3 ms·

For a comparison, 50W doesn't seem like much, right? Maybe if you're older you had 50W incandescent light bulbs in your house. Normal thing. Let's say a WISP

For a comparison, 50W doesn't seem like much, right? Maybe if you're older you had 50W incandescent light bulbs in your house. Normal thing. Let's say a WISP wanted to run a very basic off grid relay site with some radios that are 8-12W DC load each and a router that's 15W. Total around 50W 24x7x365. ((50 x 24 x 31)) / 1000 That's 37.2 kWh per month. You need a surprisingly large amount of solar panels to generate a reliable 45-50 kwH per month to refill a battery bank every day when the sun comes up, in November, December, January, February at latitude 45N or above. Like, really, a lot more than you might think. Four or more 370W 72-cell.

jakewins 4y ago
PVwatts says a 4-module array of 370w panels, including AC losses, will produce about 100kWh in January at 45N FWIW
- walrus01 4y ago
  That's assuming perfect sun exposure on a roof or ground moving with no shadowing at any time of the day and at the optimal tilt. Pvwatts says that usable energy from a 1480W system at 43.6N in Boise ID might be more like 77kWh a month in December, the shortest sunlight month of the year. An off grid system generally needs to be calculated to survive December. January will be a few percent better as days start getting longer. Realistically, to get through entire week long periods of snow and overcast, if I had a load that was 50kWh a month I would want a 75-80kWh a month predicted PV production system to make it worry free in December.
sgt 4y ago
Going against the trend here but I still use incandescent bulbs in key places like my desk and so on. I find LED to give a terrible light (not the whole spectrum), but they are getting harder and harder to find.
- bityard 4y ago
  Incandescent bulbs are not full spectrum, though. They are on the warm end of the color temperature scale, much more "orange" than mid-day sunlight. The good news is that you can get LED bulbs in any color temperature you like. My house is full of "warm white" LED bulbs and I could not tell any difference in brightness or color when I swapped them in for incandescent many years ago.
  - madaxe_again 4y ago
    The difference is colour rendering and the nature of the spectrum. An incandescent bulb is, by definition, emitting black body radiation - it’s a nice curve encompassing a good chunk of the spectrum, but as you say biased towards the red end. LEDs tend to emit discrete quantised frequencies of light, as a result both of the dopants in the LEDs and the phosphors used on bulbs. They have got better, due to better phosphors, but they still don’t render colour as well as incandescent bulbs. That said, I’m all LED here as I cannot afford within our energy budget to burn a kilowatt or more on lighting.
  - ilyt 4y ago
    They are continuous black body spectrum which we got used to
- goodpoint 4y ago
  > LED to give a terrible light Let's stop spreading this myth. Cheap LED lights can have terrible spectrum. Good LED lights have a better spectrum than incandescent.
  - sgt 4y ago
    I should have phrased it differently. See madaxe's comment: > The difference is colour rendering and the nature of the spectrum. If you compare it with your own eyes, you should definitely be able to see it.
    - nunuvit 4y ago
      Here's a good article explaining in-depth how and why LED light looks different from incandescent. https://nymag.com/strategist/article/led-light-bulbs-investigation.html https://nymag.com/strategist/article/led-light-bulbs-investi...
    - goodpoint 4y ago
      > If you compare it with your own eyes, you should definitely be able to see it. People buy cheap LEDs and then say this. Buy good quality LED bulbs and you will see no difference.
- shanebellone 4y ago
  There are a few specialty LED lightbulbs made with (old-fashioned) yellow glass that offer a warm (yellowish depending on the room) and comfortable light.
- ilyt 4y ago
  Finding LED that have light that doesn't look bad is unnecessarily complicated sadly

jakewins 4y ago

PVwatts says a 4-module array of 370w panels, including AC losses, will produce about 100kWh in January at 45N FWIW

walrus01 4y ago
That's assuming perfect sun exposure on a roof or ground moving with no shadowing at any time of the day and at the optimal tilt. Pvwatts says that usable energy from a 1480W system at 43.6N in Boise ID might be more like 77kWh a month in December, the shortest sunlight month of the year. An off grid system generally needs to be calculated to survive December. January will be a few percent better as days start getting longer. Realistically, to get through entire week long periods of snow and overcast, if I had a load that was 50kWh a month I would want a 75-80kWh a month predicted PV production system to make it worry free in December.

sgt 4y ago

Going against the trend here but I still use incandescent bulbs in key places like my desk and so on. I find LED to give a terrible light (not the whole spectrum), but they are getting harder and harder to find.

bityard 4y ago
Incandescent bulbs are not full spectrum, though. They are on the warm end of the color temperature scale, much more "orange" than mid-day sunlight. The good news is that you can get LED bulbs in any color temperature you like. My house is full of "warm white" LED bulbs and I could not tell any difference in brightness or color when I swapped them in for incandescent many years ago.
- madaxe_again 4y ago
  The difference is colour rendering and the nature of the spectrum. An incandescent bulb is, by definition, emitting black body radiation - it’s a nice curve encompassing a good chunk of the spectrum, but as you say biased towards the red end. LEDs tend to emit discrete quantised frequencies of light, as a result both of the dopants in the LEDs and the phosphors used on bulbs. They have got better, due to better phosphors, but they still don’t render colour as well as incandescent bulbs. That said, I’m all LED here as I cannot afford within our energy budget to burn a kilowatt or more on lighting.
- ilyt 4y ago
  They are continuous black body spectrum which we got used to
goodpoint 4y ago
> LED to give a terrible light Let's stop spreading this myth. Cheap LED lights can have terrible spectrum. Good LED lights have a better spectrum than incandescent.
- sgt 4y ago
  I should have phrased it differently. See madaxe's comment: > The difference is colour rendering and the nature of the spectrum. If you compare it with your own eyes, you should definitely be able to see it.
  - nunuvit 4y ago
    Here's a good article explaining in-depth how and why LED light looks different from incandescent. https://nymag.com/strategist/article/led-light-bulbs-investigation.html https://nymag.com/strategist/article/led-light-bulbs-investi...
  - goodpoint 4y ago
    > If you compare it with your own eyes, you should definitely be able to see it. People buy cheap LEDs and then say this. Buy good quality LED bulbs and you will see no difference.
shanebellone 4y ago
There are a few specialty LED lightbulbs made with (old-fashioned) yellow glass that offer a warm (yellowish depending on the room) and comfortable light.
ilyt 4y ago
Finding LED that have light that doesn't look bad is unnecessarily complicated sadly