Power factor mismatch? Grid very low, SB=1

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fcwlp
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My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: Power factor mismatch? Grid very low, SB=1

Post by fcwlp » Thu Apr 02, 2020 6:44 pm

Mike Curran wrote:
Thu Apr 02, 2020 9:35 am
There are 2 subpanels in the barn, not counting another separate subpanel for the 2012 grid-tied array which isn't shown on the schematic. The one called "BARN MAIN PNL", is grid-supplied only and supports normal lighting, outlets, a mini-split heat pump (which I may move over into the backup panel at some point) and overhead door. This is the one whose ground (#10 wire) is connected to the Main Distribution Panel. The other, called "BARN AUX PNL", is normally supplied from the Skybox load output (can be switched to grid via bypass breaker in that panel), and supports two (or 3 when thermostat calls for it) hydronic heating system circ pumps (~150 watts each) and a small fridge that only runs around 40 watts. The #10 ground connection you see is still within the grid-exclusive system. Sorry that wasn't clear in the schematic.

Are we having fun yet?
Please confirm that there is no connection between the ground rod attached to the Barn Main PNL and ground rod at the Barn Aux. PNL.

Engineers consider solving problems as fun, especially when they are someone else's problem. I will be doing some more reading on separately derived systems, the next couple of days.
Mike Curran wrote:
Thu Apr 02, 2020 9:38 am
Unfortunately, don't have an O-scope, and even if I did I'd have to relearn how to use it.
I also have not used an O-scope for years. There are some interesting, low cost units available now that connect to a PC by USB. Would be more than adequate for this application and something that I have considered purchasing.

raysun
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Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Power factor mismatch? Grid very low, SB=1

Post by raysun » Thu Apr 02, 2020 6:57 pm

"Engineers consider solving problems as fun, especially when they are someone else's problem."

And if there's no "fun" to be had, engineers make their own.

LOL!

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Thu Apr 02, 2020 8:48 pm

Please confirm that there is no connection between the ground rod attached to the Barn Main PNL and ground rod at the Barn Aux. PNL.
As far as I can tell, nope. But that is basically where I measured 1.2 ohms resistance and 0.02VAC between them. Not between the rods themselves, but between subpanels connected to those rods.

Btw, today during normal operation (a cool bright sunny day - wish we had more like this one) I measured current flow on every ground rod at my house and barn. There's a total of 5 of them including one at the house 2007 PV system (bonded to the main house ground system) and one at the 2012 Westinghouse Solar grid-tied system (also bonded to house grounding system). Every ground rod was carrying 0.00A AC, that is to say, no current flows to ground through any of them.

Haven't tried this under high grid consumption conditions yet but I suspect result will be the same. Stay tuned.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

fcwlp
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My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: Power factor mismatch? Grid very low, SB=1

Post by fcwlp » Thu Apr 02, 2020 9:08 pm

Mike Curran wrote:
Thu Apr 02, 2020 8:48 pm
As far as I can tell, nope. But that is basically where I measured 1.2 ohms resistance and 0.02VAC between them. Not between the rods themselves, but between subpanels connected to those rods.
I was going to ask where you measured that resistance next. A 1.2 ohm resistance is much lower resistance than you should see between two ground rods. Is there metal conduit between the two boxes?
Mike Curran wrote:
Thu Apr 02, 2020 8:48 pm
Every ground rod was carrying 0.00A AC, that is to say, no current flows to ground through any of them.
That is good news. When removing the ground wire from the rod and doing this type of test, one should assume that the ground wire is hot until it has been verified to not be. It is the low probability event that gets you zapped and possibly dead.

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Fri Apr 03, 2020 9:23 am

Is there metal conduit between the two boxes?
I went to extreme measures to try and insure grounds are separate. Here I installed a PVC "dutchman" to break the metal flex connection:
20200403_121943.jpg
And I took the AC amp readings using a clamp-on ammeter, no need to disconnect anything:
20200403_122215.jpg
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

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Re: Power factor mismatch? Grid very low, SB=1

Post by sparksalot » Sat Apr 04, 2020 11:15 am

Let us not forget the utility...
Counting 5 ground rods...now how bout that utility ground wire running down from transformer on pole?
Problem there may account as to why connecting the generator shows so much better than connecting the grid... :-k

fcwlp
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My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: Power factor mismatch? Grid very low, SB=1

Post by fcwlp » Sat Apr 04, 2020 7:42 pm

Mike Curran wrote:
Fri Apr 03, 2020 9:23 am
I went to extreme measures to try and insure grounds are separate. Here I installed a PVC "dutchman" to break the metal flex connection:
Creative solution and I am 7/8 Dutch. The 1.2 ohm resistance still appears to be an anomaly, unless the rods are sitting in a salty water table. Please repeat the resistance measurement
after disconnecting the ground wires at one of the rods.
sparksalot wrote:
Sat Apr 04, 2020 11:15 am
Let us not forget the utility.

Sparksalot, with Mike's present inclusion of an isolation transformer the utility should not be a factor.

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Sun Apr 05, 2020 7:36 pm

Please repeat the resistance measurement
after disconnecting the ground wires at one of the rods. 
Didnt have a chance to do this today, will try tomorrow.

Funny thing, seems like the power factors indicated by Skybox and grid (in Optics device manager) are now reversed from the OP. Only thing I've changed is I moved the barn mini-split heat pump onto the backed up loads panel, which is fed from the Skybox and was operating at about 800 watts when these screenshots were taken. Now grid PF is 1.0
Screenshot_20200405-222127_Samsung Internet.jpg
and Skybox PF is 0.94.
Screenshot_20200405-222311_Samsung Internet.jpg
When the heat pump goes off, load reduces to about 50 watts (small non-inductive fridge) and SB PF drops down to 0.11 while grid PF remains at 1.0.
Screenshot_20200405-222607_Samsung Internet.jpg
This is exactly opposite from OP and AFAICT (as far as I can tell), the same operating condition but with the heat pump connected but OFF (not calling for heat but still on, that is). This was the first full day with this new wiring arrangement so maybe things will start to make sense after some further observation. For sure, the heat pump is gonna affect PF. :-k :-k
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Mon Apr 06, 2020 7:03 pm

The 1.2 ohm resistance still appears to be an anomaly, unless the rods are sitting in a salty water table. Please repeat the resistance measurement after disconnecting the ground wires at one of the rods. 
No salt water nearby but maybe the septic...?
Disconnected 3 solid copper ground connections (DC & AC Coupled arrays, plus Skybox) to what's labeled as "Earth ground rod @Skybox" on the schematic.
20200406_233622.jpg

Voltage and resistance readings between barn grounding system and Skybox system confirm your suspicion - they were still quite low: 0.00 VAC, -0.02 ohms (yes, that's a minus sign).
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

fcwlp
Forum Czar
Posts: 542
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: Power factor mismatch? Grid very low, SB=1

Post by fcwlp » Mon Apr 06, 2020 8:44 pm

Mike Curran wrote:
Mon Apr 06, 2020 7:03 pm
Voltage and resistance readings between barn grounding system and Skybox system confirm your suspicion - they were still quite low: 0.00 VAC, -0.02 ohms (yes, that's a minus sign).
Interesting, I have never seen a negative resistance. Let us know what you find.

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Tue Apr 07, 2020 7:18 am

It just occurred to me, the new AC coupled array attached to the Skybox is mounted to the same metal roof as the direct grid tied array installed in 2012. That probably explains why there's continuity between the barn and Skybox grounding systems. D'oh! :oops:
Last edited by Mike Curran on Tue Apr 07, 2020 10:13 am, edited 1 time in total.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

raysun
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My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Power factor mismatch? Grid very low, SB=1

Post by raysun » Tue Apr 07, 2020 9:53 am

Mike Curran wrote:
Tue Apr 07, 2020 7:18 am
It just occurred to me, the new AC coupled array attached to the Skybox is mounted to the same metal roof that the direct grid tied array installed in 2012. That probably explains why there's continuity between the barn and Skybox grounding systems. D'oh! :oops:
SITE ADMIN: Can we get a new forum category labeled: "Fun With AC Coupling"?

Thank you.

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Tue Apr 07, 2020 10:55 am

SITE ADMIN: Can we get a new forum category labeled: "Fun With AC Coupling"?
Maybe as a subcategory of "AC Coupling". Of course, all forum categories could be prefixed with "Fun with..." :smile:
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

raysun
Forum Emperor
Posts: 2998
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Power factor mismatch? Grid very low, SB=1

Post by raysun » Tue Apr 07, 2020 11:02 am

Mike Curran wrote:
Tue Apr 07, 2020 10:55 am
SITE ADMIN: Can we get a new forum category labeled: "Fun With AC Coupling"?
Maybe as a subcategory of "AC Coupling". Of course, all forum categories could be prefixed with "Fun with..." :smile:
:lol:

fcwlp
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Posts: 542
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: Power factor mismatch? Grid very low, SB=1

Post by fcwlp » Wed Apr 08, 2020 8:00 am

Mike Curran wrote:
Tue Apr 07, 2020 7:18 am
It just occurred to me, the new AC coupled array attached to the Skybox is mounted to the same metal roof as the direct grid tied array installed in 2012. That probably explains why there's continuity between the barn and Skybox grounding systems. D'oh!
:eek: That does not show up in the schematics. :eek:

Is the Enphase mounting plate at AC ground potential? If so, a possible work around would be to insulate the mounting plate from the module/rail and provide a separate ground path for the module/rails. I would discuss with Enphase before doing. A quick and temporary test would be to disconnect the ground from the Enphase panels.

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Wed Apr 08, 2020 10:15 am

fcwlp wrote:
Wed Apr 08, 2020 8:00 am
Is the Enphase mounting plate at AC ground potential? If so, a possible work around would be to insulate the mounting plate from the module/rail and provide a separate ground path for the module/rails. I would discuss with Enphase before doing. A quick and temporary test would be to disconnect the ground from the Enphase panels.
There's an Enphase microinverter on each of the 30 PV panels installed in 2012, and they are bolted to the frame of each panel - they're what today are called "AC panels". The 14 AC-Coupled PV panels installed last year are bolted to mounting rails which in turn are bolted to the roof with S-5! standing seam mounting blocks and standard panel mounting clamps. It's not practical to remove their connections to the modules since that would require dismounting the panels themselves from the roof.

With the panels of both systems all bolted to the same steel roof, I'm not sure what disconnecting the ground lead on one and/or the other array would do - can you explain?
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

fcwlp
Forum Czar
Posts: 542
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: Power factor mismatch? Grid very low, SB=1

Post by fcwlp » Wed Apr 08, 2020 11:55 am

fcwlp wrote:
Wed Apr 08, 2020 8:00 am
Is the Enphase mounting plate at AC ground potential? If so, a possible work around would be to insulate the mounting plate from the module/rail and provide a separate ground path for the module/rails. I would discuss with Enphase before doing. A quick and temporary test would be to disconnect the ground from the Enphase panels.
Ignore the above post, I forgot to look at the schematic before commenting.

The 1.2 ohm resistance was between the Barn Main Pnl and Barn Aux Pnl, with the 30 M215 Enphase panels connected to the Barn Main Pnl. Is only the roof metal or is the whole building metal? Test would be to remove the ground from these 30 panels temporarily. If this resolves the issue, I believe it would be safe to move this ground wire to the earth ground at the Skybox/Barn Aux PNL.

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Wed Apr 08, 2020 5:09 pm

Just the roof is metal, it's a wooden pole barn.

Ground change sounds worth a shot - Thanks, maybe I'll try tomorrow.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Wed Apr 15, 2020 1:27 pm

Test would be to remove the ground from these 30 panels temporarily. 
I had this on my good intentions list and finally got a round tuit :smile: today.

But I forgot the details of your recommendation so now I'm reporting, but regret not doing more troubleshooting while the ground was disconnected.

Anyway, I disconnected the earth ground for the 30, 2012 Enphase microinverter array that shares the same metal roof with the arrays feeding Skybox - but forgot to look and see if this changed anything. Instead, being that it was starting to snow and in a hurry, I went ahead and connected the ground from these panels to the same earth ground that serves my Skybox, and no joy. With all PV off, minimal loads, Skybox still consumed 400 watts over the load - see photo from SB display in link: https://drive.google.com/file/d/1Jj5e2y ... p=drivesdk

Any other ideas? TIA - Mike

Edit: BTW, Outback says the PF anomaly is a bug...fyi.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

fcwlp
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Posts: 542
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: Power factor mismatch? Grid very low, SB=1

Post by fcwlp » Wed Apr 15, 2020 2:16 pm

Mike Curran wrote:
Wed Apr 15, 2020 1:27 pm
Anyway, I disconnected the earth ground for the 30, 2012 Enphase microinverter array that shares the same metal roof with the arrays feeding Skybox - but forgot to look and see if this changed anything. Instead, being that it was starting to snow and in a hurry, I went ahead and connected the ground from these panels to the same earth ground that serves my Skybox, and no joy. With all PV off, minimal loads, Skybox still consumed 400 watts over the load
The only potential issue that was not tested by not checking with an open ground, is if there is a N-G bond in the Enphase microinverters themselves. The documentation for the microinverters should cover this versus going out in the snow and checking.

Being from WI, I remember those mid-April snow storms. In AZ at 5,500' today we are 60 and sunny. I just finished chipping & mulching 2 tons of junipers from my pasture.

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Wed Apr 15, 2020 5:12 pm

Fclwp - Maybe you're onto something...

According to the installation instructions, the Enphase M215 microinverters (IG model, for "Internal Ground") in the 30 panel array have an internal (or should I say, infernal?) ground connection. These 2 statements caught my eye:
With the Enphase M-Series Microinverters, the DC circuit within the microinverter is isolated and insulated
from ground. Ground fault protection (GFP) is integrated into the microinverter. Because of this, the fourth
generation microinverters do not require a grounding electrode conductor (GEC).
These are what are in the 30 panel array.

And,
If you are installing the original M215 (M215-60-2LL-S22), a GEC or other compliant grounding method is
required. TIP: If installing a mix of IG (Integrated Ground) and non-IG microinverters, install the non-IG
microinverters closer (electrically) to the junction box to minimize GEC use.
Incidentally, I don't have a mix of both inverter types in the Westinghouse Solar array, as described in the second quote, but the newer AC-coupled array does have the non-IG model of M215, and I did run an external GEC connecting all of them to the Skybox earth ground.

The wiring for the 30 panel IG model array does bring a ground conductor down from the microinverters (no idea where or how it's connected inside them, all the wiring was prefabbed, all I got were 4 conductors to terminate from the end of the string) along with 2 - 120 volts hots and a neutral. I bonded this ground to earth along with a separate bare copper ground from the array frames themselves. That bare copper GEC is the one I disconnected today and temporarily connected to the SB earth ground.

Do you see any way that what I'm describing could be causing my high grid use? Outback has already told me they think it's being caused by a ground loop... If this is somehow the culprit, how to resolve???

Thanks again. - Mike
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

fcwlp
Forum Czar
Posts: 542
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: Power factor mismatch? Grid very low, SB=1

Post by fcwlp » Thu Apr 16, 2020 6:33 pm

Mike Curran wrote:
Wed Apr 15, 2020 5:12 pm
The wiring for the 30 panel IG model array does bring a ground conductor down from the microinverters (no idea where or how it's connected inside them, all the wiring was prefabbed, all I got were 4 conductors to terminate from the end of the string) along with 2 - 120 volts hots and a neutral. I bonded this ground to earth along with a separate bare copper ground from the array frames themselves. That bare copper GEC is the one I disconnected today and temporarily connected to the SB earth ground.
Hi Mike, I reviewed the Enphase M215 manual and I am going to attempt to summarize:
  • The 30 Westinghouse panels have have the M215-60-2LL-S2x-IG inverters which feed into the Barn Main PNL. These inverters include ground fault protection, do not bond the N-G, and do not require a GEC. You did install a bare Cu GEC that is connected to the frames and is now connected to the SkyBox ground rod.
  • The 14 Talesun panels use the M215-60-2LL-S2x inverters which feed into the SkyBox. These inverters do not have ground fault protection, do not bond the N-G, and require a GEC. You have a GEC that now connects to the SkyBox ground rod.
  • Both arrays are mounted on a metal roof, so they are both at the same ground potential.
I do not see anything wrong with the above ground wiring.

I did look at your Enphase site, which got me thinking.
- Are you using one or two Envoy Comm Gateways for the two Enphase arrays?
- If you are using two, are they connected by Ethernet or WiFi?

You can probably guess that my thought process is; is there an unintentional ground between the systems.

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Thu Apr 16, 2020 7:19 pm

Fcwlp: Pretty accurate description (my compliments) but
You did install a bare Cu GEC that is connected to the frames and is now connected to the SkyBox ground rod.
no, after testing the connection you're describing, I reconnected the 30 panel ground to the original earth ground, which also is connected to the Barn panel ground.

I'm using two Envoys, one for the 30 panel array and another for the array that's AC-coupled to the Skybox output, and they both communicate to Enphase via ethernet cable over my LAN, they are not directly connected to one another.
is there an unintentional ground between the systems
Well, yeah, it's the metal roof, no? And why would an unintentional ground between them cause what my system is doing? I mean, seems like having all grounds connected together should still be okay... or are you saying there's some kind of unintentional high impedance connection from ground to one of my 120 volt lines?

Thanks for taking the time to look at this. =D>

Edit - I probably need to go back to Outback's original advice and start disconnecting stuff until the problem goes away, but this time not confine the disconnections to just inside the Skybox BOS unit...
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

fcwlp
Forum Czar
Posts: 542
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: Power factor mismatch? Grid very low, SB=1

Post by fcwlp » Thu Apr 16, 2020 9:54 pm

Mike Curran wrote:
Thu Apr 16, 2020 7:19 pm
no, after testing the connection you're describing, I reconnected the 30 panel ground to the original earth ground, which also is connected to the Barn panel ground.
Did you check the SkyBox power draw with this ground disconnected? Since the 30 panel array does not need a GEC, I would recommend re-connecting it to the SkyBox ground rod.
Mike Curran wrote:
Thu Apr 16, 2020 7:19 pm
I'm using two Envoys, one for the 30 panel array and another for the array that's AC-coupled to the Skybox output, and they both communicate to Enphase via ethernet cable over my LAN, they are not directly connected to one another.
Two questions:
1) Are your Envoys using the CTs or the standard version?
2) Is each Envoy plugged in to circuits powered by panels it is monitoring? If this is not the case, change where they plug in.
Mike Curran wrote:
Thu Apr 16, 2020 7:19 pm
And why would an unintentional ground between them cause what my system is doing? I mean, seems like having all grounds connected together should still be okay...
It would seem that having all grounds connected together would be the ideal. However, I believe with your currently separately derived systems, there could be some issues. It seems like a stretch, but the unintentional ground, I was thinking of is the LAN cable. I would recommend unplugging and seeing what happens.

Mike Curran
Forum Emperor
Posts: 1804
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Fri Apr 17, 2020 4:29 am

Did you check the SkyBox power draw with this ground disconnected? Since the 30 panel array does not need a GEC, I would recommend re-connecting it to the SkyBox ground rod.
No, but I did check with it connected to the Skybox ground bus and still had the high use problem. Maybe I'll disconnect again and check power draw without it.

Well, last night I Googled "ground loops" and now I know enough to be dangerous :shock:

Anyway, it sounds like multiple ground connections are good from a safety standpoint, but it seems that it's possible to create induced voltages and current in the ground conductors that connect them together, especially when there are AC currents running in parallel with some of them and there are long runs with small but not zero resistance between their endpoints, which (believe it or not) is usually the case.

Typically ground loops create a hum problem in audio systems, but in my case, apparently Skybox is detecting them and for some odd reason they're causing it to consume at least twice the normal idle power. What I read suggests there are several possible solutions, one including your idea of disconnecting ground connections. May be great for eliminating ground loops but from a safety standpoint, not so much.

My system has a multitude of disconnection options, and one problem with this approach is that there very well could be more than one ground that's the culprit. Yes, there's an ethernet cable going out to the barn. There's also a landline phone cable, a CATV cable (note all these signal wires are in a separate 3/4" PVC conduit buried alongside the power conduit in the same trench), 2 different ground conductors from the house to the barn (running in the same PVC conduit with all the power conductors), not to mention all the ground conductors within the barn system itself.

I also have the battery temperature wire running in the same (PVC) conduit as the DC leads to the batteries. This has a shield connected to the Skybox ground bus at one end and to metal conduit inside the barn. The latter connection I disconnected early on; maybe I'll try disconnecting it at the other end too.

Gotta find a solution, though. I've been using the Skybox's time of use function to run my barn backed up loads off the battery at night to avoid excessive grid use (when the sun comes up the problem goes away), but even with that arrangement there's excess power drain, 'tho not as much as when running on grid:
20200417_071807.png
As far as those Envoys, they are the standard version (no CTs) and yes, each is plugged into the same circuit that it's monitoring. That's the reason I have two of them, just connecting one would not see the other array (I tried it).

Thanks again for helping me out. - Mike

Edited to add link to ground loop article: https://www.bapihvac.com/application-no ... tion-note/
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

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