SparkFun Sunny Buddy and 9W Solar Panel Not Charging Batteries

Good Morning!

I have a SparkFun 9W Solar Panel ( PRT-13784) connected to the Sunny Buddy ( PRT-12885) with 2 of the 6Ah batteries (PRT-13856) wired in parallel for a total of 12Ah. They are powering a Particle Photon and Sonar Distance Sensor that is only on for 45 seconds every 3 minutes or so. I thoroughly bench tested this setup using a 300W/m^2 artificial “sun”. I left the lights on from 0900 to 1500 and then turned them off. I monitored the entire setup for 1 week and it performed excellently. Batteries charged fully during the “day” and only discharged partially overnight. I figured it would do even better out in the field with 4 times as much energy input. However, I am finding something very odd in the reporting patterns for the sensor (it reports via WiFi and as far as I know the WiFi is up and running 24/7). It seems that during the day, the sensor is not reporting. It starts reporting at night around 2000 (8PM). It usually reports all night until early morning the following day. It seems to be dead during peak sun hours, but it must be charging as it runs all night. Am I missing something here? Any thoughts? Thank you in advance!

Am I missing something here?

Yes.

If you expect anyone to be able to help, post a complete circuit diagram, the code, the symptoms that indicate failure, and the results of whatever troubleshooting steps you have undertaken.

Artificial “sun” is not going to provide much power. You need the real thing.

Thank you. I understand that genuine sunlight will provide more power. However, the problem I’m having is that the setup performed fine under my artificial sun and now that it’s deployed in the field with genuine sun, it’s misbehaving.

Have you tried eliminating the sunny buddy and using fully charged batteries to see if you still see strange behavior? It could be some other factor that’s causing the trouble. How many mAh of energy is your circuit using per 24 hours?

For about the next 6 weeks, we’re in the darkest part of the year. Even with full noontime sunlight for 6 hours a day at most you can only put 2700mAh back into your batteries. You can really only count on maybe 2 hours of full intensity sun this time of year and that’s only if it’s not cloudy outside so it’s possible you don’t have enough energy to replace what your circuit consumes in a 24 hour period.

You might try connecting a power pack to the sunny buddy rather than a solar cell and see if the problem clears up. If it does, you aren’t collecting enough light during the day to replace what power your circuit uses when it’s too dark to charge the batteries.