Readit Newskonstruktors commented on Solar Powered Raspberry Pi Camera kaspars.net/blog/solar-ra... · Posted by u/ingve
Even if you can manage to find li-ion cheaper, you would need to build a pack of 6+ 18650 cells for comparative capacity. A single Pb is much simpler. Bam, $18, done, a single unit, 80Wh ready to go, super simple to charge too.
It's not like the size or weight matters to him, and it seems his panel is big enough to avoid deep cycling it too often.
Exactly. And I haven't found cheap charge controllers that support the voltage range of Li-ion packs (like 12.6V for a 3S pack or 16.8V for a 4S pack).
konstruktors commented on Solar Powered Raspberry Pi Camera kaspars.net/blog/solar-ra... · Posted by u/ingve
I see a house, why not use the Pi's Wifi instead of a modem?
It does use the built-in WiFi to connect to a WiFi network created by the mobile modem I placed at the neighbours house which has a permanent power supply.
I considered using a mobile USB modem attached directly to the Pi but that requires extra effort keeping it connected with something like a cron task that pings 8.8.8.8 and restarts the connection if there is no response.
konstruktors commented on Solar Powered Raspberry Pi Camera kaspars.net/blog/solar-ra... · Posted by u/ingve
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.
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.
konstruktors commented on Solar Powered Raspberry Pi Camera kaspars.net/blog/solar-ra... · Posted by u/ingve
Reading this has reminded me of something I wanted to explore in the past. Most of my applications/requirements for a Pi include GSM, but I've found GSM modules to be very expensive, often being more expensive than the Pi itself.
The author mentions a mobile USB modem, and it's just dawned on me that older 3G/HSDPA dongles are often very cheap. Does anyone have experience using them, especially what power implications they bring?
They do bring a bit of bulkiness on the Pi, and are easy to steal, but then if one can access the modem, the whole Pi might be at risk too.
Author of the blog post here. I've used [this SIM800 Raspberry Pi hat](https://www.itead.cc/wiki/RPI_SIM800_GSM/GPRS_ADD-ON_V2.0) and it requires some additional GPIO toggling to enable the modem after a power loss. [Here are the scripts](https://github.com/kasparsd/remote-pine) for doing that and creating the PPP network interface.
The USB modems are nice because you get full control over the modem with the AT commands. I've used the Huawei E173 modem which can be easily unlocked and works great out of the box.
Which is crazy given how little interactivity and DOM state a site like GitHub actually needs to manage.