This product has a replaceable battery. To ensure replacement batteries meet Plantronics high quality standards and for optimal performance, only use replacement batteries provided by Plantronics. Talk Time
With a single full charge, the CS510/CS520 will provide up to 8 hours of talk time. Talk time will be reduced when operating in wideband mode or if the headset is used consistently at a far distance from the base.
Low Battery Warning
If you are on a call and the headset battery is critically low, you will hear a repeated low tone every 15 seconds indicating that the battery is low. If this happens, you should recharge the headset immediately. If you are not on a call and press the call control button, you will hear three low tones if the battery is critically low. You should recharge the headset immediately.