you can use the empty power cell to fix the VTOL and recharge the power block
the lost rover not that useless
yeah buuut you kinda can just.... use the battery on Laurion generator (to get that water filter running) and use THAT spent battery on the Vtol (alternativly if I can't read that you need 2 batteries you can just fish it up from the dam)
yeah (but you have 100 power less in rover though)