Note: the LESU has been deprecated since Minecraft 1.5.2
The LESU is a multiblock energy storage. Its maximum stored EU, input voltage and output are variable, depending on how many LESU blocks are next to it. First place a LESU-Controller, to determine the location of your INPUT and OUTPUT. That Block is the one you connect to your Cables. It can store 1 000 000 EU by itself, has a base output of 5 EU/t and a maximum input voltage of 32 EU/p. For every LESU block adjacent to the LESU controller, the energy storage of the LESU increases by 1 000 000, the output increases by 1 EU/t and the maximum input voltage increases by 1 EU/p. The maximum EU storage is capped at , the output is capped at 512 EU/t and the maximum input voltage is capped at 512 EU/p. Note that LESU blocks are not Tile Entities but a GT_Block, hence mobs cannot spawn on top of them and they cause as much lag as a random block of Cobblestone. Monsters also cannot spawn above LESU blocks.
ID (Controller): GT_Machinery:07 ID (Block Upgrade): GT_Block2:06