Hi, Wrenchies~<br><br>If code compliance were not an issue, one might connect a Photowatt 47 in parallel with a Golden Genesis 75 to effectively yield a 122 watt unit around 17 volts @ max power...and those two resulting units could then be connected in series with the two Kyocera 120's to create a single charging string around 68 volts & 7 amps. In a situation where the client doesn't want to junk their Heinz 57 modules...that would work, wouldn't it?<br>
<br>Then the PW 1000 modules could be jumpered back to 24 volt nominal per each and chain those into a second charging string, also around 68 volts @ the max power point. <br><br>I realize Bob Clark may not want to go there for various reasons but this exercise might prove useful in other situations. Replies would be appreciated as part of my ongoing education. <br>
<br>Side note: Abandoning perfectly good but non UL modules seems of low importance when the voltage is relatively low...because the "UL compliant array combiner box" which would surely be installed has the overcurrent devices necessary to protect against potentially bad events...and those events are quite unlikely anyway.<br>
<br>Jolliness,<br><br clear="all">Mick Abraham, Proprietor<br><a href="http://www.abrahamsolar.com">www.abrahamsolar.com</a><br><br>Voice: 970-731-4675<br>
<br><br><div class="gmail_quote">On Sun, May 2, 2010 at 2:29 PM, Bob Clark <span dir="ltr"><<a href="mailto:bclark@solar-wind.us">bclark@solar-wind.us</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
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<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">Wrenches:</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;"> </span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">We were called to assess the status of an off-grid system
that is not the worst I have seen, but it comes close.</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;"> </span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">I have some preliminary thoughts about system redesign,
but would like to hear from the Wrenches about the array.</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;"> </span></p>
<p class="MsoNormal"><b><span style="letter-spacing: -0.3pt;">Givens:</span></b></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">We will not install anything unless it is to code.
It is obvious that none of the existing system was installed to code.</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">We will use the existing 24V battery bank consisting of
8, Trojan L16s. The batteries are still “relatively fresh.”</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">Pump is a Franklin pump ˝ hp 115VAC. The CFs dim
when the pump starts.</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">New load will be a GRINDER PUMP FOR SEPTIC = 2HP, 15amp
(240 or 120VAC – more than likely it will be 240V pump) – Another
light dimmer!</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">Modest daily electrical load (estimate no more than 600
WHr/day; 25AHr) – they are <i><u>very good</u></i> at managing their
electrical use.</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;"> </span></p>
<p class="MsoNormal"><b><span style="letter-spacing: -0.3pt;">Solar array – to keep or replace?</span></b></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">8 solar modules – a Heinz 57 mix of older modules -
2 Photowatt PMX500 (Are these modules UL listed? There did not appear to
be a rating label on the back.) wired in series, 2 Kyocera KC120-1 wired in
series, 2 Golden Genesis PV-75 wired in series, 2 Photowatt PW 1000 12V-24V
internally wired for 24V wired in parallel with the other modules strings
– all of these modules are wired in 5 parallel strings for approximately
34.2Vmp and 20.4Imp, ~695W (STC). Oh, and they need a new mounting
structures for the modules.</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;"> </span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">Should I try to work with these modules or advise the
customer to start over (any modules that are not UL listed will have to go)?</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;"> </span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">What is a good “rule of thumb” for a ratio of
PV watts to battery bank capacity per day of autonomy?</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;"> </span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;">Thanks for your ideas.</span></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;"> </span></p>
<p class="MsoNormal"><b><span style="font-family: Papyrus; color: rgb(227, 108, 10);">Bob Clark</span></b></p>
<p class="MsoNormal"><b><i><span style="font-family: Papyrus; color: rgb(227, 108, 10);">SolarWind
Energy Systems, LLC</span></i></b></p>
<p class="MsoNormal"><span style="letter-spacing: -0.3pt;"> </span></p>
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