This question has some controversy on how to charge a Power Tool from the Modular Powersuits mod. While it is commonly known that both EU, MJ, and UE can be used to charge it, I want to know how something can be charged with MJ.

Unlike a Batbox/MFE/MFSU/AESU/IDSU which has a slot in its GUI to charge stuff with, Redstone Energy Cells and whatever engines do not have a slot to do this.

IndustrialCraft has the Charge Pads addon, which charges stuff with EU while a player stands on it. BuildCraft/Thermal Expansion/RailCraft... do not have anything of the sort.

So, how can you charge items with MJ?

3 Answers 3


From the wiki:

MJ is the energy that BuildCraft 3 uses. MJ stands for Minecraft Joules. It is generated by any kind of Engine and can be used by any kind of BuildCraft machinery. Many types of energy can be converted to MJ by using Engines, however, transforming MJ into other power types is a more complex process, and requires the usage of energy conversion machines found in other mod packs. MJ can travel through Conductive Pipes and Redstone Energy Conduit.

It would seem @Fredley is right (although I never doubted) and that it's much harder to turn MJ to Eu than it is to turn Eu into MJ. This makes it quite difficult to charge tools using MJ.

However, it would also seem Thermal Expansion offers an item that does just this. It is called the Energetic Infuser.


If your version of FTB includes the Power Converters mod, you can use a universal charger like a IC2 charge pad.

Place a producer of your choice on one side of a bridge, and a universal charger on the other. Now all items in inventories of players who stand on it will charge with any energy. This will also charge items in adjacent inventories.


Most mods don't support Minecraft Joules (MJ) anymore, and have switched to Redstone Flux (RF).

As of Thermal Expansion (released 2014 December 25), there is the Energetic Infuser, which charges items put into it at rate of 400 RF/t (which would be 40 MJ/t) if there are no upgrades applied to it.

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