We should practically get to the point where someone can buy a roll of material at Home Depot and unravel it on their roof, nail it, and plug it in themselves.
At least in countries with strong regulations around working with electricity this is simply not going to be feasible.
I've been in the PV business for some time now and seen a person get killed by it. It's not pretty. Still remembering that smell of burnt flesh... Now, to be fair, that was at a 12MW-installation, not on a roof. But still...
What happens to a PV panel, receiving sunlight, with no load?
Does it degrade or suffer ill effects in any meaningful way? Or does it just have a potential between its outputs but otherwise isn't impacted?
At least in Germany, every PV installation of certain size (> 30kW peak) is mandated to be able to be shutdown remotely by the carrier if you supply electricity for the net and aren't just using it for yourself. (You get paid the same during shutdowns, just like it were running. Otherwise it would be quite damaging and likely reduce adoption of PV)
Point being: no, it doesn't hurt the panels and is a regular ocurence.
Which means that in winter, probably nothing, because it's cold, but on a hot summer day with peak sun, the heat might start damaging the cells. How much exactly you'd have to look at studies.
My guess is the output will permanently degrade by a few % per year if the panel is not connected. Might go down to 80% way quicker than normal (25-yr)
Solar panels are not constant-power devices. In an open circuit, they will generate their open circuit voltage at nearly zero current (except minor internal leakage), and thus nearly zero power. In a short circuit, they will generate nearly zero voltage, and thus also nearly zero power. To get maximum power out of a solar panel requires maximum power-point tracking (MPPT), where the load is adjusted such that the product of voltage and current (that is, power) is optimized for the current conditions; while significant power can be delivered to a fixed load, there's no real power being generated without a load.
And since heat radiates away at temperature to the fourth power, the increase shouldn't be particularly much.
Alternately, power can be expressed as V^2/R. But in an open circuit R is infinite, so again, zero power.
So as long as manufacturers engineer their panels to be tolerant of the maximum heat at a site (i.e. full sun, maximum temperature), the panels won't be harmed in any meaningful way. They'll just heat up a bit faster than if they were providing current.
PV panels are just like charged capacitor or a chemical battery with no loads: just holding unused potential differences with no damage to the unit.
BTW: installing solar panels DIY is apparently super easy, as I found out. I have a flat roof and used micro inverters, to make it easier, but I was done in less than a day (excluding selecting the components and layout)
I just installed 7.3Kw on my roof, and another 600W on the roof of my Jeep.
You'd have to physically stick a screwdriver into an MC-4 connector to get zapped, which is as smart as sticking one into an electrical outlet.
I don't even understand how you could get zapped plugging in MC-4 connectors.... like, at all.
As part of our daily lives, a great many of us climb into a steel box powered by explosions and packing a 20 gallon container of flammable liquids (and increasingly several hundred pounds of also flammable batteries containing more electricity than an average family uses in a week) and then pilot that box at 80Mph down a strip of concrete packed with other large high-speed objects containing flammable liquids. Occasionally, we run low on flammable liquids in our high-speed metal box and get to refill the flammable liquid container ourselves at a flammable liquids depot, which contains upwards of 40,000 gallons of the flammable liquid delivered by other larger high-speed metal boxes which also share the same strip of concrete with us.
So: I'd expect some product safety iteration here before we get to the "roll out your own solar panels", but no, I don't consider that a non-starter.
It’s not like that stuff springs up overnight!
and the end user doesn't just cut as much as they need and nail it down - the things are practically disposable appliances at this point.
PV installations on roofs typically have around 10-20kW peak output.
Let's go with 10kW. That's around 25 panels, each outputting 30V with something like 13A. Small installations are typically single-stringed, so you end up with a voltage of 25*30V=750V with 13A DC. That's pretty likely to kill you within milliseconds if you mess up.
There's a reason that stuff tends to be handled by professionals. It's a ridiculous (and pointless) risk if you aren't well educated about it and have some experience.
I'm not saying it's a future we should want :)
But isn't that kind of how super chargers work?
Of course, until all our grid hook ups are smart, we'll probably need electricians at some point.
That said, the point of "do it yourself" is that you'd nake it less dangerous for ordinarily folk. So the risk of shocks would come down.
What would concern me more is long-term fire risk. If not installed correctly, with the right spec parts etc, proper grounding etc, there's a significant risk of fire. Not immediately perhaps, but a couple years down the road.
Again DIY kits would need to be designed with this in mind.
What's the qualitative difference between 16 amps at 120V and PH v DC? Either is enough to kill a person if mishandled, and yet Home Depot sells breaker boxes over the counter.
It's funny to look at electricity from the same perspective.
And using the metal box creates toxic fumes that we inhale, which are deadly to every living thing on it.
AC power crosses the zero line twice per cycle while DC does not. AC has a lower ‘let-go’ threshold, but DC contracts your muscles and makes it harder to let go.
You are correct though, if you de-energize your panelboard and have a deadfront cover over the line side conductors and lugs, working inside a panelboard (or on electrical wiring) is safe.
And the other important part is that 60Hz needs fewer amps than DC to be dangerous. https://www.allaboutcircuits.com/uploads/articles/electricit...
And if you want to talk about power lines, then the neighborhood medium voltage lines are going to be roughly the same in most places within the same jurisdictions, and distinct from the true high voltage lines that are used for long distance transmissions.
If a 120V 15A supply puts 50mA through you, then a 120V 100A supply will also put 50mA through you.
A supply that's "5000VAC at a 1.0 nano amps" really means that it starts at 5000 volts but super rapidly drops to zero volts as it conducts. A household supply is going to have negligible voltage drop by the time it turns deadly.
Edit: The other way to put it is that 99.9% of supplies don't give you a certain number of volts and amps. They give you a certain number of volts and they have an amp limit. If you're not approaching the amp limit then the only thing that matters is the volts.
My point is that the number of amps you can get from the circuit is irrelevant, it's "more than enough" and that's all you need to know beyond the voltage and the exact way the human is being exposed.
400 ohms at 110 volts = 275 ma. More than lethal. 30 watts.
400 ohms at 220 volts is double that - a bit over half an amp. Lethal (obviously). 60 watts.
400 ohms at 1500 volts is 3.75 amps - 5.6kw. Enough to physically cook someone pretty quickly.
If Lidl can do it, why can't Walmart?
https://www.lidl.de/p/vale-balkonkraftwerk-minipv-800-et8-l-...
Essentially, any notable installation fundamentally deals with much higher currents and voltages and as such is much, much more dangerous. Once a certain size is reached, the carrier also has to be involved and professional installation is mandatory, both due to the law and requirements by insurance companies.
At least here in germany. I've been involved with building all kinds of PV installations in bavaria, from 4kwp up to 20MWp. The balkony generators aren't taken seriously by anybody in the industry right now, at least.
If you're working at that size, I'd expect you to ignore balcony systems regardless of how cost-effective they were.
My point here is simply and only that it's possible to make a system safe enough that an untrained and unskilled member of the general public can just plug it in and use it, which is exactly what was being called for up-thread with this:
> We should practically get to the point where someone can buy a roll of material at Home Depot and unravel it on their roof, nail it, and plug it in themselves.
Germany basically has that (even if it's not in the form of a roll); there's nothing fundamental preventing the USA from having it too.
They're sold for apartments, and as DIY jobs. They're designed to fit on a balcony just about wide enough to stand on, and to be installed without needing an expert.
The point of the example is to show that you don't need an expert. It's not even trying to show a specific unit that suits all people, just that one thing, that you don't need an expert to install it.
The voltages are the same regardless, because that's how domestic electricity works. (If you forced me to guess, I'd expect grid-scale PV farms to go direct to a higher voltage than domestic users, but I'm not an electrical engineer).
Don't get me wrong - I'm pretty committed to DIY a decent system, but it's not trivial and what you posted is just a toy.
The law in Germany may prevent you hooking up ten, but that's not relevant to the point or the market.
Can Americans even hook up things this size on their rental apartment balconies?
> Plus without proper meter (or CT "limiter")
Difficult term to search for, so I'm unsure what that is exactly. I get links about inverters, and I'm sure you noticed this comes with one so it's probably not that.
And this relates to the impact of module mass on (supposedly) preventing DIY installation (despite my example of a DIY installable system) how exactly?
It's very common to need licensing to do something commercially but not when doing it for yourself.
I'd be satisfied if I could simply sit the licensure exam and maybe have to pay extra to do some kind of practical demonstration. Local requirements for residential licensure include documented multi-year experience as an electrician's helper before you can even apply to take the exam.
Ironically batteries is what makes it feasible - I can dump excess into battery instead of paying 3x more for install so I get hooked up to grid in a certified way.
And "sneaking around local restrictions" can create quite the fun surprise for unsuspecting workers who need to open up walls, dig trenches, etc.
I hope you decide to play by the rules.