5 ms·

100W solar panel seems like overkill. I'm curious what the minimal size panel one would need for 24 hour usage. Assuming 5 hours of usable sun, it would seem

100W solar panel seems like overkill. I'm curious what the minimal size panel one would need for 24 hour usage. Assuming 5 hours of usable sun, it would seem like a 20 W panel would be sufficient.

prashnts 7y ago
~30-40 W would be my guess, given both Camera, and WiFi are active. (PiZero-W is rated 1.2A max)
- magicalhippo 7y ago
  FWIW, idle draw on my Pi4 4GB is 0.6A with one HDMI display connected and one wireless keyboard USB transceiver.
  - winter_blue 7y ago
    It might be easier for the reader, if we all used watts (W) when referring to power usage. Amperes (A) are useless without knowing the voltage (V). In the case of the Pi, since it runs on 5 V USB power, it was easy to calculate the wattage. But for devices of unknown voltage, amperes tell you nothing about power consumption. (For reference: a Pi at 1.2 A is using 6 W, and a Pi at 0.6 A is using 3 W.)
    - magicalhippo 7y ago
      Good point. This was indeed at 5V.
    - hutzlibu 7y ago
      Batterie advertisement sometimes uses that to mislead..
newnewpdro 7y ago
It's not like overkill in the solar panel department is harmful, especially if you're getting cheap chinesium stuff off ebay. Nothing helps functioning in low-light situations, like overcast and cloudy days, better than excess panel area. I have a minimally-sized panel I use for powering a laptop and it's rather annoying to have it underpowered in the slightest deviation from ideal circumstances. That same panel for charging smaller devices over USB like phones and tablets is an absolute dream thanks to the overkill, even overcast and cloudy days it never quits charging.
- Scoundreller 7y ago
  What circuit do you use to power the laptop?
  - newnewpdro 7y ago
    It's an Allpowers 80W portable panel, which includes power circuits for two USB ports and an 18VDC output. My laptop accepts the 18VDC input directly. It works fine when the sun is high and sky is clear, as long as I'm not doing anything particularly CPU/GPU heavy.
sigstoat 7y ago
you don't get a cookie for installing less panel. you just get headaches on low-sun days. and your battery won't last as long, as it has to discharge deeper and more often.
- hutzlibu 7y ago
  "$8 Raspberry Pi that supports the camera module. $29 Raspberry Pi Camera module. $18 any 12V battery capable of delivering 1.5W x 24h = 36Wh, such as this 7Ah Pb battery (80Wh). $8 dummy security camera. $132 100Wp solar panel. $10 12V charge controller. $15 cabling and connectors. Total: $220" Since the solarpanel is more than half of the budget, I would think, you can actually buy a cookie for ordering a cheaper one. I think it depends where you live and if the setup should also run in the winter.
  - guerby 7y ago
    100 Wp is $60-$80 if you look around
konstruktors 7y ago
100Wp is probably a bit of an overkill but it does help during the winter season when there are multiple days with almost no sun. Also, there is plenty of shading from the nearby trees so I wanted to be on the safe side. It would be nice to log the power consumption and the battery voltage but I didn't do it for this project.

100W solar panel seems like overkill. I'm curious what the minimal size panel one would need for 24 hour usage. Assuming 5 hours of usable sun, it would seem like a 20 W panel would be sufficient.

prashnts 7y ago

~30-40 W would be my guess, given both Camera, and WiFi are active. (PiZero-W is rated 1.2A max)

magicalhippo 7y ago
FWIW, idle draw on my Pi4 4GB is 0.6A with one HDMI display connected and one wireless keyboard USB transceiver.
- winter_blue 7y ago
  It might be easier for the reader, if we all used watts (W) when referring to power usage. Amperes (A) are useless without knowing the voltage (V). In the case of the Pi, since it runs on 5 V USB power, it was easy to calculate the wattage. But for devices of unknown voltage, amperes tell you nothing about power consumption. (For reference: a Pi at 1.2 A is using 6 W, and a Pi at 0.6 A is using 3 W.)
  - magicalhippo 7y ago
    Good point. This was indeed at 5V.
  - hutzlibu 7y ago
    Batterie advertisement sometimes uses that to mislead..

newnewpdro 7y ago

It's not like overkill in the solar panel department is harmful, especially if you're getting cheap chinesium stuff off ebay. Nothing helps functioning in low-light situations, like overcast and cloudy days, better than excess panel area. I have a minimally-sized panel I use for powering a laptop and it's rather annoying to have it underpowered in the slightest deviation from ideal circumstances. That same panel for charging smaller devices over USB like phones and tablets is an absolute dream thanks to the overkill, even overcast and cloudy days it never quits charging.

Scoundreller 7y ago
What circuit do you use to power the laptop?
- newnewpdro 7y ago
  It's an Allpowers 80W portable panel, which includes power circuits for two USB ports and an 18VDC output. My laptop accepts the 18VDC input directly. It works fine when the sun is high and sky is clear, as long as I'm not doing anything particularly CPU/GPU heavy.

sigstoat 7y ago

you don't get a cookie for installing less panel. you just get headaches on low-sun days. and your battery won't last as long, as it has to discharge deeper and more often.

hutzlibu 7y ago
"$8 Raspberry Pi that supports the camera module. $29 Raspberry Pi Camera module. $18 any 12V battery capable of delivering 1.5W x 24h = 36Wh, such as this 7Ah Pb battery (80Wh). $8 dummy security camera. $132 100Wp solar panel. $10 12V charge controller. $15 cabling and connectors. Total: $220" Since the solarpanel is more than half of the budget, I would think, you can actually buy a cookie for ordering a cheaper one. I think it depends where you live and if the setup should also run in the winter.
- guerby 7y ago
  100 Wp is $60-$80 if you look around

konstruktors 7y ago

100Wp is probably a bit of an overkill but it does help during the winter season when there are multiple days with almost no sun. Also, there is plenty of shading from the nearby trees so I wanted to be on the safe side. It would be nice to log the power consumption and the battery voltage but I didn't do it for this project.