Greetings! I’m using one of the 3.5w spark fun solar panels to power the sunny buddy. Output into a spark fun particle photon weather shield. LiPo battery connected. I’m measuring just above 6v on the input side generated by the solar panel. the output starts out at ~4v to the weather shield. This is with a charged battery. Over the course of the day the power output continues to drop, millivolt by millivolt, until I hit the under volt for the regulator on the shield and it shuts off. the battery continues to drain, where I’m not sure, but it’s not good. The solar panel is under full light the whole time. (happen to have a 300W full spectrum lamp to provide a constant “sun”) so I’m lost as to why there is not excess current to charge the battery and run the project. I’ve tried to limit the consumption, etc. I seem to not be able to get this board to charge my batteries. Any help or guidance is greatly appreciated, thanks!
Have you tried the solar cell in full afternoon sun on a clear day? A lamp isn’t going to have the energy output as actual sunlight and it sounds like the rest of your project is using all the available current the solar cell + Sunny Buddy together is able to provide leaving nothing to charge the battery.
I haven’t yet, but this light is brighter than the noon day sun. The specifications for the lamp are 3100K with 37,913 Lumens generated from a ceramic quartz arc lamp (converting into ~300W/m2 loosely). In Michigan we are in the overcast period of months, so outside is not a good test currently. I’m able to drive a 2.5w electric fan motor to full speed tied directly to the panel under my test setup, that should be ample power to the weather shield with spare to charge.
I also turned off the WiFi module on the Photon to reduce the current load, etc. and the battery is still not taking a charge. The battery just trickles away slowly over the course of two days. I’ve run the battery thru testing as well. It holds a charge perfectly and cycles with capacity as expected.
Thoughts?
The light might be brighter than the sun to your eye, but it can not supply the same amount of energy the sun does. Your light provides less than 1/3 the energy of actual sunlight and that’s definitely going to cause issues for your application. You might be able to compensate for the difference in energy by using a larger solar panel.
How much current is your project using and how much voltage and current are you able to get from the solar panel under artificial light? If the power output of your solar panel is less than what your project consumes, the battery will never charge.
Chris,
I don’t have a mA or uA meter (my fluke just does not cut it), so I’m not 100% certain of the draw, but all the parts are Spark Fun. Sunny buddy, 3.5w solar panel, weather shield, and particle photon. No other components. The artificial light can drive a 2W electric fan motor from the solar panel. I just hooked up my multimeter with the fan running, some quick math, and it appears to be delivering just under 400mA. perhaps that’s under the charge switch on level for the controller? That would also correlate with the fact I’ve never seen the !CHRG signal asserted. I do have two solar panels and can hook them up either parallel or serial if that will help.
More data. Switched out the battery for another 2500mA LiPo and then hooked up an LED to the !CHRG signal. It is currently asserted (LED anode to Positive, Cathode to resistor to signal pin) I’m getting 3.73v at the load side of the board with the weather shield connected.