Bad days for Solar Production.
- Thread starter Nobodybusiness
- Start date
Zwy
Emperor Of Solar
Yep, 20 minutes long. Cloud edge effect had over 8700W off 8.4Kw of panels at the beginning of the 20 minutes and the end.
James Getman
New Member
Nobodybusiness
Solar Sponge.
So glad I don’t have to deal with that but cloudy days are just as bad.
timselectric
If I can do it, you can do it.
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Made 39kwh yesterday.
4kwh today. lol
4kwh today. lol
Nobodybusiness
Solar Sponge.
Yea tot
yea today was all clouds.
timselectric
If I can do it, you can do it.
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It was raining before I woke up. And it hasn't stopped all day. I'm surprised that I managed to make 4kwh.
Zwy
Emperor Of Solar
No snow on my panels at 65 degree seasonal tilt but no sun was getting thru.
One would think a big cold front coming thru would be followed by some clear skies but this year it has been endless clouds. I received an email from my utility that my electric Kwh increased by 34% in December from November. January so far has been worse.
timselectric
If I can do it, you can do it.
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March can't get here soon enough.
RussNM
Solar Enthusiast
Reading this thread makes me happy that Im in New Mexico!
Brucey
Solar Wizard
What degree of tilt are you running?
B-Mod
Solar Addict
No sun here since December 29th. Yesterday was the closest to any sun with a bright cloudy ski, made 44.2kwh. Today snow, 2.9kwh.
sunshine_eggo
Happy Breffast!
@sunshine_eggo = jackass... battery in an uninsulated shipping container... Lost over half my available PV for the day but managed to get back to my daily peak of 75% SoC on the NMC bank (6.8kWh harvested):
Going to be warmer and sunny tomorrow, so it won't look as bad.
I have a 1500W space heater in the container that actually does almost no heating (container walls are about R 0.002), BUT pulling ~35A from the battery can warm it up a degree or three.
Going to be warmer and sunny tomorrow, so it won't look as bad.
I have a 1500W space heater in the container that actually does almost no heating (container walls are about R 0.002), BUT pulling ~35A from the battery can warm it up a degree or three.
Brucey
Solar Wizard
Which temp sensor are you using for the low temp charger disable?@sunshine_eggo = jackass... battery in an uninsulated shipping container... Lost over half my available PV for the day but managed to get back to my daily peak of 75% SoC on the NMC bank (6.8kWh harvested):
View attachment 188655
Going to be warmer and sunny tomorrow, so it won't look as bad.
I have a 1500W space heater in the container that actually does almost no heating (container walls are about R 0.002), BUT pulling ~35A from the battery can warm it up a degree or three.
sunshine_eggo
Happy Breffast!
Batrium.
The behavior is a function of the Batrium. Critical battery error (0°C) = open the circuit to the MPPT cut-off. Charging error (1-5°C) sets charge current to 0A allowing PV to power loads. It actually pulls from the battery slightly, and load changes can cause very brief charging, but these Panasonic EV NMC cells are supposedly good down to -20°C for charging AND my peak charge rate is all of 0.11C, so I'm not sweating a few amps that sneak in for a second or two before the GX throttles the MPPT.
I only have 7 temp sensors...
BMV-702
2X Quattro sensors.
3X Batrium sensors.
SBS (not compatible with VRM - was my quickly solution for FLA temp comp back in the day).
Well things went to crap tonight and I thought maybe misery loves company, so I took a look. 1.15 kWh out of my 21 REC 400W panels. Meh.I didn't even bother looking at my (lack of) production today
Nobodybusiness
Solar Sponge.
I was looking at your system tag.
Do you use the Schneider to form the grid?
Does it have the ability to phase shift the iq7s?
Use the iq7 to feed into that
or
use the iq7 to reduced grid usage and the Schneider for backup power when grid down?
James Getman
New Member
30 degrees of tilt.
This has to be a factor of temp since mine are at 60° and snow has not slid off since it would be staying below 10°F air temp.
GXMnow
Solar Wizard
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- Jul 17, 2020
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I am still grid tied but setup for backup off grid.
The Schneider XW-Pro input is connected to the grid with the 20 amp breaker in the main panel where my Enphase solar used to go. The output of the XW-Pro now feeds a sub panel. The Enphase solar is now in the sub panel along with my backup loads circuits. The usual basics are in the backup panel. The fridge, furnace, some lighting, the computers, and a few other important things.
While the grid is up, the Enphase system essentially works in parallel to the XW-Pro. I have a 3rd party PLC controller that monitors the energy production and usage and sends commands to the XW-Pro to zero the grid power. If the Enphase is making more power than I am using, it puts the XW into charge mode and adjusts the charge current to zero the grid. When the sun goes down, or any time solar is not meeting the energy usage, the PLC commands the XW to export enough power to again zero the grid current. Without the PLC, the XW can't charge on it's own from the AC coupled Enphase inverters. It is a shame the XW is such a solid piece of hardware, held back by lacking firmware. But the Modbus controls are very good, if you can program it. And yes, it even pushes current back to the main panel to cover the non backup loads as well. On good solar days, when the battery becomes full, The XW has to stop charging the battery. At that time, the extra power from the Enphase system still flows back through the XW and out to the grid and I get credit for that export just as I did before the XW was installed. Yesterday, I used zero grid power and exported a bit over 3 KWHs to the grid.
If (when) the grid does go down, then the XW-Pro does form the grid and power the backup loads panel. This does not happen very often here, and never for very long. I should do another test as Enphase has updated my firmware again. Last time, a few of my iQ7's refused to stay running and reported "grid instability". The XW also has a firmware update to improve stability, but I have not loaded it yet. Running my backup loads for 2 hours, my battery bank only lost about 5% SoC so I was doing fine. The worst issue with my setup would be if we were off grid long enough for the battery bank to run down to shut down. The system could not self start again.
To get around the off grid charging issue and the dark start problem, I added the 2,000 watts of panels with a DC charge controller. That will always just push power to the batteries when the sun shines. So even if the Enphase inverters are not happy, I will still have some power coming in, and it can charge the battery enough to make the XW power back up, even if no one is here.
On days with good sun, the Enphase panels power the house while the sun is up, and the DC panels charge the battery for power at night. And that would work even without my PLC controller now. But the PLC also forces the XW to charge when the Enphase system makes more than I need during the day. Storing the power rather than exporting it for half credit. If I was designing the system from scratch, I would go more DC coupled as it is more efficient for night time power. I lose about 1 KWH per day in extra loses with the DC to AC then AC back to DC, and finally, DC back to AC yet again. The DC panels directly charge the batteries, and the the XW just does one DC to AC conversion when I need the power.
Nobodybusiness
Solar Sponge.
Interesting setup.
Looks like you have managed to overcome the deficiencies to your advantage..
GXMnow
Solar Wizard
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I have it dialed in pretty good. Since I started with a basic grid tied system, I have a net energy NEM 2.0 agreement. So I am allowed to push up to 16 amps to the grid and up to 900 KWHs a month. I never come anywhere close to those numbers. Here is the hourly data from So Cal Edison for Thursday Jan 11.
From the night before to the 6 am bar, the house was running fully on battery, and I have it biased a bit so I was exporting about 20 to 60 watts. As the sun starts to come up, the export increases a bit. The first step in the XW is 5% or 7 amps of charge current. And the steps are 1.4 amps (1%) from there. I have it hunt to keep about 100 watts exporting when the sun shines. On that day, the XW hit it's bulk charge limit in the 1 om hour and the rest of the extra solar started exporting. It averaged nearly 1,500 watts of export for that hour. But at this time of year, you can see the power was already falling off. Exporting 750 watts for the next hours, and then just over 300 watts for the 3rd hour. 4pm to 9 pm is the highest rate. I have it export a little more, I think it holds about 40 to 60 watts of export while the system covers all the loads inthe house. After 9 pm, it drops back to the 20 watts. At the end of the day, I net exported 3.29 KWHs. For comparison, here is what the battery did over that same day.
The green line is the current. The narrow 4 cycles per hour is the furnace trying to keep up with this cold weather. The wider 1 cycle per hour is the refrigerator. The spikes going down are the microwave oven and hair dryer. The smaller loads like the lights, TV, computers barely even show. In the summer when the central A/C kicks on, you see a much bigger current step, but the XW is still able to cover it.
The blue trace is the battery voltage. My battery bank is Li NMC cells, so the voltage is actually a decent reading of state of charge. I revert to grid power if the battery falls below 50.5 volts. On this day, it never went below about 51.4 volts. Below 51 volts, the slope gets even shallower, so it takes even more watt hours to drop each 0.1 volt. At 1 pm, the XW saw 56.7 volts and went to absorb and then "no float" basically standby mode. That is where the Enphase inverters where exporting to the grid. The voltage is still climbing from the charge power coming from the DC system. The DC charge controller will push the batteries as high as 57.6 volts, but the days are just too short still to hit it. As the sun went down, you can see the discharge current return. It takes nearly an hour for the battery to actually start discharging though as the Enphase panels were helping to power the loads, and the DC panels were still feeding current to the batteries. But after 5 pm, we are basically running on battery until the next morning.
In summer, we make double the solar, but we also use a lot more trying to keep cool.
JLD
New Member
I have just under 29kw of panels. A portion of this is to a 7.7kw and 5kw SMA over paneled grid tied inverters selling back, each on a transfer switch.
That way if it is overcast or bad weather I can ac couple one or both inverters alongside my three cc to make up what needed to fill my 120kwh of battery.
That way if it is overcast or bad weather I can ac couple one or both inverters alongside my three cc to make up what needed to fill my 120kwh of battery.
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