Multiple Energy Cell Monitor v1.1

modem = peripheral.wrap("right")
monitor = peripheral.wrap("top")
monitor.setTextScale(1)

lastStoredEnergy = 0
energyRate = 0
timeEmpty = 0

function comma_value(n) -- credit http://richard.warburton.it
    local left,num,right = string.match(n,'^([^%d]*%d)(%d*)(.-)$')
    return left..(num:reverse():gsub('(%d%d%d)','%1,'):reverse())..right
end

function SecondsToClock(nSeconds)
    if nSeconds == 0 then
        return "00:00:00"
    elseif nSeconds > -math.huge and nSeconds < math.huge then
        numHours = math.floor(nSeconds/3600)
        numMins = string.format("%.2d", math.floor(nSeconds/60 - (numHours*60)))
        numSecs = string.format("%.2d", math.floor(nSeconds - numHours*3600 - numMins *60))
        return numHours..":"..numMins..":"..numSecs
    else
        return "n/a"
    end
end

while(true) do
    numCells = 0
    attachedCells = {}

    for index,value in pairs(modem.getNamesRemote()) do
        if string.find(value,'energycell',1,true) then
            numCells = numCells + 1
            attachedCells[numCells] = value
        end
    end

    for i = 1,12 do
        storedEnergy = 0
        maxStoredEnergy = 0
        for index,value in pairs(attachedCells) do
            storedEnergy = storedEnergy + modem.callRemote(value, "getEnergyStored","")
            maxStoredEnergy = maxStoredEnergy + modem.callRemote(value, "getMaxEnergyStored","")
        end
        percentStored = math.floor(100*storedEnergy/maxStoredEnergy)
        energyRate = lastStoredEnergy - storedEnergy
        timeEmpty = math.floor(storedEnergy/energyRate)
        monitor.clear()
        monitor.setCursorPos(2,1)
        monitor.write("Connected Cells: "..comma_value(numCells))
        monitor.setCursorPos(2,3)
        monitor.write("Stored Energy: "..comma_value(storedEnergy).." ("..percentStored.."%)")
        monitor.setCursorPos(2,4)
        monitor.write("Energy Use: "..comma_value(energyRate).."/s")
        monitor.setCursorPos(2,6)
        monitor.write("Time to Empty: "..SecondsToClock(timeEmpty))
        print(i)
        os.sleep(1)
        lastStoredEnergy = storedEnergy
    end
end