Send long char array (7000) via hardware serial

Whats a trailer queen?

A bike that is destined to spend it's life on a trailer, being towed from place to place to be seen (not ridden).

This is for a push bike

A what?

I just want the rear red LED's to flash at around 3Hz, which is well within any UK laws regarding additional bike lights.

I don't see the need for a timer to manage this. I don't see ANY relationship between flashing the read LEDs on a bike and sending huge amounts of data via the serial port.

Just because a riding mower can be equipped with a blender to make margaritas doesn't mean that it should.