question

Hi

Well I presume your critical loads are on AC1 out

I presume that the grid Tie is on AC1 out

now in the ess there is a Grid setpoint setting plus a Min SOC setting

I set my place at a SOC of 80% and a grid setpoint of 7000w

so anything upto 7000 watts will be supplied by the grid. over that comes from the battery, When grid failure happens AC1 out still has power and its drawn from the batteries if there is not enough solar to supply it, however if the mains is off for a while and the SOC drops below 80% to say 70 then a priority grid recharge is done until it reaches the 80% again, there is a charge limit setting as well but I have not used that

Excess solar is then used to charge the batteries and if grid export is allowed then its export or you can turn grid export off with the fronius

I think this is what you want ????

You want to be able to ignore AC Input on Battery low for the Parallel Loads, when in this case the input is from 1) Utility or 2) ESS, I don't think there is an ESS option for this, what you can do is use a load transfer switch or a Contactor, you have 2 options

1) Transfer to No Input on battery low - Only requires a contactor and Relay, effectively the same as the Ignore AC Input VE Bus option on AC Out2 with the loads still showing in the AC Loads box, you stop supplying power to the loads

2) Transfer to Utility - Requires ATS and Relay (Utility = Before you meter the power), what this does is pay for the load on your utility bill on a battery low condition, the load disappears from the AC Loads box, you transfer the loads from "after the meter" to "before the meter"

(I think this is what you want ??)

Unfortunately from my previous investigation , this assist feature cannot distinguish between DC-battery and DC-PV. It will use what’s available

what I’ve done was setup a battery charge cycle from

sunrise to sunset (preventing any discharge), then run my general loads (water geyser, oven,) during this period and also charge the battery.

at night my water geysers are timed off,

in the morning the water geysers can use what’s left of the battery till SOC 30% before the charge cycle starts at sunrise.

this has worked pretty well for me and dropped grid usage to 20% of total usage and most grid usage is eirher before sunrise or sunset by the water geysers . Winter might change that but Johannesburg has no extreme weathers so it won’t be by much.