To back up what hfiennes links to, the automotive power environment is widely regarded as one of the more challenging design environments. Your device could see anything from 4V during starting to well over 30V in a load dump event.
I haven’t looked into what sort of protection and regulation performance it provides, but a cigarette lighter phone charger will give you 5V. You can take it apart and hide it somewhere… presuming this is not a product.
If I may ask, are you deploying with a battery? I’m prototyping with just the 5V power from a USB port in the auto cabin and trying to optimize my firmware so that the Electron is consistently calling our webhook. So far the results are mixed - not sure why it can fire up the cellular radio sometimes and not all the time (every 2 minutes).
I was going to deploy without a battery, but it would be simple enough to include.
I wonder if using a battery with the electron would increase it’s tolerance to the voltage spikes that were the main concern in the replies to my original post.