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Show HN: $200 Solar Self-Sufficiency Without Your Landlord Noticing

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Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#31

Post by rbritton »

pilom wrote: post #24

> Unless you live on an RV or a boat it doesn’t make financial sense yet If you're curious about what a system for an RV does look like, I work remotely full time in an RV and built my own system: https://therecklesschoice.com/2016/04/29/diy-rv-solar/ 6.5 times the solar, 15 times the storage, 20 times the inverter (but mine is overkill for us honestly).

Are you stationary or do you move around? Four batteries + solar panels can get somewhat heavy and eat into your total capacity, so I'm curious if it's an issue.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#32

Post by ldiracdelta »

cmac2992 wrote: post #19
mchannon wrote: post #15

Far more cost-effective would have been to skip the battery and just put a cheap chinese pure-sine-wave grid-tie inverter to bridge between the wall outlet and the panel. It's simple- it has a 110V line cord and plugs into the outlet, sending current the opposite way of normal. Do a search on your favorite e-commerce site for "grid tie inverter" and you'll see what I mean. These cheap inverters have most of the same…

Does that work with a regular meter? My internet sluething says some people have been charged for the electricity the produce because they don't have a "compatible" meter.

If you hook up a ton of these and actually generate _more_ than you consume at any time, you will actually _pay_ the power company for the power you push back into the grid. You have to get a special meter that can measure the direction of the flow. I have bought two residential roof-mounted solar systems and this is what they told me. If you never generate more than you use, maybe you're ok.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#33

Post by grecy »

I built a very similar system into my Jeep-house.

I have two 100W panels on the pop-top roof, a charge controller and a dedicated solar battery (isolated from the engine-starting battery) that runs my fridge, water pump, UV treatment lamp, interior lights, air compressor and charges all my electronics (laptop, kindle, cameras, etc.) directly from 12V DC.

I can leave the Jeep parked without running the engine for days and easily have enough energy to meet my needs.

The system has been amazing, and it's fantastic to be electricity self-sufficient in remote West Africa, where grid power is often non-existent

More details and photos here: http://theroadchoseme.com/jeep-build-complete

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#34

Post by pilom »

jpk wrote: post #22
Cerium wrote: post #21

The last place I worked we did this (though with some permission). One of the guys made friends with some people at a thin film solar plant down the street. He got a bundle of manufacturing rejects (300w panels that only made 280) for free. We strung them up on the roof and were raking in the kWh. Enough to charge 3 electric vehicles without paying the power company.

This makes me wonder why the panel manufacturer doesn't bin panels like they do with CPUs? Surely they could sell them for less than the 300W panels, but more than zero?

Most do. The panels you see on rooftops are all generally exactly the same size but could generate anywhere from 315w/panel to 250w/panel depending on binning. No idea why that company didn't.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#35

Post by ldiracdelta »

jpk wrote: post #22
Cerium wrote: post #21

The last place I worked we did this (though with some permission). One of the guys made friends with some people at a thin film solar plant down the street. He got a bundle of manufacturing rejects (300w panels that only made 280) for free. We strung them up on the roof and were raking in the kWh. Enough to charge 3 electric vehicles without paying the power company.

This makes me wonder why the panel manufacturer doesn't bin panels like they do with CPUs? Surely they could sell them for less than the 300W panels, but more than zero?

When I was shopping Itek panels, I got a prices for 270W, 280W, 290W, and 300W. I suspect most companies do binning.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#37

Post by seveneightn9ne »

sand500 wrote: post #36

If we are talking about being green, what is the carbon footprint of manufacturing all those things vs the equivilent carbon to geberate thr electricity the solar panels provide?

That's at the bottom of the article:

Production footprint PV multicristalline: 4200kWhee/kW [1] * 0.1kW = 420kWh embodied energy

Production footprint lead-acid battery: 321kWhee/kWh [1] * 0.5kWh = 161kWh embodied energy

Total Footprint: 581kWh

Annual energy production system: 155kWh/y

Payback period: 581kWh / 155kWh/y = 4+ year footprint payback

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#38

Post by pilom »

rbritton wrote: post #31
pilom wrote: post #24

> Unless you live on an RV or a boat it doesn’t make financial sense yet If you're curious about what a system for an RV does look like, I work remotely full time in an RV and built my own system: https://therecklesschoice.com/2016/04/29/diy-rv-solar/ 6.5 times the solar, 15 times the storage, 20 times the inverter (but mine is overkill for us honestly).

Are you stationary or do you move around? Four batteries + solar panels can get somewhat heavy and eat into your total capacity, so I'm curious if it's an issue.

We are very mobile, usually stay in one place for a week at a time and then move a couple hours away. You're right about weight though, we are right at our GVWR (11,000 pounds) when fully loaded. The batteries weigh 100 pounds each and the panels are another 15 pounds or so each. That said though, we get terrible gas mileage already so the extra 500 pounds for everything doesn't change it much.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#39

Post by pilom »

mchannon wrote: post #15

Far more cost-effective would have been to skip the battery and just put a cheap chinese pure-sine-wave grid-tie inverter to bridge between the wall outlet and the panel. It's simple- it has a 110V line cord and plugs into the outlet, sending current the opposite way of normal. Do a search on your favorite e-commerce site for "grid tie inverter" and you'll see what I mean. These cheap inverters have most of the same…

Please do not do this. For one, it's illegal. All grid-tied solar systems require either a transfer switch or to automatically disconnect when the grid loses power. This is so that you don't electrocute an electrician working on lines he or she thinks are dead. Second, most non-"net" meters don't read negative currents. So if you are generating more than you're using, they'll keep spinning forward and you'll get charged for more than you actually used. Third, the fines if you're caught are pretty high because of the safety issues.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#40

Post by galdosdi »

xsmasher wrote: post #30
galdosdi wrote: post #8

Cool! The one thing I notice the author gets wrong is (out of modesty perhaps) claiming the system isn't very financially successful. But it actually is! > 200W system payback period: $300 / $48 = 6.5 years until payback > Either way you cut it, this is not a money saving machine. Energy prices are just too low. That represents like a 16% rate of return with little risk, which any investor would take in a second. How…

Those calculations also assume he'll use all of the energy it produces, every day, with no loss; it's a back-of-envelope best-case calculation, at best.

Given his current setup, you have a good point.

However, with a setup that includes say, his refrigerator, there'll be more than enough load to ensure no collected energy is ever "wasted"

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