NuclearControl/CC

a = peripheral.wrap("top")
b = peripheral.wrap("right")
c = peripheral.wrap("bottom")
rednet.open("left")
local mEnergy = 0
local nEnergy = 0
local pEnergy = 0
local nLit = 0
local rOutput = 0
local nLamps = 7
local excess = 0

while true do
 idA,stateA,titleA,dataA = a.get(1)
 idB,stateB,titleB,dataB = b.get(1)
 idC,stateC,titleC,dataC = c.get(1)

mEnergy = tonumber(dataA["maxStorageL"]) + tonumber(dataB["maxStorageL"]) + tonumber(dataC["maxStorageL"])
nEnergy = tonumber(dataA["energyL"]) + tonumber(dataB["energyL"]) + tonumber(dataC["energyL"])
pEnergy = (nEnergy / mEnergy) * 100
pEnergy = math.floor(pEnergy)

 if nEnergy > mEnergy then
   excess = nEnergy - mEnergy
   nEnergy = nEnergy - excess
 end

	nLit = math.floor((nEnergy / mEnergy) * nLamps)
	rOutput = (2 ^ nLit) - 1
	redstone.setBundledOutput("back",rOutput)

	term.clear()
	term.setCursorPos(1,1)
	term.write(nEnergy.."eu of "..mEnergy.."eu")
	term.setCursorPos(1,2)
	term.write((pEnergy).."%")
	term.setCursorPos(1,3)
	term.write(nLit.." leds lit")

 info = {nEnergy, mEnergy, pEnergy, nLit}
 euData = textutils.serialize(info)
 rednet.send(11, euData)
 sleep(0.5)
end