We had a lot of rain not too long ago, so all of the panels had a good rinse and looked very clean. The amount of dirt settling on them should be fairly equal. As I said a few posts ago, they look a bit dirty, but the production was excellent in good light conditions. The SilFab panels used to always out produce the garage array in any conditions when I had the BougeRV charge controller. It's appears that the Victron MPPT routine is just that much better in poor light conditions. The Garage array is also rotated closer to due south than both the SilFab Enphase array and the Hyundai pergola arrays which are about 20 degrees west. If we have better sun in the morning up to noon, then that benefits the garage array. We did have a little of that. The garage array is also at the lowest tilt angle which also helps for the first 4 hours of sunlight. The tilt between the roof and pergola is only a couple degrees and they are at the same heading southwest. The Enphase roof system does get a little more morning shading due to the second floor shading part of the lower roof array until 9:30 am. It also shades the back half of the garage array. The pergola has almost no morning shading besides a tree which clears before 9. But due to the clouds making all the light very diffuse, all of the Enphase panels produced nearly identical energy. The lowest panel which does get some palm tree shade still produced 163 watt hours and the highest produced 189 watt hours. That 189 watt hour panel is also the same one that always over produces. I think they gave me a single 350 watt panel while the rest are the 300 watt version. It even has a slightly different bluish grey shade from the others. That is a 15% difference, all the rest are within 10%, and many are within 5% at 170 to 179 WH. With the Victron string array, I only have the total power, so no idea if any panels are under or over producing. But I am very surprised to see the mix of 10 x 100 watt NewPowa panels and 5 200 watt BougeRV panels producing better than the SilFab panels. Even with shading and angles, I never expected them to hit 24% more effective sun hours. That was huge. I have to think it is just the overhead of the Enphase inverters just chopping off a bit of the very little power available. Think of it as a static draw on the system. If they draw 2 watts each, that is 32 watts to break even. As the power goes higher, that loss seems like nothing, but at just 300 watts from the whole array, it is more than a 10% loss. Of course, the DC systems will also see that loss when the energy is taken from the battery and inverted to run the house.
I did chicken out last night and I put the system into a minimum 5% charge rate which is 7 amps or about 400 watts. It's not a whole lot. The battery voltage only climbed from 51.25 to 52 volts in 7 hours. That pulled about 2.8 KWHs from the grid. On the SoC graph for the NMC cells, that is about 40% SoC to 48% SoC. 8% of my 36 KWH capacity would be 2.88 KWHs, so this is a pretty good estimate. This is also in the flattest part of the charge/discharge curve, so it is also the least accurate SoC estimate. I was surprised to see it come out that close. Charging at 7 amps is a little less than 0.01C charge rate, so it is basically a resting voltage measurement. The graph I have shows the curve for 0.25C charge and 0.25C discharge rate voltage. The resting voltage is about halfway between them.
I am going to stop the manual charge before I leave for work, but I will leave charging enabled. If the Enphase system ends up making more than the house needs, the PLC will put it into charge mode to use that energy instead of letting it export to grid.
The sun is still not up, no solar panels near me are making any power. Very few people around me have batteries, so I doubt anyone is pushing any power to the grid. My house is currently pulling about 1,200 watts from the grid with base load and the 400 watt charge going. But my grid voltage is already a bit high at 244.8 volts. I am watching it to see if it steps down at all. I really think that is what is causing the XW-Pro to go into oscillation. I found a decent ac voltage and current data logger for under $200 that will record once per second for 36 hours. And wow, I just caught it, the voltage just dropped 1.5 volts to 243.3 volts. My LED lights even did a tiny flicker which made me go look at the Schneider data page. Looking at the battery graph, the charge current also dipped from 7.01 amps to 6.95 amps. So it did respond and it had to adjust to follow the voltage change. This happened a bit before 6 am which falls in line with when I have had it go unstable. I sent this data to the Schneider tech. I hope they can simulate this in the lab.
