Can be for many needs but, intended use is on a Telescope

A (Red) light for telescope powered by a USB battery.

 

Use whatever color LED's you want.  Design is based on 2v LED's.

Power source's I use are either Jackery or Kamashi.

 

The Kamashi turns itself off if power draw is too low, so there is a single LED to keep it on. Toggle switch selects: Single_LED, Off, All_LED's

 

The power cable is from a typical USB cable.

 

The plastic Box & Cover are posted at Thingiverse (see link)