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

[Ray Walters]

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 Engineer
303 505-8760

On 1/21/2014 6:07 AM, Jason Szumlanski wrote:
> That's the answer I thought I'd get from most. It's hard to explain 
> the "days of autonomy" and extended bad weather to people. Most just 
> say, "why don't you just make a recommendation." That puts me in a 
> spot where I want to overbuild, which drives up cost.
>
> The other challenge is getting people to tell you the real story about 
> what they plan to plug in. They think 100W @ 120V continuous load 24 
> hours a day sounds like a very small load. When you hit them with a 
> ~1kW system with a ~10kWh battery (with ample reliability factors 
> considered), they freak out. Then you find out that the camera they 
> wanted to plug in only draws 18W @ 12V (no inverter required). That's 
> a big difference.
>
>
> Jason
>
>
>
> On Mon, Jan 20, 2014 at 3:46 PM, Larry Crutcher, Starlight Solar Power 
> Systems <larry at starlightsolar.com <mailto:larry at starlightsolar.com>> 
> wrote:
>
>     Jason,
>
>     We get quite a few of these from US Border Patrol, GM Proving
>     Grounds and other agencies. I always do custom design since every
>     job has different parameters like days of autonomy or remote
>     monitoring/control (SCADA).
>
>
>     Larry Crutcher
>
>
>
>
>     On Jan 20, 2014, at 1:17 PM, Jason Szumlanski
>     <Jason at fafcosolar.com <mailto:Jason at fafcosolar.com>> wrote:
>
>     What do you do for very small off-grid systems that people want
>     for specific equipment? Do you have a "go-to" configuration, or do
>     you size and design everything custom?
>
>     For example, I frequently get, "I want to run cameras at a remote
>     site and the total requirement is 100W, 24 hours a day."
>
>     It's not economical to reinvent the wheel every time.
>
>
>     Jason Szumlanski
>     Fafco Solar
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