The present invention provides a battery voltage measuring device and a battery voltage switching device for an electric reel, comprising a casing having a first end and a second end； a power connection member fixed to the second end of the casing for supplying power Connecting a battery； a circuit board module is disposed in the housing and electrically connected to the power connector, the circuit board module receives a first voltage of the battery via the power connector, and controls a first voltage according to the first voltage The display screen displays a voltage value； a voltage conversion unit is disposed on the circuit board module, and after converting the first voltage to generate a second voltage, the second voltage is output by a power output socket. In this way, it is possible to quickly measure the battery voltage and transfer the battery voltage for the purpose of charging the electronic product.本新型提供一種電動捲線器的電池電壓量測裝置及電池電壓轉接裝置，包含一外殼，具有一第一端及一第二端；一電源連接件，與外殼的第二端固接，供電連接一電池；一電路板模組，容置於該外殼內且電連接該電源連接件，該電路板模組經由該電源連接件接收該電池的一第一電壓，根據該第一電壓控制一顯示螢幕顯示一電壓數值；一電壓轉換單元，設置於該電路板模組上，並轉換該第一電壓產生一第二電壓後，由一電源輸出插座輸出該第二電壓。藉此達到快速量測電池電壓，並轉接電池電壓以供電子產品充電之目的。
