<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Allan,<div><br></div><div>I have seen the white paper from Sunpower, ( but don't have a copy) that shows the losses as the voltage rises if using neg ground.</div><div><br></div><div>But from memory, if using at low voltages such as two in series there should be minimal if any "loss" of watts.</div><div>If you could use them as singles, for say a 12v system then there is no loss.</div><div><br></div><div>Jay</div><div><br></div><div>Peltz power</div><div><br></div><div><br></div><div><div><div>On Nov 19, 2010, at 7:07 AM, Allan Sindelar wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">
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Wrenches:<br>
This has been addressed before in a slightly different context, so a
short answer is enough. Can a Sunpower module be used successfully
in a negative-grounded low-voltage system?<br>
<br>
The situation: Mark in our Taos office sent me the following: <span style="color: rgb(31, 73, 125);">"We have an old time friend and
customer. [John] and his wife used to help us on various
installations years ago. They're both retired now and living on
fixed limited income. About two months ago, we sold them a
replacement battery bank of golf carts. They have a small off
grid system with a few hundred watts of PV. Recently, [John's
wife] was put on an oxygen machine for a heart condition. The
machine consumes somewhere around 800 Watt-hours per day. Their
system can't keep up now without running the generator most every
day. I was wondering about a couple blem/cosmetic damaged panels
that PosE has at their shop in Santa Fe. I'm not sure yet whether
the best solution would be to upgrade their existing system, or
perhaps a separate system for the O2 machine. Either way, if there
is a way to help them with the equipment, then I'd be happy to
donate my time to help [John] do an upgrade. If there is some way
we can help them out, it would be a good thing. They're just a
couple of really good people who've helped a lot of others out in
their lifetime. Now they're the ones in need, and I'm just trying
to find a way to help them."<br>
<br>
We have two Sunpower 215s with cosmetic damage that can't be sold.
</span>I think that one or both can be used here, but are just
somewhat less efficient if negative grounded. <br>
<br>
What's the straight scoop here, please?<br>
Thanks,<br>
Allan<br>
<br>
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<div class="Section1"><p class="MsoNormal" style=""><span style="font-size: 10pt;">
<a href="mailto:Allan@positiveenergysolar.com" target="_blank"><span class="il">Allan</span>@positiveenergysolar.com</a><br>
NABCEP Certified Photovoltaic Installer<br>
EE98J Journeyman Electrician<br>
<b style="">Positive Energy, Inc.</b><br>
3201 Calle Marie<br>
Santa Fe, New Mexico 87507<br>
<b style="">505 424-1</b></span></p></div></div></div></blockquote></div><br></div></body></html>