E
Ecnerwal
- Jan 1, 1970
- 0
After a couple of years of construction and recovering finances, I'm
getting nearer to buying significant parts of my off-grid system. Some
parts will have to be staged purchases as more money comes in, but the
initial chunk of battery, first inverter, charge controller, one string
of panels, and all that interconnection NEC meeting "stuff" that ends up
costing a lot more than it seems like it should.
At present my offgrid system consists of an unsuitable generator (3600
RPM welder/generator, air cooled) and a bank balance.
As far as I can tell, an installation in Vermont which is off-grid gets
diddly for rebates, tax breaks, etc. Location is SW Vermont, wind
potential stinks (84 foot straight-growing trees), likely solar + fuel
for a good long time since solar alone would blow the budget (though
fuel prices are right up there at the moment with no signs of dropping).
Going to have to lay waste to more trees than planned (not a big lawn
fan) to get sun in for panels. Only hope for microhydro would be very
micro - if the gravity well pans out and has noticable excess water.
Good or bad experiences with cut-rate internet dealers welcomed - good
experiences with dealers local to me also welcomed - I may well have
missed some. Cash is definitely a limiting factor - the budget for the
inital phase is probably not much more than $12,000, assuming no
surprises with other aspects already budgeted. I admit to being somewhat
bemused by the wealth of PV cells which tout being cheaper to make, yet
which cost more per watt than other products they are supposed to be
cheaper than (eg, Unisolar, Evergreen).
My inital application is a bit odd .vs. typical offgrid houses - the
first building up is the shop. It will have need of some pumping
capacity for radiant heat (probably a couple of ~125 watt pumps, duty
cycle not certain), and sporadic use of up to 3-4 HP worth of motors,
along with as much as a kilowatt+ (even if it's _very_ efficent,
slow-starting metal halide - a few dim CFs just won't cut it) of
lighting. It might sit for most of a week (or longer) doing nothing but
running the heat, and then get used for several hours of motor-heavy
work - a low average, but high peak use. Over time more typical house
loads will be added. I'm strongly considering DC pumps for the heat, but
that might limit me to 24V (or needing to fiddle about to get 24V from
48V).
Thus far all motor loads can be run 120V (3-4hp is multiple motors at
once). While many could be switched to 240V for less amperage, messing
about with balancing 240/120V seems more complex than just sizing the
wiring correctly for 120V.
General thoughts are 48V battery bank, with a dedicated "power house"
including a nice basement/vault for them to hide from the winter (and
summer) in. All reading indicates that I should try to make the battery
as big as I need for the next 10 years right off the bat, and that the
ideal situation would be 2V individual cells in a single series string.
Of course, many people seem much happier having switched to AGM or gel
batteries (which don't appear to come in 2V cells) and the lowest
starting cost option of golf cart batteries is 6V and high maintenance
with a likely need to run several parallel strings, with associated
equalization headaches.
A liquid-cooled diesel generator has been in the plans, but is becoming
more questionable as the price of all forms of petroleum shoots up.
I will no doubt start undersized for panels, and then have to plan to
add them in chunks over time as more money comes in (I have a practical
aversion to loans if they can be avoided - saves a lot of money on the
long run). Presumably this will mean needing to run the generator to top
up the battery some, as well as to support the major loads if run for
much length of time in the early phase.
PVWatts indicates that Nov/Dec are the worst months - sounds about right
for the cloudy VT weather.
I'm mostly looking for ideas about what you would do differently if you
were starting with a blank slate, within the context of the general
background information I've provided to make it less a purely vague
question. Aspects like detailed system sizing are inherently somewhat
vague, as it's not just a matter of household appliances with
predictable use times and power draw, nor much room for "reduce power
use first" with motors that inherently need a good deal of power (even
if they could be 100% efficient, which they cannot).
getting nearer to buying significant parts of my off-grid system. Some
parts will have to be staged purchases as more money comes in, but the
initial chunk of battery, first inverter, charge controller, one string
of panels, and all that interconnection NEC meeting "stuff" that ends up
costing a lot more than it seems like it should.
At present my offgrid system consists of an unsuitable generator (3600
RPM welder/generator, air cooled) and a bank balance.
As far as I can tell, an installation in Vermont which is off-grid gets
diddly for rebates, tax breaks, etc. Location is SW Vermont, wind
potential stinks (84 foot straight-growing trees), likely solar + fuel
for a good long time since solar alone would blow the budget (though
fuel prices are right up there at the moment with no signs of dropping).
Going to have to lay waste to more trees than planned (not a big lawn
fan) to get sun in for panels. Only hope for microhydro would be very
micro - if the gravity well pans out and has noticable excess water.
Good or bad experiences with cut-rate internet dealers welcomed - good
experiences with dealers local to me also welcomed - I may well have
missed some. Cash is definitely a limiting factor - the budget for the
inital phase is probably not much more than $12,000, assuming no
surprises with other aspects already budgeted. I admit to being somewhat
bemused by the wealth of PV cells which tout being cheaper to make, yet
which cost more per watt than other products they are supposed to be
cheaper than (eg, Unisolar, Evergreen).
My inital application is a bit odd .vs. typical offgrid houses - the
first building up is the shop. It will have need of some pumping
capacity for radiant heat (probably a couple of ~125 watt pumps, duty
cycle not certain), and sporadic use of up to 3-4 HP worth of motors,
along with as much as a kilowatt+ (even if it's _very_ efficent,
slow-starting metal halide - a few dim CFs just won't cut it) of
lighting. It might sit for most of a week (or longer) doing nothing but
running the heat, and then get used for several hours of motor-heavy
work - a low average, but high peak use. Over time more typical house
loads will be added. I'm strongly considering DC pumps for the heat, but
that might limit me to 24V (or needing to fiddle about to get 24V from
48V).
Thus far all motor loads can be run 120V (3-4hp is multiple motors at
once). While many could be switched to 240V for less amperage, messing
about with balancing 240/120V seems more complex than just sizing the
wiring correctly for 120V.
General thoughts are 48V battery bank, with a dedicated "power house"
including a nice basement/vault for them to hide from the winter (and
summer) in. All reading indicates that I should try to make the battery
as big as I need for the next 10 years right off the bat, and that the
ideal situation would be 2V individual cells in a single series string.
Of course, many people seem much happier having switched to AGM or gel
batteries (which don't appear to come in 2V cells) and the lowest
starting cost option of golf cart batteries is 6V and high maintenance
with a likely need to run several parallel strings, with associated
equalization headaches.
A liquid-cooled diesel generator has been in the plans, but is becoming
more questionable as the price of all forms of petroleum shoots up.
I will no doubt start undersized for panels, and then have to plan to
add them in chunks over time as more money comes in (I have a practical
aversion to loans if they can be avoided - saves a lot of money on the
long run). Presumably this will mean needing to run the generator to top
up the battery some, as well as to support the major loads if run for
much length of time in the early phase.
PVWatts indicates that Nov/Dec are the worst months - sounds about right
for the cloudy VT weather.
I'm mostly looking for ideas about what you would do differently if you
were starting with a blank slate, within the context of the general
background information I've provided to make it less a purely vague
question. Aspects like detailed system sizing are inherently somewhat
vague, as it's not just a matter of household appliances with
predictable use times and power draw, nor much room for "reduce power
use first" with motors that inherently need a good deal of power (even
if they could be 100% efficient, which they cannot).