Framework

mAh mean nothing outside phones, because they only convert to an energy unit if they are paired with a voltage. The reason why it's valid with phones is that they all have the same voltage, so it's always an apple to apple comparison. If you change device type, it doesn't make sense anymore.

For example, my Pixel 6 has a 4700 mAh battery at 3.75 V = 17.6 Wh. But if the voltage was, say, 9V, then it would be 42 Wh. Which is a battery twice the size.

You can't compare mAh across device types which don't share the same voltage. Which is also why I hate it so much that it's become the standard way to talk about batteries for phones.

Amp hours and watt hours are related by voltage since 1W = 1v x 1A

Therefore since the portable battery pack is using lithium ion cells with a nominal voltage of 3.7v: 20,000mAh x 3.7v = 74,000mWh = 74Wh

That's actually more than I was expecting, I don't know why, I guess we all learn something new every day. It's also more than the framework battery, though I wouldn't expect it to be a straightforward 1 1/3 charge for the laptop since there will be inefficiencies in the system. I hope this helps!

So.. mAh is a bit of a useless number. Watt hours is a multiplication of amps and volts. If a product tells you the amp hours, that's only one half of the equation.

If you can find the voltage on your battery, you can use the following format to get a rough estimate of charges.

mAh÷1000×volts/55wh.

The nominal mAh of the 55Wh battery is 3572mAh

HOWEVER that is at 15.4V, while the Powerbank you linked is 20000mAh at 3.7V

So I'd actually recommend doing this the other way around, calculating the Wh of the Powerbank, because Wh is an actual representation of Energy stored inside the Battery, while mAh is only telling you half the story.

And multiplying 20Ah with 3.7V, we get 74 Wh, so that Powerbank is gonna charge the FW 13 about 1.3 times.

Given average battery life reports between 8-12 hours, that should give you between 18 and 27 hours of non-stop use (Laptop Battery + Powerbank),

I'd stick with the 18h estimate, both just to be sure and to account for Windows (assuming you're using it) thinking "Ohh look I'm plugged in so I can use even more power now to run random background tasks", but 18h of run time should still suffice for most if not all situations.

A better question is what is the Wh rating of the Baseus 65W power bank. mAh is not a useful metric unless pack voltage is also known in order to calculate Wh. Wh is the total specific energy capacity of the battery. The fine print of the 65W Baseus charger notes that the 20,000 mAh is the total addition of the 4 individual cell mAh ratings. This is misleading because the Baseus likely uses 4 cells in series to make a ~15V nominal battery pack that is then fed into a boost converter after the USB-PD handshake confirms laptop pack voltage to be higher.

That was a tangent that isn't helpful. Here's the useful calculation: cells at a nominal voltage of 3.7V × 4 × 5Ah = 74Wh for the Baseus 65W Charger. This means you'll likely be able to charge the Framework's 55Wh battery one full time.

If I can make a recommendation... the Iniu 65W 25000mah powerbank on Amazon. There's a 50% coupon every 2-3 weeks so it is $30. Just need to keep an eye on it.

It is the only powerbank I ever had out of which I get >90% of the advertised capacity. (Advertised: 92.5Wh, measured: 102Wh in, 84Wh out.)