Geoff,
The ultimate issue is how many cells are in each series string and is the voltage of the cells nearly the same. As long as the number and the voltage of the cells match up for each string, it makes no difference what arrangement the modules are in. You could have 5 + 6 + 7 = 18 cells in one group and 3+10+5 =18 cells in another group, and its all good as long as they are similar cells. Unisolar, due to the low fill factor, is actually pretty forgiving of difference modules and cells. If you need help, let me know. Bill. From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jason Lombard Sent: Friday, October 31, 2008 8:55 AM To: RE-wrenches Subject: Re: [RE-wrenches] mix-n-match Unisolar You are correct and they are not. The entire string or array will drop the lowest performing panel and seriously detain performance. On Thu, Oct 30, 2008 at 2:29 PM, Geoff Greenfield <[EMAIL PROTECTED]> wrote: I thought I knew the answer to this one, but wanted to run it by the list. We are responding to a bid where the electrical engineer has designed a system with different sized Uni-solar laminates in some series strings paralelled with consistant full size strings. (this was done to work around skylights etc). We suggested that this was a poor design and will lead to "least common denomenator" performance, exacerbated by MPPT confusion. The EE responded that "the bypass diodes allow for this". Any experience with this in practice? For a brighter energy future, Geoff Greenfield Founder and CEO Third Sun Solar & Wind Power Ltd. 340 West State Street, Unit 25 Athens, OH 45701 740.597.3111 Fax 740.597.1548 www.Third-Sun.com Clean Energy - Expertly Installed _______________________________________________ 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 -- Jason Lombard Open Hand Solar LLC. HC74 Box13 Pecos, NM. 87552 505 795 8646
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