New hardware and Solar Power

OK, loving the whole Featherwing format for the new hardware. I love the idea of tapping into all the great work Adafruit has done building out the portfolio.

However, when I was checking out the current offerings, I did not see a solar Power featherwing. I have been powering my Electrons with Solar with some success - thanks @RWB!

But, will the new hardware only need a big capacitor as the current hardware does? It takes some time to design a new carrier board so, want to get started soon if it will be needed.




OK, so I guess we don’t know the answer to my previous question yet. How about a simpler one, do we know if the new hardware will include a LiPO pin as the current one does?

I have an off board Solar module I am working on and would like to know if I can connect it via the carrier.



@chipmc, I am making inquiries. :grinning:

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Solar wing sounds like a fantastic idea!

All Particle mesh devices will have their LiPo pins exposed, in accordance to the Feather specifications.

Let me know how else may we help you get unblocked in designing this wing.




Thank you for responding and, yes, a Solar Featherwing would be awesome.

I have built a Solar Power manager that combines a charge controller, the i2c fuel gauge and a buck-boost converter to provide what looks like a fully charged LiPo battery to the micro controller. It measures only 1.5" square so it is small (see attached) but, it will be a challenge to fit in the Featherwing footprint - especially with the big capacitor.

I will take a look but, perhaps having a separate board is Ok - would be interested in feedback from you and the community.

Thanks, Chip

What chips did you go with for the charging , boost, and fuel gauge IC?


Sure, here they are:

What do you think? I have been using this combo in the park for a few years so this is a tested design.


It thinks they are fine if they work for you.

Eventually, I will make one that is designed to work with LiFePo4 cells which provide 400% longer cycle lifespan than lipo cells. That would require a different charge controller and fuel gauge.


Yes! That does seems like a cool technology. I have not had any issues with lifespan, as some of these batteries have been on Solar charge for 2+ years. But, I understand that these batteries are less of a fire risk which is a big deal for sensors deployed deep in the woods.

Will the new hardware ship with a LiPo or a LiFePo4 battery? Do we know?


I’m sure they will stick with the standard LiPo cells.

But they are talking about not including LiPo batteries with the new cellular devices to avoid having the ship them.

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Thats great too!

As for the feather wing, you can also use a bigger footprint. Maybe use twice the space.


Thank you and I think there is also the possibility of the wing sticking out on the right side too.

OK, I understand if this information may not available yet but, before I try to lay this Solar Featherwing out, I am wondering if it is required. Let me explain…

In today’s environment, only the Electron can handle the voltages required for solar power because it has the TI BQ24195 charge controller chip. So, powering it with Solar Power is simple, just add a large input cap, use a 3W / 6V panel and make some changes to the PMIC settings. This works well today.

So, with the new hardware, will there also be a charge controller and, if so, can you say what the part number is? This would make a big difference in the feather board required.

I understand if I have to wait and see but, was hoping to have my carrier boards designed and produced by July.



@chipmc - Can you expand on this? I've been using Photon's with the Power Shield and a 12V regulator chip (L7812CV 1.5A 12V) to input into the screw terminals on the Power Shield running on a 12V 10W panel. The results work (I see the Photon routinely recover from cloudy days), but curious how you've set up your system? Sounds simpler? :smiley:



Sure, since the Electron can handle up to 9V on Vin (unlike the Photon which can only handle 5.5V), you don’t need the regulator chip. I use a 6V/3W panel (which despite the 6V can put out up to 9v) and a 1000uF capacitor on the Vin line. I have some other circuitry for turning on and off the power but this is all you need for Solar to work.

Thanks, Chip

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Hello @chipmc, I had the same question.
The benefit of the Electron Power Shield is the BQ24031. It can take up to 18V on the AC input, it regulates the output to a programmable voltage and it charges your battery. I also had good results connecting it directly to a PV cell (I modified the shield with additional diodes) because it implements what TI calls DPPM, as sort of MPPT feature that limits current to maintain a minimum voltage. It still needs some bypassing at the input, but I am able to use just 22uF.
There is a paper about it (SLU394) that I can no longer find on the TI site.
It is a bit confusing to apply, but there are other documents available. Let me know if interested.


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Thanks for the input and, yes, I could see how the power shield would help as you could use 12V panels. These panels are more common and cheaper than the 6V panels I use today. However, there is no Power Shield for the Featherwing format today.

The reason I started this thread was to see what we can expect from the new hardware. Will it have the power management capabilities of the power shield, the Electron, the Photon or something else?

I am sure there is a plan to announce such information in advance of the July launch. I just ask that, if possible, this topic be revealed early enough that folks like me who use the Electron with Solar Power today, can have the right supporting circuitry ready for the launch.

Thanks, Chip

You can run a photon off an ideally placed .25w panel and a battery if you exploit low power modes. This is enough for it to report data every 30 minutes or more.

This project shows you how it is done.

I’ve since upgraded to a nicer enclosure with a .5W panel. .25W was enough and could be used with good sunlight.

It recharges remarkably quick now with the .5W panel. I can recommend the matte finish solar panels as they seem to be better off axis.

You can see my mailbox data here.

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