TL;DR
Introduce a research line to improve the logistics robots' and construction robots' power management.What ?
I am suggesting a line of research to improve robot power management, similar to how we have a research line for robot speed and carry capacity.There are four ways I can see this being implemented: larger battery capacity in the drones, less drain from moving, increasing the number of drones that can be recharged at a roboport at a time, creating a new version each drone that includes a solar panel into it (so each drone is considered to have a solar module from the armor), or some combination of all four.
(I know it's supposed to be one suggestion per post, but this is the same end goal, please let me know if I should split it across multiple posts)
The tech for improving battery life I could see as having infinite levels, +10% to the battery capacity with each tech. The research for decreased drain and increasing charging slots in the roboports should be capped at 95% reduction after 7 tech levels that give diminishing returns at the same research costs (20% reduction, then 40%, 55%, 70%, 80%, 90%, then finally 95% less drain on the batteries) and 8 maximum slots over 4 techs, each one giving another charging slot.
The new types of robots would be assembled from a robot, a solar panel, and a green circuit.