[RE-wrenches] Electrolytic Caps vs. Thin Film Caps

Thu Jan 19 15:30:04 PST 2012

Steve,

Good information. Thank you. 

I would like to see SMA offer a low temperature line of inverters in the
States. I believe that is arbitrary and foolish to demarcate Canada as COLD
and the USA as NOT AS COLD. 

The northern tier US states from the Rockies east get damn cold while
Canada's British Columbia is balmy by comparison (at least where it's
heavily populated).

Could we simply purchase the Canadian inverters here?

Thanks for listening,

David Palumbo

Independent Power LLC 

462 Solar Way Drive

Hyde Park, VT 05655

www.independentpowerllc.com 

NABCEP Certified PV Installer

Vermont Solar Partner

24 Years Experience, (802) 888-7194 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Steve
Jefferson
Sent: Thursday, January 19, 2012 6:02 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Electrolytic Caps vs. Thin Film Caps

Afternoon Wrenches,

All SMA models in the US are rated for -25C (-13F). Canadian models are
rated for both -25C and -40C.

I highly recommend if installing in areas with any extreme temperatures, to
build an enclosure around the units. Sometimes with the wind chill factor
temps can be quite more than just the ambient temp. Installing in a
conditioned building is always ideal though.

I talked with an installer in New Jersey who had a system that was not
turning on until late morning. He went out with in early morning with and
took the temperature from one of the caps and it was about -30 F. We figured
out that this extreme cold was caused by the north to south wind hitting the
inverter, mounted on the backside of the ground mount. He built a little
wall to protect from the wind, and the problem was solved.

SMA America, LLC

Steve Jefferson

Sr. Technical Service Specialist, Sunny Family

6020 West Oaks Blvd, Suite 300

Rocklin, CA 95765 - 3714

U.S.A.

Tel:  +1 916 625 0870

Fax: +1 916 624-2445

Service Line +1 877 697 6283 (Toll Free)

Email: steve.jefferson at sma-america.com

www.SMA-America.com <http://www.sma-america.com/> 

This email and any attachments thereto may contain SMA America, LLC
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From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Drake
Sent: Thursday, January 19, 2012 6:14 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Electrolytic Caps vs. Thin Film Caps

Dave,

That is really good news. I went through this with Steve Jefferson and SMA
recently.  They said that -13F was the limit.  Steve has posted to this
effect on the list, but I couldn't find it in the archives.  The
recommendation was that I get a Canadian model, but was not able to.  Where
we are, it seldom gets below zero, but has historically gotten to -26
officially, and according to many it has gotten below - 30.  The customer
has agreed to shut down the outdoor unit if it gets below -10F.  It would be
good to know that SMA's recommendations are over cautious.  What is the
coldest you have seen your inverters operate at?

Thanks,

Drake 

Drake,

Before installing Sunny Boys outside I did some checking several years ago.
I spoke with some installers in cold locations in the USA and also spoke
with contacts at SMA. The word back then was although the manual states
-13F, they felt the SB's would be OK outdoors here in Vermont. I also go the
go ahead from Solectria and Fronius.  James Worden, top boss at Solectria
said -40F. The Fronius engineer told me that the electronics in their
inverters were basically the same components that they use in their welders,
and that the welders sit outside in Siberia, in the winter. 

We try and install inverters in the basement, or garage, whenever possible
but have many outdoors with no problems so far. 

All Earth Renewables have been installing hundreds of trackers here in
Vermont and they all have Sunny Boys mounted on the pole.

Best,
Dave

From: re-wrenches-bounces at lists.re-wrenches.org [
mailto:re-wrenches-bounces at lists.re-wrenches.org
<mailto:re-wrenches-bounces at lists.re-wrenches.org> ] On Behalf Of Drake
Sent: Wednesday, January 18, 2012 6:47 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Electrolytic Caps vs. Thin Film Caps

The SMA inverters will suffer capacitor damage if operated below -10F, from
what I've been told.  Do you have different information?  

At 09:19 AM 1/15/2012, you wrote:

Hello David,

The minimum temperature rating for grid-tied inverters
is dependent on the manufacturer's specifications.  It's
a choice they make as a part of the product design
and certification.

The manufacturer must specify the coldest temperature
as a part of their UL1741 certification effort, and
that's the coldest to which it will be tested and
verified as operational by the UL certification
laboratory (NRTL).  Will it operate below the min
temperature spec?  It might.  But then again, it's
not verified to do so.  Some bad things can happen
if the components don't handle cold very well, and
power is applied (such as actual failure of parts.)

Quality electrolytic capacitors are generally rated
to -40C (which also happens to be -40F).  Film caps
are often rated for temperatures below -40C, but at
-40C, other components such as microprocessor clock
crystals and many integrated circuits will fail to
operate, so the point of film caps being rated for
colder temperatures than electrolytic caps is moot.

Note this is "fail to operate", not "fail".

Cold-temperature components rated to -55C *could* be
used in inverter construction, but parts of this type
add cost (sometimes considerably) to the finished
product price.

By the way .. to your point of cold temperature specs
not appearing in writing ...

Our PVAC Modules *are* rated to operate at -40C, and
have been tested to that temperature by the UL test
lab.  This rating is stated in writing in our brochures
as well as the PVAC Module Installation Manual/User's
Guide.

Dan

--- On Sun, 1/15/12, Dave Palumbo <dave at independentpowerllc.com> wrote:

> From: Dave Palumbo <dave at independentpowerllc.com>
> Subject: Re: [RE-wrenches] Electrolytic Caps vs. Thin Film Caps
> To: "'RE-wrenches'" <re-wrenches at lists.re-wrenches.org>
> Date: Sunday, January 15, 2012, 7:32 AM
> Dan,
> 
> Any worries with inverters located out in 30 below zero
> temps with either Electrolytic Caps or Film Capacitors?
> It's very cold here this AM (minus twenty something F)
> and it makes me wonder about all the inverters, both
> micro's and string, outside in cold weather areas. We've
> been told in the past by SMA, Fronius and Solectria that
> we should be good down to 40 below, although this is
> typically not found in their technical documents in
> print.
> 
> David Palumbo
> Independent Power LLC 
> 462 Solar Way Drive
> Hyde Park, VT 05655
> www.independentpowerllc.com <http://www.independentpowerllc.com/>  
> NABCEP Certified PV Installer
> Vermont Solar Partner
> 24 Years Experience, (802) 888-7194 

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Drake Chamberlin         
ATHENS ELECTRIC LLC
OH License 44810        
CO license 3773
NABCEP Certified PV

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