Forcing pv to run when generator is live

[keepsake]

Have a 21kw Isuzu 1800 rpm diesel generator in Florida.
Have house loads of anywhere from 3 kw to 25 kw.
Would like to adjust the grid codes on a Sunny Boy inverter to allow it to lower my fuel consumption.
Plan on constantly monitoring the house load, every 3 seconds.
Would allow so much pv into off-grid loads with genset output. And always keep the pv production about 3 to 5 kw UNDER the house load.
So lets say at house load of 10 kw, allow two strings of 2.5 kw to feed. If load goes up to 15 kw, allow 3 strings. Load goes under 5 kw, only one string, etc
Always leaving between 3 and 8 kw for the genset to push out.

Thoughts ?

 

[keepsake]

In the inverter you allow freq range from 55 to 65 Hz
Wider voltage range
And 5 seconds lockout not the utility required 300 second.

 

[keepsake]

An aside ... anyone having issues with instant hot water heater loads affecting pv inverters ?

 

[schmism]

I dont understand your setup/use case.

But I could napkin math some numbers for a normal solar setup.

lets ballpark 7.5kw @24hrs = 180kwh

so say you had 280ah LFP cells @48v = 13kwh. 4? sets of those for a battery investment of 53kwh @ a cost of like $8K.

21kw generator is like 1.5gal/hr at 13kw so to charge the battery from dead is like 4 hrs of run time. @$3/ga thats ~$20. So to pay for a 8kw battery only takes 400 days.

that battery pack 53kwh/7.5kw avg = 11 hrs so might make it through most of the night.

rooftop runs the house, if roof doesnt make enough the battery supplements, if the roof makes more it charges the battery, if the battery runs low the generator fires up and charges the battery shuts off. You never have to throttle the the roof unless the battery is full, at which point the generator isnt running so its a mute point.

Note, the napkin math above is balparkish (thus napkin math) things like ... how DO you charge 270amps (13kw) into a 48v pack is a real question.

 

[keepsake]

You got the concept wrong. If the generator is always running, and the pv supplements the energy during daylight hours, most of your math is non relevant. At this time there is no hybrid inverter, just trying to get an inverter to sync to generator and allow generator to use less fuel during those hours.

 

[keepsake]

iow -- using the genset AS the hybrid inverter.

 

[keepsake]

I can report that this is working very well. Inverter pv limits are set by the automation and allows Generator load to approximate half the load at all times. i.e. Load 8000w, two pv inverters set to limit at 2000w, so genset sees 4000w.