[RE-wrenches] How large is too large?

[Allan Sindelar]

We had a similar lead come up a year ago, although the lodge in this case
was 22 miles from mains power and 10K feet up.
Thank goodness we had contracted $3500 in design fees up front to do all of
the load projection and design research work. We determined that the
batteries were the limiting factor: at 48V, about 2,000 amp-hours, and two
or three strings max (depends on expected DOD), we couldn't provide a
battery bank large enough.
 
The only solution we arrived at was using Sunny Islands in 3 phase,
redundant generators, duplicate services, Sunny Boys on arrays, and Windy
Boys on two Provens to build an AC-coupled microgrid. That way we had
duplicate battery banks.
 
When we presented the general design approach to the owner's (common
household name, largest private landowner in the US) representatives through
the electrical engineer, with a preliminary estimate around $700K, they
decided to run the lodge on generators.

Allan Sindelar 
 <mailto:allan at positiveenergysolar.com> allan(at)positiveenergysolar.com 
NABCEP Certified Solar PV Installer 
Positive Energy, Inc. 
3201 Calle Marie 
Santa Fe NM 87507 
505 424-1112 

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Mark Dickson



Hello Wrenches, 

I have a customer that has really likes the thought of being off-grid and
they have asked me to design a system for their "lodge".  I have kicked and
screamed to get them to consider a grid-tied system using their existing
grid service-to no avail.  

After doing a preliminary load analysis, I have determined that it would
take ~35kW of solar and a couple Bergey Excels for it to work along with a
19,000Ah battery bank.  

So, how big is too big?  If we were to move forward on this, what would be
the major obstacles/show stoppers besides the price (as price is not an
issue)?

What are some of the largest battery based systems that you have installed
or heard of?

Any input is welcome. . .besides being told just to run away from this one.
. .

 

REgards, 

 

Mark Dickson

Oasis Montana Inc.

 <http://www.oasismontana.com/>  <http://www.oasismontana.com/>
www.oasismontana.com

  

 

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