> There was no mention of the voltage on the solar panel
It's right there on the label. 4th image on the amazon link. Open circuit 21.5 volts. Optimum power output at 17.6v.
You need a dc dc converter.
Here's one that takes up to 24v in, puts out 5V at up to 3A, and already has usb connector for connecting to the powerbank.
https://www.amazon.com/HOMREE-Converter-Voltage-Regulator-Standard/dp/B01MEF293V/
The red and black leads go to the solar panel. Red to the cable marked + and black to the cable marked - The plus and minus are stamped on the plastic housing on the backside of the panel where the wires come out.
There are plenty of 12v LED power supplies available cheaply on Amazon. For converting the 12V down to 5V for the Pi, you could either use a voltage regulator circuit, or you could get something already-designed from Amazon. I had good luck running a Raspberry Pi from an Astron 12v linear power supply using a buck converter from Amazon: https://smile.amazon.com/gp/product/B01MEF293V/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1
The wiring was very easy. You already have 12v coming to the seat base, since the 3rd gen console has a standard 12v outlet in it. Tap into that for power for a USB cable (I used this... https://www.amazon.com/gp/product/B01MEF293V/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) and for the wireless charger. For the data USB and aux line, I ran those directly to my head unit.
Use a device similar to this.
Use 24VDC supplies.
HOMREE DC DC Converter Buck Module 12V/24V to 5V 3A USB Output Step Down Voltage Regulator Charge for Samsung Galaxy , iPad iPhone 4S 5 6/6 Plus etc (Standard USB) https://www.amazon.com/dp/B01MEF293V/ref=cm_sw_r_cp_api_i_y74rCb7H2C7EE
It is just a dc-dc converter. It shouldn't cost $50. I think they are likely the seller and that may be why they removed their account. This is really a $5 thing on amazon.
Here is one. Which has the same power capacity as their 2 port. So, split this unit and you are golden. https://www.amazon.com/gp/product/B01MEF293V This is one I actually buy.
It can take "12v panels" (20v or so) For a 24 v panel, (almost 40v) there is another version that is for a 48v battery. That could likely take up to 3 series connected 12v panels.
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This isn't even the cheapest model. I just personally use it and thus trust it in my system. I just recently bought 4 more.
Good work!
Definitely recommend moving to a Pi3 or Pi4 at a minimum, you’ll want to do more and more and more with HA. As for the wall tablet, find a way to mount the power supply in a gang box behind it in the wall, it really makes it look professional.
I’m using a Amazon Fire 10 2019 with a 3D Printed Wall Mount. I ran 12VDC in the wall (used to have a 2GIG Alarm Panel there) and use a 12VDC buck converter stashed in a gang box to power the tablet via USB-C.
Fully Kiosk app running HA interface with DakBoard as my screen saver!
Works like a dream.
OP, you need a 12V to USB adapter like this: https://www.amazon.com/HOMREE-Converter-Voltage-Regulator-Standard/dp/B01MEF293V
Wire that in place of the old clock, and plug your USB-powered gadget into it.
USB devices use so little power, you won't have to change any fuses or wires.