Most lodges have outlets so you will be able to recharge batteries.
However, because the lodges are run on generators, the electrical current is not as strong as traditional electrical currents. Some lodges turn off their generators at midnight. Keep in mind Tanzania uses 220 Volt electricity and you will need to bring necessary converters and plug adaptors (Type D & Type G).
Some of the campsites offer outlets in the dining area. As campsites get very busy things follow a first come, first serve principle.