Xbee S2 and Xbee Pro device battery supply configuration

I am using Xbee S2 and Xbee Pro device, how can i use battery configuration for powering the device. can i use 1.2V chargeable battery in series and make 3.6V and apply to module, but i have query what if i recharge the battery it will then have 1.4V each when gets full charge. Then all will contribute to 4.2V, will it damage the module. also i have concern for long battery life application. kindly suggest method to power device with long life in considering.

You will need to use some sort of voltage regulator to make sure that you keep the power within the radios VCC limits. Otherwise you will exceed the VCC limits and run the risk of damaging the module.

For long life, try adding in solar cells.