dcbwhaley wrote:
So what? It's unlikely the phone needs more than 10 volts.

--
But the main bus voltage can fall below 6 volts when cranking the
engine, especially if it is very cold.

you won't even start a modern car on 6v.

I had two batteries die on me this year on different cars. Around 9v was
the startable limit. I stuck a meter on them to see.