[Automation] Add signal for the battery charge level #144
Description
Even though SmartPower manages power much better than Automation can do, there is one use case which it can't.
From Steam:
I have an edge case where a gravity battery signal would be useful (along with an AND operator):
Water wheels are used for power generation but during droughts they drain from a reservoir. Wind power is not consistent meanwhile. If there is a significant amount of wind, water from a reservoir can be preserved by sensing a signal from a gravity battery that it is approaching a stored energy threshold, allowing for floodgates controlling reservoir flow to be raised. In combination with and operators, automated logic can be applied to automate floodgates relative to energy in a system for drought conditions - such as to never drop below a certain amount of water in a system (to ensure headroom for crop irrigation purposes).
A caveat here is that if the battery is not 100% charged, then such signal would be triggering every tick. It's not efficient, but given there should be not many floodgates automated this way, it should be fine.