solar panel output

[georgemager]

I have a 4Kw solar array. With temperature coefficient it can produce 4.3 kw at times.
I have a Radian 4048 inverter. Can the inverter be damaged if production exceeds 4kw?

[pss]

No. The charge controller is concerned with the Voc of the array and accepts up to 150 volts. The array will only output the amount necessary to charge the batteries and supply the loads. If the load is not in excess of 4000 watts, you will be fine, and the Radian can produce higher outputs for various periods of time. But again, the PV is used to charge batteries, the batteries power the inverter. The load determines how much the output of the inverter will be, and if oad exceeds capacity, the inverter will shut down or breakers trip.

[georgemager]

OK. Thanks for that!
I am grid-tied and send excess power back. Although I can produce 4.6 kw, only 3kw goes back on grid. I either use the rest or lose it.
At night, I use electric floor heat and charge an EV. (Volt). So my loads can exceed 6kw. I assume that is coming from the grid as a pass-thru
from the inverter. I also compensate heat with a wood stove. I also charge EV during the day when I can.

[pss]

You ought to have your mate3 programmed to show you what is being taken from the grid.
In the dark, you could use Minigrid or Backup to charge your batteries and run the loads, then go to Gridzero at sunrise to supply loads and charge batteries.
Backup can charge batteries to 100% and keep them there while running loads, Minigrid can charge batteries and blend battery and grid power. Gridzero only charges from PV charge controllers, but can blend PV and grid power to supply loads.
Figure out what is best for you and program the Mate3.

[Megunticook]

If George is selling power to the grid during the day, wouldn't he want the inverter in grid-tie mode rather than Gridzero during those hours? Assuming he gets some sort of net metering credit.

I would think backup mode at night and grid-tie during the day would be the way to go.

[pss]

Yes, if he is selling, but there is no point in selling if your batteries are not fully charged when the sun goes down. Also, his supposed loads including an EV are large relative to the size of his arry. But yes, he has to be grid ties to sell. Maybe set up grid tied only during a few peak hours in the daytime.

[georgemager]

Great info. Thanks
Batteries are backup. I am net meter and time of use and grid tie. So winter on peak is .11kwh(5pm to 9pm
Off peak is .06. EV charging is .05.7 kwh 10pm to 6am. Then back to .06kwh till 5pm.
Hope this is best sceneriao.?

[Megunticook]

Not sure you have the FDNC battery monitor, but with my system it switches from backup to grid-tie mode at dawn, and all current from the array goes into recharging the batteries until the parameters are met, then selling begins. Since my battery bank is strictly for grid outages, it generally starts the day at 98-99% full and by 8am or so it's at 100% and I'm selling power back to the grid.

Referring back to your original question, George, you can limit the current output of your charge controller if you find your array is overpowering the inverter while you're selling (assuming you have a FlexMax).

[georgemager]

How is backup better at night?
I will check. I have an fm80, so if I can figure how get inverter to switch from backup to grid-tie,that would be best?

[pss]

A couple of things first.
I noticed your battery bank is 48 volts, but your strings are configured for only 60 volts.
It is advised to have charge controllers voltage 18-25 volts above battery bank voltage. A fully charged 48 volts bank may be over 58 volts. Secondly, equalizing battery bank may be up to 64 volts.
You may wish to reconfigure your strings.
Backup will charge batteries to 100% and they stay there as all load is then supplied from grid or generator, not batteries or PV.
Where I am, we are on tiered rates, $0.23 up to about 350 kWh, then $0.43, then up to $0.47! Our system makes a lot of dollars every day.

[georgemager]

OK. Thanks. Let me digest this and pencil it out.

[Megunticook]

I use the backup mode at night instead of grid-tie so the inverter wakes up and starts supplying power if the grid goes out at night. It wasn't doing that when in grid-tie mode at night. In the MATE look for "Flextime" settings where you can schedule different modes of operation for the inverter according to a 24-hour clock.

[pss]

On my system, I use Gridzero from 7 AM until 6 PM. My batteries start off at about 77% and are fully charged by PV and at 6 PM are at about 97%. At 6 PM I go to backup mode. This keeps the batteries charged at 100% and supplies the PM loads which are usually just TV and lights. Then, at 11:30 PM, I go back to Gridzero. The batteries, which start out at 100% then discharge down to about 77% and then the PV cycle starts again. During the daytime now, my system is putting out about 27.6 kWh/day with ambient temps in the low 70's and sunshine almost all day every day in San Diego county. One of the advantages to me of BACKUP vs. MINIGRID is that minigrid uses the

I do not have enough PV power to get more than about a 300 - 350 amp charge in a day plus supply the loads. My pool filter and solar pool heater use about 2500 watts for 8 hours, then washer, dryer, lights, TV, heater or AC, fridge, etc. all add to the daily load. My plan is to add another array and charge controller in a year or two.