review: 4 cheap BVM (battery voltage meter) from China
Channel: robo durden
Date: 30/05/2016

http://www.aliexpress.com/item/BVM-digital-1-8S-LCD-battery-voltage-meter-Tester-Buzzer-lipo-lion-liFe-nimh-pb/32260293512.html
$9.58 8s lcd dot matrix
WARNING, no good for constant use. The backlight of the display got so dim that it is hard to read anything on it.

http://www.aliexpress.com/item/AOK-Cell-Meter-8-without-background-light-and-Discharge-Digital-Power-Servo-Checker-Tester-2S-8S/32648661741.html
$7.95 8s backlight display

http://www.aliexpress.com/item/2-1-RC-Cell-Meter-7-Digital-Battery-Capacity-Checker-for-NiCd-NiMH-LiPo-Li-ion/32619985213.html
$5.89 7s lcd 

http://www.aliexpress.com/item/TA-LIPO-Battery-akku-Tester-RC-1-to-8S-Lipo-Li-ion-lithium-Battery-LED-Indicator/32555806567.html
$1.75 8s 

the Roland and www.kickmiss.com :-)