Sol Ark 12k with Fortress Eflex max and grid sell

[mattwil]

In Hilo, Hawaii. I Have an existing Sol Ark 12k with with about 10k of panels. It was to offset daytime loads and sell excess to the Grid. After HECO changed to a time of use format the electrical bill went up substantially. So we added 3 fortress 5.4k Eflex max. We have no critical loads attached and the CTs are on the line side before the inverter and panels

This is how I hope the system can operate.

During daytime use PV to cover loads and excess charges the batteries till full. Once full all excess goes to the grid. Also during the day if the PV is not covering the loads the batteries kick in if the have enough charge.

At night with the pv off the batteries cover the loads untill they are discharged to 20٪ and then the grid kicks in.

Right now it seems like the batteries do not cover the loads if the PV is short during the day. I am going to check tonight if the batteries cover the night time loads.

Currently have
Grid sell checked and everything else unchecked. Loads first checked
Grid charge unchecked

Do I need to have time of use setup?

Thanks

 

[DIYrich]

In the limiter setting, make sure all numbers are 20%. Although, I would charge from grid during the day when cheap and run off battery at night when more expensive.

 

[mattwil]

If 20% is put across all time frames. Will the excess PV still charge the batteries before exporting? Will the batteries sell to the Grid? I really just want the batteries to cover as much of the loads at night as they can.

 

[DIYrich]

You have 300ah of batteries, and a max charge from the inverter of 185a.
Assuming TOU rates (shift and save): Peak 64 cents: 5pm-9pm, Overnight 43 cents: 9pm-9am, Daytime 9a-5p 21 cents.
Assuming Sell rates: Peak 23 cents: 5pm-9pm, Overnight 14 cents: 9pm-9am, Daytime 9a-5p 10 cents.

At 14 cents, it does not make sense to discharge your battery to the grid before going into the daytime.

Suggested setup:
Check "time of use"
Following table: Time, Power, Batt, Charge, Sell
12:00 am, 10000, 20, uncheck, uncheck
9:00 am, 10000, 20, uncheck, uncheck
3:00 pm, 7500, 100, check, uncheck - this will topoff your batteries before end of cheap rates
4:55 pm, 10000, 20, uncheck, uncheck go back to self consumption

When sell is unchecked: Priority of solar is: Load, Battery, Grid
When Charge is unchecked, the 12k will use battery down to Batt %
When Charge is checked, the 12k will use the grid to charge the battery up to Batt%
So, between 5pm and 3:30 pm, the system will run off solar and battery.
At 3:00 pm, the 12k will charge the battery from grid up to 100%. 7500w is 0.5c, and takes about 2.0 hours if fully depleted (no solar - rain?)
At 4:55 pm, the system stops charging battery from grid (4:55 just in case there is time difference between inverter and TOU meter) and starts self consumption again.

If you get enough spread between daytime buy rate, and overnight sell rate, then you can add:
8:30 am, 10,000, 20, uncheck, check
That will export your battery for 1/2 hour down to 20%

 

[mattwil]

@DIYrich thank you for that explanation, that clarified alot. I Wish the manual would explain it that way.