I got a low battery warning for my Apple Wireless Keyboard so I charged up my spares, overnight. Then the next day I replaced the low batteries for the freshly charged ones. Now a day after replacing them I am getting a low battery warning again! Could it be that the sensor is falsely detecting a low charge? Or are the batteries likely faulty? Do Apple's rechargeable batteries just not last very long? I've had them for a few years, but recharging is what they are meant to do so I expected to get more use out of them (if that is the issue). Hoping for some helpful suggestions. Thanks.