Building Reserve and Using KWH

[Mike 134]

After a decade the 15KW system here has again developed
wiring problems. The twin 7.5KW inverters normally are a
match to around 1%, but lately EAST was lagging some. A
quick check with the clamp on DC ammeter indicated all
strings were close to a match. More checking, after half a
day running full power (that is up to 8 hours with this
configuration) the EAST DC disconnect box was getting pretty
warm.

As usual I set up a night work light and waited for the darkness.
Inside the Square D 361 box a 6 gauge wire looked like it
was cooking its insulation. The 361 is rated 30A against
the 22 I run, and 600VDC against my 400, 3 contact positions.
Something about the plus array wire was making poor contact
and getting ready to burn out. It was not my wire clamp screw.

I had this same failure on another contact years ago, I had
just moved the wires to the spare position. Something was
not making good contact, not sure if it was the bolts holding
metal together, or the switch contact. Is there a contact lube
that should be used on these?

Fortunately I have a lot of spare parts, and these boxes are
designed so a few screws from the open door side allow
replacing whole units. I found a nice switch section, made
sure all its screws were pretty tight, and soon had it installed.
Hand test today indicated proper cool operation.

There are plenty of the 361 outdoor boxes on Evil Bay, some
with 600V fuses (that I do not need), and some with just a
switch. Bruce Roe PVburnedDC.jpg

Is that brownish color light rust on the rivets? Perhaps some condensation over the past 10 years leading to the poor connection.

[bcroe]

After a decade the 15KW system here has again developed
wiring problems. The twin 7.5KW inverters normally are a
match to around 1%, but lately EAST was lagging some. A
quick check with the clamp on DC ammeter indicated all
strings were close to a match. More checking, after half a
day running full power (that is up to 8 hours with this
configuration) the EAST DC disconnect box was getting pretty
warm.

As usual I set up a night work light and waited for the darkness.
Inside the Square D 361 box a 6 gauge wire looked like it
was cooking its insulation. The 361 is rated 30A against
the 22 I run, and 600VDC against my 400, 3 contact positions.
Something about the plus array wire was making poor contact
and getting ready to burn out. It was not my wire clamp screw.

I had this same failure on another contact years ago, I had
just moved the wires to the spare position. Something was
not making good contact, not sure if it was the bolts holding
metal together, or the switch contact. Is there a contact lube
that should be used on these?

Fortunately I have a lot of spare parts, and these boxes are
designed so a few screws from the open door side allow
replacing whole units. I found a nice switch section, made
sure all its screws were pretty tight, and soon had it installed.
Hand test today indicated proper cool operation.

There are plenty of the 361 outdoor boxes on Evil Bay, some
with 600V fuses (that I do not need), and some with just a
switch. Bruce Roe PVburnedDC.jpg

[bcroe]

Here I am again, smoke from wild fires in the NW is sending haze over
the IL area again. While not terribly severe, it is enough to cause the
inverters to drop out of clipping (about 7600W each), to more like 7300
or 7400W. Bruce Roe

[DanS26]

I recently added an antenna to my mid-1800's barn with a very slick metal roof.........

IMG-0756.jpg

[bcroe]

The pair of Fronius IG 7.5 are just doing their thing after 10 years.
The new-out-of-the-box spare is mounted next to them, just need
to move 2 wires and throw a breaker if backup is needed. Guess
it might be a good idea to actually try that some day, might take
commissioning to get it going. No more worries about high line
voltage programming since the heavy feed was installed in 2020.

Looking good so far this year, the 15KW inverter plant delivered
150KWh today. The previous year was rather poor sun, generation
was a bit under 28,000 KWh. I got to keep more of that, the 2020
heavy feed is delivering close to an extra 1000KWh of generation
to the meter for credit. I made it past 1 April reset with a 1700 KWh
in the black surplus (given to the PoCo). Most stuff here just ran,
one of the 6 heat pumps needs attention.

Some energy ideas, new mounts could boost output and reduce snow
accumulation. And more house insulation, windows and in attic.
Observation of loads is ongoing, but Energy Star and some mods
have brought efficiency to a high level. Design a clipping level monitor.

However most attention today is catch up on stuff ignored for the
first PV decade. Need to get a new antenna up before the old one
falls down, still considering J.P.M.s advice how to (not) do that on
the steel roof. Some really big chunks of snow slid down this winter,
I am building some clamp on slide restrictors using the same 6061
aluminum and 18-8 SS bolts that have worked so well holding panels.
Bruce Roe

[DanS26]

hey Bruce...just wondering how those 7.5 Fronius inverters are holding up?

I wake up every morning and think I'm glad to see another day. My eleven year old Fronius transformer inverters must think the same thing........well maybe if they were AI.

[bcroe]

So another year, Nyle periodically says the unit will
be available, but once again failed to deliver it. Bruce Roe

Once again Nyle announced the e8 water heating heat pump adapter,
might soon be available. It is still in the process of being Energy Star
certified, UEF tested, UL tested, and other things. If I ever get one,
the energy reserve might be exhausted, better than giving it away.

Although this property was purchased with an eye to eliminating the
building maintenance (painting, etc), there was one standard roof on
the house. The shingles, facia, and rain gutters got replaced in 2021,
but now it was so slippery I could hardly go up there. As discussed
earlier, clamps to attach are quite expensive, $5 and up each. After
a bit of experimentation, I came up with this DIY version, using the
same 6061 aluminum and 18-8 hardware as the ground mounts. I
put some special conductive tape over the roof ridge first, to avoid
scratching the paint too much.

This is not normally under much stress, it just gives me a handhold
and a place to connect a safety strap. Note the foot friction strips
which stick to the roof. Bruce Roe

IMGP2436.jpg

[J.P.M.]

This area usually dodges most of that, but we
did get hit with -10F temps and wind giving a chill of -30F (how much
of that applies to buildings?).
Bruce Roe

Bruce:

Strictly speaking, since wind chill is defined as what the air temp. feels like to exposed human skin, not much, that is, zero.

However, dwelling heat loss (or gain) is affected by dry bulb temp. difference inside to outside a dwelling and wind velocity as well as solar input and the radiant effects of the surroundings (including the effective sky temp.)
The higher the wind velocity is on a building element (with effects for wind direction relative to the building element under consideration thrown in), the greater the heat transfer component due to wind vector will be.

I believe I understand the physiological concepts involved with the concept of wind chill, but I always thought wind chill was mostly a bunch of B.S. hype whose only use was/is to make people feel more catastrophic.

If I was out shoveling my driveway in Buffalo w/10F. air temp. and 30 MPH wind (which was pretty common), about the only parts of my body exposed to the air was my nose and eyes. Kind of like who in their right mind opens a window in a blizzard, who's out running around outside butt naked in the cold anyway ?

Give me the dry bulb temp. and the wind vector and I'll dress appropriately for the circumstances.

[Mike 134]

This area usually dodges most of that, but we
did get hit with -10F temps and wind giving a chill of -30F (how much
of that applies to buildings?). This does take a slug of energy, with
my HVAC COP not much better than 1.


Bruce Roe

The strong winds remove heat faster from an object outdoors, but the final temperature still is -10.
Same with your building, if it's fairly airtight the winds won't find ever crack and crevasse to leak in. A tent can feel ok at -10 outside with no wind disturbing the trapped air but have some 30 mph winds pushing into it and it gets pretty cold inside.

[bcroe]

Although energy reserve built up was not very high this net metering
year, warmer weather and some sun allowed it hold for several weeks
past the usual 1 Nov starting decline. I am hopeful to make it thru with
some to spare again this winter. This week weather has been really
tough for the country. This area usually dodges most of that, but we
did get hit with -10F temps and wind giving a chill of -30F (how much
of that applies to buildings?). This does take a slug of energy, with
my HVAC COP not much better than 1.

One consequence, for my first memory in northern IL, the PoCo ask
nicely that customers in a dozen states from the E coast to IL try to
conserve electricity. I do not see much I can do to help. All the
appliances we should avoid using, are not being used just now. With
the all electric conversion, almost all my KWh go to heating these
winter months. But today we did get some real sun, unusual here in
Dec, so I did clear the panels and contributed some 60KWh to the
situation.

With the nuke plant doing nicely, within sight of the property, I doubt
we will get hit with a rolling blackout. If we do, I will be burning fossil
fuels in the gen set and the propane furnace to get by, not very green.
Bruce Roe

[bcroe]

I am entering into my 5th winter of using 6 air to air mini
split heat pumps, to avoid any fossile fuel use, for 2 buildings.
I plan to report on the experience about fall 23, of a lot of
details you will not find on YouTu-e. Service incidents have
been very minimal, less than annual, essentailly all related
to installer lack of experience. However this DIYer has
saved a fortune on the work. Bruce Roe
OcHpN.JPG

[bcroe]

A paramont way to manage on less energy here, is to avoid
wasting it. Any electrical loads continuously on, are subject
to periodic review. Those located outside the living space are
especially of interest, since the energy they waste as heat does
not even contribute (at a low COP) to keeping me warm. These
include GFIs, gas detector alarms, security devices such as motion
detector lights, cameras and controls, central vacuum, garage door
opener controls, TV etc remote control receivers, computer DC
conversion power packs, and battery maintainers for infrequently
used IC engines. Some of these were addressed by plugging into
room circuits that were only on with the lights. Many were hugely
improved with the purchase of Energy Star appliances. Of those
remaining, any Wall Wart powered device aquired is suspect.

There are about 6 Battery Maintainers serving here, for electric
start IC engines. Recently I went thru the maintainers, noting that
they tended to draw maximum over 4W, and not much less even
when battery current was far less power.

It is not so easy to build a really efficient, economical, line frequency,
small line isolation/conversion transformer. There is technology to
get around this using high frequency switching. These may be
recognized by their heft, or rather lack of it.

SwitchMaint.png

I bought a couple of 12V battery maintainers using this technology.
They were set up with my standrd 12V maintainer EC3 connectors,
mating to the EC3 connectors on all my IC engine batteries which
are battery current protected by fusable links. These cannot be
connected backwards or easily come loose, I do not normally use
the supplied clip leads.

CAR WIRE 2.JPGCAR WIRE 1.JPG

This is the battery end wiring with pins ready to insert into the EC3
connector. Note the fusible link in the hot, red positivs lead. For
some wire strain relief a big piece of heat shrink tubing can be used.
I usually make a dummy mating dust cap.

I plugged the new tech maintainer into my Kill-A-Watt, and the no
load draw was 0.0 Watt! My maintainer test unit showed, drain was
very minimal, tracking needed battery current. Voltage regulation was
very good, around 13.85 VDC. Looks like this ap might save me a
couple hundred KWhours a year.

So I will be checking these units for reliability and EMI. If they prove
out over time, all the rest of the control transformers here will get
another look. Bruce Roe

[DanS26]

Bruce I hope you have a grandfathered contract that is forever renewed.

Some REMC POCOs are run by good old boy board of directors that have no clue or business sense. The deal you have is absolute economic nonsense. Good for you!

You better keep that contract in a safe because it's worth its weight in gold.

[bcroe]

Thanks to the weather this has been my worst solar production
year ever. Usually I have some 11,500KWh of energy in reserve
on this date, to be consumed over the winter. I only see
10,300KWh on the spinning disc meter. The system is working
very well, but the clouds are so common, and I may also be losing
to the smoke from the left coast. But I think it will be enough.

I took a shot at measuring net metering inverter efficiency, waiting
for stable strong sun to give clipping. If I believe the inverter
display of voltage and current, input and output, the efficiency of
each is near 93%. Maybe the readout errs, the efficiency was rated
95%. I doubt it has dropped that much, which would cause a lot
more heating. Or is it a hint they are getting old?

I continue to be bombarded with ads for Smart Thermostats. The
price listed is astronomical, which then allows these supposedly
generous rebates. I will just continue to use my little round, tilting
mercury tube thermostat, which will last a lifetime with no batteries
and no maintenance.

Seems natural gas price has tripled in 3 years, electricity is way up
too, propane is probably doing the same. Not buying any here.
Every year the solar science experiment looks like a better investment.

The energy use situation here has hardly changed in 2 years, I do
now have a pretty small attic vent fan with heat/humidity control,
runs a lot of the year. I am told it will help my energy situation,
but that is minimized by good insulation. A complete measurement
would be need to be made for the entire year.

The percent clipping meter did not get built this year.

I have shown an output graph of keeping my inverters in clipping 8
hours straight in good sun. That over the majority of months. BUT
the time never increases, even on the longest day of the year. My
observation of the cause, is the sun rising and setting so far to the
north, trees are shading the panels. One cure might be build a
different array, another is my chain saw. The snow rejection of
the older sections could be improved. We shall see.

The last, variable tilt, snow rejection array construction has been
superior. But increasingly expensive to construct, with the price of
materials. I realized it could easily be built as double sided, with
minimal additional construction cost. So mounting twice as many
PV panels on it would be more economical, with panels so cheap.
Of course this wants to face E-W, at an angle better for snow rejection.

Bruce Roe

[DanS26]

Installed my Nyle in April 2012...so over 10 years of excellent service. Replaced a relay about 5 years ago was the the only time I had to touch it. The unit is well built...I expect at least a 20 year life. My only ding is that it uses neutral switching to control the unit instead of power phase switching. I talked to their engineers about that design and they stated the new unit would not have neutral switching on their 120v systems. I added an extra thermostat control on the input side of things because I don't trust neutral switching in that type of device. Cut in set for 95* and cut out at 125*. Very quiet and efficient......I do not know if it's running unless I'm standing right next to it.

Don't know why the delay in the new E8 product......but the marketing and specs look good.......

https://www.nyle.com/water-heating-systems/units/e8/