Can I connect a 5w 5w solar panel directly into a 10k mAh portable battery bank safely via USB 2.0, or does it need some sort of protection in-between like a solar charge controller or a schottky diode?
Example of battery bank (except one with usb 2.0 input): https://www.anker.com/ca/products/a1229
Example of solar panel: https://www.aliexpress.com/item/1005006012344670.html
That is a cheap shitty knock off scam panel, just looking at the specs. it claims:
Power: 5W
Working voltage: 5v
Working current: 0-380mA
but of course, you won’t get 5w from 5v * 380mA, only 1.9w based on the specs.
the square area via the specs is 125cm^2 (assuming that’s the panel, not the package!)
and the realistic maximum power possible is 200w / m^2, so 125 / 10000 * 200 = 2.5w for that dinky panel.
get yourself a decent version of this if you really need a portable version.
something more like this, or catch a better version on sale:
https://amzn.to/3VqsztI
Then there are these kick ass USB monitors that will tell you exactly what’s going on during charging:
https://amzn.to/4ao74xU
This is very helpful. I actually have two of those panels so I can try wiring them up in parallel.
I also have that exact USB monitor which is super handy.