[RE-wrenches] Very small PV systems for surveillance or other "micro" loads

[Jason Szumlanski]

I'm well aware of load creep. After installing a 6kW off-grid system I went
out to a site to diagnose performance issues. The owner had purchased a
six-seat electric golf cart and was charging it off the inverter. I had to
bite my lip to avoid hysterical laughter over this "small" unmentioned load.

The golf cart had eight T-105's and the house battery was sixteen S-530's.
The owner didn't believe that the golf cart battery had over 25% of the
house battery capacity.

That was an expensive mistake (for him).

I like the idea of listing estimated consumption somewhere, but I don't
want to become contractually bound to supply or store a certain amount of
energy. Performance guarantees are tough, especially when you are not the
operator.


Jason Szumlanski

Fafco Solar





On Tue, Jan 21, 2014 at 12:26 PM, Dan Fink <danbob88 at gmail.com> wrote:

> I also see lots of "load creep" Ray...."oh, forgot to tell you....we need
> to add some all-night LED area lighting to the system. It won't use much
> power......"
>
> Dan Fink
>
>
>
>
> On Tue, Jan 21, 2014 at 10:22 AM, Ray Walters <ray at solarray.com> wrote:
>
>>  On these small projects, its very important to nail down the exact
>> load, to keep the pricing sane.  I list on the estimate what the system is
>> designed to do; for instance 18 w load 24 hrs/ day.  Then if something goes
>> wrong and they are running more than they should you just gently point out
>> that that was not what the system was designed to do.
>> I learned a long time ago, that you can't take name plate power draw
>> numbers, or count on the manufacturer to provide those numbers; you've got
>> to confirm it with your own monitoring equipment.
>>
>> R.Ray Walter
>> CTO, Solarray, Inc
>> Nabcep Certified PV Installer,
>> Licensed Master Electrician
>> Solar Design Engineer303 505-8760
>>
>>
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