[HN Gopher] Show HN: My $1k self-install, off-grid solar backup ...
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Show HN: My $1k self-install, off-grid solar backup build for
renters
Author : nikodunk
Score : 129 points
Date : 2024-04-13 18:59 UTC (4 hours ago)
(HTM) web link (sunboxlabs.com)
(TXT) w3m dump (sunboxlabs.com)
| thot_experiment wrote:
| I have 1.2kW of used Sunpower panels I bought for $70/pop about 3
| years ago. Buying decommissioned commercial install panels is
| insanely cost effective. It's crazy how cheap they go.
| dvdbloc wrote:
| Any tips or guides on the best ways to get them? I'm interested
| greazy wrote:
| Do they maintain efficiency?
| nikodunk wrote:
| Yeah! The Sunpower T5s mentioned above are still performing
| at near-max performance as far as I can tell. Things like
| shading or dust will influence modern panels way more than
| their age at this point IMO. Past 20 years I don't know - but
| for the next 10 years, it's seems to be a pretty good hack :)
| arrowsmith wrote:
| Why were they decommissioned if they're still at near-max
| performance?
| thot_experiment wrote:
| Because capitalism is a helluva drug.
| nikodunk wrote:
| Ya re-upping gov/state incentives is the theory I've
| heard in a few places. See e-bikes/EVs/general combustion
| leases where the same happens. Luckily, same as housing
| and transportation it dumps a bunch of lightly used but
| performant gear into the market for people like me.
| sangnoir wrote:
| I suppose the same reason companies get rid of perfectly
| serviceable laptops and servers: depreciation and chasing
| after fractionally larger efficiencies.
| ryjiao wrote:
| Do you have any ideas for where I could get a similar deal?
| voisin wrote:
| Where did you source them?
| nikodunk wrote:
| See links on https://sunboxlabs.com
| hinkley wrote:
| Do you buy "end of life" panels or panels removed during a
| remodel?
| coyotespike wrote:
| I love how clear and to the point this page/guide is. Beautifully
| summarizes the downsides as well as the upsides.
|
| The system is even tempting to me as a homeowner not renter, but
| a similarly simple system that doesn't require running wires
| through the house might work better.
| arrowsmith wrote:
| "We don't even notice power outages or public safety shut-offs
| anymore"
|
| I don't notice these where I live, because they literally never
| happen. Are there really places in the first world in 2024 where
| blackouts still happen frequently?
| loloquwowndueo wrote:
| Yes. They are very common in parts of Canada during winter.
| They get fixed relatively quickly for sure but it's a yearly
| occurrence.
| moooo99 wrote:
| I'm curious as to what the reasons for such regular shutoffs
| are. I'm now 24 years old and I cannot recall ever
| experiencing a power outage, ever. So either I'm
| extraordinarily lucky or they aren't as common here
| bryanlarsen wrote:
| Freezing rain and tornadoes.
|
| https://en.wikipedia.org/wiki/January_1998_North_American_i
| c...
| loloquwowndueo wrote:
| Recent examples:
|
| https://en.m.wikipedia.org/wiki/2023_Canada_ice_storm
|
| And
|
| https://www.msn.com/en-ca/weather/topstories/more-
| than-12600...
| beeeeerp wrote:
| I live in rural CO, and we get them pretty regularly.
| Extreme weather is pretty common out here, and the
| infrastructure isn't as redundant for the mountain
| communities (I assume due to the cost/benefit ratio of
| building new lines).
|
| It's not just power - we had a forest fire one year that
| burned a microwave tower & killed our cell phones _and_
| internet for a week. The local businesses struggled for a
| day or two, because no one really carries cash anymore.
|
| I should add that kind of like the OP, I added an enphase
| LiFePO4 house battery and panels. They'll keep critical
| loads running basically indefinitely, which has been a
| welcome change. We have gas heat, but I used to get nervous
| in the winter when the power went out (our boiler requires
| electricity to run).
| ronsor wrote:
| Unfortunately, I think OP is in San Francisco.
| bhaney wrote:
| Poor soul
| loloquwowndueo wrote:
| Power failures happen there as well.
|
| https://en.m.wikipedia.org/wiki/1989_Loma_Prieta_earthquake
| rgrieselhuber wrote:
| There are some examples of failed states that could have
| formerly claimed first-world status (such as California) that
| experience blackouts.
| bobsomers wrote:
| Calling California a "failed state" over this seems absurd
| when the most extreme example in recent history is the Texas
| freeze power outage in 2021 which left 4.5 million homes
| without power for several days during winter storms.
| Somewhere between 250-700 people died because of it.
| rgrieselhuber wrote:
| It's not the reason I call it a failed state but it does
| occur with more frequency than other states. It's a matter
| of something that happens in an emergency vs ongoing
| issues.
| simonklitj wrote:
| What is the reason, then, that California cannot be
| considered a first world state, and instead a failed
| state? And are there other states that used to have this
| designation, but have lost it in your view? Just curious.
| rgrieselhuber wrote:
| Exploding deficits, tent cities, shit covered sidewalks,
| blackouts, palpable corruption, to name a few. No, I
| don't think it's limited to California, that state just
| kind of serves as a time machine for the rest of the
| country.
| simonklitj wrote:
| Ah, okay. I think we have different ideas of what
| constitutes a failed state.
| arwineap wrote:
| You're being delusional. Maybe reconsider
| FireBeyond wrote:
| No, it doesn't.
|
| Texas has the most number of outages in the last 20 years
| of all states, where an outage is defined by the DOE has
| a power failure affecting 50,000 people or more.
|
| > https://www.texasstandard.org/stories/report-texas-has-
| the-m...
|
| It's amazing how much people will let their biases color
| their worldview.
|
| Texas has the most "ongoing issues" with power of any
| state.
| newsclues wrote:
| Reoccurring problems in California compared to a single
| storm in Texas? lol
| FireBeyond wrote:
| LOL indeed:
|
| Report: Texas has the most major power outages of any
| state in the U.S.
|
| > The study, which covers a time span of 20 years ...
| looks at a 20-year period from about 2001 to 2021. That's
| really the basis of the data, the Department of Energy >
| https://www.texasstandard.org/stories/report-texas-has-
| the-m...
|
| Sounds like Texas has rather a lot of "reoccurring
| problems". More than California, in fact.
| callalex wrote:
| The private for-profit "utility" in California, PG&E, is
| extremely corrupt but voters can't do anything about it because
| it's a one-party state which means the only people that run for
| the opposition party are completely looney. Look up the history
| of the Paradise fire and "public safety power shutoffs".
| zefhous wrote:
| I live in Boulder, Colorado. We had the Marshall Fire[1] a
| couple years ago, which burned down 1084 structures on a day
| with high winds. These winds are pretty normal around here on
| occasion, at least multiple times each year.
|
| What's not normal is that last week, our utility (Xcel Energy)
| decided to preemptively shut off power to 55,000 customers to
| reduce risk before a forecasted wind event with high fire-
| risk[2]. They had intended to restore power the next day, but
| some went without power for a couple days.
|
| The communication and execution of the shutdown seemed poor,
| and the infrastructure problems that led to the shutdown are
| still here. The impression I have from comments in local groups
| is that they are trying to avoid liability and have not
| adequately invested in fixing shoddy infrastructure that is
| going to be safe here. People are expecting regular shutoffs to
| become the new normal. Wind storms aren't going away, fixing
| the infrastructure would take a long time, and people don't
| think Xcel is interested in spending the money, even though
| they can likely afford to.
|
| This has definitely left me thinking about a DIY battery+solar
| solution to keep my heating system running, as well as
| fridge/freezers.
|
| [1] https://en.wikipedia.org/wiki/Marshall_Fire [2]
| https://www.cpr.org/2024/04/08/for-the-first-time-a-colorado...
| grosswait wrote:
| Yes, much of the rural us east coast experiences a few a month.
| So many trees mean that even with continuous maintenance, odds
| are good that a storm or two a month will have an impact to at
| least some parts of any given service area.
| r00fus wrote:
| US needs to start burying power lines. So many benefits and
| it doesn't look like crap.
| 1992spacemovie wrote:
| Buried power is 2x to 10x more expensive per mile.
| 0x0000000 wrote:
| This was less than a month ago: 85,000 homes without power in
| one metro area, many of them for 2 or 3 full days.
|
| https://www.timesunion.com/weather/article/capital-region-ad...
|
| Most of the US Northeast is at risk of major power outages
| during strong storms, especially early/late nor'easters which
| bring ice and heavy wet snow.
|
| I guess you could say the US is not a first world country if
| you want to throw shade, but I'm not buying it.
| Scubabear68 wrote:
| I live in NJ in the US. The Emerald Ash Borer has decimated ash
| tree populations here, leaving millions of dead ash trees, many
| next to power lines. Electric companies are overwhelmed and
| slow to chop dead ones down.
|
| Add in global warming bringing excessive intense rain storms to
| soften up the ground, and wind storms happening several times a
| year, and the result is we lose power at least once or twice a
| year. Some neighbors in very heavily wooded roads lose power 5+
| times a year.
| thaumaturgy wrote:
| "Frequently" is a bit subjective. This is one of those things
| where it might only happen in a specific area once every couple
| of years (for more than a few minutes or hours), but when it
| happens, it sticks around in people's memory -- usually because
| losing power is a great way to suddenly get a good look behind
| the facade of modern living.
|
| Even people living in parts of California suffering under the
| reign of PG&E and their "power safety" shutoffs during
| potential fire events don't really experience prolonged,
| frequent outages, but they are a memorable nuisance (speaking
| as someone who lived in one of those areas).
|
| That said, if you haven't experienced this yet, that's great,
| but it's likely that you will in the not-too-distant future.
| Power infrastructure almost everywhere is getting a bit wobbly
| for a couple of reasons: much of it is well beyond its
| originally designed lifetime, much of it hasn't been maintained
| as well as it should have been, and we are currently living
| through the disruptive effects of an increasingly unstable
| climate that have been predicted for decades. If your power
| comes from hydro, then freshwater ecosystems are experiencing
| deeper and longer drought cycles and the dam that provides that
| power is probably getting a bit old. If you live in a hurricane
| area, you're eventually going to get hit by a really bad one.
| If you live in an area that gets cold, you'll eventually get
| hit by a severe ice storm. If you live near a wooded area, it's
| going to burn. If you live deep in an urban setting and your
| power comes from a nuclear plant and everything has been well
| enough funded end-to-end to keep it in good working order, then
| congratulations, you probably won't experience any of these
| events directly.
|
| But a lot of other people are, regardless of who they or their
| neighbors vote for.
| bryanlarsen wrote:
| I've lost 2 freezers worth of food in the last 25 years due to
| power outages. I have since purchased a battery that can run a
| freezer in summer for a few hours or a furnace fan in winter for
| several days for the next outage. Adding a solar panel so I can
| use that battery continuously wouldn't pay for the battery, but
| it'd sure offset it considerably.
| neilv wrote:
| Were they the lid on top freestanding freezers? How long were
| the outages, and what was the environment?
| bryanlarsen wrote:
| Yes, lid on top. 4 day outages in both cases.
| lolinder wrote:
| Would a few hours of runtime actually save your freezer
| food in the event of another 4 day outage?
| Retric wrote:
| It's likely, freezers don't operate continuously.
| coffeebeqn wrote:
| It's not a few hours. It's all sunlight hours plus a few
| hours from the battery per day
| lolinder wrote:
| TFA's system, yes, but OP just bought a battery and is
| now considering _adding_ a solar system.
| briffle wrote:
| When I last had a multi-day outage, we hooked our
| generator up to our freezer. We would run for one hour,
| then off for 3-4 hours. Also good schedule for making
| more coffee, charging phones, etc.
| fooker wrote:
| >run a freezer in summer for a few hours.
|
| You can 'run' a freezer for about 10-12 hours by purchasing
| 5-10$ worth of ice from a grocery store.
|
| For something that happens twice in 25 years, that seems like
| the more pragmatic way to go?
| thaumaturgy wrote:
| You can do that so long as nobody else in the area affected
| by the outage had the same idea and got there before you.
|
| The last major outage (due to an ice event), I hit the stores
| within the first hour of the outage and they were already
| cleaned out of water, propane, ice, and getting rapidly
| cleaned out of other supplies.
| smeej wrote:
| I really don't want to be rude here, but I live in a place
| where we constantly throw the frozen stuff outside into the
| snow when the power goes out, so I'm genuinely confused.
|
| If it was an ice event, why would you have to travel to get
| ice?
| singlepaynews wrote:
| The difference is the battery can engage automatically. Do
| you want to monitor for the rare, yet anticipatable event?
|
| A self-critique: power outage isn't going to occur without
| notifying the person, except for maybe being out of town.
| That said, one less problem to solve in response to rare,
| anticipatable event.
| avar wrote:
| Did you consider buying a larger freezer (or sacrificing
| space), and just filling part of it with freezer gel packs?
|
| I wonder what the cost/benefit calculation is for that v.s. an
| entire solar backup system.
| melenaboija wrote:
| I love this. I have been waiting for some sort of off grid solar
| kit that I can install "Ikea" install, i.e. with almost no idea
| about the matter take the instructions, plug and play.
| bryanlarsen wrote:
| For more money and less effort you can purchase a "solar
| generator". It's a funny name for something that's basically a
| battery + inverter + mppt, but "solar generator" is the best
| thing to punch into Google.
| newsclues wrote:
| These exist, multiple brands make and sell battery and solar
| ecosystems.
| neilv wrote:
| The HTML title starts "The Landlord-Friendly...". It really
| depends on the landlord.
|
| I like the idea of solar, and of backups, and of figuring out how
| to live comfortably in rentals, and of being mobile, but...
|
| I'm pretty sure that my own real-life landlord would flip out, if
| he came to the door, and saw that charger box bolted to the wall,
| and the bare terminals of an Alibaba special "SCREMOWER" large
| lithium battery pack.
|
| Before he even saw that cabling. Which I think (with those
| lengths, and tacked up like that) would be an electrical code
| violation here.
|
| Would insurance even cover a fire?
|
| Also, if there's later an expensive roof leak, there'd be
| questions about whether it had been caused by installation of the
| panels (even though no holes were drilled). And is there a
| liability risk if the panel gets blown off.
|
| And would insurance cover any of that?
|
| Were I in landlord's position myself, I'd have much of the same
| concerns.
| cmclaughlin wrote:
| I just left a similar comment. We were probably composing a the
| same time.
|
| Good point about the possibility of a roof leak and placing
| blame. I didn't think of that.
| hinkley wrote:
| Years ago I fantasized about making a transformer designed to
| pass through a window. One coil on the outside, one on the
| inside. Unfortunately I don't think you can split the core of
| a transformer and still get anywhere near the efficiency
|
| Also more recently I learned that these things can vibrate.
| Which would not be good for a window.
|
| You'd be better off passing a wire ribbon around the sash.
| Animats wrote:
| Split transformers for power transmission exist, but are
| rare. Here's a 3 KW system used for non-contact charging of
| electric forklifts, industrial mobile robots, and such.[1]
| 93% efficiency claimed. Probably not worth the trouble just
| to get power through a window.
|
| [1] https://www.wiferion.com/us/
| cavisne wrote:
| Good video on the issues with extension cords in the US
|
| https://www.youtube.com/watch?v=K_q-xnYRugQ&t=1131s
| Spivak wrote:
| Yeah, I spent the money on good quality 12/3 extension cords
| that can safely pull more power than the circuit will deliver
| and have been quite happy with them. Being able to run a
| space heater off them is really nice in the winter.
| r00fus wrote:
| I think the Lithiun-Iron-Phosphate battery is actually not a
| fire hazard (not nearly as much as Lithium NMC ones - which are
| quite rare also).
|
| Explaining that to the landlord may not be fruitful however.
| dubcanada wrote:
| They are classified a fire hazard in Canada.
| angiosperm wrote:
| Incorrectly, if so.
| spacecadet wrote:
| No insurance would. Yes, looks super hazardous for a lay person
| to attempt.
|
| Ive taught a bunch of in person classes on DIY solar and I
| would never have published this, its asking people to get
| evicted or worse.
|
| I should add, mine are all in the context of fringe living...
| vans, campers, boats, alleyways, etc.
| repiret wrote:
| As a landlord, I would not approve of this tomfoolery in any of
| my buildings.
|
| Safety hazards I see include: Solar panels on the roof that
| aren't bolted dow; I don't care what wind speed they're rated
| for. Wires running from them to the inside of the house not in
| conduit and not secured. A high energy battery pack not NRTL
| listed. Extension cords draped through the house permanently
| installed (within the expansive definition of permanently
| installed used by the NEC)
|
| In addition running the wires in through a cracked window
| creates an unacceptable risk of water damage.
|
| That said, it's a cool project. Just do this in a barn you own
| not a house I own.
| jonnycoder wrote:
| While the article probably doesn't use UL listed equipment,
| I've found that equipment exists that does such as eg4. They
| run 48v which makes it legal in addition to being Ul listed.
| It's typically the installation between solar panels and
| power inverter/converter that needs to be up to code.
| jrockway wrote:
| There is also the risk of lightning hitting the wires and
| causing damage indoors.
| earthscienceman wrote:
| "Just do this in a barn you own not a house I own."
|
| Someday we'll wonder why we thought it was a good idea to
| make the need for shelter into an investment vehicle. Until
| then, I hope people use your properties as they see fit.
| waveBidder wrote:
| there's nothing wrong with paying someone else to maintain
| your dwelling and dealing with capital costs. people don't
| have a problem with the market solutions to the basic right
| to food, for the most part. The main problem comes with the
| unearned profit that comes from owning land that benefits
| from improvements made by others.
|
| tldr: land value tax and less restrictive zoning yesterday
| dylan604 wrote:
| There are a lot of people that can afford to rent a house,
| but would not qualify for a mortgage to buy a house. If
| houses were not available to rent, there would be plenty of
| people unable to live in a house.
|
| I'm in a fortunate situation where my landlord is not a
| slumlord. When things need looking into, it gets taken care
| of in a timely manner. I do not have any issue with someone
| choosing to have this as a business.
| asdefghyk wrote:
| As a landlord how does one stop people/tenants using "under
| rated" extension cords ? and therefore causing a fire.
|
| How does one stop tenants using "dodgy" chargers to charge
| their electric bike or whatever, and the battery bank causes
| a fire.?
|
| Does your insurance cover these situations???
| sudobash1 wrote:
| The extension cord "alternate electricity system" as they call
| it seems particularly harrowing. You had better make sure that
| you know what the load rating is on each of those cords and
| what they are going to be supplying (or better yet, just don't
| do this). Unlike household wiring, there will be no breakers.
| angiosperm wrote:
| The "load rating" on the cords exceeds the total power
| delivery capability of the system. It has its own circuit
| breakers.
|
| The manufacturers are well aware of risks, for liability
| reasons if nothing else, and have contained them in the
| uniform-electrical-code mandated manner. The system is no
| more risky than any other plugged-in appliance. We don't need
| to invent problems. Extension cords are _just_ extension
| cords.
| fragmede wrote:
| no they're not. Not when you're dealing with potentially
| large loads. an extension cord rated for 13 amps with 16
| gauge wiring, with a 110v dryer running on it, will cause a
| fire, sooner or later. A proper 10-gauge, 20 amp-rated
| extension cord will not.
|
| that this system won't exceed ratings is a fair point, but
| extension cords are not just extension cords.
| angiosperm wrote:
| Obviously the extension cord you use needs to be rated
| for the power it carries. Anyone buying extension cords
| can see there are different sizes. They are well-labeled,
| and it is easy to look up the gauge needed for its length
| and what is to be plugged into it. A correctly-rated
| extension cord is no more hazardous than the same-rated
| Romex, and often cheaper.
|
| All the appliances mentioned are rated to be used with
| appropriate extension cords, and cords are sold at retail
| for such use.
| bigtunacan wrote:
| You lost all credibility with, "Extension cords are just
| extension cords."
|
| For any type of generator running exterior to interior
| would require rated extension cords to reduce fire risk.
| angiosperm wrote:
| The extension cords mentioned are all interior-to-
| interior. There is no magickal difference between an
| extension-cord wire and a like-gauge Romex wire. The
| former bends easier.
|
| The only outdoor wiring mentioned is 48V.
| flemhans wrote:
| Yeah at certain points I thought they were trolling.
|
| But still inspired me to perhaps to something like this that
| bypasses the meter and the city grid, but just a little more
| limited in scope than running duplicate wiring everywhere.
| brudgers wrote:
| Read your lease because most landlords are not going to be down
| with renters putting stuff on the roof...anyway...
|
| These days, $1k will buy a fair bit of a China made power brick.
| No need for solar access -- for when the power goes out in a
| storm and/or at night.
|
| A big brick or several small ones is also less work; can live out
| of the way when not in use; and can be used when tailgating or
| car camping.
|
| For food cooling a small chest freezer has broad utility and
| unpowered will stay cool through a moderate outage.
| cmclaughlin wrote:
| I'm surprised the landlord is ok with this. I understand the
| panels might be rated to withstand some amount of wind, but
| there's a huge liability if this project lead to injury.
|
| A good job was done considering the load on the indoor wiring,
| but the exposed wires on the outside of a building concern me.
| Typically wires have some level of insulation and/or conduit that
| reduces and contains the spread of fire. If wind did move the
| panels around, those wires could pull loose and start a fire.
|
| SF does not perform frequent building inspection, but if an
| inspector saw this they would almost certainly cite that this
| violates building code. In the event of injury, insurance might
| not pay out given how this is setup.
| avar wrote:
| Around the 2 minute mark in the video you can see he's ratchet
| strapped the panels together, and in turn that strap is
| attached to the roof (looks to be looped around a pipe?).
|
| So he's not just relying on the wind rating of the panels.
|
| A better and perhaps code compliant way to do this (this is
| sometimes done this way here in NL, no idea about the US) is to
| bolt the panels to e.g. an aluminum frame, which you'd then
| hold to the roof with ballast, e.g. cinder blocks or heavy yard
| tiles.
|
| Depending on the panel area, frame and amount of ballast you
| can easily prove that there's no way the result would move due
| to weather, unless you were experiencing such apocalyptic winds
| that the house itself would be destroyed anyway.
| complexworld wrote:
| When the battery is full where does the power produced by the
| panels go?
| repiret wrote:
| Solar panels can sit in the sun without producing any power at
| all just fine. The sun will cause a voltage to develop on the
| solar panels output terminals, but if that voltage is not
| enough to cause current to flow, for example, because of
| battery charge controller is not drawing current, or because
| they're not connected to anything, nothing bad happens.
| _pdp_ wrote:
| If this is legal, it is excellent. When I remodelled our home
| some years ago, I had to rewire everything, including putting
| ethernet cables everywhere. It is not such a big deal if you are
| in the middle of it.
| smallerfish wrote:
| Tangent: can anybody recommend a hybrid invertor that can
| prioritize solar over grid _without also_ prioritizing battery
| over grid when solar isn't available?
|
| Context: I have a solar + battery system for backup power
| purposes. We have long enough grid outages every so often that
| make it worthwhile, and I need to keep the batteries charged in
| preparation for those outages. However, 98% of the time the
| batteries are charged and the solar power is just being wasted
| (there is no grid tie back here); I'd like to actually use it.
| The invertor (which is cheap chinese) can prioritize "renewable
| over grid" and thus use the solar during the day, but in this
| mode it then uses the batteries at night, and recharges them from
| grid when it runs them down; this means lots of battery cycles
| and also potential for backup to be foiled if the grid goes down
| at the wrong time.
| jonnycoder wrote:
| Check out the EG4 specs from signature solar. They have been
| reviewed a lot by Will Prowse on youtube and it's what I would
| buy.
| nikodunk wrote:
| Seconded. The thing I'm using here is basically an EG4 knock
| off and I copied the wiring from the Will Prowse EG4 3000W
| mobile solar power guide (linked under how to) - which makes
| me think it's the same board inside.
| mcbishop wrote:
| I like that their 3K inverter works with a 48-volt battery
| bank. They seem incredibly low cost for the value.
| beAbU wrote:
| Sunsynk will give you what you want. You can define a minimum
| battery level, after which it'll switch to grid if there is not
| enough solar to supply the load. If there is no grid then It'll
| continue to use battery until a final emergency cut-off that
| shuts the whole system down.
|
| The battery setting can be configured on a timer, so you can
| have different cut-offs for dulifferent times of the day.
| mcbishop wrote:
| Another option is Phocos. You can set the PV / grid / battery
| priority order.
| doctoboggan wrote:
| Definitely check out Will Prowse on YouTube, and see his
| website here:
|
| https://www.mobile-solarpower.com
|
| He has spec'd out a lot of DIY Solar Packages and lists the BoM
| on his website.
| kshacker wrote:
| I do not want to fight with the utility or the insurance for such
| work, but this made me think: Can I set up something (I have a
| house) in my backyard + frontyard to just charge my EV? Catch the
| sun when it can, and then charge the car when connected. My PG&E
| bill says 56% of my usage is from midnight to 6 AM which is just
| EV + fridge. Although I pay a low rate on that, but imagine
| dropping half of your usage.
|
| I specifically pick out the EV as an example because by
| definition my system would never need to connect to the house or
| the grid, so I guess all I have is a disconnected battery
| (powerwall) to insure.
| jonnycoder wrote:
| Yes very easy with a ground mount with 4 panels, a battery and
| inverter.
|
| I should write an article about it because I had planned to
| build something myself and keep all equipment outside and build
| a small wooden enclosure away from the house for it.
| thechao wrote:
| My EV lives outside & right beneath the only safely
| accessible part of my roof to put solar on... so an
| explanation would be grand! My only issue is that I need
| solar->battery->car, as the car is at work 3/7 days...
| yummypaint wrote:
| You might consider something on the opposite end of the
| spectrum, specifically net metering. If your grid connection is
| reliable, it's even more economical to get a solar system
| without batteries that feeds the grid. Where I'm located people
| pay the difference between the two without regard for when the
| power was generated or consumed. It also means your system is
| more efficient because there are no battery losses.
| mcbishop wrote:
| Net metering is no longer available in PG&E territory.
| winter_blue wrote:
| It sounds like the author of this piece lives in a jurisdiction
| without net metering. (The UK, perhaps?)
|
| If you have net metering, being able to push power back into the
| grid is a major plus.
| Toutouxc wrote:
| It's also a major pain in the ass in places where the grid
| isn't exactly prepared for that. My parents are allowed to sell
| power from their EV installation. Their neighbor, who built a
| much smaller one a few months later, got denied.
| FireBeyond wrote:
| I pity the poor linemen if you hook this contraption to feed
| back into the grid.
| pbnjay wrote:
| As someone living in NC and paying only $0.09/kwh, that $0.55/kwh
| in SF is just nuts to me! This setup has a 12 year payoff here...
| worstspotgain wrote:
| The rate schedules are complex. I'm paying ~$0.43/kWh, itemized
| as $0.13/kWh generation (Clean Power SF) and $0.30/kWh
| distribution (PG&E).
|
| If you use very little on the residential schedule I think it
| can drop pretty low, probably around $0.15/kWh.
| millebe wrote:
| This is dangerous and illegal everywhere in the United States. DO
| NOT DO THIS!
|
| All 50 states have adopted NFPA 70, the National Electric Code,
| and the linked article shows a bunch of things that absolutely DO
| require a permit and would absolutely FAIL to be approved:
|
| _First and foremost, running bare high voltage DC wires through
| an open window is in violation of a pile of building codes and
| very dangerous. The linked solar panels have an open circuit
| voltage of 64.8V, so with four of them in parallel there can be
| 260V of direct current. This can and will kill you, especially if
| you touch it in such a way where muscular tetanus prevents you
| from releasing the cable._
|
| _Electrical extension cords are intended to be temporary, and
| the article 's use of them violates a bunch of codes. Here are
| some of the relevant ones:_ 400.10 Uses
| Permitted (A) Uses Flexible cords and flexible
| cables shall be used only for the following: (1)
| Pendants. (2) Wiring of luminaires. (3)
| Connection of portable luminaires, portable and mobile signs, or
| appliances. (4) Elevator cables. (5)
| Wiring of cranes and hoists. (6) Connection of
| utilization equipment to facilitate frequent interchange.
| (7) Prevention of the transmission of noise or vibration.
| (8) Appliances where the fastening means and mechanical
| connections are specifically designed to permit ready removal for
| maintenance and repair, and the appliance is intended or
| identified for flexible cord connection. (9)
| Connection of moving parts. (10) Where specifically
| permitted elsewhere in this Code. (11) Between an
| existing receptacle outlet and an inlet, where the inlet provides
| power to an additional single receptacle outlet. The wiring
| interconnecting the inlet to the single receptacle outlet shall
| be a Chapter 3 wiring method. The inlet, receptacle outlet, and
| Chapter 3 wiring method, including the flexible cord and
| fittings, shall be a listed assembly specific for this
| application. 400.12 Uses Not Permitted
| Unless specifically permitted in 400.10, flexible cables,
| flexible cord sets, and power supply cords shall not be used for
| the following: (1) As a substitute for the fixed
| wiring of a structure (2) Where run through holes in
| walls, structural ceilings, suspended ceilings, dropped ceilings,
| or floors (3) Where run through doorways, windows, or
| similar openings (4) Where attached to building
| surfaces Exception to (4): Flexible cord and flexible
| cable shall be permitted to be attached to building surfaces in
| accordance with 368.56(B). (5) Where concealed by
| walls, floors, or ceilings or located above suspended or dropped
| ceilings Exception to (5): Flexible cord and flexible
| cable shall be permitted if contained within an enclosure for use
| in Other Spaces Used for Environmental Air as permitted by
| 300.22(C)(3). (7) Where subject to physical damage
| 400.17 Protection From Damage Flexible cords and flexible
| cables shall be protected by bushings or fittings where passing
| through holes in covers, outlet boxes, or similar enclosures.
|
| _You absolutely cannot and should not run bare wires through a
| window. This manages to violate basically all of Chapter 3 of the
| NEC:_ 300.3 Conductors (A) Single
| Conductors Single conductors specified in Table
| 310.104(A) shall only be installed where part of a recognized
| wiring method of Chapter 3. 300.4 Protection Against
| Physical Damage Where subject to physical damage,
| conductors, raceways, and cables shall be protected.
| 300.6 Protection Against Corrosion and Deterioration
| Raceways, cable trays, cablebus, auxiliary gutters, cable armor,
| boxes, cable sheathing, cabinets, elbows, couplings, fittings,
| supports, and support hardware shall be of materials suitable for
| the environment in which they are to be installed.
| 300.11 Securing and Supporting (A) Secured in Place
| Raceways, cable assemblies, boxes, cabinets, and fittings shall
| be securely fastened in place. 300.12 Mechanical
| Continuity -- Raceways and Cables Raceways, cable armors,
| and cable sheaths shall be continuous between cabinets, boxes,
| fittings, or other enclosures or outlets. 310.10
| Uses Permitted (C) Wet Locations Insulated
| conductors and cables used in wet locations shall comply with one
| of the following: Be moisture-impervious
| metal-sheathed Be types MTW, RHW, RHW-2, TW, THW,
| THW-2, THHW, THWN, THWN-2, XHHW, XHHW-2, or ZW Be of
| a type listed for use in wet locations (D)
| Locations Exposed to Direct Sunlight Insulated conductors
| or cables used where exposed to direct rays of the sun shall
| comply with (D)(1) or (D)(2): Conductors and
| cables shall be listed, or listed and marked, as being sunlight
| resistant Conductors and cables shall be covered with
| insulating material, such as tape or sleeving, that is listed, or
| listed and marked, as being sunlight resistant
|
| _Both the solar panels and the inverter are listed products and
| are required to be installed in accordance with their listings.
| In particular, this means they must be permanently fastened to
| the structure in the manner of the manufacturer 's instructions._
| 110.3 Examination, Identification, Installation, Use, and Listing
| (Product Certification) of Equipment (B) Installation and
| Use Listed or labeled equipment shall be installed and
| used in accordance with any instructions included in the listing
| or labeling.
|
| _The solar panels must be fastened to the structure in a way that
| resists wind and weather loads. There are entire sections of the
| NEC and various IBC codes devoted to this._
|
| _Other various code sections that this would fail:_
| 110.8 Wiring Methods Only wiring methods recognized as
| suitable are included in this Code. The recognized methods of
| wiring shall be permitted to be installed in any type of building
| or occupancy, except as otherwise provided in this Code.
| 110.12 Mechanical Execution of Work Electrical equipment
| shall be installed in a neat and workmanlike manner.
| 110.13 Mounting and Cooling of Equipment (A) Mounting
| Electrical equipment shall be firmly secured to the surface on
| which it is mounted. Wooden plugs driven into holes in masonry,
| concrete, plaster, or similar materials shall not be used.
| 110.26 Spaces About Electrical Equipment Access and
| working space shall be provided and maintained about all
| electrical equipment to permit ready and safe operation and
| maintenance of such equipment. (A) Working Space
| Working space for equipment operating at 1000 volts, nominal, or
| less to ground and likely to require examination, adjustment,
| servicing, or maintenance while energized shall comply with the
| dimensions of 110.26(A)(1), (A)(2), (A)(3), and (A)(4) or as
| required or permitted elsewhere in this Code.
| (B) Clear Spaces Working space required by this section
| shall not be used for storage. When normally enclosed live parts
| are exposed for inspection or servicing, the working space, if in
| a passageway or general open space, shall be suitably guarded.
| (E) Dedicated Equipment Space All switchboards,
| switchgear, panelboards, and motor control centers shall be
| located in dedicated spaces and protected from damage.
| (1) Indoor Indoor installations shall comply with
| 110.26(E)(1)(a) through (E)(1)(d). (a) Dedicated
| Electrical Space. The space equal to the width and depth of the
| equipment and extending from the floor to a height of 1.8 m (6
| ft) above the equipment or to the structural ceiling, whichever
| is lower, shall be dedicated to the electrical installation. No
| piping, ducts, leak protection apparatus, or other equipment
| foreign to the electrical installation shall be located in this
| zone. (2) Outdoor Outdoor installations shall
| comply with 110.26(E)(2)(a) through (c). (a) Installation
| Requirements. Outdoor electrical equipment shall be the
| following: (1) Installed in identified enclosures
| 110.27 Guarding of Live Parts (A) Live Parts Guarded
| Against Accidental Contact Except as elsewhere required
| or permitted by this Code, live parts of electrical equipment
| operating at 50 to 1000 volts, nominal shall be guarded against
| accidental contact by approved enclosures or by any of the
| following means: (1) By location in a room, vault, or
| similar enclosure that is accessible only to qualified persons.
| (3) By location on a balcony, gallery, or platform elevated and
| arranged so as to exclude unqualified persons. (4) By
| elevation above the floor or other working surface as follows:
| A minimum of 2.5 m (8 ft) for 50 volts to 300 volts between
| ungrounded conductors (B) Prevent Physical
| Damage In locations where electrical equipment is likely
| to be exposed to physical damage, enclosures or guards shall be
| so arranged and of such strength as to prevent such damage.
| mentos wrote:
| Curious to hear what you'd recommend to bring this setup in
| line with safe and legal practices
| millebe wrote:
| Your choices are either:
|
| - Install this equipment in a permanent manner consistent
| with its listings and all applicable codes. "Off-grid" does
| not mean "do whatever you want", it means you aren't
| connected to a fixed grid.
|
| - Buy equipment that is designed (and listed) for portable PV
| storage. This would most commonly be used for RVs and the
| like, and would look more like a generator than a house
| panel. You still don't get to drape extension cords all over
| your home in lieu of permanent wiring if you do this.
|
| - Start a company, design a product that can allow temporary
| whole-circuit backups without transfer switches and all the
| usual stuff, and somehow convince a NRTL to list it. Good
| luck.
| angiosperm wrote:
| Wires from panels in parallel will all be at, typically, 48VDC.
| Voltages add only when you wire in series. No "live parts" are
| exposed in modern systems.
|
| The quoted regulations govern construction. Residents have much
| greater latitude. All the appliances mentioned are approved for
| use with rated extension cords.
| thereisnospork wrote:
| Notably, even in construction/industrial settings, there are
| typically broad exemptions for 'low voltage' wiring[0],
| typically defined as < 50V or < 48V, justified because there
| is no/little 'hazard' associated with voltage that low. To
| wit you can, for instance, just duct tape/zip tie some
| flexible wire/cabling to the wall if it is only carrying e.g.
| a 5V power to a sensor, some LEDs, or other equipment. Which
| I have done and passed fire marshal inspection on multiple
| occasions in multiple jurisdictions[1].
|
| The regs (and by extension a fire marshal) would probably be
| unhappy about the extension cord, but a. 'everyone does
| it'[2], b. 'surge protecting' cords are generally exempt (at
| least in my jurisdictions), and c. trivially rectified by
| hard wiring one or both ends of the extension cord to hard
| wire or create a 'wire + receptacle'.
|
| [0]Current limitations, watt-hr limitations, etc. may apply
| in this case.
|
| [1]Obligatory disclaimer: not advice, follow your local
| regulations, etc.
|
| [2]The response would be a 'please fix this' and not fines or
| worse.
| millebe wrote:
| NEC chapter 7, article 720 covers wiring of less than 50V.
| It's important to note that elsewhere in the NEC and other
| codes, "low voltage" is defined as <600V, <1000V, or
| <2000V, depending on the code and code cycle.
|
| Your fire marshal might have passed 5V cabling duct taped
| to a wall, but it would be in violation of 720.11:
| 720.11 Mechanical Execution of Work Circuits
| operating at less than 50 volts shall be installed in a
| neat and workmanlike manner. Cables shall be supported by
| the building structure in such a manner that the cable will
| not be damaged by normal building use.
| avar wrote:
| > DO NOT DO THIS!
|
| You're probably right, but just to rules lawyer this a bit for
| fun: Flexible cords and flexible
| cables shall be used only for the following: [...] (9)
| Connection of moving parts.
|
| He could mount his panels on plywood on caster wheels, and then
| prevent excess moment by tying those "moving parts" by chain to
| cinder blocks.
|
| The rules don't specify that you must have a reason that isn't
| dumb to make those parts move.
|
| The "400.12 Uses Not Permitted" section gives the list in
| "400.10" a blanket exemption ("unless specifically permitted in
| 400.10"), and that's the section that would forbid running the
| wires through a window.
| millebe wrote:
| The rules specify equipment must be installed in a manner per
| its listing, and there are at least four nationwide codes
| that cover the attachment of solar panels. In California I
| would guess there are more, stricter codes (e.g. seismic).
|
| Even if you managed to make the panels movable, this would
| fail 690 of the NEC: 690.31 Wiring Methods
| (A) Wiring Systems All raceway and cable wiring
| methods included in this Code, other wiring systems and
| fittings specifically listed for use in PV arrays, and wiring
| as part of a listed system shall be permitted. Where wiring
| devices with integral enclosures are used, sufficient length
| of cable shall be provided to facilitate replacement.
| Where PV source and output circuits operating at voltages
| greater than 30 volts are installed in readily accessible
| locations, circuit conductors shall be guarded or installed
| in Type MC cable or in raceway. The ampacity of 105degC
| (221degF) and 125degC (257degF) conductors shall be permitted
| to be determined by Table 690.31(A)(b). For ambient
| temperatures greater than 30degC (86degF), the ampacities of
| these conductors shall be corrected in accordance with Table
| 690.31(A)(a).0
| Cheer2171 wrote:
| > It's not wired into the meter, doesn't require a permit, etc.
|
| This is 100% a fire hazard and would get your home insurance
| voided.
| valianteffort wrote:
| You can buy 256Wh battery banks for around $150 now. You can pair
| them with a timer for charging/topping off at night when
| electricity is cheap. They even accept solar input.
|
| Throw one in every room and between appliances like the fridge or
| oven. Now you have a UPS for your whole house and the cheapest
| energy rates throughout the day.
| epistasis wrote:
| Do those have an inverter built in? If not, at $600/kWh very
| pricy compared to what this guy used at $190/kWh for batteries,
| or $360/kWh including the inverter:
|
| https://www.amazon.com/dp/B08G81TKC6?ie=UTF8&th=1&linkCode=s...
|
| Also, $190/kWh is so cheap. Its hard to believe how fast costs
| are falling for energy storage.
| grobbyy wrote:
| My experience is that power banks and UPSes fail more often
| than my power.
|
| I keep a couple charged, but with nothing plugged in. I
| sometimes plug things in before a major storm, planned outage,
| or after an unplanned one.
| smeej wrote:
| This is funny to me because mine just died unceremoniously
| during a snowstorm and it made me realize there should really
| be a testing cycle built in.
| xyzzy123 wrote:
| Hm fridge sure, but oven? 256Wh is going to power an electric
| oven for like, 5 minutes. Doesn't seem useful.
| happytiger wrote:
| What's the status in insurance for this thing? Generally this
| doesn't seem like it would be covered under renters insurance.
|
| I can't imagine a landlord in existence that wouldn't throw a fit
| about something like this.
| cameldrv wrote:
| All of the code/safety/landlord issues notwithstanding, the price
| is pretty incredible. If I plug my address into the PVWatts
| calculator, given the insane price increases from PG&E over the
| past few years, the payback period is one year. Beyond the
| fantastic economics, you're getting a decent emergency backup
| system that should cover at least your fridge, lights, and
| various electronics.
| deeth_starr_v wrote:
| This reminds me of the time when I built a battery stereo power
| amplifier and then only used it a few times because I didn't want
| to risk burning the apartment complex down. It was fun building
| it though.
| magicbuzz wrote:
| The all-in-one 3kW inverter/controller that he uses is for 110V
| AC output (using the 48V battery). In the article he linked to,
| the system uses an EG4 3000EHV-48 that also outputs 110V AC.
|
| Are there equivalent all-in-ones that would provide 230/240V AC
| for use in Australia/New Zealand?
| avar wrote:
| If you search for the manufacturer shown (PowMr) it looks like
| they make both 110v and 220v variants.
|
| This looks to be the same or similar product for 220v:
| https://a.aliexpress.com/_EwlP4Cf
| mcbishop wrote:
| I think this is single phase. 230V is a common single-phase
| voltage outside North America.
| mcbishop wrote:
| I don't know of a 3kW inverter that outputs split phase. But
| you could get the higher-rated EG4 6000XP.
| threemux wrote:
| The quality of the components in this system is suspect. Check
| out Mobile Solar Power/ Will Prowse for unbiased, in depth
| reviews for this stuff
| selfie wrote:
| How is self install possible if you are not a licensed
| electrician. Something like this could shock someone if not
| earthed properly, for example.
| ricardobeat wrote:
| Hmm.. I wouldn't trust that "2,500W power distribution strip", or
| the extension cord itself, to actually be safe when you have a
| fridge, living room appliances _and_ the induction cooktop
| pulling 1.2KW all at once. Fire waiting to happen.
| chgs wrote:
| Do US cables not have appropriate fuses? If it's a 10A cable
| then have a 10A fuse. Pull more than that and the fuse goes.
| ricardobeat wrote:
| Guess you're from the UK? No, usually not, though better
| power strips will have one. But you don't need to go over the
| specified amps to cause a fire, there are multiple places
| that could overheat - extension cable, connections, solder
| points - while still being under the fuse rating if this
| thing is running at max power for a long time.
| asdefghyk wrote:
| About under rated extension cords.
|
| My question is if in a house a person plugs in a under rated
| extension cord into a normal powerpoint and connects equipment to
| the other end, such that the current exceeds the extension cords
| current rating , and a FIRE results, would the insurance company
| pay??? ( ie this is in a house without any of the this DIY solar.
| cables or battery etc) . would be interesting question.
| choilive wrote:
| Wow... This should be added to the FAQ's under "Whats the
| catch?": At least a dozen code violations that risks burning down
| your/your landlord's property, serious injury or worse - loss of
| life - and opens yourself to VERY large liabilities.
|
| A more proper way to do this would be to have one self contained
| outdoor box rated to contain high energy batteries, have your
| inverter and PDU as part of that package and then plug your the
| panels to that. When you have a power outage go out and grab your
| backup battery box. This eliminates the bulk of the issues.
|
| Although, that raises the obvious solution that you could just
| spend a bit more money and get one of those self contained
| "battery generators", which have been properly engineered and
| designed, and are also pretty portable.
|
| Another thing I would add is adding some sandbags to the solar
| panels so that they don't fly off the roof in a high wind
| scenario. Theres a reason why when doing a rooftop installation
| code will specify this if not being directly bolted. (Technically
| a structural engineer will need to do a load calculation, but for
| this size of install the risks are minimal compared to the risks
| inherent in the rest of the system)
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