Outback Skybox and AC coupling Enphase micros

[Ampster]

Earlier I had self installed 23 Enphase IQ7+ inverters powered by some 345 Watt panels. When that was inspected and I received my PTO from PG&E I was ready to install my Skybox and my 48 LF280 cells which I had acquired last year. I also added 7 used Sunpower panels on a patio cover and those are DC coupled to the Skybox.

I had to do a complete main panel change out so during that process I separated my loads into two sub panels. The micros were wired to the critical loads subpanel so that they could be AC coupled to the Skybox. That way, when the grid is down. the micros can be used to power loads and charge the batteries.
Here is a picture of the Skybox and the two subpanels. Not shown are the wiring gutters I used at the top and bottom to give me flexibility and make room for a variety of CTs to measure system performance and specific loads.

 

[wtfg]

Did you use after market CTs ?
If so witch ones, just installed my outback skybox today!!

 

[Ampster]

Did you use after market CTs ?
If so witch ones, just installed my outback skybox today!!

I did buy external CTs but have not installed them yet. My micros are connected to the same subpanel that the Skybox powers so the Skybox sees their output and labels the Load tile with the notation "AC couple" when they are producing. That tile is colored yellow and the direction arrow is showing in the direction of the Skybox. The Solar tile only shows the output of the DC coupled solar panels connected to the Skybox. Normally have have enough production so that I do not have to pull from the grid but there were some clouds when I took the picture. I could also reduce the charging Amps to reduce the grid use at this time of year. The Skybox charges from solar first then covers the loads and finally pulls what it needs from the grid as a last resort. I am using Self Consumption Mode

 

[wtfg]

I installed my outback skybox today
I have 22 Canadian solar 325watt panels with 22 enphase Iq7+ micro inverters
AC coupled to sub loads panel
Going to ad DC coupled panels in the spring
I am having trouble updating the firmware its stuck on 1.5.11 last know good is 1.5.26
Also when grid was off it seemed like the micro inverters shut off and restarted after 5 minutes
I don't think they modulated
Is there a different grid profile to make that work?
Thanks

 

[Ampster]

Is there a different grid profile to make that work?

I am using Self Consumption Mode. The micros should modulate but I have not tested my system in off grid mode yet. Try it with the grid on just to diagnose the issue. With the grid on the micros can output to the grid and there should be no need to modulate or shut down. Also check the setting for Grid Sell under the Grid tile. I have mine set to 7 kW, which is what my PTO is with PG&E. I think the Skybox would modulate the DC coupled panels first before shutting down the micros.

It did work in a previous configuration with a much smaller GT system. . You could try putting some loads on that subpanel or shut off one string of micros.

 

[wtfg]

Another question when i tried to install firmware my load sub panel went dead
Is it supposed to do that?
I have a lot of important things on that panel and hate to see it die suddenly
After the download was completed it rebooted and everything came back

 

[Ampster]

Another question when i tried to install firmware my load sub panel went dead
Is it supposed to do that?

D[d it upgrade to the latest firmware. The AC needs to be on for the upgrade to take place. From what I read on the outback Skybox forum it will not happen on batteries.

 

[wtfg]

No it did not update to the latest
I am having trouble updating the firmware its stuck on 1.5.11 last know good is 1.5.26
The AC in was still there, just my sub panel died

 

[Ampster]

I am having trouble updating the firmware its stuck on 1.5.11 last know good is 1.5.26

I am on 1.5.26. I had some difficulty a few months ago but when I re-installed the inverter I got it to take. I think you may need to login with the installer code which is 1234. If that does not work PM me and I will send you the code for Administrator.

 

[wtfg]

I tried again today to update firmware to 1.5.26 and it went into limbo
Severe system has suffered a failure and is going into limbo
When i try to login and go to firmware page it wont let me in
every other page opens but firmware page.
I was going to try to roll back to 1.5.11
Any body have an ideas?
Outback isn't open till Monday!!

 

[wtfg]

Well after several attempts I finally got a hold of the Director of program management at Outback
He sent me 1.5.26 to put on a flash, that didn't work either
Then I told him about somebody on the forums say some units shipped without the right security certificate
He sent me the certificate and the software installed.

 

[Ampster]

I had my first grid outage this morning. I was generating about 4kW from my AC coupled micros, the battery was fully charged and I only had 700 Watts of load. Needless to say the Skybox had an Over voltage fault and shutdown I restarted the Skybox and the Enhase micros fired up to a modultated output and everything worked fine from then on. Another user from the Outback forum confirmed the same thing had happened to him one time when his batteries were full and the AC coupled inverters could not ramp down quickly enough. I was in Self Consumption mode and am wondering if it would be the same situation if I had been in Backup mode. I will have to tesgt that someday. I would like to think the Skybox could manage this unattended but that was not the case today. Fortunately the grid came back a few hours later but if it happens when I am not there to restart it and the outage lasts a few days my frozen food might be in jeopardy.

 

[goldserve]

You should test grid out with full sun scenarios more. I know I will when I set up my ac coupled sma inverter. I wonder if charging the battery to 98 or 99% will help the system absorb the power from the micro inverters until the skybox can ramp up the frequency to modulate or turn off the inverters…

 

[Ampster]

I wonder if charging the battery to 98 or 99% will help the system absorb the power from the micro inverters until the skybox can ramp up the frequency to modulate or turn off the inverters…

I think I would not have had the over voltage problem if the battery pack were at 80% SOC and charging at 2-3kWs of power. At 98% the pack would be at Absorb at less than 1kW. Another Skybox user on the Outback forum agreed with the assessment that if the power goes out when battery pack is full and there is little load, that is when his Skybox whent into over voltage fault.

 

[goldserve]

Don’t you just need a little buffer to allow the skybox to do its throttling thing?

 

[Ampster]

Don’t you just need a little buffer to allow the skybox to do its throttling thing?

Yes and that is why I suggested there would be more buffer if the batteries were at 80% SOC than 98% SOC. Did I misinterpret your statement about batteries at 98%?
My point was the load of bulk charging would be some of that buffer.

 

[goldserve]

Well, not quite 98% but even at 95%, 200aH of batter could absorb 80A of charge generated by 4kw of solar power. The skybox could have enough time to ramp up frequency to knock the inverter offline so no ovp occurs.

 

[Ampster]

Yes any SOC where there is headroom for the Skybox to absorb the energy of the AC coupled solar until that solar can be ramped down. .

 

[Ampster]

I just received my True Up statement from PG&E and the total was $57. I generated 11,700 kWh for that same year and my Net generation was 1,065 kWhs. (-1065 on bill). I had installed a minisplit heat pump last year and that increased my winter consumption which meant my NEM charges were averaging $100 per month until February and then I started generating Net kwhs beginning in March.
For most of that time the Skybox was in Self Consumption mode which meant that my 42kWh pack powered the essential loads panel all the time except when we had cloudy weather, at which time I switched to Net Metering with Back Up mode which was essentially TOU. The only loads not on the essential loads panel are my oven, dryer and EV charging. If those loads were run during the day when I was producing solar they were offset by generation. I did try to charge the EVs from solar during the day but if we were going on a journey and one of them did not get full we would charge at off peak rates.
I also got a rate increase in late September. Peak rate is $0.56. Part Peak is $0.45 and Off Peak is $0.25, In October I shift to Winter rates and I will update those rates when I get them. These are all EV rates which accounts for the high peak rates. I remember a time ten years ago when the lowest EV rate was $0.13 per kWh. They called it Super Off Peak. Noting super about that rate anymore, which is why I charge my EVs from solar when i can.

 

[BentleyJ]

I just received my True Up statement from PG&E

PG&E participates in the twice per year CA Climate Credit but for some reason their customers are only getting $39.30 While SCE is at $59 and Pacific Power is at $132.85. Has something to do with the Carbon Credits the electricity generators/suppliers are forced to purchase to offset their carbon emissions.
Wow, Could the billing system in CA be any more convoluted? Winter, Summer, Tiers, TOU, Baseline Allowances.
In the beginning, NEM 1.0 had no monthly minimum interconnect fees now we have a $10 fee for any month with net production. However, Seems like the CA climate credit more than compensates for the few months we do have negative usage on our bill.
Overall we are finishing our 12 month cycle with negative several hundred kWh which gets paid out at 0.03/kWh + or -. In total we end up with an annual SCE credit of about $150 but only have 5-7 months where the $10 net production fee kicks in.
Being grandfathered in on NEM 1.0 has really worked out better than I expected, even factoring in the fact I knew back then it was just a matter of time until CA really started "screwing" us on energy prices, I just didn't know how bad it was going to get. Not looking forward to the end of the 20 year solar lease when we have to go back to being regular rate payers.