Solar panel

Components & Accessories Power
1

Hi there!

A few months ago, I ordered a solar panel of 6W for powering my photon particle and weather shield (it is used for a meteo station) during day. During night, it is powered thanks to a 4400mAh lithium-ion battery. Despite of a low data acquisition frequency (every 10 minutes), this seems to remain insufficient because of the limited sunshine (I live in France). Before ordering, I therefore would like to know if it would be better to get a solar panel of 9W or a second solar panel of 6W (e.g. mounted in parallel of the first one). Thanks in advance for your help.

Best regards,

–

NL.

2

Hi NL,

Either option will probably work but adding a 6W Solar Panel in parallel is probably the best solution here. It will theoretically double your peak power output in ideal conditions, which should be more than enough to power the Photon and the Photon Weather Shield. If you are using it to charge the attached battery using something like the [SparkFun Sunny Buddy be sure to factor in that power loss. [This comment from a very helpful user on the 9W Solar Panel page goes into some more detail on the math behind calculating the power you can expect from a solar panel. The link they provide is only for the US but [this map from the Global Solar Atlas can help you calculate your average solar irradiance in France.

I hope this information helps you decide on the appropriate solar panel to give your project the power it needs. Let us know if you have any other questions about these panels or any of our products and we would be happy to help as much as we can.](https://globalsolaratlas.info/)](https://www.sparkfun.com/products/13784#comment-568fe931ce395f72418b4567)](https://www.sparkfun.com/products/12885)

3

Thanks a lot for your quick answer. I forgot to mention that I use the Photon Battery Shield to both connect the solar panel, the battery and the Photon particle. According to your remarks, I will therefore order a second solar panel of 6W and Air Quality breakout to measure pollutants. Additional questions:

  • Is it preferable to protect the panels against water or hail?

  • What is the maximum length for connecting the panels (there are a bit short as is)?

Thanks in advance for your help.

Best regards,

–

Nicolas.

4

Hi Nicolas,

Sorry for the late reply here. The second solar panel will help but you will most likely be losing a lot of power efficiency to charge the battery in that configuration since the Photon Battery Shield expects a consistent power supply to charge the battery. An MPPT Charger like the [Sunny Buddy is a much more efficient solar charging circuit than using a solar panel directly.

The solar panels we carry already have a urethane coating to protect them from water and that coating should be able to protect from minor hail damage. I would not recommend adding a second protective layer as the coating that comes on the panels is specifically designed to allow for maximum efficiency while also protecting from physical and UV damage. To connect the panel, I would limit your power connections to within 10-feet/~3m. If you extend the power cable, just make sure that it is weather-proofed to prevent water damage from getting into the power circuit.](https://www.sparkfun.com/products/12885)