For others trying to find how many charges you actually get from power banks, because it turned out to be not that easy to find, especially with all these variables (see below) and a lot of misleading comments/posts/review from people who are mistaken. Sharing is caring, so please add your devices in comments.
Some thoughts for other lurkers:
- Amper-hours depend on voltage, so 20000mAh (why not 20Ah, god damn marketing and our monkey brains) might differ from power bank to another.
- Watt-hours (Wh) might also be a lie, according to some reviewer even known brands might sin.
- On top you have conversion loss 80-90% roughly speaking.
I bought INIU 20000mah 65w mini P62-E1 for ~50$. It says it is 73Wh. I got exactly one charge 0-100% for my Steam Deck OLED (50Wh) while it being off.
It was as fast as wall charger and thing is small and weights 320g, which is perfect for me. Also design/surface is above what I expected. Included cable is crap and does not support 65w charging, don't ask me why. Steam deck will on repeat go full charging and then stop with that cable. I can recommend it I guess, but for sure there is something better, depends on discounts, too.
Few things:
The Deck can't support 65W charging either. It prefers, and maxes out, at a 45W charge, specifically 15V@3A. It can charge using 12/9/5V standards as well, but obviously does so slower.
5V charging is only recommended while the deck is off/sleeping as there is a batch with bad charging chips that can overheat and burn out otherwise (as it has to boost the 5V up to 7.4V and above for the battery)
Slower chargers still work even while gaming - they just extend the time it takes to drain.
If a powebank advertises mAh, it's using the nominal voltage of a single lithium cell, 3.6 or 3.7V. If they use Wh (and aren't blatant scams), then that's the only thing that matters. What you get out is always less, due to the conversion losses.
LCD has a 40Wh battery, OLED has 50Wh. Get at least 20% more if you truly want a full charge.
The deck has power passthrough, once it's full it uses the charger only. Sometimes this means it "refuses" to charge to 100% and instead stops just shy, that's kinda normal.