The Medium Battery has 16 visible columns, each of which is equivalent to 16 Units.
Like the Small Battery, Medium Batteries accumulate power when production of energy exceeds demand for energy. The Medium Battery will give away its stored energy whenever the network doesn't produce enough energy.
Lacking visible horizontal lines to mark individual 'bars' found on the Small Battery, each of the 16 vertical columns is effectively four bars on a Small Battery.
Accounting for size efficiency, it could ostensibly be useful in some situations to fill a Medium Storage with Small Batteries if throughput is desired. The total energy capacity remains the same (Each of the 8 Small Batteries holds 1/8th the power of the Medium Battery), however, this costs 8 Lithium and 2 Resin. Using Medium Storage Silos instead increases the total cost to 24 Lithium and 2 Titanium, but also allows you to store 3x the energy in the same space, with 8x the power transfer rate.
Medium Batteries used to be able to be found deep in caves at the end of tunnels rarely.
Traveling to different planets will make the yellow bars move off of the center of the battery. The moved bars can not be collided with, but do move the outline of the battery when hovered over. Extensive space travel worsens the effect. This can normally be fixed by either resetting the game or packing the battery, then unpacking it.