaspberryPi, taking some power:
- a USB DAC (for better audio quality),
- a USB MIDI keyboard (Akai LPK25),
- a USB SD card reader,
- a 7-segment 4-digits display,
so this means it could even be longer without these devices! I also read somewhere that it's possible to completely disable USB hubs, this could be useful for some other project.
And some other ideas for even longer battery-life (see this discussion):
- CPU throttling (allowing to decrease from 700Mhz to as low as 100Mhz when the RaspberryPi doesn't need much power),
- disable Ethernet port,
- plus many other ideas in this discussion...