[RE-wrenches] AC Coupling Fronius IG Plus 10.0 inverter

Wed Apr 13 10:25:18 PDT 2011

No, the FSPC cannot be disabled. AFRA can, but that is something a little different.
The FSPC is the main protection against overcharging your battery bank with the SI. Without it, the next protection is the battery charging voltage, which if/when exceeded the SI will disconnect from all sources as a protection measure.
SMA America, LLC
Steve Jefferson
Sr. Technical Service Specialist, Sunny Family
6020 West Oaks Blvd, Suite 300
Rocklin, CA 95765 - 3714
U.S.A.
Tel:  +1 916 625 0870
Fax: +1 916 624-2445
Service Line +1 877 697 6283 (Toll Free)
Email: steve.jefferson at sma-america.com
www.SMA-America.com<http://www.sma-america.com/>

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From: Mark Frye [mailto:markf at berkeleysolar.com]
Sent: Wednesday, April 13, 2011 10:12 AM
To: Steve Jefferson; Gary at IcarusSolarServices.com; 'RE-wrenches'
Subject: RE: [RE-wrenches] AC Coupling Fronius IG Plus 10.0 inverter

Thanks Steve,

Isn't it also possible to disable FSPC in the SI so that the AC coupled inverters can be controlled by a mechanism independent of the SI?

Mark Frye
Berkeley Solar Electric Systems
303 Redbud Way
Nevada City,  CA 95959
(530) 401-8024
www.berkeleysolar.com<http://www.berkeleysolar.com/>

________________________________
From: Steve Jefferson [mailto:Steve.Jefferson at sma-america.com]
Sent: Wednesday, April 13, 2011 10:03 AM
To: Gary at IcarusSolarServices.com; RE-wrenches; Mark Frye
Subject: RE: [RE-wrenches] AC Coupling Fronius IG Plus 10.0 inverter
A Fronius Inverter can be AC coupled with a Sunny Island just fine. The only thing to keep in mind is, that when the SI starts the FSPC, the Fronius unit will go offline with a Frequency A/C error. Wait five minutes, then try to reconnect, it will not reconnect until the SI lowers the FSPC to below 60.5Hz.
I don't know if Fronius has an "off-grid" mode, but if so, you could also place the unit in this mode. It should open the parameters, which will allow for the FSPC to work correctly.
With FSPC, it is a range of + 2Hz from the nominal system frequency that it will occur in.  The nominal Hz can be adjusted in the SI, but is almost always left at 60Hz
IE: Grid fails, SI is generating a frequency of 60Hz. Batteries are charged, and loads in the protected loads panel are low. The SI will start the FSPC and raise one Hz to 61Hz, if the load demand continues to drop the FSPC will continue to rise to 62Hz, thus forcing the PAC on the Sunny Boy to drop to 0W. Both the FAC-Start-Delta (the point where the PAC will start to drop), and FAC-Limit-Delta (the range of the PAC drop) can be adjusted.
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SMA America, LLC
Steve Jefferson
Sr. Technical Service Specialist, Sunny Family
Service Line +1 877 697 6283 (Toll Free)
Email: steve.jefferson at sma-america.com

From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Gary Willett
Sent: Wednesday, April 13, 2011 3:06 AM
To: Mark Frye
Cc: 'RE-wrenches'
Subject: Re: [RE-wrenches] AC Coupling Fronius IG Plus 10.0 inverter

Thanks Mark for educating me about FSC.

Reading SMA docs, FSC allows the Sunny Boy's AC output to be varied from maximum to zero when the
Sunny Island varies its AC output frequency between 60Hz and 61Hz.

Based on your response - do you - or any other Wrenches - have any experience AC coupling the
Fronius inverters? Do they have any problem maintaining connectivity to the "local" grid
when the big grid is down? Are there any battery-based inverter/chargers that Fronius does not like?

I don't want to be on the "bleeding edge" and be the first one to ever design an AC coupled battery
backup system using Fronius. I will call Fronius support next, but any feedback from the group will
be much appreciated.

Gary Willett, PE
Icarus Solar Services LLC

On 4/12/2011 11:37 PM, Mark Frye wrote:
Gary,

I have been looking at some AC coupled stuff lately. The "FSC" is propriatary to SMA, Sunny Island to Sunny Boy.  Pretty much anything else you need something to sense the voltage of the battery bank so you can open a contactor on the AC line to the Fronius when the battery voltage gets too high. Once the voltage drops the contactor can close and bring the Fronius back on line and then the 5-minute start up delay before it is feeding the line again.

Mark Frye
Berkeley Solar Electric Systems
303 Redbud Way
Nevada City,  CA 95959
(530) 401-8024
www.berkeleysolar.com<http://www.berkeleysolar.com/>

________________________________
From: re-wrenches-bounces at lists.re-wrenches.org<mailto:re-wrenches-bounces at lists.re-wrenches.org> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Gary Willett
Sent: Tuesday, April 12, 2011 8:35 PM
To: re-wrenches at lists.re-wrenches.org<mailto:re-wrenches at lists.re-wrenches.org>
Subject: [RE-wrenches] AC Coupling Fronius IG Plus 10.0 inverter
Working on a proposal to add battery backup and a generator to an existing 10kW grid-tie system using the Fronius IG Plus 10.0 inverter.

Does anyone have any experience AC coupling this inverter to a Sunny Island 5048, or a Xantrex 6048? Is the Fronius capable of Frequency Shift control (FSC) that comes from the battery-connected inverter?

Any other suggested solutions is appreciated.

Gary Willett, PE
Icarus Solar Services LLC
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