<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">Wrenches,<br><br>I wish this urban myth about electrolytic capacitors would<br>die, but it won't. It's been a wonderful marketing ploy for<br>some time now.<br><br>Simply stated, existence of electrolytic capacitors in inverters<br>does NOT mean the inverters are less reliable. Satellites<br>have been using electrolytic caps for decades, and look<br>how long THEY last! (I know, because I've helped to design<br>power supplies for aerospace applications.)<br><br>What it boils down to is this: if a quality electrolytic capacitor<br>is used within its specifications, you can expect 60+ years<br>of life from it in an inverter application. Conversely, if a<br>circuit is poorly designed, you can ruin any electronic part<br>in a very short time.<br><br>What defines capacitor "life"? It's defined as the doubling<br>of the internal effective
series resistance of the capacitor<br>from the value it had when it (the cap) was new.<br><br>This is energy lost. It also causes the capacitor to operate<br>at a slightly higher internal temperature than when it was<br>new (all other factors being the same).<br><br>Result? It all depends on how the circuit is designed. In<br>our case, the inverter efficiency decreases approximately<br>a quarter to one half of a percent. The waveform distortion<br>also increases, but it takes lab grade equipment to detect<br>the change. If you're worried about a 1/2 percent drop in<br>the inverter efficiency, your concern is misplaced. After all,<br>PV degrades over time much more than that!<br><br>So why the bad rap on capacitors?<br><br>Like tires, they DO wear out. 40 years ago, "premium"<br>tires were rated for 30,000 miles. Could you wear them<br>out in less? Absolutely! Drive like a 16 year old kid
with<br>a muscle car, and it's easy. On the other hand, I just bought<br>a new set of tires. The old ones still had tread, but at 88,000<br>miles, they'd seen their better days. This is a far cry from 30k<br>mile tires.<br><br>Capacitors have progressed in the same manner. A long time<br>ago, capacitors wore out in 5 to 10 years. Today, it's an entirely<br>different story.<br><br>As long as the circuits in which the electrolytic capacitors are<br>used are well designed, you have nothing to worry about.<br>Electrolytic capacitors in a well-designed application will outlive<br>all of us.<br><br><br>Dan Lepinski<br>Senior Engineer<br>Exeltech<br><br><br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;">From: Andrew Truitt <atruitt@gmail.com><br>Subject: Re: [RE-wrenches] SolarEdge v Enphase<br>To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org><br>Date: Thursday,
January 12, 2012, 12:25 AM<br><br><div id="yiv763444694"><div><br></div><div>Does anyone have any experience installing SolarEdge? The advantage that I see over microinverters from a reliability standpoint is that the power optimizers do not contain electrolytic capacitors. The inverter is also supposed to last longer since it does not handle the MPPT duties so the electronics are less complex.</div>
<div><br></div><div>Marv - Do you have any SolarEdge reliability and / or performance data you can share beyond the white paper on the SolarEdge website? Also, one issue that I've had with Enphase is an occasional loss of data transfer between inverters and the monitoring system - does SolarEdge have that issue? If not, how have you overcome it? Can you share a link to a live SolarEdge system monitoring interface?</div>
<div><br></div><div><br></div><div><br></div><div>Andrew Truitt</div><div>Truitt Renewable Energy Consulting</div><div><br></div><br><br><div class="yiv763444694gmail_quote">On Thu, Jun 9, 2011 at 12:40 PM, Mark Frye <span dir="ltr"><<a rel="nofollow" ymailto="mailto:markf@berkeleysolar.com" target="_blank" href="/mc/compose?to=markf@berkeleysolar.com">markf@berkeleysolar.com</a>></span> wrote:<br>
<blockquote class="yiv763444694gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><u></u>
<div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial"><span>Indeed.....</span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial"><span></span></font> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial"><span>Yes it is 1v per module when not operating, but still
>250V when operating. That means that all code requirements for >250V
still apply to the DC wiring such as bonding bushings for conduit as required
etc.</span></font></div>
<div><font color="#0000ff" face="Arial"></font> </div>
<div><span><font color="#0000ff" face="Arial">SolarEdge is
making hay off of this safety feature, but this feature is inherent in
microinverters as well. </font></span></div><div class="yiv763444694im">
<p><span lang="en-us"><font face="Arial"></font></span> <br><span lang="en-us"><font face="Arial">Mark Frye</font></span> <br><span lang="en-us"><font face="Arial">Berkeley Solar Electric Systems</font></span> <br><span lang="en-us"><font face="Arial">303 Redbud Way</font></span> <br>
<span lang="en-us"><font face="Arial">Nevada City, CA 95959</font></span> <br><span lang="en-us"><font face="Arial"><a rel="nofollow">(530) 401-8024</a></font></span> <br>
<span lang="en-us"></span><a rel="nofollow" target="_blank" href="http://www.berkeleysolar.com/"><span lang="en-us"><u><font color="#0000ff" face="Arial">www.berkeleysolar.com</font></u></span></a><span lang="en-us"><font face="Arial"> </font></span> </p>
<div> </div><br>
</div><div dir="ltr" lang="en-us" align="left">
<hr>
<font face="Tahoma"><b>From:</b> <a rel="nofollow" ymailto="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank" href="/mc/compose?to=re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>
[mailto:<a rel="nofollow" ymailto="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank" href="/mc/compose?to=re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>benn
kilburn<br><b>Sent:</b> Thursday, June 09, 2011 10:54 AM<br><b>To:</b>
Wrenches<br><b>Subject:</b> Re: [RE-wrenches] SolarEdge v
Enphase<br></font><br></div><div class="yiv763444694im">
<div></div>Mark,
<div>I thought that the SolarEdge reduced the 'string' voltage to 1V per
unit/module, reducing the high DC voltage risk factor, until the inverter switch
was turned on?</div>
<div><br>The fact that by hitting the "off" switch on the inverter will reduce
the potentially high DC voltage to 1V per unit/module could be an advantage from
a safety perspective (maintenance, firemen/utility workers)</div>
<div><br></div>
<div>Labor/time-wise, it is like installing both a microinverter system and a
string inverter system together, soooooo....</div>
<div><br></div>
<div>benn</div>
<div><br><span style="COLOR:rgb(0,32,96);"><font face="'Franklin Gothic Medium'">DayStar Renewable Energy
Inc. </font></span>
<div>
<div><font face="'Franklin Gothic Medium'"><a rel="nofollow" ymailto="mailto:benn@daystarsolar.ca" target="_blank" href="/mc/compose?to=benn@daystarsolar.ca">benn@daystarsolar.ca</a></font></div>
<div><font face="'Franklin Gothic Medium'"><a rel="nofollow">780-906-7807</a> </font></div>
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