Skybox SOC reset button doesn't reset SOC

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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

Skybox SOC reset button doesn't reset SOC

Post by Mike Curran » Tue Apr 07, 2020 8:30 am

My SimpliPhi battery is currently at 53.7 volts, and Skybox indicates SOC = 90%. According to Simpliphi, anything above 52.5 volts is 100% charged.[attachment=1]Screenshot_20200407-111850.jpg[/attachment]They also say that, unlike FLA batteries, voltage is a better indicator of SOC than a battery monitor current in vs. out comparison. So I go into the Skybox GUI and try to reset SOC to 100%, but all it does is start a bulk charge while maintaining the 90% SOC reading. Am I misunderstanding what the reset button does?[attachment=0]Screenshot_20200407-112929.jpg[/attachment]
Attachments
Screenshot_20200407-112929.jpg
Screenshot_20200407-111850.jpg
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

Mark Walters
Applications Engineering
Posts: 8
Joined: Mon Sep 09, 2019 9:46 am

Re: Skybox SOC reset button doesn't reset SOC

Post by Mark Walters » Wed Apr 08, 2020 3:00 pm

Mike, you are misunderstanding the "reset" SoC process. This doesn't force the S0C "counter" to 100% what it does is force a Bulk charge in hopes that we drive the batteries to their "fully charged" state as defined by the battery manufacturer.

For the Simpliphi's that is an Absorb voltage of at least 54.4v AND less than 4 return amps PER battery. So, if you have 3 batteries then you want 12 return amps.

With SkyBox it is critical that the Absorb is at least 54.4v and the timer is long enough to get to less that 4 amps of charge current at this voltage per battery. I recommend at least an hour.

It is critical that the LBCO is set at 48v. This defines the 0% SoC point. We stop discharge with Min SoC NOT LBCO. 20% SoC is approx 50.8v.

The SoC calculator in SkyBox expects to see the listed Amp Hour capacity to be fit inside this 100% point and this 0% point.

Hence, it is also critical to put in the proper Amp Hour capacity for the battery bank.

Additionally, the charge efficiency for the Simplicity's should be 98%.

And last but certainly not least, it is critical that the Battery Series be set to Simpliphi or to Configuration 1, NOT Custom. This sets up the proper charge and discharge constants so the SoC calculation can be as accurate as possible.

SkyBox has an "intelligent" algorithm that accumulates inaccuracy and calculates a Battery Health fudge factor that attempts to correct of loss of battery capacity over time. Because of this, and because it takes a few cycles to get zeroed in, IT IS CRITICAL to go through a few discharge and COMPLETE 100% charge cycles to reestablish a proper SoC reading anytime anything to do with battery charging is changed.

It is also important for battery health and accurate SoC readings to ensure that you get to 100% SoC fairly regularly as this "calibrates" or "zeros" the counter. Kind of like slamming a stepper motor against a hard stop from time to time.

If you have any questions, please feel free to contact me.

Mark Walters
Manager, Technical Services.

Mark Walters
Applications Engineering
Posts: 8
Joined: Mon Sep 09, 2019 9:46 am

Re: Skybox SOC reset button doesn't reset SOC

Post by Mark Walters » Thu Apr 09, 2020 7:28 am

Mike,

Yes you are miss-understanding the "reset" function. It does not reset the gage, it attempts to force a complete charge cycle, which is V above 54.4 AND less than 4 amps current flowing PER battery. This is 100% full according to SimpliPhi. The second you drop the charger the voltage will drop to a "resting" voltage that will be in the 53.7v ish range. If you have not taken any energy out that battery at 53.7v will still be considered full or at 100% SoC. You can't ensure you are at 100% SoC by merely holding the battery at 53.7v, you must "jam it against the stops" to know it is full. Also, please see my comment regarding, "you must go through several complete charge / discharge cycles, charging to 100%, before the SoC will track". All of the conditions and settings in my previous post must be met before the reported SoC will be reliable.

Best regards
Mark Walters
Manager, Technical Services.

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: Skybox SOC reset button doesn't reset SOC

Post by Mike Curran » Thu Apr 09, 2020 7:32 am

Thanks! I think it's starting to sink in now... :-s
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

Mark Walters
Applications Engineering
Posts: 8
Joined: Mon Sep 09, 2019 9:46 am

Re: Skybox SOC reset button doesn't reset SOC

Post by Mark Walters » Thu Apr 09, 2020 10:19 am

Mike,

Yes you are misunderstanding the "reset" function. It does not reset the gage, it attempts to force a complete charge cycle, which is V above 54.4 AND less than 4 amps current flowing PER battery. This is 100% full according to SimpliPhi. The second you drop the charger the voltage will drop to a "resting" voltage that will be in the 53.7v ish range. If you have not taken any energy out that battery at 53.7v will still be considered full or at 100% SoC. You can't ensure you are at 100% SoC by merely holding the battery at 53.7v, you must "jam it against the stops" to know it is full. Also, please see my comment regarding, "you must go through several complete charge / discharge cycles, charging to 100%, before the SoC will track". All of the conditions and settings in my previous post must be met before the reported SoC will be reliable.

Best regards
Mark Walters
Manager, Technical Services.

Photon Kapture
Forum Member
Posts: 12
Joined: Tue Jan 14, 2020 4:54 pm
My RE system: 3.9 Kilowatt (13) Solar World sw300 Array.
Outback Skybox
(3) Simpliphi Lithium Iron Phosphate Batteries (2) 3.5 and (1) 3.8KWH
Location: Schroeder, Minnesota

Re: Skybox SOC reset button doesn't reset SOC

Post by Photon Kapture » Fri Apr 10, 2020 9:03 am

Mike great question, I've been wondering about this function as well.

2 related questions for Mark or those in the know that may help us simpliphi/skyboxers better understand our systems.

1. What its the difference between "Return Amps" and "Absorb End Amps"? The Skybox menu does not have an option to enter Return Amps that I know of. Only the option for the Absorb End Amps is available.

2. In both the Outback and Simpliphi integration guides, the recommended setting for Absorb End Amps is zero. The Charged Return Amps is recommended as 4 using the FN-DC. but that is not an option for Skybox that I am aware of. What should we be doing here?

Thanks for the explanations.

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: Skybox SOC reset button doesn't reset SOC

Post by Mike Curran » Fri Apr 10, 2020 9:13 am

Hi Photon - You definitely want your Skybox end amps setting set at 4 amps × # Simpliphi 3.8 batteries you have = 12 amps. The integration guide I'm looking at https://documentcloud.adobe.com/link/tr ... 5febf6f1e2 has 4 amps/battery recommended for this setting. It's for an FNDC setup but the same for Skybox:
20200410_120920.jpg
I think return amps are the same as end amps.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

Photon Kapture
Forum Member
Posts: 12
Joined: Tue Jan 14, 2020 4:54 pm
My RE system: 3.9 Kilowatt (13) Solar World sw300 Array.
Outback Skybox
(3) Simpliphi Lithium Iron Phosphate Batteries (2) 3.5 and (1) 3.8KWH
Location: Schroeder, Minnesota

Re: Skybox SOC reset button doesn't reset SOC

Post by Photon Kapture » Thu Apr 16, 2020 1:49 pm

Thanks Mike. I was just curious why the difference in recommendations between end amps and return amps if they are the same thing. But maybe it's because skybox uses a coulomb counter. Admittedly I'm new to this and tying to get up to speed. 8-[

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