Board Thread:Questions and Answers/@comment-208.107.154.62-20140107062443/@comment-96.35.103.214-20140122021244

No,  it is a voltage problem. Solar panels output too little energy to be carried by copper cables. Use ultra low current cables (crafted like copper cables except with tin and without rubber). Copper cables lose energy the father they carry EU. ULC cables don't lose any EU until around 40 blocks of wire. Solar panels output like 1 EU per tick. Check the wiki page on cables for more information on the types of cables.