ball = peripheral.wrap("back")

maxE = ball.getMaxEnergyStored()

function update()
	local dumping = false
	while true do
		pct = ball.getEnergyStored() * 100 / maxE

		print("Power: " .. pct .. "%")

		if pct >= 90 then
			dumping = true
		end
		if pct < 50 and dumping then
			dumping = false
		end

		if dumping then
			redstone.setAnalogOutput("left", 1)
		else
			redstone.setAnalogOutput("left", 0)
		end
		sleep(5)
	end
end

parallel.waitForAny(update)