diff --git a/.test/akku.lua b/.test/akku.lua
deleted file mode 100644
index 9537fc8..0000000
--- a/.test/akku.lua
+++ /dev/null
@@ -1,85 +0,0 @@
--- for lazy programmers
-local S = function(pos) if pos then return minetest.pos_to_string(pos) end end
-local P = minetest.string_to_pos
-local M = minetest.get_meta
-
-local CYCLE_TIME = 2
-local PWR_PERF = 10
-local PWR_CAPA = 300
-
-local Cable = techage.ElectricCable
-local power = techage.power
-
-local function in_range(val, min, max)
-	if val < min then return min end
-	if val > max then return max end
-	return val
-end
-
-local function formspec(pos, mem)
-	return "size[5,3]"..
-		default.gui_bg..
-		default.gui_bg_img..
-		default.gui_slots..
-		"image[0,0.5;1,2;"..techage.power.formspec_power_bar(PWR_CAPA, mem.capa or 0).."]"..
-		"label[0.2,2.5;Load]"..
-		"button[1.1,1;1.8,1;update;Update]"..
-		"image[4,0.5;1,2;"..techage.power.formspec_load_bar(-(mem.delivered or 0), PWR_PERF).."]"..
-		"label[4.2,2.5;Flow]"
-end
-
-local function node_timer(pos, elapsed)
-	--print("node_timer akku "..S(pos))
-	local mem = tubelib2.get_mem(pos)
-	if mem.running then
-		mem.delivered = power.secondary_alive(pos, mem, mem.capa, PWR_CAPA)
-		--print("provided", mem.delivered)
-		mem.capa = mem.capa - mem.delivered
-		mem.capa = in_range(mem.capa, 0, PWR_CAPA)
-	end
-	return mem.running
-end
-
-
-local function on_receive_fields(pos, formname, fields, player)
-	if minetest.is_protected(pos, player:get_player_name()) then
-		return
-	end
-	
-	local mem = tubelib2.get_mem(pos)
-	techage.power.network_changed(pos, mem)
-	
-	if fields.update then
-		M(pos):set_string("formspec", formspec(pos, mem))
-	end
-end
-
-minetest.register_node("techage:akku", {
-	description = "Akku",
-	tiles = {
-		-- up, down, right, left, back, front
-		'techage_electric_button.png^techage_appl_source.png',
-		'techage_electric_button.png^techage_appl_source.png',
-		'techage_electric_button.png^techage_appl_source.png^techage_electric_plug.png',
-		'techage_electric_button.png^techage_appl_source.png',
-		'techage_electric_button.png^techage_appl_source.png',
-		'techage_electric_button.png^techage_appl_source.png',
-	},
-	paramtype2 = "facedir",
-	groups = {cracky=2, crumbly=2, choppy=2},
-	is_ground_content = false,
-	on_receive_fields = on_receive_fields,
-	on_timer = node_timer,
-})
-
-techage.power.register_node({"techage:akku"}, {
-	power_network  = Cable,
-	after_place_node = function(pos, placer)
-		local mem = tubelib2.init_mem(pos)
-		mem.running = true
-		mem.capa = 0
-		minetest.get_node_timer(pos):start(CYCLE_TIME)
-		power.secondary_start(pos, mem, PWR_PERF, PWR_PERF)
-		M(pos):set_string("formspec", formspec(pos, mem))
-	end,
-})
diff --git a/energy_storage/heatexchanger1.lua b/energy_storage/heatexchanger1.lua
index cde6fee..19d2b8d 100644
--- a/energy_storage/heatexchanger1.lua
+++ b/energy_storage/heatexchanger1.lua
@@ -66,7 +66,7 @@ local function play_sound(pos)
 	if not mem.handle or mem.handle == -1 then
 		mem.handle = minetest.sound_play("techage_booster", {
 			pos = pos, 
-			gain = 0.2,
+			gain = 0.3,
 			max_hear_distance = 10,
 			loop = true})
 		if mem.handle == -1 then
@@ -88,12 +88,9 @@ local function stop_sound(pos)
 end
 
 local function on_power(pos)
-	play_sound(pos)
 end
 
 local function on_nopower(pos)
-	nvm.needed = 0
-	stop_sound(pos)
 end
 
 local function start_node(pos, nvm)
@@ -164,7 +161,9 @@ local function node_timer(pos, elapsed)
 	local taken = 0
 	local given = 0
 	
-	if nvm.capa < (nvm.capa_max * 0.9) then
+	if nvm.capa < (nvm.capa_max * 0.9) and not nvm.charging then
+		taken = power.consumer_alive(pos, Cable, CYCLE_TIME)
+	elseif nvm.capa < nvm.capa_max and nvm.charging then
 		taken = power.consumer_alive(pos, Cable, CYCLE_TIME)
 	end
 	if nvm.capa > 0 then
@@ -193,6 +192,8 @@ local net_def = {
 	pipe2 = {
 		sides = {L = 1, R = 1},
 		ntype = "con1",
+		on_power = on_power,
+		on_nopower = on_nopower,
 	},
 }
 
@@ -212,7 +213,7 @@ minetest.register_node("techage:heatexchanger1", {
 	after_place_node = after_place_node,
 	can_dig = can_dig,
 	after_dig_node = after_dig_node,
-	--tubelib2_on_update2 = tubelib2_on_update2,
+	tubelib2_on_update2 = tubelib2_on_update2,
 	networks = net_def,
 	
 	paramtype2 = "facedir",
@@ -228,11 +229,10 @@ Cable:add_secondary_node_names({"techage:heatexchanger1"})
 -- command interface
 techage.register_node({"techage:heatexchanger1"}, {
 	on_transfer = function(pos, indir, topic, payload)
-		print("on_transfer")
 		local nvm = techage.get_nvm(pos)
 		-- used by heatexchanger2
 		if topic == "state" then
-			return nvm.capa_max, nvm.capa, PWR_PERF, math.max(nvm.needed, 0)
+			return nvm.capa_max, nvm.capa, PWR_PERF, math.max(nvm.needed or 0, 0)
 		elseif topic == "integrity" then
 			return inlet_cmnd(pos, "volume", payload)
 		elseif topic == "state" then
diff --git a/energy_storage/heatexchanger2.lua b/energy_storage/heatexchanger2.lua
index a310ea3..a7e950d 100644
--- a/energy_storage/heatexchanger2.lua
+++ b/energy_storage/heatexchanger2.lua
@@ -80,7 +80,6 @@ local State = techage.NodeStates:new({
 })
 
 local function node_timer(pos, elapsed)
-	print("node_timer")
 	local nvm = techage.get_nvm(pos)
 	local res = check_TES_integrity(pos, nvm)
 	if res ~= true then
diff --git a/energy_storage/turbine.lua b/energy_storage/turbine.lua
index fae2e80..a05aba0 100644
--- a/energy_storage/turbine.lua
+++ b/energy_storage/turbine.lua
@@ -145,18 +145,7 @@ techage.register_node({"techage:ta4_turbine", "techage:ta4_turbine_on"}, {
 			if not transfer_heatexchanger3(pos, topic, payload) then
 				return 0
 			end
-			local power = transfer_generator(pos, topic, payload)
-			if not power or power <= 0 and nvm.running then
-				swap_node(pos, "techage:ta4_turbine")
-				stop_sound(pos)
-				nvm.running = false
-				return 0
-			elseif power and power > 0 and not nvm.running then
-				swap_node(pos, "techage:ta4_turbine_on")
-				play_sound(pos)
-				nvm.running = true
-			end
-			return power
+			return transfer_generator(pos, topic, payload)
 		elseif topic == "start" then  -- used by generator
 			swap_node(pos, "techage:ta4_turbine_on")
 			play_sound(pos)
diff --git a/init.lua b/init.lua
index d934fdd..abe4bd8 100644
--- a/init.lua
+++ b/init.lua
@@ -177,8 +177,6 @@ else
 	dofile(MP.."/recipe_checker.lua")
 	dofile(MP.."/.test/sink.lua")
 	dofile(MP.."/.test/meta_node.lua")
-	--dofile(MP.."/.test/source.lua")
-	--dofile(MP.."/.test/accu.lua")
 	
 	-- Solar
 	dofile(MP.."/solar/minicell.lua")
diff --git a/power/node_api.lua b/power/node_api.lua
index 009b9fe..e9f0bd5 100644
--- a/power/node_api.lua
+++ b/power/node_api.lua
@@ -162,13 +162,12 @@ function techage.power.consumer_alive(pos, Cable, cycle_time)
 		local rv = (cycle_time / 2) + 1
 		if def["netID"] and def["calive"] and def["calive"] < rv then -- network available
 			def["calive"] = rv
+			return def["taken"] or 0
 		elseif not def["cstate"] or def["cstate"] == RUNNING then
 			local ndef = net_def(pos, Cable.tube_type)
 			ndef.on_nopower(pos, Cable.tube_type)
 			def["cstate"] = NOPOWER
-			return 0
 		end
-		return def["taken"] or 0
 	else
 		local ndef = net_def(pos, Cable.tube_type)
 		ndef.on_nopower(pos, Cable.tube_type)
diff --git a/ta3_power/akkubox.lua b/ta3_power/akkubox.lua
index 99437cc..87dbed4 100644
--- a/ta3_power/akkubox.lua
+++ b/ta3_power/akkubox.lua
@@ -43,6 +43,11 @@ local function formspec(self, pos, nvm)
 		"image[4,1.7;1,2;"..techage.power.formspec_load_bar(needed, PWR_PERF).."]"
 end
 
+local function on_power(pos)
+end
+
+local function on_nopower(pos)
+end
 
 local function start_node(pos, nvm, state)
 	nvm.running = true
@@ -159,6 +164,8 @@ local net_def = {
 		sides = {R = 1},
 		ntype = {"gen2", "con2"},
 		nominal = PWR_PERF,
+		on_power = on_power,
+		on_nopower = on_nopower,
 	},
 }