Skyboxes 'fighting' each other during periods of the day

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SHunsader
Forum Whiz
Posts: 48
Joined: Mon Feb 15, 2021 2:54 pm
My RE system: Identically configured pair of Outback Skybox Systems each with 12 - LG 340 panels, and a Discovery 6.5kwh 48V battery, both running as Masters. External CT's, one using L1 CT input and the other using L2 CT input so as to help share load more evenly.
Location: SF Bay, California

Skyboxes 'fighting' each other during periods of the day

Post by SHunsader »

I'm a new Skybox system owner, but pretty hands on in regards to this installation. I've read every piece of information I could get my hands on over the past week. The system finally went live on Friday, and configuration looks identical on both Skyboxes now. Of course, one is configured as a master, the other a slave. They recognize each other, and am currently configured as "Netmetering".

In order to test my installation, I'm only running a small "Load" directly from the "Load" connection on the Skyboxes, around 200w (.2kw). The rest of the power from my 8kw system is either charging my 2-6.5kw Discovery batteries, or being sent to the grid.

For the past 3 days of use, when looking at the either the Skybox display panel, or the Optics website, I can see that during most of the 24 hour period, the 200w load is pretty evenly split between both Skyboxes. BUT, at around 5a, I notice that the load shown on both boxes diverge, today's episode being the most dramatic. The divergence starts out small at first, a few hundred watts, but by 7a, Sky 1 has 1.7kw of load, and Sky 2 has -1.5kw of load. On optics, the graphs look crazy. It appears that the 'load' from each inverter is opposite the other, but the net is still 200 w. By 8am, things have nearly come back together again, and the inverse starts happening. This time Sky 1 is showing a negative load, whilst Sky 2 is showing a positive number, but 200w greater.

Obviously this isn't the scenario I would think Outback would want for a pair of inverters, supposedly working in harmony. What's more, it makes it very difficult to really see what's happening.

Glad I'm still in the testing phase. I could only imagine trying to figure this out when under higher loads.

Anyone have a clue as to what to do?

Yes, running latest firmware, even though latest firmware doesn't show that it's the latest. (Yes, another firmware bug that they should address)

Steve
Attachments
_2021.02.15_SkyboxLoadInversion.jpg
Mike Curran
Forum Emperor
Posts: 2278
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof:
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 - replaced MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
- 2 grid-tied VFXR3524A-01's series stacked, replaced GVFX's (2020)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS. Tigo ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 30 (2x15) 235W panels with Enphase M215 microinverters, grid-tied

Outback Skybox - Barn roof: (2019)
- 14 Talesun 275W in series (DC array input to SB inverter/charger)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W, Enphase M215 microinverters

All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: Skyboxes 'fighting' each other during periods of the day

Post by Mike Curran »

That's a very small load for your 2 Skyboxes, and maybe that's why the strange behavior. I'd try adding load to see if things return to some semblance of normal. Note each Skybox will consume over 100 watts from grid when there's no PV input.
https://smart.tigoenergy.com/p/pZXn7SZQyO45?date=2021-04-19
https://enlighten.enphaseenergy.com/public/systems/Hctc107221
SHunsader
Forum Whiz
Posts: 48
Joined: Mon Feb 15, 2021 2:54 pm
My RE system: Identically configured pair of Outback Skybox Systems each with 12 - LG 340 panels, and a Discovery 6.5kwh 48V battery, both running as Masters. External CT's, one using L1 CT input and the other using L2 CT input so as to help share load more evenly.
Location: SF Bay, California

Re: Skyboxes 'fighting' each other during periods of the day

Post by SHunsader »

Mike,

Happy to do so once I'm sure that things are operating correctly. The only load shown is the 200 A panel that has my new construction and sound system on it. I can get to about 600w, but I need to turn on everything....all 126 lights, and turn up the music. It wasn't obvious that I needed current sensors until I decided to pick up the software manual. The designers and installers didn't want to touch it.

TODAY the system performed much better. Last night I noticed that things get a little funky when one battery isn't charged when the other IS. Then I read the part in the manual which said that the batteries should be initialized....could zero and start the charge process again. Needed to do it 3x to get both batteries to 100%. This morning's chart looked more like I would expect. Not sure why one of the batteries stopped charging at 87% and the other ran all the way to 100%. I DID notice that the one which made it to 87% is the one that has panels lower on the house, and the solar output was much less than the one which charged completely.

Currently have Netmetering w/Backup selected, and, although it's not supposed to matter, I've set the battery price to be .16/kwh, and 2 slices of time for the schedule... 20c for everything except 40c during the 4p-9p window.
SHunsader
Forum Whiz
Posts: 48
Joined: Mon Feb 15, 2021 2:54 pm
My RE system: Identically configured pair of Outback Skybox Systems each with 12 - LG 340 panels, and a Discovery 6.5kwh 48V battery, both running as Masters. External CT's, one using L1 CT input and the other using L2 CT input so as to help share load more evenly.
Location: SF Bay, California

Re: Skyboxes 'fighting' each other during periods of the day

Post by SHunsader »

This morning my PGE information became available for the same time window. It appears that it's not just a visual thing, but in reality, it caused some type of load on the PGE grid as well. Our household has never used more than 5 1/2 kwh in a single hour except for this time period shown, and that peak was during a heat wave that we were running our air conditioning system. NOTHING out of the ordinary was happening during this time window (it's between 7-9a during the week).

This is something that hopefully Outback can do a little research on.
Attachments
_2021.02.15_SkyboxLoadInversion.jpg
PGE_EnergyUse.jpg
Mike Curran
Forum Emperor
Posts: 2278
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof:
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 - replaced MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
- 2 grid-tied VFXR3524A-01's series stacked, replaced GVFX's (2020)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS. Tigo ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 30 (2x15) 235W panels with Enphase M215 microinverters, grid-tied

Outback Skybox - Barn roof: (2019)
- 14 Talesun 275W in series (DC array input to SB inverter/charger)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W, Enphase M215 microinverters

All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: Skyboxes 'fighting' each other during periods of the day

Post by Mike Curran »

It might be useful to forum viewers if you could post the summary graph. That would show what else is going on in your system besides just the load. Please show battery voltage, not SOC, if you can. Would there be 2 different battery voltage lines, one for each Skybox?
https://smart.tigoenergy.com/p/pZXn7SZQyO45?date=2021-04-19
https://enlighten.enphaseenergy.com/public/systems/Hctc107221
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