Constant grid draw when running air conditioner

[KTDN]

I recently had a 42kW Fox battery installed with a 10kW hybrid inverter. The system was AC coupled to an existing solar system (6.6kW panels and 5 kW inverter).

Today, I used my air conditioner for the first time since having the system installed. When watching the Foxcloud app, I noticed a constant draw of 2.0-2.5kW from the grid and only 1-1.5kW from the battery. I have attached a screenshot from the app after running the air conditioner for about 40-45mins

I was wondering why the system was drawing so much from the grid. I expected there to be temporary draw from the grid on start up but then the hybrid inverter would sense the increase load and increase battery output accordingly after which power drawn from the grid would decrease significantly.

[Will]

What is your workmode/scheduler set to?

[KTDN]

I have forced charge set from 11:00-14:00 to take advantage of free time period and forced discharge between 18:00-20:00 to take advantage of high FIT. Self use at all other times (see attached screenshot)

[evilbunny]

I noticed in the schedule you have forced discharge set at 3kW, do you have self use limited anywhere at about 3.5kW or someone entered the wrong limits in the inverter?

I only have a 5kW inverter with 42kWh battery stack, but the meter data doesn't show any ramp/response lag time and it's reported in 10ths of a Wh so I'd expect it would show something if there was.

There initially was an issue with grid/meter compensation not set and we were importing at about 40Wh/h, but is now set to -50W and we're now importing at most 15Wh/h but that's a limitation of using CT clamps I believe.

[KTDN]

Hi Evilbunny,

As far as I can see, when I go onto the inverter settings, it has 32A for max battery discharge current which I assume to be roughly 7.5kW. I am not sure what other settings I should be looking at.

[evilbunny]

I haven't touched mine but when I looked the lowest setting was 40A.

The limit I was referring to is in watts, grid export on mine is set at 5000W because that's all that's currently allowed by the distributor here.

The battery also monitors an AC coupled 1kW system but given the usual house load it's unlikely we'd exceed the limit with a 5kW inverter.

[KTDN]

I will need to have a look for that setting.

My system is also AC coupled like yours, monitoring a 5kw inverter. I would have expected the the battery to have been able to make up the difference given that the house load was 5kW, and incoming solar was 2kW so the battery should have made up the remaining 3kW.

I have also tried running the air condition later on at night when solar was not working however the system was still pulling a bit over 1kW from the grid.

[evilbunny]

My system is also AC coupled like yours, monitoring a 5kw inverter.

I actually have 2 systems, the first is a 1kW system thanks to Kevin '07 and a second 3kW system now DC coupled to the new inverter.

I would have expected the the battery to have been able to make up the difference given that the house load was 5kW, and incoming solar was 2kW so the battery should have made up the remaining 3kW.

That's how it's supposed to work, but incorrect limits, or incorrect CT settings might stop that happening.

I have also tried running the air condition later on at night when solar was not working however the system was still pulling a bit over 1kW from the grid.

You didn't mention about asking your installer or Fox tech support.