Flashlight with 9 LED bulbs, you need a few batteries, a few sections, volts, how much time can take?
So you should be 3 to 4 batteries in series. As for how long can bright, depends on the capacity of the battery, that is 2000ma/h, which is 2000mA can work for 1 hours, then 200mA current work can work for 10 hours.
With 3 batteries can be connected in series, if the brightness is not enough, you can try 4 batteries in series. As for the number, it doesn't matter. Batteries 5, 7, or other models are basically different in size and capacity
A LED bulb is about 10-20ma, and the voltage is about 5V. When a battery is working, the current is about 0.5A
