A Branch in Time
Backpack sized energy storage devices. These devices hold rotational energy which can be discharged at a range of different speeds with different torques (higher torque with lower speeds).
These devices cause neither sparks nor (significant) heat in discharging.
The CAs are normally charged by connecting them to a large steam engine, which winds the device. Charging normally takes up to 30 minutes. Discharge time depends upon what the CA is connected to. Unconnected, discharge can take up to 24 hours. The efficiency of the device (% value) tells how this time is modified. E.g. a 25% efficient device will run for 6 hours.