Wholesale Two-Way Radios 799 New Design Double Band VHF 136~174MHz, 220~260MHz, UHF 400~490MHz 13.8V Two Way Radio for Vehicle Item No.799 Vehicle platform operation The rated voltage of the vehicle battery must be to ensure that the vehicle battery with sufficient current capacity is used. If the current supplied to the intercom is insufficient, the display screen may dark or the power output of the transmitter may drop significantly during transmission. 1. Determine the cabling of the tributary power cable (delivered with a walkie-talkie). Lead it directly from the intercom to the wiring terminal of the vehicle battery (do not connect temporarily), pay attention to the shortest route through the cable. A. It is recommended not to use cigarette lighter jack, because some cigarette lighter jack will cause voltage drop. B. Arrange the entire cable away from heat, moisture and isolation from the engine's secondary (high voltage) ignition system/cable. 2. After the cables are laid out, wrap heat-resistant tape around the fuse box to prevent dampness and secure the entire length of the cable. 3. http://www.sifangradios.com/two-way-radios/