I could not agree more! Many times the only way to know is to take it apart and look at the marking on the battery cells. However you also need to look at the wiring of the battery cells. For example that apple battery pack actually uses 3.7v battery cells, but has two is series for the total 7.4v. Other brands, like Anker use one larger cell or several 3.7 cells in parallel. Knowing the number of cells, their configuration and their individual rating is all needed to truly understand the battery bank’s raw capacity.

However, raw capacity doesn’t mean much. It’s the net capacity the battery bank can output. Some brands use more efficient circuity than others. Therefore it is entirely possible a lower [raw] rated battery bank can outperform one with more raw battery capacity.

Thank goodness for YouTube channels that take everything apart and do rigorous testing.

Wish manufacturers listed raw wh rating and charging efficiency, but we are stuck with less meaningful, but bigger, more impressive sounding numbers.

Agreed. I have many battery banks of many sizes - some with wireless (but not MagSafe) chargers built in. I have found if I need to charge my phone via a battery bank, it’s because I need to use the phone. The Anker 621 is small enough that I always have it with me, but also keeps the phone very usable while charging. It easily charges my 13 pro over 80% which is plenty to hold me over till I get to a wired charger in my car or at home. In the heat, it does slow the rate of charging but it’s so small on the back of the phone, there is no rush.

Just an FYI, the nominal voltage of most battery banks is 3.7v. The circuitry bumps it up to 5v (or higher) to charge the phone. However the 3.7v should be used when calculating the overall capacity. So 37wh for a 10ah (10,000mah). So a 3.7v nominal battery pack with a mah rating under 27,000 can be taken on aircraft. Which make sense why manufacturers top out near that rating.

One exception is the apple MagSafe battery pack. That uses a 7.4v nominal voltage. This is why despite the lower mah rating it still has similar overall capacity to the Anker options.