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Jay Leno talks about installing solar on his house (which he did himself) and commenting that he was getting shocked a lot, bc as soon as the PVs are in the sun

Jay Leno talks about installing solar on his house (which he did himself) and commenting that he was getting shocked a lot, bc as soon as the PVs are in the sun, they're making electricity. He said it made handling the units tricky.

ethbr1 2y ago
Stupid question I've been curious about. 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?
- lompad 2y ago
  A small current is going to flow internally, but nothing else happens. It's quite normal to have solar panels running with zero load in regions with lots of PV - reason being, that the carriers need to keep their electricity nets stable and have to carefully balance electricity entering and leaving the net. 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.
- antisthenes 2y ago
  The generated power will be dissipated through the panel as heat, AFAIK. 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)
  - addaon 2y ago
    > The generated power will be dissipated through the panel as heat, AFAIK. 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.
    - CorrectHorseBat 2y ago
      Where's the power going to then? Either it's heating the panels or it's reflected back, no?
      - dzhiurgis 2y ago
        Given ~20% efficiency it's almost negligible amount of heat.
      - Dylan16807 2y ago
        The sunlight heats the panel a bit more than usual but there isn't really generation/dissipation going on. And since heat radiates away at temperature to the fourth power, the increase shouldn't be particularly much.
      - addaon 2y ago
        The thermal power of the sun will heat the panel, to the extent that it is not reflected. But no electrical power (or any power) is being "generated" by the panel, the panel is just absorbing photons like anything else with low albedo.
        CorrectHorseBat 2y ago
        That's just nitpicking. There is thermal power generated from the electromagnetic power from the sun and GP is right that a solar panel turned off will be hotter than one turned on.
cwalv 2y ago
Really? Couldn't you just tape a piece of cardboard over it?
ragebol 2y ago
I installed an additional 12 505Wp panels by myself last weekend, the panels came with MC4 connectors installed which is pretty standard I think. Hard to get zapped by solar DC juice that way. 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)
weaksauce 2y ago
if it were really a problem moving forward and diy becomes the norm(which i doubt is the case) it's pretty trivial to apply an opaque sticker or cardboard covering to the panel during manufacture.
- hughesjj 2y ago
  I've already gotten smaller solar panels in shrinkwrap, I could easily see it becoming standard to package it in a scratch proof blackout layer
ChainOfFools 2y ago
Why can't they just be covered with blackout film until they're ready to be activated?
- snypher 2y ago
  I just left mine half in the packaging, but I'm not Jay Leno.
  - bee_rider 2y ago
    He got a funny story out of it, maybe he could write them off as a work expense.
- SoftTalker 2y ago
  Or have interconnecting cables, plugs, and sockets that are designed to prevent you from touching the conductors. Yeah you could probably still shock yourself but you'd bascially have to be trying to do it.
grecy 2y ago
That... makes no sense. 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.
triceratops 2y ago
Do you have a link to that video? I've never thought of Leno as a particular handy guy so it sounds fascinating.
- grecy 2y ago
  Also I can't imagine him up on a roof. He's 74 and not a pillar of health and fitness.
  - triceratops 2y ago
    I doubt this interview was last week. It might have been 10 years ago.

ethbr1 2y ago

Stupid question I've been curious about. 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?

lompad 2y ago
A small current is going to flow internally, but nothing else happens. It's quite normal to have solar panels running with zero load in regions with lots of PV - reason being, that the carriers need to keep their electricity nets stable and have to carefully balance electricity entering and leaving the net. 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.
antisthenes 2y ago
The generated power will be dissipated through the panel as heat, AFAIK. 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)
- addaon 2y ago
  > The generated power will be dissipated through the panel as heat, AFAIK. 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.
  - CorrectHorseBat 2y ago
    Where's the power going to then? Either it's heating the panels or it's reflected back, no?
    - dzhiurgis 2y ago
      Given ~20% efficiency it's almost negligible amount of heat.
    - Dylan16807 2y ago
      The sunlight heats the panel a bit more than usual but there isn't really generation/dissipation going on. And since heat radiates away at temperature to the fourth power, the increase shouldn't be particularly much.
    - addaon 2y ago
      The thermal power of the sun will heat the panel, to the extent that it is not reflected. But no electrical power (or any power) is being "generated" by the panel, the panel is just absorbing photons like anything else with low albedo.
      - CorrectHorseBat 2y ago
        That's just nitpicking. There is thermal power generated from the electromagnetic power from the sun and GP is right that a solar panel turned off will be hotter than one turned on.

cwalv 2y ago

Really? Couldn't you just tape a piece of cardboard over it?

ragebol 2y ago

I installed an additional 12 505Wp panels by myself last weekend, the panels came with MC4 connectors installed which is pretty standard I think. Hard to get zapped by solar DC juice that way. 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)

weaksauce 2y ago

if it were really a problem moving forward and diy becomes the norm(which i doubt is the case) it's pretty trivial to apply an opaque sticker or cardboard covering to the panel during manufacture.

hughesjj 2y ago
I've already gotten smaller solar panels in shrinkwrap, I could easily see it becoming standard to package it in a scratch proof blackout layer

ChainOfFools 2y ago

Why can't they just be covered with blackout film until they're ready to be activated?

snypher 2y ago
I just left mine half in the packaging, but I'm not Jay Leno.
- bee_rider 2y ago
  He got a funny story out of it, maybe he could write them off as a work expense.
SoftTalker 2y ago
Or have interconnecting cables, plugs, and sockets that are designed to prevent you from touching the conductors. Yeah you could probably still shock yourself but you'd bascially have to be trying to do it.

grecy 2y ago

That... makes no sense. 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.

triceratops 2y ago

Do you have a link to that video? I've never thought of Leno as a particular handy guy so it sounds fascinating.

grecy 2y ago
Also I can't imagine him up on a roof. He's 74 and not a pillar of health and fitness.
- triceratops 2y ago
  I doubt this interview was last week. It might have been 10 years ago.