Power factor mismatch? Grid very low, SB=1

True Hybrid Energy System
Mike Curran
Forum Emperor
Posts: 1800
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 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

Power factor mismatch? Grid very low, SB=1

Post by Mike Curran » Tue Mar 31, 2020 7:50 am

Can anyone explain the difference between the Skybox power factor indication (here it shows 1)
Screenshot_20200331-104210_Samsung Internet.jpg
and the grid power factor (here, at the same time, it shows 0.07)?
20200331_104054.jpg
And why is the grid PF so low? The load on the SB is just a small fridge without a compressor (piezoelectric or some such cooling device) and two small fans. Fyi, the grid feed to the Skybox comes through an isolation transformer - maybe that's why PF is so low?

Thanks in advance - Mike

Edit: Here's a snapshot of power flows around when the earlier screenshots were taken:
Screenshot_20200331-105303_Samsung Internet.jpg
Note there's no load because of the AC coupled array generating power in excess of the load.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
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raysun
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Posts: 2964
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 Mar 31, 2020 8:19 am

I do believe you have answered your own question. The way I read it:

The load side PF=1 represents a purely resistive load.

The grid side PF~0 represents a reactive (inductive) load doing no work.

With such a large inductance on the grid side, I'd be very careful about disconnecting the Skybox. Make sure the load side is disconnected first (including charging if applicable) before disconnecting the grid to avoid man-made lightning somewhere.

Mike Curran
Forum Emperor
Posts: 1800
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 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 Mar 31, 2020 8:39 am

Okay...but now grid PF=0.65, without anything changing except more PV input...
Screenshot_20200331-113433.jpg
It seems to vary all over the map without anything electrical changing.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

raysun
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Posts: 2964
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 Mar 31, 2020 9:10 am

Mike Curran wrote:
Tue Mar 31, 2020 8:39 am
Okay...but now grid PF=0.65, without anything changing except more PV input...Screenshot_20200331-113433.jpgIt seems to vary all over the map without anything electrical changing.
I bet if you poked around, you'd find a small load somewhere, if even just what the inverter draws. Power factor is easy to measure, but hard to make sense of. It's not steady state in most systems unless it's a single source of power and a single load.

If looking at a snapshot and not a continuous readout it's even more difficult to correlate.

After wrestling with surveying everything in my household that causes the PF to vary between 0.45 and 0.9, I've concluded there's nothing to be done about it and quit trying to measure it.

Mike Curran
Forum Emperor
Posts: 1800
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 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 Mar 31, 2020 9:49 am

I agree, it's hard to judge what's going on with a snapshot, and normally I wouldn't be too concerned about power factor.

But my Skybox system draws an unusual amount of grid power when there's no solar input (mainly at night). Outback says normal grid draw under those conditions is around 150 watts. Mine draws 450 watts, that's 300 over normal.

I connected a generator to the Skybox and idle power draw was less than what OB says is normal for a grid connection, so I figured there was something funky with my grid connection. That prompted me to install the transformer to electrically isolate my system from grid, but that hasn't changed the excess grid draw. At OB's suggestion I connected the grid to the Skybox gen input and still got high power draw.

All this, to explain why I'm pondering the low PF. I'm posting this thread in the hope that someone out there has an idea about what's wrong with my system. I also have a tech support case with OB but they seem just as mystified about what's going on as I am. ](*,)
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

raysun
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Posts: 2964
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 Mar 31, 2020 10:01 am

Mike Curran wrote:
Tue Mar 31, 2020 9:49 am
I agree, it's hard to judge what's going on with a snapshot, and normally I wouldn't be too concerned about power factor.

But my Skybox system draws an unusual amount of grid power when there's no solar input (mainly at night). Outback says normal grid draw under those conditions is around 150 watts. Mine draws 450 watts, that's 300 over normal.

I connected a generator to the Skybox and idle power draw was less than what OB says is normal for a grid connection, so I figured there was something funky with my grid connection. That prompted me to install the transformer to electrically isolate my system from grid, but that hasn't changed the excess grid draw. At OB's suggestion I connected the grid to the Skybox gen input and still got high power draw.

All this, to explain why I'm pondering the low PF. I'm posting this thread in the hope that someone out there has an idea about what's wrong with my system. I also have a tech support case with OB but they seem just as mystified about what's going on as I am. ](*,)
I've been lurking in your other posts about this issue, and thanking my luck stars I'm just some country hick with a battery, PC panels and an inverter. And a generator.

And a still. We country hicks must maintain appearances AND provide our own sanitizer.

Good luck my friend! I hope the parasitic load thing gets resolved.

raysun
Forum Emperor
Posts: 2964
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 Mar 31, 2020 11:45 am

I know you've probably gone over this, but what happens when the the AC OUT on the Skybox is disconnected?

Mike Curran
Forum Emperor
Posts: 1800
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 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 Mar 31, 2020 2:43 pm

I've stepped through connecting everything, one item at a time. Starting with the battery, and nothing else (no PV, no load) obviously there'll be 0 grid use. But as soon as I connect the grid, grid use goes up to the high value. I documented this late in December to Outback:
With the grid connected, all PV (both DC and AC-coupled arrays) shut off, all loads shut off (Skybox AC output disconnected - loads powered directly from grid, Skybox bypassed), and battery ON:

With load L1 disconnected
Grid L1:  2.6A
         L2:  2.6A
          N:  0.0A
Load L1: ---
          L2:  0.0A
           N:  0.22A

With load L2 disconnected
Grid L1:  2.6A
         L2:  2.6A
           N:  0.0A
Load L1:  0.0A
          L2:  ---
            N:  0.3A

Note, if I turn the  battery OFF with loads and PV disconnected, as reported in my earlier email, Grid L1=L2=0.13A, N=0.0A, which matches your experience under those conditions.  So something about turning the battery on causes the excess current draw. 
Current values measured with an AC clamp-on ammeter inside the Skybox. Note also, this was done before the isolation xfrmr was installed.
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fcwlp
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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 » Tue Mar 31, 2020 7:52 pm

Mike Curran wrote:
Tue Mar 31, 2020 9:49 am
I connected a generator to the Skybox and idle power draw was less than what OB says is normal for a grid connection, so I figured there was something funky with my grid connection. That prompted me to install the transformer to electrically isolate my system from grid, but that hasn't changed the excess grid draw. At OB's suggestion I connected the grid to the Skybox gen input and still got high power draw.

All this, to explain why I'm pondering the low PF. I'm posting this thread in the hope that someone out there has an idea about what's wrong with my system. I also have a tech support case with OB but they seem just as mystified about what's going on as I am.
Hi Mike, thanks for the update. Interesting performance with the generator test. During the generator test, did you observe the PF? So with the generator test, you had a local N-G bond at the generator or the SkyBox and did not rely on the grid's N-G bond. With the isolation transformer, where is the N-G bond.

You could start by checking the ground rods at the main panel and the connections to these ground rods. Acorn nuts are supposed to be checked yearly but no one does. My local power company requires the use of irreversible connections. I use the Cadweld brazing/welding technology to make up to four connections to each ground rod for ~$15 per ground rod.

It could be a N-G problem further back in the grid system from your house. You may be able to get the power company to look at it by telling them it is causing issues with your system.

Mike Curran
Forum Emperor
Posts: 1800
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 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 01, 2020 4:30 am

I've got ground rods out the yim yam. Attached is a schematic of my system. I've sent a copy to Outback as well.
2019 Barn PV add'n WD.pdf
(613.87 KiB) Downloaded 101 times
Maybe someone can see something I don't.

And unfortunately, didn't observe PF with genny running. Yes, locat ground rod at transformer with N-G bond made there. No connection to house system - that's why I put in the xfmr.

Edit: note I forgot to show the outside fused disconnect switches for the solar arrays. They're there, though.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

fcwlp
Forum Czar
Posts: 536
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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 » Wed Apr 01, 2020 7:56 am

Hi Mike, three things that I observed in your schematic. Going back to at least 2008, the NEC requires or at least how my AHJ and power company interprets it, requires:

1) Two ground rods 8' apart at that are connected (i.e. bonded) together. It look like you have two ground rods at the barn, but per your note (*) they are not connected together. Was there a reason to do this? Are the ground rods at the house bonded together? The purpose of two rods is just to improve the ground performance at a given location and reduce the probability of a single point of failure. Ground rods also lose effectiveness overtime and some recommend replacement after X number of years depending on soil conditions, type of rod, moisture, etc.

2) A GEC (Grounding Electrode Conductor) which is a bare Cu wire buried in the trench, outside the conduit. For your application a #6 bare Cu is required, which is also the minimum size. The purpose of the GEC is to ensure that the entire ground systems is at the same potential.

3) The ground rod by the isolation transformer is not connected to the main distribution panel. Is there a reason for this? This should not affect the N-G bond that you have.

The GEC can help with stray voltages and improved lightening protection. Stray voltages can cause issues in remote structures, as was often an issue with barns where cows would get shocked drinking water from their metal bowls which impacts milk production. We had this issue on a dairy farm I worked on in WI.

Initial steps:
1) Connect main distribution panel to ground rod.
2) Bond the two ground rods at the barn together.
3) For test purposes run a wire (#12 should be adequate for testing) above ground between the ground rod by the house and the ground rods at the barn.

There are several good books on grounding and bonding. I have one from ARRL (Amateur Radio Relay League) and I just got the NEC 2014 Grounding & Earthing Handbook by David Stockton for some light reading: :wink:

Mike Curran
Forum Emperor
Posts: 1800
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 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 01, 2020 8:11 am

fcwlp wrote:
Wed Apr 01, 2020 7:56 am
Hi Mike, three things that I observed in your schematic. Going back to at least 2008, the NEC requires or at least how my AHJ and power company interprets it, requires:

1) Two ground rods 8' apart at that are connected (i.e. bonded) together. It look like you have two ground rods at the barn, but per your note (*) they are not connected together. Was there a reason to do this? Yes. I was trying to keep the house and barn backup systems electrically isolated. Are the ground rods at the house bonded together? Yes, but not the service entry ground to the ground at the transformer. . The purpose of two rods is just to improve the ground performance at a given location and reduce the probability of a single point of failure. Ground rods also lose effectiveness overtime and some recommend replacement after X number of years depending on soil conditions, type of rod, moisture, etc.Oldest ground rod is at the meter entry point. All others are 2010 or newer.

2) A GEC (Grounding Electrode Conductor) which is a bare Cu wire buried in the trench, outside the conduit. For your application a #6 bare Cu is required, which is also the minimum size. The purpose of the GEC is to ensure that the entire ground systems is at the same potential. I measured the resistance and voltage between these 2 separate grounding systems just now with a DVM and R = 1.2 ohms, VAC = <0.02 V. Did this without opening up the two separate sub panels, all I did was measure between two cover plate screws. If I'd gone on the internal ground busses, probably would've gotten lower readings. Unless I've missed a hard-wired connection somewhere, this seems to indicate resistance through my earth grounds is very low.

3) The ground rod by the isolation transformer is not connected to the main distribution panel. Is there a reason for this? This should not affect the N-G bond that you have.Again, attempting to isolate house from barn/Skybox backup system. Also, I did not think there should be more than one N-G bond in a residence system. In effect, I have two separate electric systems here, one directly connected to grid and one separated from grid by a transformer. Also note that part of the barn is powered directly from the house grid system, and that's the part whose ground rod isn't connected to the Skybox backup system.
Note that the excess grid consumption is what prompted me to add the xfmr and separate grounding system. Before that, there was no ground rod at the xfmr (no xfmr., period), and all grounds were connected together. Separating them hasn't changed the excess power consumption.
Last edited by Mike Curran on Wed Apr 01, 2020 9:25 am, edited 1 time in total.
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Mike Curran
Forum Emperor
Posts: 1800
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 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 01, 2020 9:03 am

PS Right now I have oodles of PV coming in including some AC coupling input (quantity not indicated on power flow)
Screenshot_20200401-120125_Samsung Internet.jpg
and grid PF is 0.97
Screenshot_20200401-120102_Samsung Internet.jpg
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

raysun
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Posts: 2964
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 » Wed Apr 01, 2020 9:33 am

So there's more power flowing to the grid than is being generated by PV, and zero load. There is another AC coupled PV source, and it is supplying the loads?

Power factor is 0.97 as the inverter sells to the grid. It would make a certain amount of sense that the power company would want to maintain a high PF on the lines, wouldn't it? Tough on their transformers otherwise.

Mike Curran
Forum Emperor
Posts: 1800
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 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 01, 2020 10:03 am

The AC coupled array is connected to the load side in this power flow diagram. Unfortunately it does not show the net power above what the load is consuming. I've only seen a number there when there was no AC coupled input, load only. I have a request in to the the Optics team to improve this indicator...

Btw, the grid PF screenshot in my OP was taken when the grid was connected, but 0 power flow since PV was supplying my load and charging requirements....or, maybe it disconnects in these circumstances.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

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

Post by sparksalot » Wed Apr 01, 2020 12:52 pm

MC, don't mix-up low resistance readings for being equal to "bonding not required" ...without solid bonding resistance(s) can and do change.

The fact that you have unaccounted current flow is trying to tell you something...

BTW: Don't let your body parts get in series with 2 unbonded grounds... many have died from this...

Mike Curran
Forum Emperor
Posts: 1800
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 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 01, 2020 6:57 pm

sparksalot wrote:
Wed Apr 01, 2020 12:52 pm
MC, don't mix-up low resistance readings for being equal to "bonding not required" ...without solid bonding resistance(s) can and do change.

The fact that you have unaccounted current flow is trying to tell you something...

BTW: Don't let your body parts get in series with 2 unbonded grounds... many have died from this...
Sparks - What constitutes an "unbonded ground"? All the ground rods in each of my two systems (one backup/PV, one a grid supplied conventional residence with a grid-tied array connected to it) are connected together, with only one (at each power source) bonded to neutral. Don't forget, my house system is electrically separate from my barn backup system, but each has an N-G bond.

You're probably right about unaccounted power flow (obviously it's going somewhere...). That was the direction I got from OB tech support initially - look for current flow in ground conductors or somewhere else it shouldn't be (e.g., a neutral conductor). I measured them all and couldn't find one with any current flow. All I could measure was about 2.4 A AC through the Skybox grid connections with all PV shut off and all loads disconnected. That's 2.4A × 240V = 576 watts. No loads but the Skybox, which is only supposed to draw 120W at idle.

Tomorrow I plan to revisit those current measurements. Maybe, hopefully, it'll turn up something now with the isolation transformer that I couldn't spot before.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

sparksalot
Forum Guru
Posts: 312
Joined: Sun Jul 17, 2016 5:31 am
My RE system: FLEXpower TWO VFXR3648A Grid-Tied and Battery Backup Hybrid, Mate3s
Using Two Midnite 200 Classic Charge Controllers

Traction battery FLA 48 volt 805Ahr.

32 SolarWorld 245w mono, 2x-4S-4P
6 REC 320w on micro-inverters

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

Post by sparksalot » Wed Apr 01, 2020 8:24 pm

You say they are two isolated systems so they are exempt for need of EGC bonding them...must be alright then...carry on.

Mike Curran
Forum Emperor
Posts: 1800
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 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 5:44 am

sparksalot wrote:
Wed Apr 01, 2020 8:24 pm
You say they are two isolated systems so they are exempt for need of EGC bonding them...must be alright then...carry on.
I didn't say they're exempt from bonding. Each is bonded to neutral within its own system. All I've done is separate the ground connection between two, separately bonded systems in my residential system. I would say that there is still a question about whether the grounding systems for two separate systems on the same property need to be connected together, but this is not my issue.

The problem is high grid use when there's no PV. That problem exists whether both systems' grounding networks are connected together, or not.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

sparksalot
Forum Guru
Posts: 312
Joined: Sun Jul 17, 2016 5:31 am
My RE system: FLEXpower TWO VFXR3648A Grid-Tied and Battery Backup Hybrid, Mate3s
Using Two Midnite 200 Classic Charge Controllers

Traction battery FLA 48 volt 805Ahr.

32 SolarWorld 245w mono, 2x-4S-4P
6 REC 320w on micro-inverters

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

Post by sparksalot » Thu Apr 02, 2020 6:24 am

I see. Some confusion exists, my bonding refers to only ground to ground everywhere and assumes single N-G, your bonding refers to Neutral to Ground and you want to do that twice as there are 2 systems. But as you say, makes no difference either way, I understand that.
Bottom-line, there can be no difference in potential or there will be current flow...does SB maybe have egg on their face here?

Mike Curran
Forum Emperor
Posts: 1800
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 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 8:45 am

Thanks Sparks - The funny thing is, when I connect my generator to the generator input of the Skybox and try to duplicate the high grid use condition (no PV in, no loads, just battery and generator connected), grid (genny) use is less than what OB calls normal (120W) - it was only 70 watts viewtopic.php?f=47&t=14520&start=25

But when I connect the grid to the Skybox generator input, I still get the high power draw. :!: :-s
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

fcwlp
Forum Czar
Posts: 536
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 02, 2020 9:00 am

sparksalot wrote:
Wed Apr 01, 2020 8:24 pm
You say they are two isolated systems so they are exempt for need of EGC bonding them...must be alright then...carry on.
Your schematic does show an EGC (#10 ground wire as note) between the Main Distribution Panel and Barn Main Panel.

raysun
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Posts: 2964
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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 » Thu Apr 02, 2020 9:18 am

Mike Curran wrote:
Thu Apr 02, 2020 8:45 am
Thanks Sparks - The funny thing is, when I connect my generator to the generator input of the Skybox and try to duplicate the high grid use condition (no PV in, no loads, just battery and generator connected), grid (genny) use is less than what OB calls normal (120W) - it was only 70 watts viewtopic.php?f=47&t=14520&start=25

But when I connect the grid to the Skybox generator input, I still get the high power draw. :!: :-s
My first notion was to say check the floor below the SB, there's probably a big pool of electrons there. But that's just me being a jerk. ;)

It's interesting that the generator, bypassing the SB works as expected, but the grid, presumably bypassing the SB?, does not.

This is way out of left field, but is it possible the grid waveform itself is causing some issue with the SB? Maybe causing it to do a lot of switching between grid and inverter?

Is there any sort of verbose logging that could be turned on to capture such events?

An ocilloscope on the input would kill this theory in short order, or open another avenue of exploration.

Mike Curran
Forum Emperor
Posts: 1800
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 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 9:35 am

fcwlp wrote:
Thu Apr 02, 2020 9:00 am
sparksalot wrote:
Wed Apr 01, 2020 8:24 pm
You say they are two isolated systems so they are exempt for need of EGC bonding them...must be alright then...carry on.
Your schematic does show an EGC (#10 ground wire as note) between the Main Distribution Panel and Barn Main Panel.
Yes, good eye, but that's still within the non-backed-up portion of the barn system.

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?
Last edited by Mike Curran on Thu Apr 02, 2020 9:48 am, edited 1 time in total.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

Mike Curran
Forum Emperor
Posts: 1800
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 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 9:38 am

This is way out of left field, but is it possible the grid waveform itself is causing some issue with the SB? Maybe causing it to do a lot of switching between grid and inverter?

Is there any sort of verbose logging that could be turned on to capture such events?

An ocilloscope on the input would kill this theory in short order, or open another avenue of exploration
Unfortunately, don't have an O-scope, and even if I did I'd have to relearn how to use it.

But I have the same suspicion. That's why I opened this thread about power factor.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

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