Show HN: My $1k self-install, off-grid solar backup build for renters

The HTML title starts &quot;The Landlord-Friendly...&quot;. It really depends on the landlord.<p>I like the idea of solar, and of backups, and of figuring out how to live comfortably in rentals, and of being mobile, but...<p>I&#x27;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 &quot;SCREMOWER&quot; large lithium battery pack.<p>Before he even saw that cabling. Which I think (with those lengths, and tacked up like that) would be an electrical code violation here.<p>Would insurance even cover a fire?<p>Also, if there&#x27;s later an expensive roof leak, there&#x27;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.<p>And would insurance cover any of that?<p>Were I in landlord&#x27;s position myself, I&#x27;d have much of the same concerns.

Wow... This should be added to the FAQ&#x27;s under &quot;Whats the catch?&quot;: At least a dozen code violations that risks burning down your&#x2F;your landlord&#x27;s property, serious injury or worse - loss of life - and opens yourself to VERY large liabilities.<p>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.<p>Although, that raises the obvious solution that you could just spend a bit more money and get one of those self contained &quot;battery generators&quot;, which have been properly engineered and designed, and are also pretty portable.<p>Another thing I would add is adding some sandbags to the solar panels so that they don&#x27;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)

All of the code&#x2F;safety&#x2F;landlord issues notwithstanding, the price is pretty incredible. If I plug my address into the PVWatts calculator, given the insane price increases from PG&amp;E over the past few years, the payback period is one year. Beyond the fantastic economics, you&#x27;re getting a decent emergency backup system that should cover at least your fridge, lights, and various electronics.

Tangent: can anybody recommend a hybrid invertor that can prioritize solar over grid _without also_ prioritizing battery over grid when solar isn&#x27;t available?<p>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&#x27;d like to actually use it. The invertor (which is cheap chinese) can prioritize &quot;renewable over grid&quot; 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.

I have 1.2kW of used Sunpower panels I bought for $70&#x2F;pop about 3 years ago. Buying decommissioned commercial install panels is insanely cost effective. It&#x27;s crazy how cheap they go.

Read your lease because most landlords are not going to be down with renters putting stuff on the roof...anyway…<p>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&#x2F;or at night.<p>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.<p>For food cooling a small chest freezer has broad utility and unpowered will stay cool through a moderate outage.

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.<p>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&#x2F;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.<p>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.

As someone living in NC and paying only $0.09&#x2F;kwh, that $0.55&#x2F;kwh in SF is just nuts to me! This setup has a 12 year payoff here...

Nice Project!<p>I did a similar project in 2003, but obviously the technology has improved a lot since then. I&#x27;ve previously posted some details here: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=36000824">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=36000824</a><p>The thing that stood out to me about this project was the lack of any hardware to secure the panels to the roof, which is absolutely necessary to prevent wind damage.

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&amp;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.<p>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.

I love this. I have been waiting for some sort of off grid solar kit that I can install &quot;Ikea&quot; install, i.e. with almost no idea about the matter take the instructions, plug and play.

I love how clear and to the point this page&#x2F;guide is. Beautifully summarizes the downsides as well as the upsides.<p>The system is even tempting to me as a homeowner not renter, but a similarly simple system that doesn&#x27;t require running wires through the house might work better.

About under rated extension cords.<p>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.

I&#x27;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&#x27;t pay for the battery, but it&#x27;d sure offset it considerably.

It sounds like the author of this piece lives in a jurisdiction without net metering. (The UK, perhaps?)<p>If you have net metering, being able to push power back into the grid is a major plus.

You can buy 256Wh battery banks for around $150 now. You can pair them with a timer for charging&#x2F;topping off at night when electricity is cheap. They even accept solar input.<p>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.

The all-in-one 3kW inverter&#x2F;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.<p>Are there equivalent all-in-ones that would provide 230&#x2F;240V AC for use in Australia&#x2F;New Zealand?

What’s the status in insurance for this thing? Generally this doesn’t seem like it would be covered under renters insurance.<p>I can’t imagine a landlord in existence that wouldn’t throw a fit about something like this.

This is dangerous and illegal everywhere in the United States. DO NOT DO THIS!<p>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:<p><i>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.</i><p><i>Electrical extension cords are intended to be temporary, and the article&#x27;s use of them violates a bunch of codes. Here are some of the relevant ones:</i><p><pre><code> 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. </code></pre> <i>You absolutely cannot and should not run bare wires through a window. This manages to violate basically all of Chapter 3 of the NEC:</i><p><pre><code> 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 </code></pre> <i>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&#x27;s instructions.</i><p><pre><code> 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. </code></pre> <i>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.</i><p><i>Other various code sections that this would fail:</i><p><pre><code> 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.</code></pre>

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.

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.

Forget the landlord (who is already unlikely to give roof access, let alone run electrical wires outside), this immediately fails the WAF (wife acceptance factor) due to the hideous cable install.

When the battery is full where does the power produced by the panels go?

The quality of the components in this system is suspect. Check out Mobile Solar Power&#x2F; Will Prowse for unbiased, in depth reviews for this stuff

You should absolutely NEVER place solar panels directly upon a roof as many of the linked website photographs demonstrate.<p>Solar cells need ventilation on their undersides, and without it will rapidly be damaged (i.e. become more inefficient). Long-term, water trapped underneath may encourage shinglerot.

Hmm.. I wouldn&#x27;t trust that &quot;2,500W power distribution strip&quot;, or the extension cord itself, to actually be safe when you have a fridge, living room appliances <i>and</i> the induction cooktop pulling 1.2KW all at once. Fire waiting to happen.

Any tips for going through doors with the cabling?

How is self install possible if you are not a licensed electrician. Something like this could shock someone if not earthed properly, for example.

&quot;We don&#x27;t even notice power outages or public safety shut-offs anymore&quot;<p>I don&#x27;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?

&gt; It&#x27;s not wired into the meter, doesn&#x27;t require a permit, etc.<p>This is 100% a fire hazard and would get your home insurance voided.