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The SMA inverters will suffer capacitor damage if operated below -10F,
from what I've been told. Do you have different information?
<br><br>
At 09:19 AM 1/15/2012, you wrote:<br>
<blockquote type=cite class=cite cite="">Hello David,<br><br>
The minimum temperature rating for grid-tied inverters<br>
is dependent on the manufacturer's specifications. It's<br>
a choice they make as a part of the product design<br>
and certification.<br><br>
The manufacturer must specify the coldest temperature<br>
as a part of their UL1741 certification effort, and<br>
that's the coldest to which it will be tested and<br>
verified as operational by the UL certification<br>
laboratory (NRTL). Will it operate below the min<br>
temperature spec? It might. But then again, it's<br>
not verified to do so. Some bad things can happen<br>
if the components don't handle cold very well, and<br>
power is applied (such as actual failure of parts.)<br><br>
Quality electrolytic capacitors are generally rated<br>
to -40C (which also happens to be -40F). Film caps<br>
are often rated for temperatures below -40C, but at<br>
-40C, other components such as microprocessor clock<br>
crystals and many integrated circuits will fail to<br>
operate, so the point of film caps being rated for<br>
colder temperatures than electrolytic caps is moot.<br><br>
Note this is "fail to operate", not "fail".<br><br>
Cold-temperature components rated to -55C *could* be<br>
used in inverter construction, but parts of this type<br>
add cost (sometimes considerably) to the finished<br>
product price.<br><br>
<br>
By the way .. to your point of cold temperature specs<br>
not appearing in writing ...<br><br>
Our PVAC Modules *are* rated to operate at -40C, and<br>
have been tested to that temperature by the UL test<br>
lab. This rating is stated in writing in our brochures<br>
as well as the PVAC Module Installation Manual/User's<br>
Guide.<br><br>
<br>
Dan<br><br>
<br><br>
--- On Sun, 1/15/12, Dave Palumbo <dave@independentpowerllc.com>
wrote:<br><br>
> From: Dave Palumbo <dave@independentpowerllc.com><br>
> Subject: Re: [RE-wrenches] Electrolytic Caps vs. Thin Film Caps<br>
> To: "'RE-wrenches'"
<re-wrenches@lists.re-wrenches.org><br>
> Date: Sunday, January 15, 2012, 7:32 AM<br>
> Dan,<br>
> <br>
> Any worries with inverters located out in 30 below zero<br>
> temps with either Electrolytic Caps or Film Capacitors?<br>
> It's very cold here this AM (minus twenty something F)<br>
> and it makes me wonder about all the inverters, both<br>
> micro's and string, outside in cold weather areas. We've<br>
> been told in the past by SMA, Fronius and Solectria that<br>
> we should be good down to 40 below, although this is<br>
> typically not found in their technical documents in<br>
> print.<br>
> <br>
> David Palumbo<br>
> Independent Power LLC <br>
> 462 Solar Way Drive<br>
> Hyde Park, VT 05655<br>
>
<a href="http://www.independentpowerllc.com/" eudora="autourl">
www.independentpowerllc.com</a> <br>
> NABCEP Certified PV Installer<br>
> Vermont Solar Partner<br>
> 24 Years Experience, (802) 888-7194 <br><br>
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