[SpookyZalost]

well... usb is dc 5volts 1.5 - 3.5 amps so that should be within normal draw from the accessory circuit of a car.

I ran a PI 3 plugged into a USB to accessory adapter without issue, in fact it ran normally, I only really ran into overheating issues.

but then again most "wardriving" I did was scanning for networks, capturing the packets using deauth and getting encrypted wifi addresses using an alfa usb wifi antenna (you can program these like SDR and they're great for hacking... also compatible with linux out of the box).

then I'd take those encrypted files and feed them to my main desktop at home to crack the passwords and next time I'd log into that network when I was there. usually only if I needed the connection though and only for basic stuff.

the majority of my wardriving was making a list of open wifi networks and their gps coordinates for further investigation, then go back using signal strength to determine where it's coming from and writing an anonymous letter informing them of their network security issue if it was a private residence.

it was fun