Thanks Stephen.  Your questions are interesting.  ;-)

I've measured the 400V run just now with a pole, and calculate it at
about 45.5 m.

(Half width of the array string is 4.5 m, then about 3 m to get into
trench, then 35 m of trench, then about 3 m to get out of trench to
equipment bay.  Tall trees that we are unwilling to remove are the
cause of 20 m extra trench length.)

Don't know if the four runs will be bundled or separately trenched,
but the layout of the array suggests two trenches in a V or Y shape
would maintain minimum lengths.

System was sized for extended outages; minimum loads for domestic
health; water pump, heat pumps, and cooking.  Export uninteresting,
because of high regulatory compliance costs, low price paid, and no
time of export pricing.  That may change later.  Reposit looks good.

(Grid did nearly collapse last summer; forecast demand above available
generator capacity, and I'm estimating 10% probability of a day long
collapse this summer, and 30% the year after. It is difficult to plan
when so many factors may perturb the system on a whim, and the
perturbations haven't been long term lately.  Call me the leading edge
of the death spiral.)

Array is to be ground mounted on a structural steel frame with
concrete around the verticals.

Two tiers; 18 modules on upper tier, 18 modules on lower tier; about
18 m wide, and 3.3 m from top to bottom.  Fixed orientation to solar
North, and not tracking.

You didn't ask, but I'll also mention the equipment bay is to be
inside the house envelope, to increase the life of the batteries.  We
had some 45=B0C 10% RH days last summer.

On Tue, Sep 05, 2017 at 04:25:19AM +0000, stephen.forrest@agilent.com wrote=
:
> Nice system James -
> A couple of q's... (if you don't mind)
>=20
> How long is the 400V run (maybe mentioned previously but??)
> Are the four runs bundled or separately trenched?
> How did you size your system? Was it on existing consumption with net exp=
ort, coverage for outage, price break point, best within budget?
> I remember you planned ground based panels - yes?
> Will they all be at a level or tiered?
> Same orientation or differently optimised for time/season? (I guess not t=
racking.)
>=20
> I'll probably think of other questions after I hit send ;o)
>=20
> I lived off grid for 7 years with an old late 90's - early 00's era syste=
m that came with the property, and newish 12 V 700 Ah LA cells. We were mor=
e than 2 km from the nearest mains power so no other option. Our system onl=
y had a 1200 W inverter with about the same in PV capacity. Fridge was gas,=
 hot water solar/fuel stove and back-up of one of two generators, depending=
 on load. We were very frugal with our power, especially in winter!
>=20
> It was a beautiful place to live (central Victoria). Weeks of 40+ C weath=
er was tough though with no A/C. We are no longer there (work) but how I mi=
ss it.
>=20
> Anyway, good luck with the install. Don't forget to double the works cost=
 ;o)
>=20
> Stephen

--=20
James Cameron
http://quozl.netrek.org/
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.