I have just bought this VST-706 car gadget which plugs into the car cigarette lighter socket and function as 3-in-1:
- Battery voltmeter
- Digital thermometer
- USB 2.0 charger
This little car gadget cost less than RM30 and works with car using 12V battery or 24V battery.
The interpretation of its voltmeter reading is as follow:
Its thermometer measuring range is -9 ~ 80 degree Celsius.
The maximum output current of its USB charging port is 2.1A.
With it, you can always monitor the voltage of your car battery and be alerted of its faulty and timing for its end-of-life, before it went flat. The thermometer and USB charger are extra features that good to have too.