Adding storage to my Enphase system

[GXMnow]

While looking at the Enphase logs with my breaker trip, I saw something I neve did before.



This is the very end of the logs after grid was restored and everything was going back to normal. All 16 inverters reported all of the clear messages for AC frequency high and low, Grid Instability etc. But the last 2 entries caught my eye.

"AGF Profile CA Rule21 201902 VV VW FW/01.02.08.00 deactivation okay"
I am assuming it detected it was off grid and switched to an off grid mode of operation, so it stopped using the Rule 21 profile. But it is odd the deactivate and then reactivate posted in the same minute.

Earlier in the logs, I found the exact point I messed up. As the power to the Envoy was lost at the same moment, it was not able to log the actual power fail events. But it did log the system starting back up while the XW was running in off grid mode. At 11:33 am it has this message.

"translation missing: en.env_enl_api.event_type.emu.lvrt_ac_loss_event"

Then all 16 inverters report "Grid Instability" "AC Voltage Low" "DC Power Low" "AC Frequency High" AND "AC Frequency Low".

I like this one
"AC Voltage Out Of Range - Phase 1: Set"

I never see a "Phase 2" but it looks like they newer firmware takes multiple steps to try and recover from grid issues. I have to say, the system handled this situation very well.

Had I fully understood what happened, I would have taken a bit more time and recorded more data before getting it back on grid. I only had about 100 watts running from grid, all the main loads in my house were running just fine off grid, except of course I crashed 2 PCs and my Dish Network DVR had to reboot and reacquire the signals. My router and internet came back up pretty fast, even as it was running off grid.

In the Enphase logs, the grid loss was at 11:31 and it looks like I restored the grid power connection at 11:49 am. The time in the Schneider Gateway is showing 2 minutes faster, so that would be 11:33 and 11:51 am.

At 11:33 the XW goes to pulling 10 amps from the battery to power the 600 watts of loads in the house on the backup panel. But then it swings to charging at 20 amps as the Enphase inverters start producing power into the backup panel at 11:34 much earlier than 5 minutes. So this must be an off grid mode. But again, my battery was full. So the next minute, the charge current is down to 10 amps for 2 minutes. Then the current ramps down, through zero and over the next 4 minutes, it settles in at 10 amps of discharge again, running the backup loads with no help from the Enphase system. I must assume this is when the frequency went high enough for them to just stop making power completely. This holds steady for 11 minutes to 11:51 when I turned the grid side breaker back on. The XW saw the grid return, so it did what it always does and went back into charge mode at the 35 amps set by my PLC. But the battery voltage was still high enough, it went back into No Float after 3 minutes.

From 11:56 all the way to 6:32 pm, the XW-Pro just sat in Pass Through again with the Enphase back powering the house and exporting all it's excess. From 6:32 until 7:11 the solar dropped off and the XW ramped up from battery to cover the loads. All as it should work again.

At 7:11 PM all the Enphase inverters started reporting DC Power Too Low as the sun goes down behind the palm trees. So it's running on battery until sunrise tomorrow.

And even with the Enphase system being shut off for a bit and tanking the production for 20 minutes, it still produced 30 KWHs for the day. That is the first 30 all year. The Victron only did a bit over 8 KWHs as it had to go into float with the battery being full so quickly, even after the bad production yesterday.

Here are the traces for the full day.
Enphase

XW

I tried to line up the time, it's pretty obvious where it fits.

 

[GXMnow]

All I can say is "WOW!"

The sun is out in force, but the temps are still reasonable, so I am not running any A/C yet. My Enphase system is producing just shy of 30 KWHs again. It would do more if the panels were not getting so hot and there is a bit of settled dust/pollen on them. Add in the DC system pushing 7+ KWHs even with it in Float for half the day and it turns out I am exporting over 20 KWHs a day back to the grid. Actually almost 22 KWHs today. I really should be charging an EV with that. That is over 60 miles worth.

My estimated bill from So Cal Edison is at $ -101 for this billing month with 9 days left.

 

[faccnator]

Man you have a sweet setup. Here in Florida we almost have to run the air year round

 

[400bird]

Yeah, it's been pretty good the past few days!

51kWh from my AC coupled (limited by the 6kW inverter) and 7.8kWh DC coupled.
But just like your system, the battery was charged by 12:15, so it could have been about double that. The AC this summer will be the real test of the added DC panels.

Man you have a sweet setup. Here in Florida we almost have to run the air year round

Feels like that here sometimes too, but we get a few weeks in the spring and fall where the temp is right to open up and not need heat or AC.

 

[GXMnow]

51kWh from my AC coupled, limited by the 6kW inverter) and 7.8kWh DC coupled.

How many watts of panels are on your 6 KW AC coupled inverter?

My system is only 4.8 KW of panels on 3.9 KW worth of Enphase iQ7 inverters. With some haze in the air and hot panels, it didn't quite go into clipping today, maxing out at just 3.7 KW out of the microinverters, far below your 6 KW capability. Total for the day was 28.7 KWHs from Enphase and 7.2 KWHs out of the Victron DC system, even with it in Absorb for 40 minutes, and float for 5:25 while it could have been making more power. I just checked the battery summary for the day. The voltage never went below .6 volts, or about 3.9 volts per cell. Looking at the Li NMC SoC chart, that is still around 77% SoC. That battery was hardly discharged because it didn't have to start running the house until after 6:30 pm. The XW-Pro only charged 2 KWHs into the battery before it shut down, and the Victron pushed 7.2 KWHs to max it out to my full level of 57.8 volts (4.13 volts per cell) or 95% SoC. 95 - 77 = 18% used and charged. This is obviously a very rough estimate of capacity. But... If 9.2 KWHs = 18% then full capacity should be 9.2 / 0.18 = 51 KWHs!!! That is a bit too optimistic. It turns out the Victron was still counting up energy going to the battery that was actually being inverter into AC. Adding up the energy inverted in the XW-Pro, I get 9.524 KWHs of DC was fed into the inverter. But again, the DC system pushed 7.17 KWHs in as it was inverting some of that out. Going by the SoC graph I have, it loks like I really only discharged the battery about 7 KWHs, the other 2.2 went from the DC charge controller to the inverter, or was lost to heat in the conversions. And my battery state of health is obviously still excellent. But one of these days, I really should just run it down and top it back up to get a true capacity test.

Here in Florida we almost have to run the air year round

By the end of June, we will be running A/C most of the days, but hopefully will be able to open up windows at night. In August, we will certainly have several days well into the 100's. I am just a few miles from the Mojave Desert. The old saying "at least it's a dry heat" is sort of true, but when it hits 120F in the shade, it's still stupid hot. The Solar panels lose about 12% of their power in the heat. And my microinverters, being on the roof under the panels, also get hot enough that they reduce output a bit as well. In the heat of summer, my AC system will be down to about 27 KWHs per day, even with better sun angles and longer days. My hope is the DC system is going to make back most of that loss. The panels will still lose some production, but the charge controller will stay cool and won't drop to Absorb or Float unless it still manages to fill up the battery. I have already seen the system produce over 11 KWHs in a day, and it should even beat that on a long summer day.

My Central A/C pulls about 4,000 watts when running, and will run a solid 5-6 hours a day. That is 24 KWHs just to keep the house cool. Just over what I managed to export today. It will be an interesting balance to see where it falls. There is no doubt the Victron charge controller is doing far better than the BougeRV one did last year. The old one neve did better than 90% of the production of the Enphase micros, based on panel watts to watt hours out. The Victron has done that several times. So I am looking at nearly 10% more energy from the DC array when it does not go into power limiting.

 

[400bird]

How many watts of panels are on your 6 KW AC coupled inverter?

About 8kW
Yesterday, it was clipping from 11:40 to 3:20

The old saying "at least it's a dry heat" is sort of true, but when it hits 120F in the shade, it's still stupid hot.

Agreed
I really hate that saying

The Solar panels lose about 12% of their power in the heat.

Yup, I doubt I'll see any clipping once into the heat of summer.

And my microinverters, being on the roof under the panels, also get hot enough that they reduce output a bit as well.

Luckily my string inverter is in the afternoon shade, I don't have that problem.

 

[GXMnow]

Luckily my string inverter is in the afternoon shade, I don't have that problem.

The iQ7's are technically in the shade about 3 inches clear under the panels, but they still reported hitting 140F last summer. That seems to be the temp where they start to power limit a little. Watching the temp graph, it flat lined as the power dipped about 10-15 watts off on each panel. 140F works out to 60C so it does make sense. That is a common temp limit for a lot of IC chips. I am certainly happier with a little less power than I would be with fried inverters.

 

[GXMnow]

I am doing a little experiment today.

Th XW-Pro hit it's full charge level 56.5 volts at just 10:20 AM and it is very sunny, with just a few passing clouds. The DC system was getting close to hitting absorb after just 2 more hours at 12:20. With the strong sun, the Enphase system is cranking out nearly my full 16 amp limit. But each time a cloud passes, it dips a bit. I shut off my PLC and just told the XW-Pro to export 16 amps to the grid. It has now been like this for a bit less than 2 hours. Each time a cloud goes by, the XW cranks up and exports to keep the 16 amps flowing to my main panel. The sun is now past solar noon and the Enphase production is dipping as well. When no clouds are over the panels, the Enphase system is now producing about 3,600 watts, but 500 of that is running the house loads, leaving 3,100 watts to the grid. So the XW is pulling 800 watts from the battery bank to keep it at the max 16 amps, 3,900 watts. But at the same time, the Victron charge controller is pulling nearly 1,500 watts from the 2,000 watt DC array. So the battery is still charging at over 600 watts. The battery voltage is getting very close to where the Victron will go into Absorb at 57.6 volts. I should have started the XW exporting an hour earlier to have more room for the Victron to charge and export. After another 2 hours, I will report back how it is doing and grab some screen shots. This will likely end up being the most I have ever exported to grid in a day. I am already past 11 KWHs of export at 2:30 pm.

 

[GXMnow]

Okay... It's been more like 3 hours, but I wanted to catch the end of it.

I'll start with the Enphase production for the day.
That day is not over, but the energy is falling at 5:50 pm
__
The power dips after noon were from a band of clouds that moved through. Overall, production is still a bit down from last year, but it is above yesterday. It should end the day over 28 KWHs.
Here is the battery summary for the XW over the same day.
-
I tried to scale and line up the images so the hours match. You can see where the big battery current spikes line up with the power drops from the clouds on the Enphase system. I had started the export at 1:30 and the clouds moved in about 1 pm. The battery handled it no problem, so I still used no grid power. In fact, when all my neighbors Grid Tied systems vastly reduced their power, I kept pushing 15 amps to the grid. The visible step in the battery power are where I reduced the export current as the sun was dropping. I left it alone for nearly 2 hours, and the batter voltage only dropped 0.4 volts by 4:30 pm. I lowered the export current 4 more times after that to try and zero the battery current. Once I write the PLC code, it will be adjusting it every 10 seconds.

Here is the "Performance" page from the XW.


The yellow bars are power exported to the main panel. Almost all of that goes to the grid as my main panel loads are typically small unless the laundry or A/C are running. We did run one load of laundry, but since I was exporting close to my 16 amp limit, it just reduced what truly exported, but it does not show in the data here. The 20 amp back feed breaker keeps me from sending more power to the main panel, even if my export drops to 5 amps. I understand the reasons for the 120% rule, so I am doing my best to not violate it. I have priced out a 90 amp main breaker which will allow a 30 amp back feed breaker for 24 amps back to my main panel. But unless I change my NEM deal with So Cal Edison, I am still contract limited to 16 amps of export, but I could then push 24 to the main panel, as long as the main panel is consuming at least 8 amps of it. When my A/C is running, I am pulling over 14 amps from the main panel.

Looking at this last bar chart, it is a bit confusing. Looking at just the yellow bars from 10 am to 5 pm we get
1.6 + 2.6 + 2.6 + 3.9 + 3.7 + 3.3 + 3.2 + 1.4 = 22.3 KWHs of export for those 8 hours. The way the XW works, this is both the Enphase energy passing through and the power inverted from the batteries added together. The DC system produced just shy of 11 KWHs as of the time I took these screen shots. Here is the Data from the Victron MPPT

11.96 KWHs as of 5:49 when I took the screen shot. Again, you can see the power dips when the band of clouds went by. The power dip from 3 pm to 3:40 is when the battery voltage got high enough that the Victron went into CV Absorb mode. I had to raise the export power to pull the battery voltage down a bit. Then as the sun went down, the Victron had to go back into Bulk CC mode and as the sun dipped more, I dropped the export current. Here is a zoom in on the Absorb mode

You can easily see how the voltage flat lined at 57.6 volts. But I didn't lose much production as the power never dropped below about 900 watts. It could have been over 1,100, but this is minor.
And some final good news....

No more shading on the Enphase panels from the palm trees for the rest of the summer. The sun is just high enough to clear the trees and the lower row produced nearly the same power/energy as the upper row.
Too bad the same is not true for the DC panels. The shadow may not hit until later in the day, but now at 6:30 PM, most of the DC panels have some shade on them from the palm trees.

The whole 2,000 watt array is down to just making 77 watts. This is why I turned them towards true south. The west heading is useless. I may turn then even further east. When I check the poor power on the Victron just now, it has topped 11 KWHs for the day.

I'll post the So Cal Edison power data when it is posted, but it might not be until Monday or even Tuesday.

 

[GXMnow]

I was surprised to see it, but So Cal Edison posted the Saturday usage data on Sunday morning. Here it is.

It fell just a tick short of my maximum export.

I am doing it a little different today. I already started it exporting before noon. The battery voltage is above 57 volts, so I just set it to export at 15.5 amps. At 12:15 it is taking just 700 watts from the battery (about 13 amps), but the Victron charge controller is pushing 26.6 amps 1,540 watts, so the battery bank is still charging at over 13 amps. That means the battery voltage is still climbing. What I think I am going to do is quite simple. When the battery voltage goes above 57.2 volts, I will have it se the grid sell power to 15.5 amps. No calculations needed. When the battery falls back below 56.9 volts, I will have it revert back to just supplying the loads in the house as it does now. Since the XW-Pro stops charging at 56.5 volts, this solves a few issues with the control routine. If the DC does not make enough to hit 57.2, it will not step up the export. If the DC was small, it may step up export for a short time, but as soon as it falls it will stop the extra export. I think this is a good plan. It will only take one or two steps in the ladder sequence in the PLC to add this simple control. I already read the battery voltage from the XW, and I already control the sell register, so all the data I need to work with is already in the PLC. This does not take advantage of the time of use rates, it will sell the power as it is produced. But it is still way better than just having the charge controller throw the power away.

 

[Ampster]

Thanks for the details. Are you on a paired storage arrangement with SCE? The reason I asked, is a friend in SCE got a notice that his export was capped. However the amount shown as forfeited was the same as that month's export and the math on his bill actually showed full credit for the export and no deduction. I read on another forum a post from 2021 that had the same language and SCE confirmed the message was in error.

 

[GXMnow]

Are you on a paired storage arrangement with SCE? The reason I asked, is a friend in SCE got a notice that his export was capped.

I am on an NEM 2.0 deal with SCE. On my contract it only says peak export of 16 amps and maximum 900 KWHs of export per month. While I am now close to the maximum current, I am well short of the energy limit. It looks like I might be able to get to 26 KWHs per day, so for 30 days, that would hit 780 KWHs a month, so I think I am safe there.

I have not heard of anyone getting fined, but I don't want to be the test case.

 

[Ampster]

I have not heard of anyone getting fined, but I don't want to be the test case.

I have not heard of anyone getting fined either. It does not look like you are on a paired storage plan because SCE does not know about your batteries, correct? The users who have reported that any credits above the cap in kWhs is only forfeited not fined. In my friends case, the message about the cap is meaningless because from what I can tell by reviewing his bill, no deduction of forfeiture actually took place. I was more interested if you have that message on page 4 of your SCE bill in a box on the right side in the middle of the page? The message says a certain number of kWhs above the cap were forfeited.

 

[Hedges]

Are you on a paired storage arrangement with SCE?

I am on an NEM 2.0 deal with SCE.

I have not heard of anyone getting fined, but I don't want to be the test case.

I figure export under the cover of night would be suspicious with basic NEM.

I tried to start a battery system reservation for my new place, which has NEM 2.0 reservation but not installed yet.
The PG&E web page said I couldn't do that with the PV reservation outstanding, to call. Which I haven't done yet. I hate calling.

 

[Ampster]

I tried to start a battery system reservation for my new place

Are you trying for an SGIP grant? I do not see any advantage in having PG&E know about my battery unless I am getting some subsidy or incentive. I am sure if I emailed or called them about it, they would tell me that I have to apply to get permission to install a battery system. I do have an approved and finalled building permit for the ESS.

 

[GXMnow]

It does not look like you are on a paired storage plan because SCE does not know about your batteries, correct?

Correct.
At this point, SCE knows I have solar, but I have not officially told them I have batteries. But the fact I am "exporting" 20 watts at 1 am looks a bit fishy. They have never said anything, but for 6 months, they added an offset so it was showing as 20 watts of import instead of export. But once it hit winter and I was really importing in the mornings, the offset went away again. If the offset appears again, I will just make sure I import again for a bit a few days to make it go away. Maybe I should set the PLC to force a small import each night.

If SCE ever questions me, I will say I only added a backup UPS, I didn't know it was pushing any power to the grid. I didn't take the 30% solar tax credit on any of my battery system. It looks like I just bought a UPS backup inverter. 90% of my export all still happens as the sun is shining.

I did a bit more extensive test today, had it exporting 3,000 watts to 6 pm. I was going to stop it at 5, but I got distracted. As the sun was going down, it pulled the battery voltage down to 56 volts. Not a problem at all, it will still easily fully charge back up tomorrow.

Of course this also meant the Victron never hit absorb. It stayed in bulk, and has already produced 11.38 KWHs, a new record high. It is still producing, but only 70 watts now as the palm tree shadows are back on the DC panels. The XW-Pro is reporting that it sent 25.7 KWHs to the grid input. But it only charged 3.4 KWHs into the battery. 12.7 KWHs have been pulled from the battery, so I did use a little more than the Victron put into them. I need to get this coded into the PLC. It does not get distracted and walk away.

 

[GXMnow]

I ordered a 16S 1amp smart active "100 Balance" cell balancer. The package arrived today, but they sent me just a 10S version. Oops. The new one should be coming on Tuesday, and then I have to send this one back, assuming they get the order right the next time. If they mess up again, I may just keep it. I popped the cover off this one, and it is wired inside for 16S, and the setup let me choose 14S without an error. It just has the smaller 11 pin JST connector. So it might work as a 14 or 16S. If I get the wrong one again, I will have to try it.

I wired it to 10 cells of one of my E-Bike batteries. I know they are way out of balance, but WOW, it was far worse than I expected. One cell group is down to 3.3 volts while another is still at 4.2 volts. The balancer is chugging away trying to pull them together from 0.8 volts apart. It may be an active energy transfer balance, but it is getting warm pushing the power around. It claims 1 amp of balance current. It is pulling 0.9 amps from the high cell and pushing 0.8 amps into the low cell. Unlike the JK, it does appear it is pulling and pushing at the same time. It uses an array of switching FET's to connect the high cell to the input of the DC to DC converter, and the output of the converter to the low cell. The converter seems to be input to output isolated, so it can pull from any one cell, and push to any one cell at the same time. It does not have the big Super Caps like the JK, and it neve puts the energy into temp storage, it is going directly from cell to cell.

Being only 0.8 amps on average, it is balancing slow, but it is working, I see the cell voltages moving together. Right now it is balancing the upper 10 cells in one of my E-Bike 14S 6 amp hour batteries. Hopefully I can get both packs fully balanced by the time the new balancer arrives in 2 days.

Amazon... Please send the correct 16S version.

 

[Hedges]

Are you trying for an SGIP grant? I do not see any advantage in having PG&E know about my battery unless I am getting some subsidy or incentive. I am sure if I emailed or called them about it, they would tell me that I have to apply to get permission to install a battery system. I do have an approved and finalled building permit for the ESS.

No. Is there a grant? What's it worth? Does it involve allowing PG&E into my shorts?

I have approval for about 15kW of GT PV (2x Sunny Boy with REC, will have Tigo RSD), haven't pulled the permit yet but getting close.

Because I've got 3x SBS 5.0 and 2x LG RESU-10H, thinking of connecting two, up to 10kW export. Would only be done 4:00 to 9:00 PM during peak rates, PV should be down then but need to stay under 80A due to 100A fuses in disconnect switch.

This would just be to export/avoid import when rates are ~$0.60/kWh vs. ~0.40/kWh off-peak.
The hardware cost me $0.08/kWh amortized over its cycle life.
But not really beneficial unless consumption exceeds production/credits.

Having PTO means no nastygrams if I'm seen exporting after dark.

I got SBS hoping it would play nice with Sunny Island, use frequency shift to control both charging and discharging. Lithium would then cycle while off-grid, keeping AGM on SI at float.

I didn't take the 30% solar tax credit on any of my battery system.

I would. You're entitled to it. IRS isn't going to say anything to PG&E.

 

[GXMnow]

After sun down, I checked my final numbers. The 2,000 watts of DC panels produced a solid 11.38 KWHs. That is 5.69 sun hours. Not too bad at all. The Victron is doing way better than I ever saw from the BougeRV charge controller. But the Enphase system still did better. It pulled 28.5 KWHs from 4,800 watts of panels for 5.94 sun hours. And that was with a little thermal throttling on the Enphase micros.

I have 30 days to ship the wrong balancer back. I left it hooked it up to my E-Bike battery. It is working very well, but being only the 1 amp version, it is not super fast. But it is certainly pulling the cells closer. The delta on the poorly balanced pack was over 1.5 volts. One cell was down to just 2.65 volts. I had to put it on charge to bring it over 3 volts for the balancer to start working. But now, in about 2 hours, the delta is just under 0.7 volts. OUCH!! So glad I checked them. No wonder my range was a bit short on my last ride. I charged the battery up, but since the balance was so bad, the BMS obviously stopped the charge early for the high cells as 2 were still over 4.1 volts. The other pack is a bit better, but still not great. The little Daly BMS units on those batteries only have the 30 ma passive balancing. That is obviously not enough for those cells.

I just ordered extra JST connectors. I am going to make up harnesses so I can move the new balancer easily between the 2 E-Bike batteries and the 2 strings of cells in the new house battery cabinet. If it ends up working out well, I may buy another one, maybe the 2 amp version.

The only big complaint that Andy (Off Grid Garage) had about this balancer was the logic that it would only start balancing when all cells are above the balance stat voltage. I saw that with the one cell below 3 volts also. I agree that is pretty dumb as it can't catch a single runner cell. But as long as the cells are reasonable balanced, it should not cause me any issues with the NMC cells. I am fine with it balancing down at 3.2 volts. And I don't intend to leave it connected all the time. I will use it as a maintenance tool. In the time it took to type this, the balance delta dropped to 0.569 volts, it keeps jumping around a little though. It's still very bad, but it is getting better. The high cell is down to 4.11 volts (was 4.15) and the low cell has come up to 3.536. 90% SoC to 45% SoC Wow that is still bad balance. That's what I get for not riding the e-bike for 3 months. Lithium batteries do not like to sit. I had charged them for a total voltage to be about nominal 50% charge, but with the balance so out of whack, that didn't help much.

 

[Ampster]

No. Is there a grant? What's it worth? Does it involve allowing PG&E into my shorts?

Yes there is still some equity resilience money in SGIP for fire risk and medical equipment needs. My neighbor got his batteries reimbursed because he has a CPAC machine. It can be as much as $0.75 a Watt hour. Yes PG&E administers it and I believe you sign a paired storage agreement that allows them to forfeit exports above a cap.