Drake, The key to your question may be in the "old Arco units". Most Arcos (all predate 1990, when Siemens bought Arco) are 36 cell, but both Arco and Solarex made some 33-cell, 32-cell, and even 30-cell "self-regulating" modules in those years. With fewer cells, the MPPT was too low to benefit much from Boost technology.
I have one customer with Arco M52L "Tri-Lams" and another with 32-cell Solarexes. In both cases I had recommended upgrade to MPPT, but when I saw what modules they had, I told them not to go ahead with the upgrade, as it wouldn't be cost-effective. Allan Sindelar allan(at)positiveenergysolar.com NABCEP Certified Solar PV Installer Positive Energy, Inc. 3201 Calle Marie Santa Fe NM 87507 505 424-1112 www.positiveenergysolar.com Please consider the environment before printing this e-mail. -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake Chamberlin At 09:46 AM 3/20/2009, you wrote: >The CTI-90, rated at 5.15 amps, will reach 7 amps here in Yuma with >the Blue Sky 3024i. Do you use the Blue Sky metering, or have you checked the MPPT output with independent metering? I retrofitted a 12 V Blue Sky charger on an old cabin system. The CC had no on-board metering. My measured result showed almost the same output and input on a cool, sunny day. The modules were ancient Arco units, but I still expected some improvement. Drake Chamberlin _______________________________________________ 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
