Try the SunSaver MPPT. It is 15A and be wired with Modbus and a display. Thank you,
Maverick Maverick Brown BSEET, NABCEP Certified Solar PV Installer ® President & CEO Maverick Solar Enterprises, Inc. Office: 512-919-4493 Cell: 512-460-9825 Sent from an iPhone. On Oct 11, 2012, at 12:04 PM, Allan Sindelar <al...@positiveenergysolar.com> wrote: > Wrenches, > I'm posting this for Carl Bickford, prof emeritus of the renewable energy > training program at San Juan College in Farmington, New Mexico. I'll forward > your responses to him. > I have a very interesting and talented friend who is rebuilding a blue-water > sailboat for a round-the-world trip. He is well versed in solar and is trying > to use a relatively large array to charge a big battery bank that will be > used for propulsion as well as general electrical. The propulsion system will > be backed up with a propane generator he is building himself out of a Toyota > truck engine. > > As you can imagine, there is no place on a sailboat where shading isn’t a > problem. He and I were wondering if there were products out there that could > MPPT either individual modules, or small groups of them for 12 V battery > charging. I have seen such things for the inputs of grid-tied inverters, but > nothing yet for off-grid. The other choice is to go with many small MPPT > charge controllers like the ones from Solar Converters. > > Any advice you can offer? > > Take care, > Carl > > Carl Bickford > Professor of Engineering and Renewable Energy > San Juan College > 4601 College Blvd. > Farmington, NM 87402 > 505-566-3503 > bickfo...@sanjuancollege.edu > > > I offered the suggestion below. Certainly open to other and better ideas. > Allan > > I have not encountered this situation, so I have no advice from experience. > At 12V, it's hardly an issue as it is with high voltage parallel strings, > where a few shaded cells can cause a whole string to drop out of the > inverter's MPPT. At most, a shaded cell weakens the output of that module. > And since it's charging batteries, there's a greater amount of head room. > > I would suggest looking into Blue Sky Energy's "i" series - smaller MPPT > controllers that can be networked. We seldom use them, as our residential > applications are different. But you could put a controller on a group of > modules and network several together. One advantage, I think (you'd want to > check this) is that Blue Sky's MPPT algorithm is analog, unlike Outback and > others: on the old Solar Boost series, the MPPT boost was set with a trim pot > to a particular voltage above battery voltage; the target is to set it to > where the boost was greatest. You could set this boost slightly lower than > peak, and output just a little below MPP. That way the overall output would > be minimally reduced, and a modest amount of shading would not cause the > shaded module to drop below collective MPP as readily. > > Allan Sindelar > al...@positiveenergysolar.com > NABCEP Certified Photovoltaic Installer > NABCEP Certified Technical Sales Professional > New Mexico EE98J Journeyman Electrician > Founder and Chief Technology Officer > Positive Energy, Inc. > 3209 Richards Lane (note new address) > Santa Fe, New Mexico 87507 > 505 424-1112 > www.positiveenergysolar.com > > > > > > _______________________________________________ > 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 >
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