I have had that error quite a few times so i "pick up" the offending combiner (usually) then connect a few splitters to the output at the end of the combiner row , then replace the removed combiner and the problem usually goes away. my Test batteries are set to 750w each and my power supply rooms are usually outputing between 5500w-9500w total, I dont know what the "depth" is set up as i have it come up with various outputs. Here is a pic of  one of my power supply rooms , total wattage is 15000w fed into one main splitter then to another 3 going to switches to other splitters for turrets etc
https://i.imgur.com/RLPn0hG.jpg