<div dir="ltr"><div>Richard,</div><div><br></div>Your response is effectively a testing manual. Thanks! Hopefully my intern and I will get started at least on the prep tomorrow if I get the soldering done tonight. We have 2 XO-1s ready to have the log scripts installed. A few responses below:<br>
<div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Jun 20, 2013 at 7:36 AM, Richard Smith <span dir="ltr"><<a href="mailto:richard@laptop.org" target="_blank">richard@laptop.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div class="im">
On Thu, Jun 20, 2013 at 2:16 AM, Mike Lee <<a href="mailto:curiouslee@gmail.com">curiouslee@gmail.com</a>> wrote:<br>
<br>
> Hi,<br>
><br>
> In case your last 2 days are a quieter ramp down rather than a frenzy...<br>
<br>
</div>:) I've cc:ed power@ so that this is archived and can be referenced later.<br>
<div class="im"><br>
> I ordered this $29.99 12 volt, 10 watt resin panel from eBay in the hopes<br>
> that it might be a serviceable and affordable replacement for the original<br>
> 10 watt GP unregulated solar panel for G1G1 XO-1s.<br>
><br>
> <a href="http://www.ebay.com/itm/10W-Solar-panel-10-Watt-12-V-Garden-Fountain-pond-Battery-Charger-Diode-cable-/251190599766?ssPageName=ADME:L:OU:US:3160" target="_blank">http://www.ebay.com/itm/10W-Solar-panel-10-Watt-12-V-Garden-Fountain-pond-Battery-Charger-Diode-cable-/251190599766?ssPageName=ADME:L:OU:US:3160</a><br>
<br>
> It arrived today (Wednesday) from Xiamen Fujian, China by China Post in only<br>
> 7 business days and one weekend.<br>
<br>
</div>Sweet find. Finally! At $3/W its absolutely a replacement. It won't<br>
be quite as good though as that looks like its a poly-Si panel. So<br>
its going to have a lot more derate when it heats up to NOC. Ask the<br>
supplier if they can provide you with a VI curve. Also ask if they<br>
have a 15W version.<br></blockquote><div><br></div><div>I've contacted the seller to request the VI curve and to see if they have 15 watt or larger in the same panel. Maybe I'll hear from them tomorrow.</div><div>
<br></div><div>Here are some initial photos:</div><div><br></div><div><span class="" style="color:rgb(0,0,0);font-family:Arial;font-size:medium"><a href="http://www.flickr.com/photos/curiouslee/sets/72157634232528701/">http://www.flickr.com/photos/curiouslee/sets/72157634232528701/</a></span><br>
</div><div><br></div><div> </div><blockquote class="gmail_quote" style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="im"><br>
> I'm hoping to install the supplied diode on the positive lead and solder on<br>
<br>
</div>Not necessary for the XO. The XO input already has diodes in the<br>
path. Additional ones will only result in more loss.<br>
<div class="im"><br>
> an XO power cord to do a quick 2-point measure test today or Friday with an<br>
> XO-1 running 12.1.0. Let me know if there might be any gotchas I should be<br>
> aware of. I will run Power Log Collector.<br>
<br>
</div>Use 2 XOs one with the old GP panel and 1 with this new panel so you<br>
can do a relative compare. Do a crossover test as well where half-way<br>
through you swap the panels so that each XO gets run from each panel.<br></blockquote><div><br></div><div>Never would have thought to do crossover.</div><div><br></div><div> </div><blockquote class="gmail_quote" style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<br>
You are using the olpc-panelpwr-log test right? Not just<br>
olpc-pwr-log? panelpwr is what you want for panel testing as it puts<br>
the XO into the lowest possible power mode that you can still log data<br>
from.<br></blockquote><div><br></div><div>Yes, olpc-panelpwr-log. It took a couple extra pokes in Google to find that zip package on GitHub.</div><div> </div><blockquote class="gmail_quote" style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<br>
Oh and make sure you discharge the batteries in the XOs down to the<br>
same level. My suggestion would be that you run each XO on battery<br>
until powerd shuts the system down. Then charge each XO from the wall<br>
for 10 minutes. Just so they have a bit of juice to run on. Then put<br>
them out in the sun for 30 minutes, swap panels and then let them run<br>
until they charge up or your sun dies. A voltmeter on the panel<br>
output while connected would be nice too especially if you have one<br>
that can log readings.<br></blockquote><div><br></div><div>The meter I currently have is pretty basic. But I will have my intern record some readings off the two solder points of the panel using some alligator clip jumper wires.</div>
<div> </div><blockquote class="gmail_quote" style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<br>
Ideally you would run multiple runs of each XO+panel combination with<br>
a battery discharge cycle in between each run so the starting point<br>
was the same for each test. But thats a much longer test. You want<br>
to see 2 things. How does it perform in the bulk charge zone when the<br>
XO is trying to draw more power than the panel can provide (about 1 to<br>
1.5 hours) and then what happens as the battery charges and the<br>
required power draw drops below the output of the panel. This is<br>
where the XO-1 gets into problems with unregulated panels as once you<br>
cross into that zone the voltage on the input to the XO will begin to<br>
rise and if it crosses the 18V threshold then the XO-1 can go into<br>
overvoltage mode. I say 18V because thats the worst case but typical<br>
is about 20V.<br>
<br>
This also can happen when the panel is put in the sun unconnected to<br>
the XO. In that case the load on the panel is zero and the output<br>
voltage will be at it maximum value. If thats > 18V (20V typical)<br>
then when you connect up to the XO it might think its overvoltage and<br>
shut off the input. This is why the GP panels for XO-1 have a 18V<br>
limiter in them.<br></blockquote><div><br></div><div>We'll make it standard practice to place the panel face down before plugging it in. Then flipping it over to start the test.</div><div> </div><blockquote class="gmail_quote" style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="im"><br>
> With a successful test, my hope is that for the ongoing contributor's<br>
> program granting XO-1s and the steady trickle of donated units, this could<br>
> be a solution we can point to for the tinkerer or suitcase deployment<br>
> voluntourist.<br>
<br>
</div>I look forward to the test results and hopefully you have made a great<br>
find that small deployments can use to get solar panels in qty < 100.<br>
<br>
--<br>
Richard A. Smith<br>
One Laptop per Child<br>
</blockquote></div><br></div></div>