Power banks - help me understand the numbers

[AeroMocha]

I have a heated shawl that needs a USB power bank. I bought the one that amazon sold as 'recommended' to go with it - a 10,000mAh one, but at 220g, it's so heavy that it pulls the shawl down on that side and clunks around (there isn't a pocket for it as it's from China and not brilliantly well made, but basically does the job of keeping me warmer when working form home but still letting me move around).

So I'm looking for a significantly lighter power bank, and there are so many numbers to consider. The shawl says: input voltage 5V, rated power 4W.

I'd like the lightest weight/thinnest power bank I can get, that would last for 2-3 hours at least.

I think the numbers mean that the current needed is 0.8A, and 2.5Ah would last for about 3 hours then; I've heard you only get 2/3 of the listed value though because it converts power inefficiently, so it might only be around 2 hours. Does that sound right?

Are there other numbers that I need to consider? If some of them only charge phones, is that just because of the connectors and not anything to do with the power? I don't want to use the wrong power and burn out the device, or risk a fire or anything.

I don't mind if it takes a long time to charge. It needs to have a USB (big) output, or a USB-C one, as I have a doodad that can convert from one to the other.

Would something like these work:

www.amazon.co.uk/Portable-Charger-5000mAh-Battery-Ultra-Compact/dp/B09B3HRVW5?th=1&tag=mumsnetforu03-21

www.amazon.co.uk/TNTOR-5000mAh-Portable-Charger-Android/dp/B085HH6WCL/ref=psdc_1326521031_t2_B07PYHBRD5?tag=mumsnetforu03-21

(that shows a 57g one in the comparison chart, which is the smallest I've seen, but I think it's just got a phone connector).

Or something like this? Wrong connectors though I think, but maybe I could use the USB-C both the charge and as output?!

www.travelcardcharger.com/

Any help or explanations appreciated! Which one should I get or can anyone find any other lightweight ones that would work? It's the weight (and to a lesser extent the size) that matter most for me

The two in your links hold half the power of the one you have. That’s shown in them saying 5000mah while the one you have it 10000mah.

Really go for around 20000mah to give a decent amount of charge that will last.

I’ve fallen into the trap of buying a “brick” too much to the hilarity of my work colleagues.

Look in the details to see if they mention the dimensions of the phone do you get an idea of the width. How heavy it is, as you found is another indicator that it could be a brick.

I have this one, it is heavy but holds oodles of charge. www.amazon.co.uk/gp/aw/d/B08PY2XT8V?psc=1&ref=ppx_pop_mob_b_asin_title&tag=mumsnetforu03-21

And I also have this one which is also a good charger but lighter than the first one: www.amazon.co.uk/gp/aw/d/B07VHGNQ75?psc=1&ref=ppx_pop_mob_b_asin_title&tag=mumsnetforu03-21

Not helpful but I am interested in your heated shawl

It's weight that's most important to me.

I don't mind that it doesn't last as long, as long as I get 2-3 hours out of it.

But 220g like the one I have is just too heavy to be usable. So I am looking for something smaller - not as much charge is OK as long as it's reasonable. But weight is the big concern. It's just totally impractical to have the 200g one in the shawl, and anything more than that would be even worse!

shawl is kind of like this;
www.amazon.co.uk/gp/product/B08LD19FB5/ref=ppx_yo_dt_b_asin_title_o03_s00?psc=1&tag=mumsnetforu03-21&ie=UTF8