Hi: When we developed the AC coupling capability of the XW's we of course looked at what happens when the AC coupled power is larger than the XW power.
As William points out as long as the loads are larger than what the AC coupled inverter can supply, then there is no problem. However, this only works if the loads are consistently larger. A load such as a pump or heater will not meet this requirement if it switches off as it cycles in normal operation. If a large load falls off during AC coupling, then whatever power is being produced by the AC coupled inverter above any used by remaining AC loads will within one AC cycle show up as a charging current to the battery. Depending on the particulars, this abrupt and immediate increase in charging current can cause an overload shutdown of the inverter/charger. For this reason we do not support AC coupling in systems which have a grid tie inverter with a power output larger than the inverter charger. Having said that, engineering is currently working on improvements to AC coupled charging operation, so the situation may change. JARMO _____________________________________________________________________________________ Jarmo Venalainen | Schneider Electric | Solar Business | CANADA | Training & Development Specialist - Senior Phone: +604-422-2528 | Fax: +604-420-1591 | Mobile: +604-505-0291 Email: [email protected] | Site: www.SEsolar.com | Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 *** Please consider the environment before printing this e-mail From: William Korthof <[email protected]> To: RE-wrenches <[email protected]>, Date: 09/14/2014 09:17 AM Subject: Re: [RE-wrenches] Max AC coupling backfeed? Sent by: "RE-wrenches" <[email protected]> I've successfully operated isolated temporary installations where the ac-coupled inverter output significantly exceeds the battery-backup inverter nameplate rating. Obviously there has to be enough "firm" AC load to absorb at least the portion of the AC coupled output that exceeds the grid tie inverter capacity. Hypothetical example: (3) Power One 6 kW 240 output grid-tie inverters with 7.5 kW of PV modules each. (2) Schneider XW6048 battery backup inverters Suppose the supported AC load consisted of a mix of refrigeration and other heavy loads with minimum demand during sunny hours of 6 kW. Or suppose the solar array consisted of modules on steep 45 degree East/West roof surfaces... /wk On Sep 14, 2014, at 8:55 AM, Tump <[email protected]> wrote: All, I am wondering what the max AC Coupled back feed into an OBGTVX 3648 might be. I have installed a 4.9 STC array into a SMA TL5k inverter and the customer presently has an single OB GTVX with a T240 into a Eback up load panel. I would like to know if there are any limitations in this type of configuration using an AC coupling situation to operate during a grid failure. Thoughts please. [email protected] www.SWNL.net Solarwinds Northernlights Serving Mid Coast Maine & Northern California 207-832-7574 Cl. 610-517-8401 Blair "TUMP" May ******** MAINE'S CHARTER ******** NABCEP "Certified PV Installer" ******** MAINE'S CHARTER ******** Trace Xantrex "Certified" Dealer / Installer" _______________________________________________ List sponsored by Redwood Alliance List Address: [email protected] Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/[email protected]/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. ______________________________________________________________________ _______________________________________________ List sponsored by Redwood Alliance List Address: [email protected] Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/[email protected]/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
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