OK so an LED won't light up on 1 battery. It won't light up with 2 batteries. 3 batteries will smoke the LED. What about the LED flasher I built with Chinese bargan pack of LEDs it runs on 2 AA batteries from Harbor Freight meter shows each battery voltage 1.4v x 2 = 2.8v total. But wait, better batteries will be about 1.6v x 2 = 3.2v LED lights up on 2 batteries. 3 batteries will be close to 4.5v.Most of my solar garden lights use an RGB LED that changes its colors. The circuit that powers them steps up the 1.2V from an AAA Ni-MH rechargeable cell and limits the current. I never tried blowing one up by connecting directly to a battery.
Since the maximum allowed voltage of the Chinese LEDs is only 3.6V then they probably need a series current-limiting resistor and will not light up with a 3V battery that drops to 2V.
Auto blinker LED must be a different voltage.
If I want a single Red LED blinker I need to build this circuit. I don't believe 9v is correct my other circuit said 9v I tested with with 1 battery then 2 batteries. Wait a minutes I can't build this I don't have these transistors.