Portable power banks

Portable power banks are nice for recharging your cell phone or as emergency power backup.
So far I have only bought and tested out USB based portable power banks that are intended for powering and recharging low power devices such as cell phones.
I hope to test out larger systems after my YouTube channel grows youtube.com/c/electronzap , my product links do better, or I gain more Patreon support. https://www.patreon.com/electronzap

I like the power banks above after a little bit of testing. I always put them on my wish list and try to get them when they go on sale. I look for a price of about $1 per advertised 1,000 mAh no matter which power bank I buy. Some sellers are more misleading than others, so I look for reviews that indicate the power bank might provide close to the advertised value.

The power bank above was OK based on some quick testing I did. I also got 2 power banks that looked exactly the same, other than product description sticker, on Ebay. They claimed to have an impossibly higher amount of energy storage for the lower price that they were offered at. The 2 I bought from Ebay ended up storing a lot less power than this one. I think this case is sold without batteries and people add the batteries they want to it before selling it to others.

The fan above is powered via USB but it also has 2 li ion batteries and a USB output to power the fan and/or other devices as a power bank. The unit charges the batteries while attached to another USB power source.

In the video below, I test a cheap hand crank generator I bought that is intended for charging 5V USB devices. There was some problems with one of my knockoff powerbanks that I hope will not arise with any of my better powerbanks.

The video can be watch directly at YouTube by clicking Quick tests of really cheap USB hand crank generator to charge portable USB powerbanks

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