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.
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?
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?
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.
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.
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.