Sunny Buddy won't power arduino, appears to charge battery

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Joined: Sat Aug 12, 2017 11:07 am

Sunny Buddy won't power arduino, appears to charge battery

Post by modulo1 » Sat Aug 12, 2017 11:49 am

Hey there,

So for my first big project, I decided to build the weather station, detailed here.

However, I seem to have gotten stuck on the "power the arduino with the Sunny Buddy" step.

Here's what I have so far:
  • 3.5W Solar Panel (store link)
  • 6aH Battery pack (store link)
  • Sparkfun Sunny Buddy (store link | hookup guide)
  • Screw Terminal 3.5mm pitch, 2-pin (store link)
  • Male barrel plug pigtail, connected to screw terminal, center pin positive
  • Arduino Uno x2 (I was thinking my arduino was at fault, but now I'm not so sure).
Per the Sunny Buddy hookup guide, I connected the solar panel to the Sunny Buddy, and without a battery or load, measured the voltage at the SET and GND pins. I adjusted the potentiometer until it read 3.0V.

However, when I plug the Arduino in, nothing appears to happen.
  • Just the Arduino: the "on" LED lights up, but the pin 13 LED appears much dimmer. The arduino is running the weather station code found here, without the GPS module, so the TX LED should blink when the arduino reads the sensor data off the weather shield.
  • Arduino with the Electric Imp shield connected and the Imp card inserted: the green "on" LED is lit, but flickers. The LED on the Imp card does not light up at all.
  • Arduino with the weather shield connected: the blue LED on the weather shield does not light up at all.
I've read the datasheet for the Sunny Buddy, and some searching on the forums and web, and found that the GND and FAULT pads drop to 0.2V if there's a problem, but I haven't seen that here.

And this is where I'm stuck. I'm not sure what to check next. This is my first real electronics project, and an ambitious one at that, so I'm lost on what I can check to narrow down the problem to either something I did wrong, or a problem with the Sunny Buddy, or the arduino(s), or what have you.

Any help or guidance would be greatly appreciated.


Posts: 1
Joined: Sun Sep 03, 2017 3:58 am

Re: Sunny Buddy won't power arduino, appears to charge batte

Post by PHoliday » Sun Sep 03, 2017 4:38 am


Doing the exact same project and have exactly the same problem. Did you manage to get a response or solve the issue?

Posts: 4
Joined: Sun Oct 08, 2017 11:56 am

Re: Sunny Buddy won't power arduino, appears to charge batte

Post by TCIII » Sun Oct 08, 2017 12:11 pm

Where do you have the power cable from the output of the Solar Buddy hooked to on the Weather Station stack of Shields? It may not be obvious but the author of the Weather Shield Weather Station hooked the output of the Solar Buddy to the IMP Shield +5vdc and GND pins on the Shield header. You can see the attachment points in the Weather Station build instructions by looking at the picture entitled "Modified for wireless Arduino bootloading".
One thing that I am wondering is why the author did not use a +3vdc to +5vdc boost converter like the Sparkfun Li-power Boost Converter to power the Weather Station stack? This converter can supply up to 600ma at +5vdc.

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