Input greater than output, yet still deficient?

Cable loss, Some areas are 5 blocks or more so only 1 or 2 solar panels are acutally working. Copper cables lose 1 Eu/t every 5 blocks, solars only produce one, so only one solar is actually getting ANY energy to the bat box. Add another bat box right by the solar panels.

You should always try to use tin cables in your Solar Panel-> X machine connection, those are cheap and super efficient.

If you are going the Energy Storage -> Machine route then you need a proper cable for it (Copper+ for batbox,Gold+ for MSU,Iron+ for MFSU)

From what I can tell from the picture, the cable loss is so big your batbox isn't even getting a single EU.