[TurnNBurn]

After my EV Motorcycle conversion I'll have a row of little 12v 3 amp hour batteries (I think 12 batteries total). I want to make a server farm out of raspberry Pis. Don't let this post scare you off immediately, it's a pretty basic question.

The pi runs on 5v and 1.2 amp.

(keep in mind I'm new to solar stuff and the math behind it all).

If I run the batteries in parallel, how do I do the math to figure out how long the raspberry Pi will last on the batteries?

After this math is figured out, next I want to figure out what solar panel(s) I could use to charge the batteries. I live in the desert, so it'd be cool if I could use the panel to run the pi during the day and at night have it run off the battery pack. The solar panel during the day could also charge the battery pack.