通常安装在电池放电指示器中-警告指示器的功能是通过闪烁的指示灯（光），喇叭或蜂鸣器（声音）或电子联锁装置（电气）来警告操作员。联锁装置通常连接到叉车的起重功能上，从而限制了它的使用，但不会阻止车辆返回电池充电区域。

Normally incorporated within the Battery Discharge Indicator - the warning indicator has the function to alert the operator either with flashing light (optic), horn or beeper (acoustic) or an electronic interlock (electrical). The interlock is normally connected to the lift function in a forklift truck - limiting its use but not disabling the vehicle from returning to the battery charging area.