Tired of not knowing when or if your batteries are low so this we bring you a solution from Happymodel the Breath LED. 

Happymodels breath LED is a battery voltage indicator. Solder it directly to the VCC and Ground pad of the battery lead and it will give you a live indication of the battery voltage.

Specifications:

Brand Name: Happymodel

Work voltage: 3.7v~16v

Weight:0.36g

Size:10mm*10mm*0.5mm

Customized for Mobula7 HD

Breath Light color indicates:

If the single cell of voltage from the battery > 3.6v, the color turn on Green

If the single cell of voltage from the battery< 3.3v, the color turn on Red

Connection diagram: