Power Storage
Mechanical power may be stored in pumped water gravity batteries. In this mod, these batteries are a simple multiblock: a vertical column, capped with a Battery Base at the bottom and a Battery Cap at the top, with a variable number (>=0) of Battery Core blocks in the middle. They must form an uninterrupted line from the base to the cap, and they must be facing in the right direction.
A battery's capacity and output rate is defined by its height (H). A battery with no battery core blocks is 1 tall, and each battery core block adds 1 height.
A battery may store 20 x H MU power. It accepts any amount of MU per tick via its input sides, but only outputs H MU power per tick. This means that a battery needs H seconds to charge up, but always only one second to discharge.
You may supply a redstone signal to the battery cap block to prevent it from discharging automatically. This will keep the charge at the top of the battery, and discard any charge coming in via the inputs.
The battery base has two inputs on its sides and one output on its facing side. This means it may be used as a simple power transformer, or "adder".
Battery Base
Battery Core
Battery Cap