Depends on the manufacturer. Mine will blink yellow when it is in absorption mode. Flashing green is in maintenance mode. Red flashing is a battery problem, either over charged, not connected, etc. This is on Minn Kota.
It could be a battery too low, charging too high, took too long to charge, a bad fuse, bad battery or connection problem. If you can find an online manual, it will narrow it down some.