Hello Ron, I'll try to point you in the right direction here, but yes you want to move forward cautiously. Good training is easily available all over the place now. I will say that you can be an excellent and successful solar installer these days without any experience with string inverters like this. MLPE has made this possible recently.
If this is on the roof, and you are on a 2014 NEC code or later, you will need some type of module level or string level rapid shutdown device. Tigo seems to work well with the Sol-Ark built in RSS system. As far as stringing, you need to apply your local climate's cold factor to the Voc of the string, or use the module nameplate to figure out the true Voc of each string and stay below the MPPT limit for Voc. If you haven't done this before, I would take a class. You can use Sol-Arks string calculator here: https://www.sol-ark.com/solar-panel-sizing/SolarPanelSizing.html I always check any calculator's output by hand and verify that the Voc goes up as temperature goes down. This step should not be overlooked because you can damage the MPPTs input. The cold temp factor here in Colorado can drive the Voc to 25% above the nameplate ratings, so don't ignore this. Once you have your maximum string length, you want to figure out how to wire this in as efficiently as possible. You can combine 2 strings per MPPT typically, but these parallel strings need to be the same number of modules. You also want the strings to face ~ same direction and have similar shading characteristics for the most efficient operation over time. Be careful and good luck! On Wed, Apr 13, 2022 at 5:29 AM Scot Arey via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: > I agree with an earlier response…isn’t this a NABCEP PV Installation > Professional-only forum? The original question is DC-string design 101. > Jerry is spot on for coldest temp adjustments, RSD considerations if > required. But selecting a home run wire for separate string inputs to the > inverter??? How can this be asked here? > > Ron, are you NABCEP PV Installation Pro certified? > > > > Scot Arey > > Owner, Solar CenTex > > > > *From:* RE-wrenches <re-wrenches-boun...@lists.re-wrenches.org> *On > Behalf Of *Jerry Shafer via RE-wrenches > *Sent:* Tuesday, April 12, 2022 10:27 PM > *To:* RE-wrenches <re-wrenches@lists.re-wrenches.org> > *Cc:* Jerry Shafer <jerrysgarag...@gmail.com> > *Subject:* Re: [RE-wrenches] Sol-Ark install > > > > Need more than this, we have amperage, we need distance, temp, # of wires > per conduit, also at 480 you may want to verify cold temp for over the top > voltage @ VOC, any RSD device(s) being used? Help to have total module > count, as an example use a combiner to make 4 strings, 2 of equal voltage > per input. For battery backup or off grid, Solark is the easiest you will > get. > > Jerry > > NABCEP PV Inspector > > > > On Tue, Apr 12, 2022, 7:42 PM Ron Young via RE-wrenches < > re-wrenches@lists.re-wrenches.org> wrote: > > Hi Wrenches, trying to wrap my head around a first time Sol-Ark install. > Because the max DC voltage is 500v at 18a and the PV I’m using is 40v DC > each I will have to create three strings each 480v. What would be the best > choice for a home run wire? I’ve always used smaller strings with micro > inverters, a combiner at the array and a single Teck home run cable but the > string inverter presents a different scenario and it looks like I’ll need > to use three home run cables, one for each string. > > > > Ron Young > > > > earthRight Products - Solareagle.com > Alternative Energy Solutions ~ Renewable Energy Products > > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > > -- Mac Lewis *"Yo solo sé que no sé nada." -Sócrates*
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