We have a 7 year old Outback Dual GTFX 3624 system with around 1100 AHR of 24 volt battery backup supplied by 2400 PV watts - 1200 PV watts tracked [wins by 32% output over the fixed array] and 1200 PV watts fixed on the roof of our office. Consistently the utility back feed is 750-900 watts/hour during a sunny day after meeting all of our home and office loads. Home, Office, battery charging & approx. 750-900 watts spin the meter backwards during the sunny part of the day. Right now it is 724 watts back feed to the utility and hazy with little cumulus floating about.
Dana Orzel - Great Solar Works, Inc - E - d...@solarwork.com - V 970.626.5253 F - 970.626.4140 C - 970.209.4076 web - www.solarwork.com "Responsible Technologies for Responsible People since 1988" P Please consider the environment before printing this email -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of David Katz Sent: Wednesday, April 18, 2012 3:01 AM To: RE-wrenches Subject: Re: [RE-wrenches] PV harvest in grid-tied systems William I have a grid tie system with a Outback Radian and Xantrex 600 volt charge controller with 4kw of modules and it sells back flawlessly. I have revenue-grade monitoring on the system and I am very happy with the output. David Katz Sent from my iPhone On Apr 16, 2012, at 6:51 AM, "William Miller" <will...@millersolar.com> wrote: > Friends: > > There has been recent discussion on this forum about PV production in > grid-tied with battery systems. I have been faced with this same > problem in a 3 XW system installed in 2009. > > The customer's power bill never went down. PV harvest was abysmal. > The system would create great short circuit current but would not > harvest into the batteries. > > It is starting to appear the XW firmware was at fault. The inverters > would charge the batteries too high so the charge controllers would > back off. Upgraded firmware seems to be helping, but the data set is still limited. > > Remember this: just because a PV system can produce does not mean it > will. The charge controller knows only one thing: battery voltage. > If it is high, production is curtailed. > > Off-grid production will also be reduced is consumption is curtailed. > > Charge controllers that can be set for grid-tied applications help, > but only if the inverter(s) do not keep the battery voltage too high. > > William Miller _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
