Add energy storage (e.g. display SOC)

[martinjaeger]

As far as I can see, there is no possibility to show information about a battery system (for off-grid applications or for increased self-consumption).

I think it would be nice to show a graph of the State of Charge (SOC) in the "My Solar" app. Could be retrieved from a feed called "soc".

I'm currently only using emoncms.org, but will set up a local emoncms version soon and try to implement the energy storage integration.

Should I integrate it into the "My Solar" app or should I make another separate app, e.g. "My Off-Grid Solar"?