I couldn't find the answer on the forum, so I'm answering it for the next person to look :-)
In an ESS with an energy meter, if the connection to the meter fails, the system will not charge the batteries at the scheduled charge time even though you are still connected to the grid.
If you experience this, you can simply swap Settings->ESS->Grid Metering to "Inverter/Charger". This will allow the batteries to charge and at least supply their energy to any connections on the inverter a/c outputs. Once you get the energy meter back online, swap the setting back to "External meter", and the inverter will again also balance out energy use on the A/C input side as well.
[In my case this was an ET112 connected via a cat5e cable, which was failing intermittently - oddly, especially on cold nights. I replaced a section of the cable and all is good again.]
Paul.
