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After searching quite a bit on this topic I'm a little lost. I am new to the electronics side and am constantly learning more as I go along. I have a project where I'd like to power an Arduino Uno by a solar panel and battery. The Uno would run off the solar cell or battery depending on power is available (sun is up or down).

For simplicity, I was thinking of using a LiPo Rider Pro + a Solar Panel. I saw this came as a kit: http://www.seeedstudio.com/depot/wireless-sensor-node-solar-kit-p-919.html It claims it will output 5V which is what I believe the Arduino requires to run (is this right?). The kit does not list the components so I'm a little lost on what size solar panel to get. I believe this: http://www.seeedstudio.com/depot/1w-solar-panel-80x100-p-633.html would output the right voltage (lists: Typical Voltage: 5.5V). However, a 1W Solar panel outputs 170mA and a 3W solar panel outputs 540mA.

On the battery I was looking at this: http://www.seeedstudio.com/depot/lithium-ion-polymer-battery-2a-p-603.html It outputs: 3.7V at 2000mA.

Will this solution 1) power the Arduino and 2) will the solar panels charge the battery?

Another idea is to use the Solar Charger Shield V2: http://www.seeedstudio.com/depot/solar-charger-shield-v2-p-914.html?cPath=1_75 However, I'm still unsure about the solar panel and battery to choose.

Any guidance on this would be very helpful. I am very comfortable on the programming side, setting the Arduino to sleep, etc. The electronics side (the whole point) is a challenge I am enjoying!

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  • \$\begingroup\$ One important thing you haven't told us is how much light exposure you can expect. I doubt that any solar panel will keep the battery charged through a winter in Minsk. \$\endgroup\$ – Joe Hass Jan 5 '14 at 12:58
  • \$\begingroup\$ the light is a variable I am not sure of yet. There are two locations 1) on top of a building and 2) in a field (data logging no communications). Is it correct to assume a larger solar panel will collect more light on a cloudy day? But on a sunny day that extra power would have to just be discarded? \$\endgroup\$ – David Nelson Jan 6 '14 at 16:46
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I have used the Seeeduino Stalker with Waterproof Solar Kit successfully. I think this kit is a great place to start as it will work out of the box. It consists of an Arduino compatible board with LiPo charger, solar panel input, SD card, real time clock, and water resistant case.

The wireless sensor node kit you suggest is a standalone board for XBees, it would not go with the UNO.

The solar panel and charger should work with the UNO. The battery is the same one as in the Stalker kit.

By the way, the Arduino UNO has an inefficient regulator with about 10mA quiescent current so it consumes a fair bit of power just sitting idle. This can be an issue with solar powered devices. The Stalker has a more efficient regulator. You may also want to have a look at sleeping the Arduino to save more power.

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  • \$\begingroup\$ I did see the stalker and noticed you have to have a UartSBee module to program it. After connecting this is it any different than programming the Uno? And last, does the board fit all other shields? We're wanting to attach this to a WiFi shield and with the board looking a little different it's hard to tell what to do next. Thanks for the info on the Uno. I do plan on sleeping it. \$\endgroup\$ – David Nelson Jan 6 '14 at 16:44
  • \$\begingroup\$ Yep you can use a UARTSBee or any arduino mini compatible USB to UART converter. It is then same as programming the UNO except you choose "Arduino mini, 3.3v, 8mhz" in the IDE. All arduino shields will fit, but keep in mind the board is 3.3v. Wifi will chew a bit of power too. The stalker has an extra socket for an XBee, but they have also made other boards such as th wifibee to fit. This could be a good alternative to a wifi shield seeedstudio.com/depot/wifi-bee-v20-p-1637.html \$\endgroup\$ – geometrikal Jan 6 '14 at 20:57
  • \$\begingroup\$ If you already have an uno and wifi shield, perhaps you could develop on that and port to a stalker later? I think the biggest factor in the design will be your power consumption. With solar you need to have a battery with enough capacity for about 3 days of operation (to get through really cloudy periods) and a panel that can supply say 2 times as much energy than is required in one day. Check the minimum 'sun hours' at you location and multiply by the panel wattage to get the expected energy produced by the panel. Btw what is your application? \$\endgroup\$ – geometrikal Jan 6 '14 at 21:05
  • \$\begingroup\$ The goal is to have it sleep for a much time as possible. The way I understand it, the Uno can only sleep for about 8 seconds at a time. I'd then have it check how much time has passed, and decide to run a check or sleep again. If it runs it gathers info such a temp, moisture, and a few other things and either stores it or sends it off to a server via a wifi connection. Then goes back to sleep (including sleeping the wifi shield if possible). I would think this would keep it fairly low power consumption as it only runs maybe 5-10 times a day for < 1 min each time. This is for a research proj. \$\endgroup\$ – David Nelson Jan 6 '14 at 23:11
  • \$\begingroup\$ With the stalker being 3.3v how does this impact shields? Does it reduce the compatibility with some shields since they may require 5v or do you simply have to supply additional power to the shields? \$\endgroup\$ – David Nelson Jan 6 '14 at 23:13

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