Many electronics require certain conditions in order to operate. However, when the balloon goes up to 100,000 ft, the temperature goes down to -70 Celsius . This is is too cold for cameras or trackers to operate. Additionally, some batteries may not work in that condition.
The best solution is to include long-term hand warmers. These warmers should be included within the package of the electronics or the cameras. Hand warmers aren't very large, and they don't weigh much either. Just be sure to get long-term hand warmers so that they last throughout the whole flight.