take 2 geothermals and place them on the ground, set the electric wrench to lossless mode. put some lava cells in the geo's to where theres excess in the lower slot and then pick the first one up with the wrench, wrench will now have next to no power, don't recharge it. you should have the excess cells and the geothermal, now do the same to the other generator with the underpowered wrench, it'll eerror that it doesn't have enough power and the geothermal will now be empty of extra cells. poof, into the aether they go.