Skybox Faults while trying to charge EV from PV

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murr
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Posts: 20
Joined: Sun Oct 18, 2020 6:50 pm

Skybox Faults while trying to charge EV from PV

Post by murr »

I have a Skybox with 4.5kW of PV directly connected and an additional 2.1kW AC coupled (6 x Enphase iq7s). I also have a 14s LG Li-Ion battery connected. The Skybox is running FW 1.5.33 and is configured in Net Metering with Backup and TOU configured so it should only buy from the grid between midnight and 6am. My EVSE is connected on the grid side and I can adjust the charge current. When trying to charge my EV off of the sun I try to leave a buffer of around 1kW.

I keep getting the following faults randomly while charging the EV:
Event Description Timestamp
Battery input overvoltage fault 06/07/2024 11:56
Battery input overvoltage fault 06/07/2024 13:24
NPC output overcurrent fault 06/07/2024 13:32
NPC output overcurrent fault 06/07/2024 13:33
NPC output overcurrent fault 06/07/2024 13:34
Battery input overvoltage fault 06/07/2024 13:35
NPC output overcurrent fault 06/07/2024 13:35
NPC output overcurrent fault 06/07/2024 13:35

These all happened while the panels were in full sun. The Enphase system was producing 1.7-1.9kW the whole time. Meanwhile the Skybox was producing 3.7-4.1kW until is faulted and then it completely stops producing and takes a while to ramp back up even after the fault is cleared. I'm including some pictures from the Skybox PV screen and the Optics summary. Does anyone have any idea how to stop the faults? I opened a case with support but never heard back.
SkyboxPV.jpg
OpticsRE.jpg
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Mike Curran
Forum Emperor
Posts: 3324
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof (2007/2017):
- 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)
- 24 (2x12) 235W Lightways panels with Enphase M215 microinverters plus 6 - 275W Talesun panels, also with M215s, grid-tied

Outback Skybox - Barn roof: (2019)
- 14 Trina Solar 270W in series (DC array input to SB inverter/charger), installed 3/5/24 (replaced original 2019 Talesun DC array)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W (manually switched during outages), Enphase M215 microinverters

Battery systems operate in grid-tied, net metering w/backup mode
All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: Skybox Faults while trying to charge EV from PV

Post by Mike Curran »

I have an EV charger that's on the same circuit as one of my grid-tied arrays, but that array is entirely independent of Skybox (labeled "Westinghouse Solar" in my profile), except that Skybox is fed from same grid supply (it's set up as net-metering with backup, same as yours). Since I'm selling to grid most of the spring-summer-fall months, this has the effect you're looking for - my EV is charged from the sun (but I sell that much less).

Since you are also operating net metering with backup, my suggestion is to just connect your EV charger directly to grid and charge only during daylight hours (which it sounds like you're already doing).

I am a bit puzzled though. Why limit your grid connection to the hours between midnight and 6 a.m.? That means your net metering connection won't benefit you by selling to grid when you have excess PV.
https://ei.tigoenergy.com/p/pZXn7SZQyO45
https://enlighten.enphaseenergy.com/public/systems/Hctc107221
murr
Forum Member
Posts: 20
Joined: Sun Oct 18, 2020 6:50 pm

Re: Skybox Faults while trying to charge EV from PV

Post by murr »

Mike Curran wrote: Sun Jun 09, 2024 1:03 pm I am a bit puzzled though. Why limit your grid connection to the hours between midnight and 6 a.m.? That means your net metering connection won't benefit you by selling to grid when you have excess PV.
To clarify, the grid is connected all the time for exporting but importing power should only happen between midnight and 6am if everything is working correctly.
User avatar
Mike Curran
Forum Emperor
Posts: 3324
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof (2007/2017):
- 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)
- 24 (2x12) 235W Lightways panels with Enphase M215 microinverters plus 6 - 275W Talesun panels, also with M215s, grid-tied

Outback Skybox - Barn roof: (2019)
- 14 Trina Solar 270W in series (DC array input to SB inverter/charger), installed 3/5/24 (replaced original 2019 Talesun DC array)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W (manually switched during outages), Enphase M215 microinverters

Battery systems operate in grid-tied, net metering w/backup mode
All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: Skybox Faults while trying to charge EV from PV

Post by Mike Curran »

Okay, got it. Your system is able to support all your loads from 6 a.m. to midnight, right? If so then why not stay connected to grid during those hours? As long as your system output exceeds your loads and your battery is happy, you shouldn't draw from the grid anyway. What am I missing?

Sorry for getting off-topic. TBH I cannot help with the faults you are experiencing, but hoped to offer an alternative that I've found works for my system.
https://ei.tigoenergy.com/p/pZXn7SZQyO45
https://enlighten.enphaseenergy.com/public/systems/Hctc107221
murr
Forum Member
Posts: 20
Joined: Sun Oct 18, 2020 6:50 pm

Re: Skybox Faults while trying to charge EV from PV

Post by murr »

Without those TOU settings the skybox would import from the grid instead of using the battery any time there isn't enough sun to cover my loads. At the very least between sundown and midnight and some in the morning too. Those are all billed at a higher rate than the super off peak between midnight and 6am.
User avatar
Mike Curran
Forum Emperor
Posts: 3324
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof (2007/2017):
- 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)
- 24 (2x12) 235W Lightways panels with Enphase M215 microinverters plus 6 - 275W Talesun panels, also with M215s, grid-tied

Outback Skybox - Barn roof: (2019)
- 14 Trina Solar 270W in series (DC array input to SB inverter/charger), installed 3/5/24 (replaced original 2019 Talesun DC array)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W (manually switched during outages), Enphase M215 microinverters

Battery systems operate in grid-tied, net metering w/backup mode
All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: Skybox Faults while trying to charge EV from PV

Post by Mike Curran »

Thanks. I didn't think through how your battery would drop below float voltage during times of low PV input, prompting draw from the grid. Sorry for being so obtuse (Tim Robbins' accusation in "The Shawshank Redemption" :grin: )
https://ei.tigoenergy.com/p/pZXn7SZQyO45
https://enlighten.enphaseenergy.com/public/systems/Hctc107221
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