Hello, Allan. I¹m actually just sitting at my desk looking at a grid-direct string inverter guide we¹re going to publish in the first issue of SolarPro magazine.
The SMA 700, of course , is three inverters in one box. It looks to me like you¹d be operating it in the middle setting w/ 9 modules in series. You¹d have 675Wstc in to a 600W inverter w/ a MPPT range of 100-200Vdc. The smallest Fronius inverter has a MPPT range of 150-450. There are actually two string inverter products with MPPT ranges between these devices: 1. the Kaco 1501xi has a MPPT range of 125-300Vdc 2. the PV Powered 1100EVR (extended voltage range) has a MPPT range of 115 450Vdc Maybe one of these works for you? Mick Abraham¹s idea about using the Enphase micro-inverter (1 per every 2 modules) is very interesting and worth exploring. This device has a MPPT range of 25 40Vdc and is rated at 175 watts continuous. These inverters are shipping, so maybe we¹ll get some installer feedback. Regards, David Brearley, Technical Editor SolarPro magazine NABCEP Certified PV Installer [EMAIL PROTECTED] Direct: 541.261.6545 Fax: 541.512.0343 Visit our Web site at solarprofessional.com On 8/6/08 9:55 AM, "Allan Sindelar" <[EMAIL PROTECTED]> wrote: > Wrenches, > Occasionally, but more frequently recently, we get requests to turn off-grid > systems into grid-tie systems. Usually this involves sale of a property to a > new owner, and either grid is brought in to facilitate an easier sale or the > new owner brings it in. Once grid is in, the off-grid-based system is of > limited utility, as the equipment won't sell back. Most of these new owners > want a maintenance-free batteryless system. > > Unfortunately, most off-grid arrays don't easily convert, as the string sizing > doesn't match. Here's my question: I have two of these requests right now. > Both are systems we installed in the late 90s. One has ten BP 275s, one has > twelve. These are standard 12V 75W modules common to that time. I need advice > on inverters that will work with these strings. > > The Sunny Boy 700, which is the only small inverter model SMA still offers, > will handle one string of up to nine of these in our temperature range. Larger > models require higher string voltage. Fronius also requires higher voltage. > > You know, it's a real problem to have to explain to new green-oriented > homeowners that there's nothing I can do with their ten-year-old PV system to > make it spin their new meter backward. It doesn't do much for the mainstream > perception of PV for these folks. > > What will work with these existing arrays, please? > > Allan Sindelar > allan_(at)_positiveenergysolar.com <mailto:[EMAIL PROTECTED]> > NABCEP certified solar PV installer > Positive Energy, Inc. > 3225A Richards Lane > Santa Fe NM 87507 > 505 424-1112 > > > _______________________________________________ > List sponsored by Home Power magazine > > RE-wrenches@lists.re-wrenches.org > > http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > >
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