Added the Mv and HV down converters.

Doing that required some changes to the batteries in that they have new meta data
aligned with the other machines.
I also added a BA type machine in addition to the existing PR and RE types.
This way it is easy to find he batteries on the network.

technic/battery_box.lua

@@ -1,11 +1,7 @@
-LV_machines = {}
+-- register LV machines here
-registered_LV_machines_count=0
+local LV_machines = {}
-
 function register_LV_machine(string1,string2)
-registered_LV_machines_count=registered_LV_machines_count+1
+   LV_machines[string1] = string2
-LV_machines[registered_LV_machines_count]={}
-LV_machines[registered_LV_machines_count].machine_name=string1
-LV_machines[registered_LV_machines_count].machine_type=string2
 end
 
 power_tools ={}
@@ -18,7 +14,6 @@ power_tools[registered_power_tools_count].tool_name=string1
    power_tools[registered_power_tools_count].max_charge=max_charge
 end
 
-
 register_power_tool ("technic:battery",10000)
 register_power_tool ("technic:red_energy_crystal",100000)
 register_power_tool ("technic:green_energy_crystal",250000)
@@ -67,28 +62,28 @@ battery_box_formspec =
    "label[1,3;Power level]"..
    "list[current_player;main;0,5;8,4;]"
 
-minetest.register_node("technic:battery_box", {
+minetest.register_node(
-	description = "Battery box",
+   "technic:battery_box", {
+      description = "LV Battery Box",
       tiles = {"technic_battery_box_top.png", "technic_battery_box_bottom.png", "technic_battery_box_side0.png",
 	       "technic_battery_box_side0.png", "technic_battery_box_side0.png", "technic_battery_box_side0.png"},
       groups = {snappy=2,choppy=2,oddly_breakable_by_hand=2},
       sounds = default.node_sound_wood_defaults(),
-	technic_power_machine=1,
-	last_side_shown=0,
       drop="technic:battery_box",
       on_construct = function(pos)
+			     if pos == nil then return end
 			     local meta = minetest.env:get_meta(pos)
+			     local inv = meta:get_inventory()
 			     meta:set_string("infotext", "Battery box")
 			     meta:set_float("technic_power_machine", 1)
 			     meta:set_string("formspec", battery_box_formspec)
-		local inv = meta:get_inventory()
+			     meta:set_float("internal_EU_buffer", 0)
+			     meta:set_float("internal_EU_buffer_size", 60000)
 			     inv:set_size("src", 1)
 			     inv:set_size("dst", 1)
-		battery_charge = 0
-		max_charge = 60000
-		last_side_shown=0
 			  end,
       can_dig = function(pos,player)
+			if pos == nil then return end
 			local meta = minetest.env:get_meta(pos);
 			local inv = meta:get_inventory()
 			if not inv:is_empty("dst") then
@@ -102,28 +97,28 @@ minetest.register_node("technic:battery_box", {
 
 
 for i=1,8,1 do
-minetest.register_node("technic:battery_box"..i, {
+   minetest.register_node(
-	description = "Battery box",
+      "technic:battery_box"..i, {
+	 description = "LV Battery Box",
 	 tiles = {"technic_battery_box_top.png", "technic_battery_box_bottom.png", "technic_battery_box_side0.png^technic_power_meter"..i..".png",
 		  "technic_battery_box_side0.png^technic_power_meter"..i..".png", "technic_battery_box_side0.png^technic_power_meter"..i..".png", "technic_battery_box_side0.png^technic_power_meter"..i..".png"},
 	 groups = {snappy=2,choppy=2,oddly_breakable_by_hand=2,not_in_creative_inventory=1},
 	 sounds = default.node_sound_wood_defaults(),
-	technic_power_machine=1,
-	last_side_shown=0,
 	 drop="technic:battery_box",
 	 on_construct = function(pos)
+			     if pos == nil then return end
 			     local meta = minetest.env:get_meta(pos)
+			     local inv = meta:get_inventory()
 			     meta:set_string("infotext", "Battery box")
 			     meta:set_float("technic_power_machine", 1)
 			     meta:set_string("formspec", battery_box_formspec)
-		local inv = meta:get_inventory()
+			     meta:set_float("internal_EU_buffer", 0)
+			     meta:set_float("internal_EU_buffer_size", 60000)
 			     inv:set_size("src", 1)
 			     inv:set_size("dst", 1)
-		battery_charge = 0
-		max_charge = 60000
-		last_side_shown=0
 			  end,
 	 can_dig = function(pos,player)
+			if pos == nil then return end
 			local meta = minetest.env:get_meta(pos);
 			local inv = meta:get_inventory()
 			if not inv:is_empty("dst") then
@@ -136,8 +131,6 @@ minetest.register_node("technic:battery_box"..i, {
       })
 end
 
-LV_nodes_visited = {}
-
 function get_RE_item_load (load1,max_load)
    if load1==0 then load1=65535 end
    local temp = 65536-load1
@@ -158,25 +151,27 @@ item_stack["wear"]=tostring(temp)
    return item_stack
 end
 
-minetest.register_abm({
+minetest.register_abm(
-	nodenames = {"technic:battery_box","technic:battery_box1","technic:battery_box2","technic:battery_box3","technic:battery_box4",
+   {nodenames = {"technic:battery_box","technic:battery_box1","technic:battery_box2","technic:battery_box3","technic:battery_box4",
 		 "technic:battery_box5","technic:battery_box6","technic:battery_box7","technic:battery_box8"},
     interval = 1,
     chance = 1,
     action = function(pos, node, active_object_count, active_object_count_wider)
 		local meta       = minetest.env:get_meta(pos)
-	charge= meta:get_int("battery_charge")
+		local max_charge = 60000 -- Set maximum charge for the device here
-	max_charge= 60000
+		local charge     = meta:get_int("internal_EU_buffer")
+
+		-- Select node textures
 		local i=math.ceil((charge/max_charge)*8)
 		if i > 8 then i = 8 end
-	j=meta:get_float("last_side_shown")
+		local j = meta:get_float("last_side_shown")
 		if i~=j then
 		   if i>0 then hacky_swap_node(pos,"technic:battery_box"..i)
 		   elseif i==0 then hacky_swap_node(pos,"technic:battery_box") end
 		   meta:set_float("last_side_shown",i)
 		end
 		
---loading registered power tools
+		--charge registered power tools
 		local inv = meta:get_inventory()
 		if inv:is_empty("src")==false  then
 		   local srcstack = inv:get_stack("src", 1)
@@ -197,13 +192,10 @@ minetest.register_abm({
 			       src_meta["charge"]=0
 			    end
 			 end
-				item_max_charge=power_tools[i].max_charge
+			 -- Do the charging
-			end
+			 local item_max_charge = power_tools[i].max_charge
-		end
+			 local load1           = src_meta["charge"]
-		
+			 local load_step       = 1000 -- how much to charge per tick
-		if item_max_charge then
-			load1=src_meta["charge"] 
-			load_step=1000
 			 if load1<item_max_charge and charge>0 then
 			    if charge-load_step<0 then load_step=charge end
 			    if load1+load_step>item_max_charge then load_step=item_max_charge-load1 end
@@ -214,7 +206,9 @@ minetest.register_abm({
 			    src_item["metadata"]=set_item_meta(src_meta)
 			    inv:set_stack("src", 1, src_item)
 			 end
-			meta:set_int("battery_charge",charge)
+			 meta:set_int("internal_EU_buffer",charge)
+			 break
+		      end
 		   end
 		end
 		
@@ -237,13 +231,9 @@ minetest.register_abm({
 			       src_meta["charge"]=0
 			    end
 			 end
-				item_max_charge=power_tools[i].max_charge
+			 local item_max_charge = power_tools[i].max_charge
-			end
-		end
-
-		if item_max_charge then
 			 local load1           = src_meta["charge"]
-		load_step=1000
+			 local load_step       = 4000 -- how much to discharge per tick
 			 if load1>0 and charge<max_charge then
 			    if charge+load_step>max_charge then load_step=max_charge-charge end
 			    if load1-load_step<0 then load_step=load1 end
@@ -254,30 +244,32 @@ minetest.register_abm({
 			    src_item["metadata"]=set_item_meta(src_meta)
 			    inv:set_stack("dst", 1, src_item)
 			 end
+			 meta:set_int("internal_EU_buffer",charge)
+			 break
+		      end
 		   end
 		end
-		
-	meta:set_int("battery_charge",charge)
 
 		local load = math.floor(charge/60000 * 100)
 		meta:set_string("formspec",
 				battery_box_formspec..
 				   "image[1,1;1,2;technic_power_meter_bg.png^[lowpart:"..
-						(load)..":technic_power_meter_fg.png]")
+				   (load)..":technic_power_meter_fg.png]"
+			     )
 
+		-- Next index the surrounding network the get the producers and receivers on the power grid
 		local pos1={}
-
 		pos1.y=pos.y-1
 		pos1.x=pos.x
 		pos1.z=pos.z
 
-
 		meta1 = minetest.env:get_meta(pos1)
 		if meta1:get_float("cablelike")~=1 then return end
 
 		local LV_nodes = {}
 		local PR_nodes = {}
 		local RE_nodes = {}
+		local BA_nodes = {}
 
 		LV_nodes[1]={}
 		LV_nodes[1].x=pos1.x
@@ -285,26 +277,21 @@ minetest.register_abm({
 		LV_nodes[1].z=pos1.z
 		LV_nodes[1].visited=false
 
-
+		local table_index=1
-table_index=1
 		repeat
-	check_LV_node (PR_nodes,RE_nodes,LV_nodes,table_index)
+		   check_LV_node(PR_nodes,RE_nodes,BA_nodes,LV_nodes,table_index)
 		   table_index=table_index+1
 		   if LV_nodes[table_index]==nil then break end
 		until false
 
 
-local pos1={}
+		-- Get power from all connected producers
-i=1
+		local pr_pos
-	repeat
+                for _,pr_pos in ipairs(PR_nodes) do
-	if PR_nodes[i]==nil then break end -- getting power from all connected producers
+		   local meta1              = minetest.env:get_meta(pr_pos)
-		pos1.x=PR_nodes[i].x
-		pos1.y=PR_nodes[i].y
-		pos1.z=PR_nodes[i].z
-	local meta1 = minetest.env:get_meta(pos1)
 		   local internal_EU_buffer = meta1:get_float("internal_EU_buffer")
+		   local charge_to_take     = 200
 		   if charge<max_charge then
-	charge_to_take=200	
 		      if internal_EU_buffer-charge_to_take<=0 then
 			 charge_to_take=internal_EU_buffer
 		      end
@@ -314,22 +301,17 @@ i=1
 			 meta1:set_float("internal_EU_buffer",internal_EU_buffer)
 		      end
 		   end
-	i=i+1
+		end
-	until false
 
 		if charge>max_charge then charge=max_charge end
 
-i=1
+		-- Provide power to all connected receivers
-	repeat
+		local re_pos
-	if RE_nodes[i]==nil then break end
+                for _,re_pos in ipairs(RE_nodes) do
-		pos1.x=RE_nodes[i].x         -- loading all conected machines buffers
+		   local meta1                   = minetest.env:get_meta(re_pos)
-		pos1.y=RE_nodes[i].y
-		pos1.z=RE_nodes[i].z
-	local meta1 = minetest.env:get_meta(pos1)
 		   local internal_EU_buffer      = meta1:get_float("internal_EU_buffer")
 		   local internal_EU_buffer_size = meta1:get_float("internal_EU_buffer_size")
-
+		   local charge_to_give          = math.min(200, charge/table.getn(RE_nodes))
-	local charge_to_give=200
 		   if internal_EU_buffer+charge_to_give>internal_EU_buffer_size then
 		      charge_to_give=internal_EU_buffer_size-internal_EU_buffer
 		   end
@@ -338,18 +320,22 @@ i=1
 		   internal_EU_buffer=internal_EU_buffer+charge_to_give
 		   meta1:set_float("internal_EU_buffer",internal_EU_buffer)
 		   charge=charge-charge_to_give;
-	
+		end
-	i=i+1
-	until false
 		charge=math.floor(charge)
-	charge_string=tostring(charge)
+		meta:set_string("infotext", "LV Battery box: "..charge.."/"..max_charge);
-	meta:set_string("infotext", "Battery box: "..charge_string.."/"..max_charge);
+		meta:set_int("internal_EU_buffer",charge)
-	meta:set_int("battery_charge",charge)
-
 	     end
  })
 
+-- Register as a battery type
+-- Battery type machines function as power reservoirs and can both receive and give back power
+register_LV_machine("technic:battery_box","BA")
+for i=1,8,1 do
+   register_LV_machine("technic:battery_box"..i,"BA")
+end
+
 function add_new_cable_node (LV_nodes,pos1)
+   if LV_nodes == nil then return true end
    local i=1
    repeat
       if LV_nodes[i]==nil then break end
@@ -360,49 +346,48 @@ function add_new_cable_node (LV_nodes,pos1)
    LV_nodes[i].x=pos1.x
    LV_nodes[i].y=pos1.y
    LV_nodes[i].z=pos1.z
-	LV_nodes[i].visited=false
    return true
 end
 
-function check_LV_node (PR_nodes,RE_nodes,LV_nodes,i)
+function check_LV_node(PR_nodes,RE_nodes,BA_nodes,LV_nodes,i)
    local pos1={}
    pos1.x=LV_nodes[i].x
    pos1.y=LV_nodes[i].y
    pos1.z=LV_nodes[i].z
-	LV_nodes[i].visited=true
-	new_node_added=false
 
    pos1.x=pos1.x+1
-	check_LV_node_subp (PR_nodes,RE_nodes,LV_nodes,pos1)
+   check_LV_node_subp (PR_nodes,RE_nodes,BA_nodes,LV_nodes,pos1)
    pos1.x=pos1.x-2
-	check_LV_node_subp (PR_nodes,RE_nodes,LV_nodes,pos1)
+   check_LV_node_subp (PR_nodes,RE_nodes,BA_nodes,LV_nodes,pos1)
    pos1.x=pos1.x+1
 
    pos1.y=pos1.y+1
-	check_LV_node_subp (PR_nodes,RE_nodes,LV_nodes,pos1)
+   check_LV_node_subp (PR_nodes,RE_nodes,BA_nodes,LV_nodes,pos1)
    pos1.y=pos1.y-2
-	check_LV_node_subp (PR_nodes,RE_nodes,LV_nodes,pos1)
+   check_LV_node_subp (PR_nodes,RE_nodes,BA_nodes,LV_nodes,pos1)
    pos1.y=pos1.y+1
 
    pos1.z=pos1.z+1
-	check_LV_node_subp (PR_nodes,RE_nodes,LV_nodes,pos1)
+   check_LV_node_subp (PR_nodes,RE_nodes,BA_nodes,LV_nodes,pos1)
    pos1.z=pos1.z-2
-	check_LV_node_subp (PR_nodes,RE_nodes,LV_nodes,pos1)
+   check_LV_node_subp (PR_nodes,RE_nodes,BA_nodes,LV_nodes,pos1)
    pos1.z=pos1.z+1
    return new_node_added
 end
 
-function check_LV_node_subp (PR_nodes,RE_nodes,LV_nodes,pos1)
+function check_LV_node_subp (PR_nodes,RE_nodes,BA_nodes,LV_nodes,pos1)
-meta = minetest.env:get_meta(pos1)
+   local meta = minetest.env:get_meta(pos1)
-if meta:get_float("cablelike")==1 then new_node_added=add_new_cable_node(LV_nodes,pos1) end
+   local name = minetest.env:get_node(pos1).name
-for i in ipairs(LV_machines) do
+   if meta:get_float("cablelike")==1 then
-	if minetest.env:get_node(pos1).name == LV_machines[i].machine_name then 
+      add_new_cable_node(LV_nodes,pos1)
-		if LV_machines[i].machine_type == "PR" then
+   elseif LV_machines[name] then
-			new_node_added=add_new_cable_node(PR_nodes,pos1) 
+      --print(name.." is a "..LV_machines[name])
-			end
+      if     LV_machines[name] == "PR" then
-		if LV_machines[i].machine_type == "RE" then
+	 add_new_cable_node(PR_nodes,pos1)
-			new_node_added=add_new_cable_node(RE_nodes,pos1) 
+      elseif LV_machines[name] == "RE" then
-			end
+	 add_new_cable_node(RE_nodes,pos1)
+      elseif LV_machines[name] == "BA" then
+	 add_new_cable_node(BA_nodes,pos1)
       end
    end
 end

technic/battery_box_hv.lua

@@ -1,12 +1,8 @@
-HV_machines = {}
+-- register MV machines here
-
+technic.HV_machines = {}
-registered_HV_machines_count=0
+local HV_machines = technic.HV_machines
-
 function register_HV_machine(string1,string2)
-registered_HV_machines_count=registered_HV_machines_count+1
+   technic.HV_machines[string1] = string2
-HV_machines[registered_HV_machines_count]={}
-HV_machines[registered_HV_machines_count].machine_name=string1
-HV_machines[registered_HV_machines_count].machine_type=string2
 end
 
 minetest.register_craft({
@@ -30,28 +26,26 @@ hv_battery_box_formspec =
    "label[1,3;Power level]"..
    "list[current_player;main;0,5;8,4;]"
 
-minetest.register_node("technic:hv_battery_box", {
+minetest.register_node(
+   "technic:hv_battery_box", {
       description = "HV Battery Box",
       tiles = {"technic_hv_battery_box_top.png", "technic_hv_battery_box_bottom.png", "technic_hv_battery_box_side0.png",
 	       "technic_hv_battery_box_side0.png", "technic_hv_battery_box_side0.png", "technic_hv_battery_box_side0.png"},
       groups = {snappy=2,choppy=2,oddly_breakable_by_hand=2},
       sounds = default.node_sound_wood_defaults(),
-	technic_mv_power_machine=1,
-	last_side_shown=0,
       drop="technic:hv_battery_box",
       on_construct = function(pos)
+			if pos==nil then return end
 			local meta = minetest.env:get_meta(pos)
+			local inv = meta:get_inventory()
 			meta:set_string("infotext", "HV Battery Box")
 			meta:set_float("technic_hv_power_machine", 1)
 			meta:set_string("formspec", battery_box_formspec)
-		local inv = meta:get_inventory()
 			inv:set_size("src", 1)
 			inv:set_size("dst", 1)
-		battery_charge = 0
-		max_charge = 1500000
-		last_side_shown=0
 		     end,
       can_dig = function(pos,player)
+		   if pos==nil then return end
 		   local meta = minetest.env:get_meta(pos);
 		   local inv = meta:get_inventory()
 		   if not inv:is_empty("dst") then
@@ -63,9 +57,9 @@ minetest.register_node("technic:hv_battery_box", {
 		end,
    })
 
-
 for i=1,8,1 do
-minetest.register_node("technic:hv_battery_box"..i, {
+   minetest.register_node(
+      "technic:hv_battery_box"..i, {
 	 description = "HV Battery Box",
 	 tiles = {"technic_hv_battery_box_top.png", "technic_hv_battery_box_bottom.png", "technic_hv_battery_box_side0.png^technic_power_meter"..i..".png",
 		  "technic_hv_battery_box_side0.png^technic_power_meter"..i..".png", "technic_hv_battery_box_side0.png^technic_power_meter"..i..".png", "technic_hv_battery_box_side0.png^technic_power_meter"..i..".png"},
@@ -73,20 +67,15 @@ minetest.register_node("technic:hv_battery_box"..i, {
 	 sounds = default.node_sound_wood_defaults(),
 	 paramtype="light",
 	 light_source=9,
-	technic_power_machine=1,
-	last_side_shown=0,
 	 drop="technic:hv_battery_box",
 	 on_construct = function(pos)
 			   local meta = minetest.env:get_meta(pos)
+			   local inv = meta:get_inventory()
 			   meta:set_string("infotext", "HV Battery box")
 			   meta:set_float("technic_hv_power_machine", 1)
 			   meta:set_string("formspec", battery_box_formspec)
-		local inv = meta:get_inventory()
 			   inv:set_size("src", 1)
 			   inv:set_size("dst", 1)
-		battery_charge = 0
-		max_charge = 1500000
-		last_side_shown=0
 			end,
 	 can_dig = function(pos,player)
 		      local meta = minetest.env:get_meta(pos);
@@ -101,37 +90,34 @@ minetest.register_node("technic:hv_battery_box"..i, {
       })
 end
 
-
+minetest.register_abm(
-HV_nodes_visited = {}
+   {nodenames = {"technic:hv_battery_box","technic:hv_battery_box1","technic:hv_battery_box2","technic:hv_battery_box3","technic:hv_battery_box4",
-
-
-minetest.register_abm({
-	nodenames = {"technic:hv_battery_box","technic:hv_battery_box1","technic:hv_battery_box2","technic:hv_battery_box3","technic:hv_battery_box4",
 		 "technic:hv_battery_box5","technic:hv_battery_box6","technic:hv_battery_box7","technic:hv_battery_box8"
 	      },
     interval = 1,
     chance = 1,
     action = function(pos, node, active_object_count, active_object_count_wider)
 		local meta       = minetest.env:get_meta(pos)
-	charge= meta:get_int("battery_charge")
+		local max_charge = 1500000
-	max_charge= 1500000
+		local charge     = meta:get_int("internal_EU_buffer")
+
+		-- Select node textures
 		local i = math.ceil((charge/max_charge)*8)
 		if i > 8 then i = 8 end
-	j=meta:get_float("last_side_shown")
+		local j = meta:get_float("last_side_shown")
 		if i~=j then
 		   if i>0 then hacky_swap_node(pos,"technic:hv_battery_box"..i)
 		   elseif i==0 then hacky_swap_node(pos,"technic:hv_battery_box") end
 		   meta:set_float("last_side_shown",i)
 		end
 
---loading registered power tools
+		--charge registered power tools
 		local inv = meta:get_inventory()
 		if inv:is_empty("src")==false  then
 		   local srcstack = inv:get_stack("src", 1)
 		   local src_item=srcstack:to_table()
 		   local src_meta=get_item_meta(src_item["metadata"])
 
-		local item_max_charge=nil
 		   for i=1,registered_power_tools_count,1 do
 		      if power_tools[i].tool_name==src_item["name"] then
 			 src_meta=get_item_meta(src_item["metadata"])
@@ -145,13 +131,10 @@ minetest.register_abm({
 			       src_meta["charge"]=0
 			    end
 			 end
-				item_max_charge=power_tools[i].max_charge
+			 -- Do the charging
-			end
+			 local item_max_charge = power_tools[i].max_charge
-		end
+			 local load1           = src_meta["charge"]
-		
+			 local load_step       = 16000 -- how much to charge per tick
-		if item_max_charge then
-			load1=src_meta["charge"] 
-			load_step=16000
 			 if load1<item_max_charge and charge>0 then
 			    if charge-load_step<0 then load_step=charge end
 			    if load1+load_step>item_max_charge then load_step=item_max_charge-load1 end
@@ -162,11 +145,13 @@ minetest.register_abm({
 			    src_item["metadata"]=set_item_meta(src_meta)
 			    inv:set_stack("src", 1, src_item)
 			 end
-			meta:set_int("battery_charge",charge)
+			 meta:set_int("internal_EU_buffer",charge)
+			 break
+		      end
 		   end
 		end
 
--- dischargin registered power tools
+		-- discharging registered power tools
 		if inv:is_empty("dst") == false then
 		   srcstack = inv:get_stack("dst", 1)
 		   src_item=srcstack:to_table()
@@ -185,13 +170,9 @@ minetest.register_abm({
 			       src_meta["charge"]=0
 			    end
 			 end
-				item_max_charge=power_tools[i].max_charge
+			 local item_max_charge = power_tools[i].max_charge
-			end
-		end
-
-		if item_max_charge then
 			 local load1           = src_meta["charge"]
-		load_step=16000
+			 local load_step       = 16000 -- how much to discharge per tick
 			 if load1>0 and charge<max_charge then
 			    if charge+load_step>max_charge then load_step=max_charge-charge end
 			    if load1-load_step<0 then load_step=load1 end
@@ -202,10 +183,12 @@ minetest.register_abm({
 			    src_item["metadata"]=set_item_meta(src_meta)
 			    inv:set_stack("dst", 1, src_item)
 			 end
+			 meta:set_int("internal_EU_buffer",charge)
+			 break
+		      end
 		   end
 		end
 
-	meta:set_int("battery_charge",charge)
 
 		local load = math.floor((charge/1500000) * 100)
 		meta:set_string("formspec",
@@ -214,19 +197,19 @@ minetest.register_abm({
 				   (load)..":technic_power_meter_fg.png]"
 			     )
 
+		-- Next index the surrounding network the get the producers and receivers on the 
 		local pos1={}
-
 		pos1.y=pos.y-1
 		pos1.x=pos.x
 		pos1.z=pos.z
 
-
 		meta1 = minetest.env:get_meta(pos1)
 		if meta1:get_float("hv_cablelike")~=1 then return end
 
 		local HV_nodes = {}
 		local PR_nodes = {}
 		local RE_nodes = {}
+		local BA_nodes = {}
 
 		HV_nodes[1]={}
 		HV_nodes[1].x=pos1.x
@@ -234,25 +217,20 @@ minetest.register_abm({
 		HV_nodes[1].z=pos1.z
 		HV_nodes[1].visited=false
 
-table_index=1
+		local table_index=1
 		repeat
-	check_HV_node (PR_nodes,RE_nodes,HV_nodes,table_index)
+		   check_HV_node (PR_nodes,RE_nodes,BA_nodes,HV_nodes,table_index)
 		   table_index=table_index+1
 		   if HV_nodes[table_index]==nil then break end
 		until false
 
-
+		-- Get power from all connected producers
-local pos1={}
+		local pr_pos
-i=1
+                for _,pr_pos in ipairs(PR_nodes) do
-	repeat
+		   local meta1              = minetest.env:get_meta(pr_pos)
-	if PR_nodes[i]==nil then break end -- gettin power from all connected producers
-		pos1.x=PR_nodes[i].x
-		pos1.y=PR_nodes[i].y
-		pos1.z=PR_nodes[i].z
-	local meta1 = minetest.env:get_meta(pos1)
 		   local internal_EU_buffer = meta1:get_float("internal_EU_buffer")
+		   local charge_to_take     = 4000
 		   if charge<max_charge then
-	charge_to_take=4000
 		      if internal_EU_buffer-charge_to_take<=0 then
 			 charge_to_take=internal_EU_buffer
 		      end
@@ -262,22 +240,17 @@ i=1
 			 meta1:set_float("internal_EU_buffer",internal_EU_buffer)
 		      end
 		   end
-	i=i+1
+		end
-	until false
 
 		if charge>max_charge then charge=max_charge end
 
-i=1
+		-- Provide power to all connected receivers
-	repeat
+		local re_pos
-	if RE_nodes[i]==nil then break end
+                for _,re_pos in ipairs(RE_nodes) do
-		pos1.x=RE_nodes[i].x         -- loading all conected machines buffers
+		   local meta1                   = minetest.env:get_meta(re_pos)
-		pos1.y=RE_nodes[i].y
-		pos1.z=RE_nodes[i].z
-	local meta1 = minetest.env:get_meta(pos1)
 		   local internal_EU_buffer      = meta1:get_float("internal_EU_buffer")
 		   local internal_EU_buffer_size = meta1:get_float("internal_EU_buffer_size")
-
+		   local charge_to_give          = math.min(4000, charge/table.getn(RE_nodes))
-	local charge_to_give=4000
 		   if internal_EU_buffer+charge_to_give>internal_EU_buffer_size then
 		      charge_to_give=internal_EU_buffer_size-internal_EU_buffer
 		   end
@@ -286,18 +259,22 @@ i=1
 		   internal_EU_buffer=internal_EU_buffer+charge_to_give
 		   meta1:set_float("internal_EU_buffer",internal_EU_buffer)
 		   charge=charge-charge_to_give;
-	
+		end
-	i=i+1
-	until false
 		charge=math.floor(charge)
-	charge_string=tostring(charge)
+		meta:set_string("infotext", "MV Battery box: "..charge.."/"..max_charge);
-	meta:set_string("infotext", "HV Battery Box: \n"..charge_string.."/"..max_charge);
+		meta:set_int("internal_EU_buffer",charge)
-	meta:set_int("battery_charge",charge)
-
 	     end
  })
 
+-- Register as a battery type
+-- Battery type machines function as power reservoirs and can both receive and give back power
+register_HV_machine("technic:hv_battery_box","BA")
+for i=1,8,1 do
+   register_HV_machine("technic:hv_battery_box"..i,"BA")
+end
+
 function add_new_HVcable_node (HV_nodes,pos1)
+   if HV_nodes == nil then return true end
    local i=1
    repeat
       if HV_nodes[i]==nil then break end
@@ -308,50 +285,47 @@ HV_nodes[i]={}
    HV_nodes[i].x=pos1.x
    HV_nodes[i].y=pos1.y
    HV_nodes[i].z=pos1.z
-HV_nodes[i].visited=false
    return true
 end
 
-function check_HV_node (PR_nodes,RE_nodes,HV_nodes,i)
+function check_HV_node(PR_nodes,RE_nodes,BA_nodes,HV_nodes,i)
    local pos1={}
    pos1.x=HV_nodes[i].x
    pos1.y=HV_nodes[i].y
    pos1.z=HV_nodes[i].z
-		HV_nodes[i].visited=true
-		new_node_added=false
 
    pos1.x=pos1.x+1
-		check_HV_node_subp (PR_nodes,RE_nodes,HV_nodes,pos1)
+   check_HV_node_subp (PR_nodes,RE_nodes,BA_nodes,HV_nodes,pos1)
    pos1.x=pos1.x-2
-		check_HV_node_subp (PR_nodes,RE_nodes,HV_nodes,pos1)
+   check_HV_node_subp (PR_nodes,RE_nodes,BA_nodes,HV_nodes,pos1)
    pos1.x=pos1.x+1
 
    pos1.y=pos1.y+1
-		check_HV_node_subp (PR_nodes,RE_nodes,HV_nodes,pos1)
+   check_HV_node_subp (PR_nodes,RE_nodes,BA_nodes,HV_nodes,pos1)
    pos1.y=pos1.y-2
-		check_HV_node_subp (PR_nodes,RE_nodes,HV_nodes,pos1)
+   check_HV_node_subp (PR_nodes,RE_nodes,BA_nodes,HV_nodes,pos1)
    pos1.y=pos1.y+1
 
    pos1.z=pos1.z+1
-		check_HV_node_subp (PR_nodes,RE_nodes,HV_nodes,pos1)
+   check_HV_node_subp (PR_nodes,RE_nodes,BA_nodes,HV_nodes,pos1)
    pos1.z=pos1.z-2
-		check_HV_node_subp (PR_nodes,RE_nodes,HV_nodes,pos1)
+   check_HV_node_subp (PR_nodes,RE_nodes,BA_nodes,HV_nodes,pos1)
    pos1.z=pos1.z+1
-return new_node_added
 end
 
-function check_HV_node_subp (PR_nodes,RE_nodes,HV_nodes,pos1)
+function check_HV_node_subp (PR_nodes,RE_nodes,BA_nodes,HV_nodes,pos1)
-meta = minetest.env:get_meta(pos1)
+   local meta = minetest.env:get_meta(pos1)
-if meta:get_float("hv_cablelike")==1 then new_node_added=add_new_HVcable_node(HV_nodes,pos1) end
+   local name = minetest.env:get_node(pos1).name
-for i in ipairs(HV_machines) do
+   if meta:get_float("hv_cablelike")==1 then
-	if minetest.env:get_node(pos1).name == HV_machines[i].machine_name then 
+      add_new_HVcable_node(HV_nodes,pos1)
-		if HV_machines[i].machine_type == "PR" then
+   elseif HV_machines[name] then
-			new_node_added=add_new_HVcable_node(PR_nodes,pos1) 
+      --print(name.." is a "..HV_machines[name])
-			end
+      if     HV_machines[name] == "PR" then
-		if HV_machines[i].machine_type == "RE" then
+	 add_new_HVcable_node(PR_nodes,pos1)
-			new_node_added=add_new_HVcable_node(RE_nodes,pos1) 
+      elseif HV_machines[name] == "RE" then
+	 add_new_HVcable_node(RE_nodes,pos1)
+      elseif HV_machines[name] == "BA" then
+	 add_new_HVcable_node(BA_nodes,pos1)
       end
    end
 end
-end
-

technic/battery_box_mv.lua

@@ -1,15 +1,13 @@
-MV_machines = {}
+-- register MV machines here
-
+technic.MV_machines = {}
-registered_MV_machines_count=0
+--local MV_machines = {}
-
+local MV_machines = technic.MV_machines
 function register_MV_machine(string1,string2)
-registered_MV_machines_count=registered_MV_machines_count+1
+   technic.MV_machines[string1] = string2
-MV_machines[registered_MV_machines_count]={}
-MV_machines[registered_MV_machines_count].machine_name=string1
-MV_machines[registered_MV_machines_count].machine_type=string2
 end
 
-minetest.register_craft({
+minetest.register_craft(
+   {
       output = 'technic:mv_battery_box 1',
       recipe = {
 	 {'technic:battery_box', 'technic:battery_box', 'technic:battery_box'},
@@ -30,28 +28,28 @@ mv_battery_box_formspec =
    "label[1,3;Power level]"..
    "list[current_player;main;0,5;8,4;]"
 
-minetest.register_node("technic:mv_battery_box", {
+minetest.register_node(
+   "technic:mv_battery_box", {
       description = "MV Battery Box",
       tiles  = {"technic_mv_battery_box_top.png", "technic_mv_battery_box_bottom.png", "technic_mv_battery_box_side0.png",
 	        "technic_mv_battery_box_side0.png", "technic_mv_battery_box_side0.png", "technic_mv_battery_box_side0.png"},
       groups = {snappy=2,choppy=2,oddly_breakable_by_hand=2},
       sounds = default.node_sound_wood_defaults(),
-	technic_mv_power_machine=1,
-	last_side_shown=0,
       drop   = "technic:mv_battery_box",
       on_construct = function(pos)
-		local meta = minetest.env:get_meta(pos)
+			if pos==nil then return end
+			local meta = minetest.env:get_meta(pos);
+			local inv = meta:get_inventory()
 			meta:set_string("infotext", "MV Battery box")
 			meta:set_float("technic_mv_power_machine", 1)
 			meta:set_string("formspec", battery_box_formspec)
-		local inv = meta:get_inventory()
+			meta:set_float("internal_EU_buffer", 0)
+			meta:set_float("internal_EU_buffer_size", 300000)
 			inv:set_size("src", 1)
 			inv:set_size("dst", 1)
-		battery_charge = 0
-		max_charge = 300000
-		last_side_shown=0
 		     end,
       can_dig = function(pos,player)
+		   if pos==nil then return end
 		   local meta = minetest.env:get_meta(pos);
 		   local inv = meta:get_inventory()
 		   if not inv:is_empty("dst") then
@@ -60,33 +58,33 @@ minetest.register_node("technic:mv_battery_box", {
 		      return false
 		   end
 		   return true
-	end,
+		end
    })
 
 
 for i=1,8,1 do
-minetest.register_node("technic:mv_battery_box"..i, {
+   minetest.register_node(
+      "technic:mv_battery_box"..i, {
 	 description = "MV Battery Box",
 	 tiles  = {"technic_mv_battery_box_top.png", "technic_mv_battery_box_bottom.png", "technic_mv_battery_box_side0.png^technic_power_meter"..i..".png",
 		   "technic_mv_battery_box_side0.png^technic_power_meter"..i..".png", "technic_mv_battery_box_side0.png^technic_power_meter"..i..".png", "technic_mv_battery_box_side0.png^technic_power_meter"..i..".png"},
 	 groups = {snappy=2,choppy=2,oddly_breakable_by_hand=2,not_in_creative_inventory=1},
 	 sounds = default.node_sound_wood_defaults(),
-	technic_power_machine=1,
-	last_side_shown=0,
 	 drop   = "technic:mv_battery_box",
 	 on_construct = function(pos)
-		local meta = minetest.env:get_meta(pos)
+			   if pos==nil then return end
+			   local meta = minetest.env:get_meta(pos);
+			   local inv = meta:get_inventory()
 			   meta:set_string("infotext", "MV Battery box")
 			   meta:set_float("technic_mv_power_machine", 1)
 			   meta:set_string("formspec", battery_box_formspec)
-		local inv = meta:get_inventory()
+			   meta:set_float("internal_EU_buffer", 0)
+			   meta:set_float("internal_EU_buffer_size", 300000)
 			   inv:set_size("src", 1)
 			   inv:set_size("dst", 1)
-		battery_charge = 0
-		max_charge = 300000
-		last_side_shown=0
 			end,
 	 can_dig = function(pos,player)
+		      if pos==nil then return end
 		      local meta = minetest.env:get_meta(pos);
 		      local inv = meta:get_inventory()
 		      if not inv:is_empty("dst") then
@@ -95,43 +93,42 @@ minetest.register_node("technic:mv_battery_box"..i, {
 			 return false
 		      end
 		      return true
-	end,
+		   end
       })
 end
 
-
+minetest.register_abm(
-MV_nodes_visited = {}
+   {nodenames = {"technic:mv_battery_box","technic:mv_battery_box1","technic:mv_battery_box2","technic:mv_battery_box3","technic:mv_battery_box4",
-
-
-minetest.register_abm({
-	nodenames = {"technic:mv_battery_box","technic:mv_battery_box1","technic:mv_battery_box2","technic:mv_battery_box3","technic:mv_battery_box4",
 		 "technic:mv_battery_box5","technic:mv_battery_box6","technic:mv_battery_box7","technic:mv_battery_box8"
 	      },
     interval = 1,
     chance = 1,
     action = function(pos, node, active_object_count, active_object_count_wider)
 		local meta       = minetest.env:get_meta(pos)
-	charge= meta:get_int("battery_charge")
+		local max_charge = 300000 -- Set maximum charge for the device here
-	max_charge= 300000
+		local charge     = meta:get_int("internal_EU_buffer")
+
+		-- Select node textures
 		local i = math.ceil((charge/max_charge)*8)
 		if i > 8 then i = 8 end
-	j=meta:get_float("last_side_shown")
+		local j = meta:get_float("last_side_shown")
 		if i~=j then
 		   if i>0 then hacky_swap_node(pos,"technic:mv_battery_box"..i)
 		   elseif i==0 then hacky_swap_node(pos,"technic:mv_battery_box") end
 		   meta:set_float("last_side_shown",i)
 		end
 
---loading registered power tools
+		--charge registered power tools
 		local inv = meta:get_inventory()
 		if inv:is_empty("src")==false  then
 		   local srcstack = inv:get_stack("src", 1)
 		   local src_item=srcstack:to_table()
 		   local src_meta=get_item_meta(src_item["metadata"])
 
-		local item_max_charge=nil
+		   -- Power tools should really be made into a hash table to avoid linear search. But the list is short so okay...
 		   for i=1,registered_power_tools_count,1 do
 		      if power_tools[i].tool_name==src_item["name"] then
+			 -- What is this code doing? Setting tool properties if not set already????
 			 src_meta=get_item_meta(src_item["metadata"])
 			 if src_meta==nil then
 			    src_meta={}
@@ -143,13 +140,10 @@ minetest.register_abm({
 			       src_meta["charge"]=0
 			    end
 			 end
-				item_max_charge=power_tools[i].max_charge
+			 -- Do the charging
-			end
+			 local item_max_charge = power_tools[i].max_charge
-		end
+			 local load1           = src_meta["charge"]
-		
+			 local load_step       = 4000 -- how much to charge per tick
-		if item_max_charge then
-			load1=src_meta["charge"] 
-			load_step=4000
 			 if load1<item_max_charge and charge>0 then
 			    if charge-load_step<0 then load_step=charge end
 			    if load1+load_step>item_max_charge then load_step=item_max_charge-load1 end
@@ -160,11 +154,13 @@ minetest.register_abm({
 			    src_item["metadata"] = set_item_meta(src_meta)
 			    inv:set_stack("src", 1, src_item)
 			 end
-			meta:set_int("battery_charge",charge)
+			 meta:set_int("internal_EU_buffer",charge)
+			 break
+		      end
 		   end
 		end
 
--- dischargin registered power tools
+		-- discharging registered power tools
 		if inv:is_empty("dst") == false then
 		   srcstack = inv:get_stack("dst", 1)
 		   src_item=srcstack:to_table()
@@ -183,13 +179,9 @@ minetest.register_abm({
 			       src_meta["charge"]=0
 			    end
 			 end
-				item_max_charge=power_tools[i].max_charge
+			 local item_max_charge = power_tools[i].max_charge
-			end
-		end
-
-		if item_max_charge then
 			 local load1           = src_meta["charge"]
-		load_step=4000
+			 local load_step       = 4000 -- how much to discharge per tick
 			 if load1>0 and charge<max_charge then
 			    if charge+load_step>max_charge then load_step=max_charge-charge end
 			    if load1-load_step<0 then load_step=load1 end
@@ -200,10 +192,11 @@ minetest.register_abm({
 			    src_item["metadata"]=set_item_meta(src_meta)
 			    inv:set_stack("dst", 1, src_item)
 			 end
+			 meta:set_int("internal_EU_buffer",charge)
+			 break
+		      end
 		   end
 		end
-		
-	meta:set_int("battery_charge",charge)
 
 		local load = math.floor((charge/300000) * 100)
 		meta:set_string("formspec",
@@ -212,45 +205,39 @@ minetest.register_abm({
 				   (load)..":technic_power_meter_fg.png]"
 			     )
 
+		-- Next index the surrounding network the get the producers and receivers on the power grid
 		local pos1 = {}
-
 		pos1.y = pos.y-1
 		pos1.x = pos.x
 		pos1.z = pos.z
 
-
 		meta1 = minetest.env:get_meta(pos1)
 		if meta1:get_float("mv_cablelike")~=1 then return end
 
 		local MV_nodes = {}
 		local PR_nodes = {}
 		local RE_nodes = {}
+		local BA_nodes = {}
 
 		MV_nodes[1]   = {}
 		MV_nodes[1].x = pos1.x
 		MV_nodes[1].y = pos1.y
 		MV_nodes[1].z = pos1.z
-		MV_nodes[1].visited=false
 
-table_index=1
+		local table_index=1
 		repeat
-	check_MV_node (PR_nodes,RE_nodes,MV_nodes,table_index)
+		   check_MV_node(PR_nodes,RE_nodes,BA_nodes,MV_nodes,table_index)
 		   table_index=table_index+1
 		   if MV_nodes[table_index]==nil then break end
 		until false
 
-
+		-- Get power from all connected producers
-local pos1={}
+		local pr_pos
-i=1
+                for _,pr_pos in ipairs(PR_nodes) do
-	repeat
+		   local meta1              = minetest.env:get_meta(pr_pos)
-	if PR_nodes[i]==nil then break end -- gettin power from all connected producers
-		pos1.x=PR_nodes[i].x
-		pos1.y=PR_nodes[i].y
-		pos1.z=PR_nodes[i].z
-	local meta1 = minetest.env:get_meta(pos1)
 		   local internal_EU_buffer = meta1:get_float("internal_EU_buffer")
+		   local charge_to_take     = 1000
 		   if charge<max_charge then
-	charge_to_take=1000	
 		      if internal_EU_buffer-charge_to_take<=0 then
 			 charge_to_take=internal_EU_buffer
 		      end
@@ -260,22 +247,17 @@ i=1
 			 meta1:set_float("internal_EU_buffer",internal_EU_buffer)
 		      end
 		   end
-	i=i+1
+		end
-	until false
 
 		if charge>max_charge then charge=max_charge end
 
-i=1
+		-- Provide power to all connected receivers
-	repeat
+		local re_pos
-	if RE_nodes[i]==nil then break end
+                for _,re_pos in ipairs(RE_nodes) do
-		pos1.x=RE_nodes[i].x         -- loading all conected machines buffers
+		   local meta1                   = minetest.env:get_meta(re_pos)
-		pos1.y=RE_nodes[i].y
-		pos1.z=RE_nodes[i].z
-	local meta1 = minetest.env:get_meta(pos1)
 		   local internal_EU_buffer      = meta1:get_float("internal_EU_buffer")
 		   local internal_EU_buffer_size = meta1:get_float("internal_EU_buffer_size")
-
+		   local charge_to_give          = math.min(1000, charge/table.getn(RE_nodes))
-	local charge_to_give=1000
 		   if internal_EU_buffer+charge_to_give>internal_EU_buffer_size then
 		      charge_to_give=internal_EU_buffer_size-internal_EU_buffer
 		   end
@@ -284,18 +266,22 @@ i=1
 		   internal_EU_buffer=internal_EU_buffer+charge_to_give
 		   meta1:set_float("internal_EU_buffer",internal_EU_buffer)
 		   charge=charge-charge_to_give;
-	
+		end
-	i=i+1
-	until false
 		charge=math.floor(charge)
-	charge_string=tostring(charge)
+		meta:set_string("infotext", "MV Battery box: "..charge.."/"..max_charge);
-	meta:set_string("infotext", "Battery box: "..charge_string.."/"..max_charge);
+		meta:set_int("internal_EU_buffer",charge)
-	meta:set_int("battery_charge",charge)
-
 	     end
  })
 
+-- Register as a battery type
+-- Battery type machines function as power reservoirs and can both receive and give back power
+register_MV_machine("technic:mv_battery_box","BA")
+for i=1,8,1 do
+   register_MV_machine("technic:mv_battery_box"..i,"BA")
+end
+
 function add_new_MVcable_node (MV_nodes,pos1)
+   if MV_nodes == nil then return true end
    local i=1
    repeat
       if MV_nodes[i]==nil then break end
@@ -306,50 +292,47 @@ MV_nodes[i]={}
    MV_nodes[i].x=pos1.x
    MV_nodes[i].y=pos1.y
    MV_nodes[i].z=pos1.z
-MV_nodes[i].visited=false
    return true
 end
 
-function check_MV_node (PR_nodes,RE_nodes,MV_nodes,i)
+function check_MV_node(PR_nodes,RE_nodes,BA_nodes,MV_nodes,i)
    local pos1={}
    pos1.x=MV_nodes[i].x
    pos1.y=MV_nodes[i].y
    pos1.z=MV_nodes[i].z
-		MV_nodes[i].visited=true
-		new_node_added=false
 
    pos1.x=pos1.x+1
-		check_MV_node_subp (PR_nodes,RE_nodes,MV_nodes,pos1)
+   check_MV_node_subp(PR_nodes,RE_nodes,BA_nodes,MV_nodes,pos1)
    pos1.x=pos1.x-2
-		check_MV_node_subp (PR_nodes,RE_nodes,MV_nodes,pos1)
+   check_MV_node_subp(PR_nodes,RE_nodes,BA_nodes,MV_nodes,pos1)
    pos1.x=pos1.x+1
 
    pos1.y=pos1.y+1
-		check_MV_node_subp (PR_nodes,RE_nodes,MV_nodes,pos1)
+   check_MV_node_subp(PR_nodes,RE_nodes,BA_nodes,MV_nodes,pos1)
    pos1.y=pos1.y-2
-		check_MV_node_subp (PR_nodes,RE_nodes,MV_nodes,pos1)
+   check_MV_node_subp(PR_nodes,RE_nodes,BA_nodes,MV_nodes,pos1)
    pos1.y=pos1.y+1
 
    pos1.z=pos1.z+1
-		check_MV_node_subp (PR_nodes,RE_nodes,MV_nodes,pos1)
+   check_MV_node_subp(PR_nodes,RE_nodes,BA_nodes,MV_nodes,pos1)
    pos1.z=pos1.z-2
-		check_MV_node_subp (PR_nodes,RE_nodes,MV_nodes,pos1)
+   check_MV_node_subp(PR_nodes,RE_nodes,BA_nodes,MV_nodes,pos1)
    pos1.z=pos1.z+1
-return new_node_added
 end
 
-function check_MV_node_subp (PR_nodes,RE_nodes,MV_nodes,pos1)
+function check_MV_node_subp (PR_nodes,RE_nodes,BA_nodes,MV_nodes,pos1)
-meta = minetest.env:get_meta(pos1)
+   local meta = minetest.env:get_meta(pos1)
-if meta:get_float("mv_cablelike")==1 then new_node_added=add_new_MVcable_node(MV_nodes,pos1) end
+   local name = minetest.env:get_node(pos1).name
-for i in ipairs(MV_machines) do
+   if meta:get_float("mv_cablelike")==1 then
-	if minetest.env:get_node(pos1).name == MV_machines[i].machine_name then 
+      add_new_MVcable_node(MV_nodes,pos1)
-		if MV_machines[i].machine_type == "PR" then
+   elseif MV_machines[name] then
-			new_node_added=add_new_MVcable_node(PR_nodes,pos1) 
+      --print(name.." is a "..MV_machines[name])
-			end
+      if     MV_machines[name] == "PR" then
-		if MV_machines[i].machine_type == "RE" then
+	 add_new_MVcable_node(PR_nodes,pos1)
-			new_node_added=add_new_MVcable_node(RE_nodes,pos1) 
+      elseif MV_machines[name] == "RE" then
+	 add_new_MVcable_node(RE_nodes,pos1)
+      elseif MV_machines[name] == "BA" then
+	 add_new_MVcable_node(BA_nodes,pos1)
       end
    end
 end
-end
-

technic/down_converter_hv.lua

@@ -0,0 +1,225 @@
+-- The HV down converter will step down HV EUs to MV EUs
+-- If we take the solar panel as calibration then the
+-- 1 HVEU = 5 MVEU as we stack 5 MV arrays to get a HV array.
+-- The downconverter does of course have a conversion loss.
+-- This loses 30% of the power.
+-- The converter does not store any energy by itself.
+minetest.register_node("technic:down_converter_hv", {
+        description = "HV Down Converter",
+	tiles  = {"technic_hv_down_converter_top.png", "technic_hv_down_converter_bottom.png", "technic_hv_down_converter_side.png",
+		  "technic_hv_down_converter_side.png", "technic_hv_down_converter_side.png", "technic_hv_down_converter_side.png"},
+	groups = {snappy=2,choppy=2,oddly_breakable_by_hand=2},
+	sounds = default.node_sound_wood_defaults(),
+	drawtype = "nodebox",
+	paramtype = "light",
+	is_ground_content = true,
+	node_box = {
+	   type = "fixed",
+	   fixed = {-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},
+	},
+	selection_box = {
+	   type = "fixed",
+	   fixed = {-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},
+	},
+	on_construct = function(pos)
+			  local meta = minetest.env:get_meta(pos)
+			  meta:set_float("technic_hv_power_machine", 1)
+			  meta:set_float("technic_mv_power_machine", 1)
+			  meta:set_float("internal_EU_buffer",0)
+			  meta:set_float("internal_EU_buffer_size",0)
+			  meta:set_string("infotext", "HV Down Converter")
+			  meta:set_float("active", false)
+		       end,
+     })
+
+minetest.register_craft({
+	output = 'technic:down_converter_hv 1',
+	recipe = {
+		{'technic:stainless_steel_ingot', 'technic:stainless_steel_ingot','technic:stainless_steel_ingot'},
+		{'technic:hv_transformer',        'technic:hv_cable',             'technic:mv_transformer'},
+		{'technic:hv_cable',              'technic:rubber',               'technic:mv_cable'},
+	}
+})
+
+minetest.register_abm(
+	{nodenames = {"technic:down_converter_hv"},
+	interval   = 1,
+	chance     = 1,
+	action = function(pos, node, active_object_count, active_object_count_wider)
+		    -- HV->MV conversion factor
+		    local hv_mv_factor = 5
+		    -- The maximun charge a single converter can handle. Let's set this to
+		    -- what 5 HV solar arrays can produce - 30% loss (2880*5*0.7)
+		    local max_charge = 10080*hv_mv_factor
+
+		    local meta             = minetest.env:get_meta(pos)
+		    local meta1            = nil
+		    local pos1             = {}
+		    local available_charge = 0 -- counted in MV units
+		    local used_charge      = 0 -- counted in MV units
+
+		    -- Index all HV nodes connected to the network
+		    -- HV cable comes in through the bottom
+		    pos1.y = pos.y-1
+		    pos1.x = pos.x
+		    pos1.z = pos.z
+		    meta1  = minetest.env:get_meta(pos1)
+		    if meta1:get_float("hv_cablelike")~=1 then return end
+
+		    local HV_nodes    = {} -- HV type
+		    local HV_PR_nodes = {} -- HV type
+		    local HV_BA_nodes = {} -- HV type
+
+		    HV_nodes[1]         = {}
+		    HV_nodes[1].x       = pos1.x
+		    HV_nodes[1].y       = pos1.y
+		    HV_nodes[1].z       = pos1.z
+
+		    local table_index = 1
+		    repeat
+		       check_HV_node(HV_PR_nodes,nil,HV_BA_nodes,HV_nodes,table_index)
+		       table_index = table_index + 1
+		       if HV_nodes[table_index] == nil then break end
+		    until false
+
+		    --print("HV_nodes: PR="..table.getn(HV_PR_nodes).." BA="..table.getn(HV_BA_nodes))
+
+		    -- Index all MV nodes connected to the network
+		    -- MV cable comes out of the top
+		    pos1.y = pos.y+1
+		    pos1.x = pos.x
+		    pos1.z = pos.z
+		    meta1  = minetest.env:get_meta(pos1)
+		    if meta1:get_float("mv_cablelike")~=1 then return end
+
+		    local MV_nodes    = {} -- MV type
+		    local MV_RE_nodes = {} -- MV type
+		    local MV_BA_nodes = {} -- MV type
+
+		    MV_nodes[1]         = {}
+		    MV_nodes[1].x       = pos1.x
+		    MV_nodes[1].y       = pos1.y
+		    MV_nodes[1].z       = pos1.z
+
+		    table_index = 1
+		    repeat
+		       check_MV_node(nil,MV_RE_nodes,MV_BA_nodes,MV_nodes,table_index)
+		       table_index = table_index + 1
+		       if MV_nodes[table_index] == nil then break end
+		    until false
+
+		    --print("MV_nodes: RE="..table.getn(MV_RE_nodes).." BA="..table.getn(MV_BA_nodes))
+
+		    -- First get available power from all the attached HV suppliers
+		    -- Get the supplier internal EU buffer and read the EUs from it
+		    -- No update yet!
+		    local pos1
+-- FIXME: Until further leave the producers out of it and just let the batteries be the hub
+--		    for _,pos1 in ipairs(HV_PR_nodes) do
+--		       meta1  = minetest.env:get_meta(pos1)
+--		       local internal_EU_buffer = meta1:get_float("internal_EU_buffer")
+--		       available_charge = available_charge + meta1:get_float("internal_EU_buffer") * hv_mv_factor
+--		       -- Limit conversion capacity
+--		       if available_charge > max_charge then
+--			  available_charge = max_charge
+--			  break
+--		       end
+--		    end
+--		    --print("Available_charge PR:"..available_charge)
+
+		    for _,pos1 in ipairs(HV_BA_nodes) do
+		       meta1  = minetest.env:get_meta(pos1)
+		       local internal_EU_buffer = meta1:get_float("internal_EU_buffer")
+		       available_charge = available_charge + meta1:get_float("internal_EU_buffer") * hv_mv_factor
+		       -- Limit conversion capacity
+		       if available_charge > max_charge then
+			  available_charge = max_charge
+			  break
+		       end
+		    end
+		    --print("Available_charge PR+BA:"..available_charge)
+
+		    -- Calculate total number of receivers:
+		    local MV_receivers = table.getn(MV_RE_nodes)+table.getn(MV_BA_nodes)
+
+		    -- Next supply power to all connected MV machines
+		    -- Get the power receiver internal EU buffer and give EUs to it
+		    -- Note: for now leave out RE type machines until producers distribute power themselves even without a battery
+--		    for _,pos1 in ipairs(MV_RE_nodes) do
+--		       local meta1                   = minetest.env:get_meta(pos1)
+--		       local internal_EU_buffer      = meta1:get_float("internal_EU_buffer")
+--		       local internal_EU_buffer_size = meta1:get_float("internal_EU_buffer_size")
+--		       local charge_to_give = math.min(4000, available_charge/MV_receivers) -- power rating limit on the MV wire
+--		       -- How much can this unit take?
+--		       if internal_EU_buffer+charge_to_give > internal_EU_buffer_size then
+--			  charge_to_give=internal_EU_buffer_size-internal_EU_buffer
+--		       end
+--		       -- If we are emptying the supply take the remainder
+--		       if available_charge<used_charge+charge_to_give then charge_to_give=available_charge-used_charge end
+--		       -- Update the unit supplied to
+--		       internal_EU_buffer = internal_EU_buffer + charge_to_give
+--		       meta1:set_float("internal_EU_buffer",internal_EU_buffer)
+--		       -- Do the accounting
+--		       used_charge = used_charge + charge_to_give
+--		       if available_charge == used_charge then break end -- bail out if supply depleted
+--		    end
+		    --print("used_charge RE:"..used_charge)
+
+		    for _,pos1 in ipairs(MV_BA_nodes) do
+		       local meta1 = minetest.env:get_meta(pos1)
+		       local internal_EU_buffer      = meta1:get_float("internal_EU_buffer")
+		       local internal_EU_buffer_size = meta1:get_float("internal_EU_buffer_size")
+		       --print("internal_EU_buffer:"..internal_EU_buffer)
+		       --print("internal_EU_buffer_size:"..internal_EU_buffer_size)
+		       local charge_to_give = math.min(math.floor(available_charge/MV_receivers), 4000) -- power rating limit on the MV wire
+		       --print("charge_to_give:"..charge_to_give)
+		       -- How much can this unit take?
+		       if internal_EU_buffer+charge_to_give > internal_EU_buffer_size then
+			  charge_to_give=internal_EU_buffer_size-internal_EU_buffer
+		       end
+		       --print("charge_to_give2:"..charge_to_give)
+		       -- If we are emptying the supply take the remainder
+		       if available_charge<used_charge+charge_to_give then charge_to_give=available_charge-used_charge end
+		       -- Update the unit supplied to
+		       --print("charge_to_give3:"..charge_to_give)
+		       internal_EU_buffer = internal_EU_buffer + charge_to_give
+		       --print("internal_EU_buffer:"..internal_EU_buffer)
+		       meta1:set_float("internal_EU_buffer",internal_EU_buffer)
+		       -- Do the accounting
+		       used_charge = used_charge + charge_to_give
+		       --print("used_charge:"..used_charge)
+		       if available_charge == used_charge then break end -- bail out if supply depleted
+		    end
+		    --print("used_charge RE+BA:"..used_charge)
+
+		    -- Last update the HV suppliers with the actual demand.
+		    -- Get the supplier internal EU buffer and update the EUs from it
+		    -- Note: So far PR nodes left out and only BA nodes are updated
+		    local HV_BA_size = table.getn(HV_BA_nodes)
+		    for _,pos1 in ipairs(HV_BA_nodes) do
+		       meta1  = minetest.env:get_meta(pos1)
+		       local internal_EU_buffer = meta1:get_float("internal_EU_buffer")
+		       local charge_to_take = math.floor(used_charge/HV_BA_size/hv_mv_factor) -- HV units
+		       if internal_EU_buffer-charge_to_take <= 0 then
+			  charge_to_take = internal_EU_buffer
+		       end
+		       if charge_to_take > 0 then
+			  internal_EU_buffer = internal_EU_buffer-charge_to_take
+			  meta1:set_float("internal_EU_buffer",internal_EU_buffer)
+		       end
+		    end
+
+		    if used_charge>0 then
+		       meta:set_string("infotext", "HV Down Converter is active (HV:"..available_charge.."/MV:"..used_charge..")");
+		       meta:set_float("active",1) -- used for setting textures someday maybe
+		    else
+		       meta:set_string("infotext", "HV Down Converter is inactive (HV:"..available_charge.."/MV:"..used_charge..")");
+		       meta:set_float("active",0) -- used for setting textures someday maybe
+		       return
+		    end
+	end,
+})
+
+-- This machine does not store energy it receives energy from the HV side and outputs it on the MV side
+register_HV_machine ("technic:down_converter_hv","RE")
+register_MV_machine ("technic:down_converter_hv","PR")

technic/down_converter_mv.lua

@@ -0,0 +1,226 @@
+-- The MV down converter will step down MV EUs to LV EUs
+-- If we take the solar panel as calibration then the
+-- 1 MVEU = 5 LVEU as we stack 5 LV arrays to get an MV array.
+-- The downconverter does of course have a conversion loss.
+-- This loses 30% of the power.
+-- The converter does not store any energy by itself.
+minetest.register_node(
+   "technic:down_converter_mv", {
+      description = "MV Down Converter",
+      tiles  = {"technic_mv_down_converter_top.png", "technic_mv_down_converter_bottom.png", "technic_mv_down_converter_side.png",
+		"technic_mv_down_converter_side.png", "technic_mv_down_converter_side.png", "technic_mv_down_converter_side.png"},
+      groups = {snappy=2,choppy=2,oddly_breakable_by_hand=2},
+      sounds = default.node_sound_wood_defaults(),
+      drawtype = "nodebox",
+      paramtype = "light",
+      is_ground_content = true,
+      node_box = {
+	 type = "fixed",
+	 fixed = {-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},
+      },
+      selection_box = {
+	 type = "fixed",
+	 fixed = {-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},
+      },
+      on_construct = function(pos)
+			local meta = minetest.env:get_meta(pos)
+			meta:set_float("technic_mv_power_machine", 1)
+			meta:set_float("technic_power_machine", 1)
+			meta:set_float("internal_EU_buffer",0)
+			meta:set_float("internal_EU_buffer_size",0)
+			meta:set_string("infotext", "MV Down Converter")
+			  meta:set_float("active", false)
+		       end,
+   })
+
+minetest.register_craft({
+	output = 'technic:down_converter_mv 1',
+	recipe = {
+		{'technic:stainless_steel_ingot', 'technic:stainless_steel_ingot','technic:stainless_steel_ingot'},
+		{'technic:mv_transformer',        'technic:mv_cable',             'technic:lv_transformer'},
+		{'technic:mv_cable',              'technic:rubber',               'technic:lv_cable'},
+	}
+})
+
+minetest.register_abm(
+	{nodenames = {"technic:down_converter_mv"},
+	interval   = 1,
+	chance     = 1,
+	action = function(pos, node, active_object_count, active_object_count_wider)
+		    -- MV->LV conversion factor
+		    local mv_lv_factor = 5
+		    -- The maximun charge a single converter can handle. Let's set this to
+		    -- what 5 MV solar arrays can produce - 30% loss (720*5*0.7)
+		    local max_charge = 2520*mv_lv_factor
+
+		    local meta             = minetest.env:get_meta(pos)
+		    local meta1            = nil
+		    local pos1             = {}
+		    local available_charge = 0 -- counted in LV units
+		    local used_charge      = 0 -- counted in LV units
+
+		    -- Index all MV nodes connected to the network
+		    -- MV cable comes in through the bottom
+		    pos1.y = pos.y-1
+		    pos1.x = pos.x
+		    pos1.z = pos.z
+		    meta1  = minetest.env:get_meta(pos1)
+		    if meta1:get_float("mv_cablelike")~=1 then return end
+
+		    local MV_nodes    = {} -- MV type
+		    local MV_PR_nodes = {} -- MV type
+		    local MV_BA_nodes = {} -- MV type
+
+		    MV_nodes[1]         = {}
+		    MV_nodes[1].x       = pos1.x
+		    MV_nodes[1].y       = pos1.y
+		    MV_nodes[1].z       = pos1.z
+
+		    local table_index = 1
+		    repeat
+		       check_MV_node(MV_PR_nodes,nil,MV_BA_nodes,MV_nodes,table_index)
+		       table_index = table_index + 1
+		       if MV_nodes[table_index] == nil then break end
+		    until false
+
+		    --print("MV_nodes: PR="..table.getn(MV_PR_nodes).." BA="..table.getn(MV_BA_nodes))
+
+		    -- Index all LV nodes connected to the network
+		    -- LV cable comes out of the top
+		    pos1.y = pos.y+1
+		    pos1.x = pos.x
+		    pos1.z = pos.z
+		    meta1  = minetest.env:get_meta(pos1)
+		    if meta1:get_float("cablelike")~=1 then return end
+
+		    local LV_nodes    = {} -- LV type
+		    local LV_RE_nodes = {} -- LV type
+		    local LV_BA_nodes = {} -- LV type
+
+		    LV_nodes[1]         = {}
+		    LV_nodes[1].x       = pos1.x
+		    LV_nodes[1].y       = pos1.y
+		    LV_nodes[1].z       = pos1.z
+
+		    table_index = 1
+		    repeat
+		       check_LV_node(nil,LV_RE_nodes,LV_BA_nodes,LV_nodes,table_index)
+		       table_index = table_index + 1
+		       if LV_nodes[table_index] == nil then break end
+		    until false
+
+		    --print("LV_nodes: RE="..table.getn(LV_RE_nodes).." BA="..table.getn(LV_BA_nodes))
+
+		    -- First get available power from all the attached MV suppliers
+		    -- Get the supplier internal EU buffer and read the EUs from it
+		    -- No update yet!
+		    local pos1
+-- FIXME: Until further leave the producers out of it and just let the batteries be the hub
+--		    for _,pos1 in ipairs(MV_PR_nodes) do
+--		       meta1  = minetest.env:get_meta(pos1)
+--		       local internal_EU_buffer = meta1:get_float("internal_EU_buffer")
+--		       available_charge = available_charge + meta1:get_float("internal_EU_buffer") * mv_lv_factor
+--		       -- Limit conversion capacity
+--		       if available_charge > max_charge then
+--			  available_charge = max_charge
+--			  break
+--		       end
+--		    end
+--		    print("Available_charge PR:"..available_charge)
+
+		    for _,pos1 in ipairs(MV_BA_nodes) do
+		       meta1  = minetest.env:get_meta(pos1)
+		       local internal_EU_buffer = meta1:get_float("internal_EU_buffer")
+		       available_charge = available_charge + meta1:get_float("internal_EU_buffer") * mv_lv_factor
+		       -- Limit conversion capacity
+		       if available_charge > max_charge then
+			  available_charge = max_charge
+			  break
+		       end
+		    end
+		    --print("Available_charge PR+BA:"..available_charge)
+
+		    -- Calculate total number of receivers:
+		    local LV_receivers = table.getn(LV_RE_nodes)+table.getn(LV_BA_nodes)
+
+		    -- Next supply power to all connected LV machines
+		    -- Get the power receiver internal EU buffer and give EUs to it
+		    -- Note: for now leave out RE type machines until producers distribute power themselves even without a battery
+--		    for _,pos1 in ipairs(LV_RE_nodes) do
+--		       local meta1                   = minetest.env:get_meta(pos1)
+--		       local internal_EU_buffer      = meta1:get_float("internal_EU_buffer")
+--		       local internal_EU_buffer_size = meta1:get_float("internal_EU_buffer_size")
+--		       local charge_to_give = math.min(1000, available_charge/LV_receivers) -- power rating limit on the LV wire
+--		       -- How much can this unit take?
+--		       if internal_EU_buffer+charge_to_give > internal_EU_buffer_size then
+--			  charge_to_give=internal_EU_buffer_size-internal_EU_buffer
+--		       end
+--		       -- If we are emptying the supply take the remainder
+--		       if available_charge<used_charge+charge_to_give then charge_to_give=available_charge-used_charge end
+--		       -- Update the unit supplied to
+--		       internal_EU_buffer = internal_EU_buffer + charge_to_give
+--		       meta1:set_float("internal_EU_buffer",internal_EU_buffer)
+--		       -- Do the accounting
+--		       used_charge = used_charge + charge_to_give
+--		       if available_charge == used_charge then break end -- bail out if supply depleted
+--		    end
+		    --print("used_charge RE:"..used_charge)
+
+		    for _,pos1 in ipairs(LV_BA_nodes) do
+		       local meta1 = minetest.env:get_meta(pos1)
+		       local internal_EU_buffer      = meta1:get_float("internal_EU_buffer")
+		       local internal_EU_buffer_size = meta1:get_float("internal_EU_buffer_size")
+		       --print("internal_EU_buffer:"..internal_EU_buffer)
+		       --print("internal_EU_buffer_size:"..internal_EU_buffer_size)
+		       local charge_to_give = math.min(math.floor(available_charge/LV_receivers), 1000) -- power rating limit on the LV wire
+		       --print("charge_to_give:"..charge_to_give)
+		       -- How much can this unit take?
+		       if internal_EU_buffer+charge_to_give > internal_EU_buffer_size then
+			  charge_to_give=internal_EU_buffer_size-internal_EU_buffer
+		       end
+		       --print("charge_to_give2:"..charge_to_give)
+		       -- If we are emptying the supply take the remainder
+		       if available_charge<used_charge+charge_to_give then charge_to_give=available_charge-used_charge end
+		       -- Update the unit supplied to
+		       --print("charge_to_give3:"..charge_to_give)
+		       internal_EU_buffer = internal_EU_buffer + charge_to_give
+		       --print("internal_EU_buffer:"..internal_EU_buffer)
+		       meta1:set_float("internal_EU_buffer",internal_EU_buffer)
+		       -- Do the accounting
+		       used_charge = used_charge + charge_to_give
+		       --print("used_charge:"..used_charge)
+		       if available_charge == used_charge then break end -- bail out if supply depleted
+		    end
+		    --print("used_charge RE+BA:"..used_charge)
+
+		    -- Last update the MV suppliers with the actual demand.
+		    -- Get the supplier internal EU buffer and update the EUs from it
+		    -- Note: So far PR nodes left out and only BA nodes are updated
+		    local MV_BA_size = table.getn(MV_BA_nodes)
+		    for _,pos1 in ipairs(MV_BA_nodes) do
+		       meta1  = minetest.env:get_meta(pos1)
+		       local internal_EU_buffer = meta1:get_float("internal_EU_buffer")
+		       local charge_to_take = math.floor(used_charge/MV_BA_size/mv_lv_factor) -- MV units
+		       if internal_EU_buffer-charge_to_take <= 0 then
+			  charge_to_take = internal_EU_buffer
+		       end
+		       if charge_to_take > 0 then
+			  internal_EU_buffer = internal_EU_buffer-charge_to_take
+			  meta1:set_float("internal_EU_buffer",internal_EU_buffer)
+		       end
+		    end
+
+		    if used_charge>0 then
+		       meta:set_string("infotext", "MV Down Converter is active (MV:"..available_charge.."/LV:"..used_charge..")");
+		       meta:set_float("active",1) -- used for setting textures someday maybe
+		    else
+		       meta:set_string("infotext", "MV Down Converter is inactive (MV:"..available_charge.."/LV:"..used_charge..")");
+		       meta:set_float("active",0) -- used for setting textures someday maybe
+		       return
+		    end
+	end,
+})
+
+-- This machine does not store energy it receives energy from the MV side and outputs it on the LV side
+register_MV_machine ("technic:down_converter_mv","RE")
+register_LV_machine ("technic:down_converter_mv","PR")

technic/init.lua

@@ -36,6 +36,7 @@ dofile(modpath.."/cnc_nodes.lua")
 dofile(modpath.."/wires_mv.lua")
 dofile(modpath.."/battery_box_mv.lua")
 dofile(modpath.."/solar_array_mv.lua")
+dofile(modpath.."/down_converter_mv.lua")
 dofile(modpath.."/electric_furnace_mv.lua")
 dofile(modpath.."/alloy_furnace_mv.lua")
 dofile(modpath.."/forcefield.lua")
@@ -44,6 +45,7 @@ dofile(modpath.."/forcefield.lua")
 dofile(modpath.."/wires_hv.lua")
 dofile(modpath.."/battery_box_hv.lua")
 dofile(modpath.."/solar_array_hv.lua")
+dofile(modpath.."/down_converter_hv.lua")
 
 --Tools
 if technic.config:getBool("enable_mining_drill") then dofile(modpath.."/mining_drill.lua") end

technic/solar_array_mv.lua

@@ -83,7 +83,8 @@ minetest.register_abm(
 			meta:set_float("active",1)
 			internal_EU_buffer=internal_EU_buffer+charge_to_give
 			meta:set_float("internal_EU_buffer",internal_EU_buffer)
-			
+			-- Idea: How about letting solar panels provide power without battery boxes?
+			-- This could provide an even distribution to all receivers.			
 		else
 			meta:set_string("infotext", "Solar Array is inactive");
 			meta:set_float("active",0)