Adding storage to my Enphase system

[ChrisG]

I've got an XW pro with the mini PDP.
I run the entire house though the 60 amp breakers including the bypass breaker.
That's a lot of juice. You might want to examine your use to see if you need the 150 amp bypass.
The 60 amp breakers will support 11.5 kw continuous or 14.5 kw without tripping. Even running the central AC and cooking (oven/stove etc) the highest we've ever recorded is about 7 kw. But, our energy needs are modest, more modest than many.

The XW does open the internal relays when powered down or in standby mode.

But there are options to try. You might be able to use search mode or energy saver to limit power used when not actively making power.
Also, you can turn off the "inverter" or "charger" without powering down the entire unit. That would probably do what you want.

Goal is to have this running our cabin and deep freezers all of the time as well as other circuits when present. I want to make sure that if the inverter fails completely for any reason and grid is available, power will continue to circuits. Not sure of the XW can do that which is why I’m asking the question.

 

[GXMnow]

The transfer relays in the XW-Pro are normally open, so if it does fail or go dumb they will go open and you will lose power without an external transfer switch. I currently don't have an external transfer switch in my system. So if my XW-Pro fails, I would need to move a couple wires over. It would take me 10 minutes to put grid power back to my backup loads panel. The only bad thing would be if no one was here, the fridge would not get power.

If I was really worried and had a device I felt was truly critical while no one was here, I would have it on a separate UPS and/or an automatic transfer unit. I purchased a 60 amp rated cam switch to wire in as a manual transfer to power up the backup loads panel from the grid, but when I got it, I just don't trust those contacts for the load. They are an okay size, but the springs are not putting a lot of force on them. When I picture a 60 amp contactor, then just seem a lot tougher.

It has not been an issue yet. Any time something has gown wrong, the XW-Pro has been able to keep the relay closed. Even when my BMS sense lead failed and cut off the battery, it just went into AC Bypass mode with the grid connected to the backup loads panel.

 

[ChrisG]

The transfer relays in the XW-Pro are normally open, so if it does fail or go dumb they will go open and you will lose power without an external transfer switch. I currently don't have an external transfer switch in my system. So if my XW-Pro fails, I would need to move a couple wires over. It would take me 10 minutes to put grid power back to my backup loads panel. The only bad thing would be if no one was here, the fridge would not get power.

If I was really worried and had a device I felt was truly critical while no one was here, I would have it on a separate UPS and/or an automatic transfer unit. I purchased a 60 amp rated cam switch to wire in as a manual transfer to power up the backup loads panel from the grid, but when I got it, I just don't trust those contacts for the load. They are an okay size, but the springs are not putting a lot of force on them. When I picture a 60 amp contactor, then just seem a lot tougher.

It has not been an issue yet. Any time something has gown wrong, the XW-Pro has been able to keep the relay closed. Even when my BMS sense lead failed and cut off the battery, it just went into AC Bypass mode with the grid connected to the backup loads panel.

Thank you. So as long as the XW is on, even with battery cutoff, grid can still power the loads. Maybe I need two for resiliency.

 

[Shimmy]

That's a lot of juice. You might want to examine your use to see if you need the 150 amp bypass.
The 60 amp breakers will support 11.5 kw continuous or 14.5 kw without tripping. Even running the central AC and cooking (oven/stove etc) the highest we've ever recorded is about 7 kw. But, our energy needs are modest, more modest than many.

I'll have AC-coupled enphase downstream, so I know when the sun is shining it isn't a problem. I just need to either make sure my wife and I communicate during the day so we aren't charging the car, running the oven and dryer at the same time. My peaks that I hit are about 12kW/15kVA a couple times a month, so I am on the edge (unless I get a hot tub). I need to figure out some ways to shed load automatically and gracefully, but that is a project way down the list.

 

[400bird]

I'll have AC-coupled enphase downstream, so I know when the sun is shining it isn't a problem. I just need to either make sure my wife and I communicate during the day so we aren't charging the car, running the oven and dryer at the same time. My peaks that I hit are about 12kW/15kVA a couple times a month, so I am on the edge (unless I get a hot tub). I need to figure out some ways to shed load automatically and gracefully, but that is a project way down the list.

Well, I lied. Not everything goes through the XW. The EVSE is in the main panel, grid side of the XW's transfer relays. If I had a hot tub, I'd do the same thing, power it from the main panel.

 

[GXMnow]

One of the great features of the XW-Pro is that it can send a controlled amount of power back to the main panel. With my PLC controlling it, I have the XW-Pro providing the power needed to zero out my grid. Right now I have it limited to a maximum of 16 amps back to the main panel, since it is wired through a 20 amp breaker, but that has not been a limitation yet. Today was a prefect example. It was 100F (38C) outside, so my Central A/C had to run for almost 4 hours to keep the house comfortable. 2 hour of it was before 4 pm. My current program with the grid up keeps the XW-Pro in charge mode until 4 pm since I am on the cheap power still. It would not make sense to use battery power yet, I want to save it for the high rate time slot. So when I have big loads in the house, but solar still producing, I have it drop the charge current to just 5% (about 6.5 amps) so most of the solar can help run the loads, and I just have to buy a little from the grid at the low tier rate. But at 4 pm, even if the battery is not full, it shuts off charging. If the solar is making more than the house is using, I let it export to build up credit. But when the A/C is running, the solar is currently not enough to run it. I do need a few more panels. So at 4 pm, with decent sun shining still, the XW-Pro only had to supply the difference to zero the grid current. In this case, it was drawing about 40 amps at 54.5 volts from the battery, that works out to 2,180 watts. At the same time, the solar was also producing 2,800 watts. Add those together, and everything in my house, including the A/C was using 4,980 watts. And the grid power was basically zero.

The A/C cycled off for about 45 minutes after 5 pm. At that time, the solar was still producing 2,000 watts, enough to run everything in the house, so the battery power dropped back to zero, and I was even exporting a little, at the high grid rate. The A/C then cycled on again, but now solar was making less at 6 pm, and the battery voltage is a little lower, so now it pulled 60 amps from the battery at 53.3 volts. That is about 3,200 watts. Solar was still making about 1,200 watts, so it was now taking about 4,400 watts to zero the grid. It made it on battery and/or solar all the way past 9 pm, so we didn't buy any high time of use power yet again. The house will probably run on battery to nearly midnight.

My solar panel rinse off certainly helped. Production today, even in 100F weather made 28.9 KWHs while it made just 26.8 KWHs the day before. That is almost an 8% increase in total energy. Certainly worth 10 minutes on my roof with a garden hose.

 

[Shimmy]

I do need a few more panels.

Are you still planning on DC-coupling them? Will your logic on the PLC need to change at all when you add the panels?

It made it on battery and/or solar all the way past 9 pm, so we didn't buy any high time of use power yet again. The house will probably run on battery to nearly midnight.

Do you consider more battery in your future, or does what you have today satisfy your goals sufficiently?

 

[GXMnow]

Are you still planning on DC-coupling them? Will your logic on the PLC need to change at all when you add the panels?

Do you consider more battery in your future, or does what you have today satisfy your goals sufficiently?

Still undecided about AC vs DC coupling the new panels. There are certainly advantages both ways. DC coupled will start charging earlier in the morning and will also keep charge current going in all the way to sun down. It is more efficient charging the batteries as well.

The only down sides to going DC coupled are the cost of the arc fault protection, and if the battery does become full, the system will have to just curtail the power, it is difficult to export it.

With my current PLC programming, it only adjusts the XW charge and discharge rate to try to zero the grid. If I go AC coupled, it will just crank up the charge rate more and top up the battery faster. Once the battery is full, it will then export more power out to the grid. At 4 pm, I think I am safe from exceeding my 16 amp limit, unless I add more than 1,500 watts of solar. At that point, I may need to add a way for the PLC to turn off some panels to ensure I do not exceed my export limits.

If I go DC coupling, the DC solar can be set to charge the battery a little higher, if solar production exceeds consumption by too much. I still won't go past 95%, but even an extra 5% is another 1.8 KWH of energy into the battery. The last few days in this crazy heat, I have not been able to even get the battery to 90%, at 4pm, when I stop charging, the battery has only been getting up to about 80%. Getting to my usual 90% already needs another 3.6 KWH from solar. I had 6 sun hours today, so that would only need 600 watts of solar panels to cover that. But if my A/C is running this much, my current battery settings won't make it the full night to sun up, but it does not have to. I really just have to make it past 9 pm. Only getting to 80% is making it to midnight tonight. DC charging will also keep charging, or at least reduce discharging after 4 pm when the XW-Pro is inverting to help power the A/C. Where if I used AC coupling, it directly helps power it, and any extra just exports if the battery is full. And if I go with more Enphase inverters, it is all monitored in one spot.

My current settings are only allowing the battery to use 14 KWHs, going from 90% charged down to 50% charged. I keep the other 50% incase I have a grid failure. That energy will keep the house alive until sun up. And that is the one big advantage of the DC coupling. If I do have a long grid outage, and the battery runs too low, the XW-Pro will not start back up on it's own with just AC coupling. I have not had this happen yet, but it could. If the XW shuts down, then the microinverters have no grid and can't produce any power. I would need to power up enough of my network on batteries to change the low battery settings to get the XW o form a grid for the Enphase inverters to also power back up. My plan is to watch my battery level and turn off loads to ensure it makes it to sun up. I may be able to automate that with the PLC, but it is not programmed for it now. If I add DC solar panels, they will start charging as soon as the sun hits them, and once the battery voltage climbs just 0.5 volts, the XW will power up by itself, and then the AC coupled panels will come to life 5 minutes later.

I don't think I need more battery capacity at this time. I just don't have enough solar available to fully use what I have. I was only able to get 10.4 KWHs of charging power today. I need 14.4 KWHs of charging power to take them from grid support cut off to my full 90% setting. On hot summer days, my current 4,800 watts of solar panel is making over 29 KWHs, but the house loads with A/C running used 19 KWHs and some grid power today.

 

[GXMnow]

Finally got around to this, it has been a crazy 2 weeks here.
Here is the before picture of my panels after the brush fire one mile away.

That is mostly ash from the fire. It almost looked like a light layer of snow on the cars.
Here is what the production looked like on the Enphase app.

The upper line is last year, making 31.5 KWHs in the day. I think it was cooler, so it is not completely fair, but you can see the previous day (lower line) and that current day, bars, there down 3 KWHs from the year before.
After a quick rinse off with a hose, no soap or brushing etc., the panels now look like this.

Since it was mostly settled dust, it just flowed right off. If you look around the top of the panel pictures, you can see several of my neighbors also have solar panels. The ones at the top right on the image look almost as dirty as mine were.
This production graph is a couple days later, when we had a nice clear sky and only 90s, not over 100F. This is what the Enphase App shows now.

Production is right back to matching last year within 0.1 KWH. This is the biggest change I have seen from rinsing off the panels, but it was pretty extreme. That is about a 12% boost in production.
That big shadow you can see in the dirty panel pic is because I went up on the roof at 7 am before there is any real production, (or crazy heat) to clean them. In the clean pic, the roof shadow has reached the edge of the solar panels, but you can still see the shadow of my old antenna mast hitting 2 panels. I decided to leave it there as a lightning rod. It has it's own ground rod on the other side of the house.
That is only half my array, there is a matching 8 panels on the upper roof. I did about the same rinse off to them as well. I am a bit chicken to actually climb up onto the upper roof, but I can stand on a short ladder on the lower roof, and spray the hose onto the panels. I actually hold onto the old antenna mast to keep myself stable. We get some odd wind gusts here.

 

[el-guapin]

Nice Job!... Do you clean the panels on the regular?

 

[GXMnow]

I only do it when I can clearly see the power production is down. As you can see in the first plot from Enphase, something was wrong. And I knew that fire was close, and saw all the ash on the cars as well. This is only the 6th time I have climbed on the roof to do it. One more time I tried to just spray the hose up from the ground, but that didn't work very well.

One time I did use a soft brush with a long handle, meant for washing vans and RVs. It got them nice and clean, but it was a lot more work for virtually no improvement over just the good rinse.

 

[pvdude]

I've been observing the behavior of the system this Summer, after doing the "over paneling" Winter project.
It might be possible to get more out of the PV currently installed.
The existing, single MPPT charge controller maxes out @ 5300 watts.
There are 8760 watts of PV available, and room for more, should I find the motivation to get on the roof of the shed again....thus tempting fate for a fall.

Considering adding a second Conext XW MPPT 100A-600V Charge Controller,
and move one string of PV to controller #2.

This would allow the PV to support more of the load, avoiding what happens now, the inverters source the grid when the single SCC is maxed out:

 

[GXMnow]

pvdude,

Even a single XW-Pro should have been able to pull 6,800 watts from the DC bus (Solar + Battery) and then only need about 1.6 KW from the grid. I wonder if you have a limit set somewhere in the XW that kept it from pulling from the battery. When you have an 8,300 watt load, the XW inverters should be in grid support and run the load from the stored battery energy. The screen shot you posted shows 100% charge and just 0.1KW at the battery, was that going in or out though? Obviously the batteries should be able to help power the load. Check the time settings, make sure it was not blocking to use solar only.

It is obvious the inverters are inverting, as your solar is only putting DC to the battery bus. So what was keeping it from putting out more current from battery? In theory, your pair of XW inverters should be able to crank out 13,600 watts and pull up to 280 amps from the DC bus.

How long do you have loads like that running? I rarely ever get over 5,000 watts in my whole house total.

 

[pvdude]

Yes, I have it limited to 53 volts in the "Grid Support" config.
When the DC coupled PV output sags, the inverters go to battery, then to switch grid, after the batteries are down to 53 volts.
As the batteries are FLA, I don't cycle them much, but rather treat them as "standby".

Really wish I could find some BOLT packs, as you did, then it would be a different situation here!

When the grid is down, the inverters whack the batteries pretty hard, if all the loads (>8kw) need power simultaneously.
But grid down is when we shut things off that are not essential, so the batteries are not active for very long.

I was working in the shed a couple of days ago, oblivious to the big storm outside until the UPS started beeping as it saw the grid go down, as trees fell on the power lines in the neighborhood.
Heat pump, pool pumps, etc, all switched over to the inverter batteries, I heard the CLACK from the inverter relays operating!
As soon as it was safe to go outside, I started the generator, and switched the house over.
Batteries started recharging slowly from PV, due to thick cloud cover.

Some loads are scheduled, some are on-demand. I try to set the timers so as to correspond with peak solar.
Automatic water timers for the citrus trees cycle on @ 10am for 40 minutes, 1800 watts from the well pump cycling on and off during watering.
Two pool pumps (filter & booster).
Filter pump comes on @ 11am, off @ 4PM. Booster is on @ 2PM, off @ 3PM.
1500 watts each = 3000 watts.

House heat pump compressor is two-speed, it uses 2500 watts or 3700, depending on the heat load. Cycles very little until the outside temperature is in the 80's.
When it is close to 100˚f, the compressor shifts to high speed.

Shed wall AC uses 1800 watts, but I only turn it on if I am working out there.

I'll probably a second SCC, both to maximize PV output and for some redundancy.
Just have to move some things around...again.....to make room.

 

[GXMnow]

WOW!!! The last 3 days have been crazy. 100F outside, so the A/C is running, and the solar production is off from the temp. I have not taken a direct measurement, but 180F on the panels would not be exaggerating. Yesterday, I had to buy 16 KWH from So Cal Edison, but only 3 KWHs of it was at the peak time rate. The battery ran out a little too early. I think it will do a bit better today, it got the battery over 55 volts. It only managed to get it up to 54 volts yesterday. With the A/C running, my controller drops the charge rate to 5%, but keeps it charging until 4 pm. My solar is making 3,310 watts, about 1,400 watts is running the backup loads panel, including the fan in the furnace for the A/C. Another 400 watts are being used to keep charging the battery, and 1,500 watts are going back to the main panel to help run the A/C and any other non backed up loads. So I am buying about 1,600 watts now to run the rest of the A/C load. At 4 pm, it will stop charging, no latter what the charge state is. And then it will start inverting and zero out the grid power using battery as needed until the battery falls to 51 volts again.

The way I have the logic right now, after 4 pm, if the A/C does manage to shut off, any extra solar will export for credit at the higher rate. I have thought about putting it back into charge mode, but I think getting 51 cent per KWH credit is better than cycling that power in and out of the batteries. It just is not worth charging when the grid rate is that high. I gain nothing by charging and discharging at the same high rate. I only discharge and zero the grid at the low rate to reduce or eliminate the taxes and delivery fees. Keeping grid power close to zero using the free solar power is good, and I think selling my solar power at the high rate is good too, as long as I am not buying at the high rate. I might have to plug a bunch of numbers into a spreadsheet and see how it really works out. When my battery does run out, I should only have to buy a little at the low rate. I only ran out before 9 pm because of a storm front that knocked my base state low, and then 3 crazy hot days after that.

 

[400bird]

I think you're doing better than we are here.

Pack voltage topped out at 53.6 volts today, but we charged the car some this morning.

Yesterday was 54.8 volts

PGE is slower to update daily usage, the most recent day is Wednesday, it says I purchased 19.4 kWh. My system says 19.1 kWh, close enough for me.
That day was overcast and hot. I was buying power for most of the day with very little battery charging happening.
Ha, I just checked and only made it to 51.6 volts.

This old house needs better insulation and a more efficient AC unit.
But, prob still more PV.

 

[GXMnow]

Here is my battery charge graph for today.

The battery dropped below my 51 volt cut off the night before, and it didn't start charging until 8:15 am when the solar was putting out over 1,200 watts. That is 800 or so watts to run my house, and 400 watts to charge the battery. That is the minimum setting using the charge rate % control, 5% of 140 amps. It is a bit odd, but the voltage does jump up that 0.4 volts when it first starts charging, but I know that is not due to any wire resistance etc. I think the voltage actually recovers a bit since the inverter is not drawing any current, but it does not show the rise, until it produces charge current. It kind of does it on the discharge side as well. If you look at 5:40 pm, I think we used the microwave while the A/C was running. The spike to 80 amps shows the battery voltage drop 0.3 volts in just a minute. But when the load comes off, you don't see the voltage rebound. It just stays down until the voltage falls lower again. If you follow the curve before and after the quick jumps and drops, the curve fits together nicely.

This day, the A/C kicked on 3 times. 1:50 to 3:10, then 4 to 5:30, and once again, 7 to 7:30. The first time, it just dropped the charge current to 5% again. So the solar and some grid power was running it. But after 4 pm, it started with only needing 40 amps from the battery. As the sun went down, and the battery voltage fell, the current ramped to almost 51 amps before it cycled off. Then after 7 pm, there was no solar left to help, so it took 77 amps, ramping to 83 amps as the voltage fell. Now it's only 75 degrees out, so the A/C is off, and I am back to just 18 amps from the battery. At this rate, the voltage is falling at 0.4 volts per hour, it might make it to 1 am before it shuts down for the night.

As of 11:48 pm, the system shows that it charged 11.7 KWH into the battery bank, but has only discharged 9.5 KWH out, but the voltage is still 0.5 volt higher than it started, so it has another KWH to give before it hits cutoff. That will be about right, I lose about 1 KWH each time I cycle the battery bank. I should get about 10.5 out from the 11.7 that went in.

My son just got gaming on his Xbox, so the power from the battery is up to 1,100 watts. I just went out to measure at the batteries with my clamp meter. The old battery bank is supplying 12 amps, and the new battery bank is supplying 13 amps. My XW always seems to under report the DC battery current. It is showing only 22 amps total, not the 25 I got on my clamp meter. I know it is under reporting because it also shows it is outputting 1,200 watts AC. At 100% efficiency, and just 51.4 volts at the battery, it would need to pull 23.3 amps. 23.3 / 25 = about 93% efficient. That seems pretty close to reality.

 

[GXMnow]

And my solar actually did very good for such a hot day.

I am surprised it was able to hit 3,500 watts, but it started making some power as early as 6:15 am, and was still producing out to 7:30 pm. That is 13 hours of production. The Enphase inverters are simply amazing at getting every last watt hour out of the panels. My friends Solar Edge system take a full hour longer to start making power in the morning, and his panels are due south, mine are turned 20 degrees west. Of course, the extra morning hour is not a whole lot of energy, but it's something. My west heading is helping in the evening as his system also stops making power more than an hour earlier.

 

[GXMnow]

And I was just now able to download yesterday's usage graph from So Cal Edison. I am pretty happy with this.

That is only buying 7 KWH of cheap rate power on a 100F day. Not too bad at all.

Since the inverter was shut down from the night before, my house used 600-900 watts from the grid on the cheap rate from midnight to 7 am as the sun started to make power. From 8 am to noon, I have it push as much as I can to the battery, while making sure it exports a little. If I charge even 1% faster, it might take from the grid, I can't cut it any closer. Between 1 pm and 3 pm is when the A/C ran. Since it is low rate time, I let it pull from the grid. But since solar was still producing well, I only bought a little over 2.2 KWH then, and even while the A/C is running, I still had the battery charging at 400 watts. The A/C ran a bunch more from 4 pm to 9 pm to keep the house comfortable while it was still close to 100F outside, but the XW was supplying all of the power needed to run it from the battery. The maximum I saw from the battery was 82.86 amps at 52.48 volts. That works out to almost 4,350 watts, but I know that reading is a little lower than reality, so let's call it 4,500 watts from battery. That is still just 2/3 of the rating on the XW-Pro inverter. That was at 7:30 pm. That was running everything in my house, even the A/C at full power, and I was exporting 20 watts to the grid. I think I have a pretty efficient house.

The extra export in the 5pm and 6 pm hours is from the time the A/C cycles off and the solar is still making more than the rest of the house needed, so it exports at the high rate. The tiny export from 8 pm on is just me slight overcompensation to ensure I am not importing. I think I have it at just 20 to 40 watts of export now. The export current is being set in milliamps. That is much finer control than the 1% charge current steps.

This time, the battery did stay running out to about 1:30 am. And it started charging at 8:13 am this morning. It is also a bit cooler today, still predicting 99 at 2:30 pm though. Hopefully it can recover a bit. It would be nice to see the battery bank get over 56 volts again. To truly zero out the grid in these conditions, I need to produce another 8 KWH from solar. The battery has the capacity to store that. I was getting right about 6 sun hours out of my existing panels, so to get 8 more KWHs, I really only need another 1,400 watts of solar panels. My plan is to add about 2,000 watts. And putting them flat on the garage will actually produce better than the sloped roof in the summer, when I need the power the most anyways. My only concern is I need to be able to limit export to 16 amps if the battery bank becomes fully charge close to solar noon. With my minimum base house load of just 600 watts, I could theoretically hit 19 amps to 20 amps with 2 KW of added panels.

 

[mizermizer]

And I was just now able to download yesterday's usage graph from So Cal Edison. I am pretty happy with this.
View attachment 100022
That is only buying 7 KWH of cheap rate power on a 100F day. Not too bad at all.

Since the inverter was shut down from the night before, my house used 600-900 watts from the grid on the cheap rate from midnight to 7 am as the sun started to make power. From 8 am to noon, I have it push as much as I can to the battery, while making sure it exports a little. If I charge even 1% faster, it might take from the grid, I can't cut it any closer. Between 1 pm and 3 pm is when the A/C ran. Since it is low rate time, I let it pull from the grid. But since solar was still producing well, I only bought a little over 2.2 KWH then, and even while the A/C is running, I still had the battery charging at 400 watts. The A/C ran a bunch more from 4 pm to 9 pm to keep the house comfortable while it was still close to 100F outside, but the XW was supplying all of the power needed to run it from the battery. The maximum I saw from the battery was 82.86 amps at 52.48 volts. That works out to almost 4,350 watts, but I know that reading is a little lower than reality, so let's call it 4,500 watts from battery. That is still just 2/3 of the rating on the XW-Pro inverter. That was at 7:30 pm. That was running everything in my house, even the A/C at full power, and I was exporting 20 watts to the grid. I think I have a pretty efficient house.

The extra export in the 5pm and 6 pm hours is from the time the A/C cycles off and the solar is still making more than the rest of the house needed, so it exports at the high rate. The tiny export from 8 pm on is just me slight overcompensation to ensure I am not importing. I think I have it at just 20 to 40 watts of export now. The export current is being set in milliamps. That is much finer control than the 1% charge current steps.

This time, the battery did stay running out to about 1:30 am. And it started charging at 8:13 am this morning. It is also a bit cooler today, still predicting 99 at 2:30 pm though. Hopefully it can recover a bit. It would be nice to see the battery bank get over 56 volts again. To truly zero out the grid in these conditions, I need to produce another 8 KWH from solar. The battery has the capacity to store that. I was getting right about 6 sun hours out of my existing panels, so to get 8 more KWHs, I really only need another 1,400 watts of solar panels. My plan is to add about 2,000 watts. And putting them flat on the garage will actually produce better than the sloped roof in the summer, when I need the power the most anyways. My only concern is I need to be able to limit export to 16 amps if the battery bank becomes fully charge close to solar noon. With my minimum base house load of just 600 watts, I could theoretically hit 19 amps to 20 amps with 2 KW of added panels.

For the last few weeks I've been reading and trying to catch up through the 47 pages of this post, lots of reading. I'm preparing to add storage to my existing 4kW IQ7 solar system. Question: I seem to recall you also have about 4kW of panels, is that 16 amp limit spelled out in your NEM agreement, or is it a breaker thing? Oh by the way, you are really getting your system dialed in!

Maybe I could ask differently: @GXMnow does your NEM agreement specify a max number of daily/monthly KWHr export to the grid amount? or a instantaneous Watt export number? I'm trying to get my NEM agreement (SDG&E) to see what mine says. I think I'll have to call SDG&E.