Perhaps not appropriate on this forum, but pertinent in this time of world energy crisis!
I have in the last week completed installation of a 20KW Solar system. It has been running for a week. It performs very well, but is is summer now, so that is not a good test yet!
We do have regular cloudy and very misty days here on the coast, and since commissioning on the 12th, we have had 3 days of solid mist with the rest bright and sunny.
At 10.00am during the mist days the system provided 4 to 5KW, while at midday with visibility approx 400meters in the mist, power was 6 to 7KW.
Batteries are 6x5KW/hr Lithium, dischargeable down to 20%. Discharge has been to 58% min at present – using oven, coffee machine, stove etc at night. Geyser is on a timer – 8to10am and 2to4pm, set to 45degC
As I have 3phase lathes, shaper, woodworking machines, etc, the system consists of 20KW of PV panels, with a possible 6KW more to come, a FRONIUS PV to 3Phase inverter ( 15KW) , an MPPT PV to 55VDC charger for batteries and three 10KW 3Phase inverter/chargers.
The latter take DC feed from batteries and when batteries are charged , DC feed from the MPPT battery charger (a 200amp/55V charger). These inverters also reverse roles and can charge batteries when needed.
The PV panels are in three strings – 2 of 600volt strings feed the Fronius 3PH inverter, and one string at 400volts feeds the MPPT charger.
Excess power is fed back into the mains grid.
Unfortunately, our power supplier is behind the times and cares nothing about our carbon footprint…They gladly accept my excess power ( some 10KW/hr for 6 to 8 hours at the moment..) and give me a credit for it – they won't pay me money for it, but credit against my use of their power. Also, they credit at 45% of the sold tariff only, so I have to give them two units to get almost one unit credit…AND any credit I have at the end of a month is lost..does not roll over.
2x600V strings on the ground floor roof.The 1x400V string is on the roof of the 2nd story
![pv_lower.jpg pv_lower.jpg](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
Power room – left 3x DC-mains inverters, then (grey box) Fronius PV to 3PH mains, then MPPT DC Charger and right side the main DB
![inverters.jpg inverters.jpg](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
3PH 10KW each DC to Mains inverter/chargers
![3ph inverters.jpg 3ph inverters.jpg](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
PV to 3PH mains @ 15KW
![3ph_pv inverter.jpg 3ph_pv inverter.jpg](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
MPPT PV Charger, 200amp
![mppt charger.jpg mppt charger.jpg](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
6 battery stack 5KW/hr each. Intelligent monitoring system in each pack.
Space above for the next 6 batteries..When I add the 4th PV string upstairs..
![6x5kw battery pack.jpg 6x5kw battery pack.jpg](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
10.5KW today at 10H00 this morning![pv_inverter at 10h00.jpg pv_inverter at 10h00.jpg](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
Control panel LCD at various times and loads..Still tuning and playing..
upper left is the national grid – minus numbers are feed into the grid from my PV system. Positive number would be from grid to me.Critical loads are house and workshop – AC loads are underfloor heating, currently off in summer.
![control panel.jpg control panel.jpg](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
I even ran my big 3ph mig welder from the system at 250amps – all it did was halve my power export to the grid!
There are 3ph power monitors on incoming/outgoing grid and on the critical and AC loads and all that data as well as power generated, PV power, battery condition, etc is logged and accessed by network interface. All very neat…