90 lines
4.6 KiB
Markdown
90 lines
4.6 KiB
Markdown
---
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title: Sunpowered server setup
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date: 2014-02-16 21:13:46
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tags: [hardware, raspberry pi, sunpowered]
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bigimg: [{ src: "/galleries/sunpowered/IMG_0942.jpg" }]
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series: sunpowered
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---
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Remember my [NAS](/tags/nas) ? It
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turned out great ! Very reliable storage, I had a disk failure once and
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haven't noticed for some time because all the files were just there.
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Hardware enhanced virtualization is another great stuff. I ended up
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migrating all my of infrastructure there, each service in separate
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virtual machine; email, calendar, contacts, tor node and such. Only
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caveat ? Power consumption. This setup just eats Watts. About 50W
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constant power usage is not something you want to have turned on
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24h/day. One such day I had a realization that this giant ball of plasma
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that is hanging out there might be of some use. One side of my balcony
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is to the south somewhat, gets lots of sunshine no matter whether it's
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morning or evening. Why not exploit that ? That's how my first
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solarpowered server setup was born. Enjoy the photos ! Also please find
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upgrade options and general notes after the break ! There's a [part 2](/posts/2014/04/21/adding-voltage-current-measurements-sunpowered-pi/) of this post you might be interested in as well.
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Setup itself consists of:
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- 144W solar panel
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- 33Ah 12V battery
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- trusty old WRT54GL
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- Raspberry Pi model B
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- charging controller
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- 12V and 5V step up/step down converters. Don't use linear converters,
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especially for the 5V rail. As these will give you the 5V by
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dissipating the difference from 12V directly onto their heatsinks,
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huge power loses.
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- around one hundred M3 hexhead screws with nuts and washers. yup.
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The router acts as wireless bridge to my home WiFi network, there are no
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cables running from inside the house to the balcony. Router and raspi
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use about 8W total. It is winter in here now and this seems to be
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holding nicely, panel being able to charge the battery for the night
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during relatively short day, even if the weather is bad. However, I want
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more computing power there and this setup does not seem to be very
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scalable. Another raspi model B means another 4W constant power usage. I
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estimate the whole thing will start loosing power during the night with
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about 15W constant consumption. Which is okay for stuff like email
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server, but not really for blog or other sites. Hence my first idea for
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improvement: discard router and change for the separate raspis, model A,
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with wireless network cards each. Should be much better. Some general
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notes:
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- Use equipment specifically designed for DC. You want to disconnect
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the solar panel or battery sometimes. To be able to to that without
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that fancy sparks show you need proper DC switch able to handle high
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currents. AC switches as any other equipment dragged from AC land are
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not really a choice. If you use AC mains switch to switch high
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current DC you might end up with nice weld in place of your switch.
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Same for fuses.
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- My ability to cut acrylic to line is nonexistent. Probably maybe use
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better tools ? Or even, since I now know how the box should be cut -
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just order pieces for box 2.0 cut to size already.
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- Same for my ability to make stuff look nice and clean
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- I like the look of bare PCBs inside of transparent box though
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- The box itself seems to be holding up nicely against below zero
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temperatures as well as rain.
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- Air flow is nice, nothing is heating up. Air enters from the bottom,
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heats up a bit and moves up. Goes through the holes on the left, into
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the funnel and exist on the right. Water does not enter as there is
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pretty steep slope there.
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- Watch for SD card corruption. Most often, the cause is having 5V not
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really being 5V. Raspi does not really like lower voltages. One
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preventive measure would be not to use some cheap voltage converters.
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Another is to mount SD card with very conservative options. I use `/dev/mmcblk0p2 / ext4 defaults,rw,data=journal,journal_checksum,discard 0 1`
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- Make sure your electronic components are rated for -40C to +80C
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- I'm a bit worried of battery being in such proximity to the airco
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unit. We'll see in the summer whether it needs relocation, for now
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the unit is completely powered off.
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- mountain climbing equipment comes in handy when hanging stuff from
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your balcony
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Future improvements:
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- most pressing: get the power usage down by changing to model A + wifi
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card
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- add monitoring, something like ADC connected to raspi's GPIO ports,
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gathering voltages all across. I would like to get readings on: solar
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panel voltage, battery voltage, 5V rail actual voltage and the whole
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system power usage at least
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- more safety fuses and bypass diodes
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{{< gallery dir="galleries/sunpowered" />}}
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