I have built a super cheap
"UPS" for the raspberry pi that now have been tested for more than a year sucessfully without any issues.
I'm running the raspberry headless with a dAISy AIS
hat so the power consumption
What you will need:
2 x Backup External Portable USB Power Bank Battery Charger DIY
18650 Case LINK TO EBAY: Backup External Portable USB Power Bank Battery Charger DIY 18650 Case | eBay
1 x bank of two parallel connected 18650 batteries
LINK TO EBAY : Panasonic 18650 Li-ion battery 3.7V 6200mAh DIY for Portable Power bank 1S2PT | eBay
You may as well use two regular 18650 batteries
and using a short wire and solder them in Paralell
Connect the micro usb port for the charger
on the one "bank" and the power outlet to the raspberry pi on the " other bank.
The theory is simple. the Power bank is originally only capable to either be charged, or to supply power output, and is not capable to be charged and supply power at the same time. When connecting two 18650 batteries in parallel and using two " single" 18650 power banks as shown in the photos, one of the power banks will supply the power to the raspberry, and the other will charge both batteries at the same time.
I have tested this for more than a year with the raspberry running
"24/7 /365" and it just works.
No more suddenly crashes of the raspberry when starting the engine
or other power problems. It will keep the raspberry running for many hours without mains or other power supply.
You can even use much cheaper batteries than the "expensive" Panasonic ones i bought, but ebay is ebay and you will find a lot of fake and poor quality 18650 batteries there and I hoped for that paying a little bit more for the so called "original" Panasonic batteries that the quality would be fine and it seems that that strategy worked for me.
I would recommend to wrap some electrical
tape in each end around the boxes to keep them together - not shown in photos.
Difficulty in a scale from 1 to 6 : 1 - super easy - less than 1 minute work
Tools required: None.
Originally Posted by conachair
Might be easier not loosing power...
I changed the power supply to a buck/boost one set to just over 5v so the Pi doesn't loose power when starting the engine.
Also, openplotter has a forum of its' own, might be worth asking in there...