Battery Packs- Misleading Advertised Capacities?

[Brado16]

I have used various battery packs for hunts for many years. I have used brands such as Anker, Dark Energy, and various "China" brands from Amazon. I have yet to find a battery pack that gets anywhere near the advertised charge capacity. For instance, a September Archery hunt in WY, I brought with a 50,000 and a 40,000 mAh power banks from Amazon to charge my iPhone 16 Pro (3,582mAh Capacity) and a Garmin Inreach Mini2 (1,250mAh Capacity), which is about 5,000mAh Capacity between the two electronic devices. This would mean the 50,000mAh should be able to charge both devices 10 times, and the 40,000mAh should be able to charge both devices 8 times. In actual practice, the 50,000mAh was able to do each 3 times, and the 40,000mAh about 2.5 times. This was more than enough "juice" for my needs, but if these packs were at, or at least "closer" to advertised capacity, I would only need to haul one device vs 2. The Anker seems to be closer to advertised capacity, but still no where near what the label claims. I understand the cold will hamper the battery capacity so I try to keep them in a bag wrapped with clothing the best I can or in my bag at night while sleeping and charging devices. Does anyone have recommendations on Battery Packs that are darn near close to their advertised charging capacity?

 

[Marbles]

What is the voltage of the power bank vs the voltage of your device? MAh is for a given voltage, Watt hour (Wh) is directly comparable. Looks like your phone has a 13.94 Wh battery, the inReach mini2 is 4.5 Wh. What is the Wh for the battery banks? Then subtract 20% of its capacity.

Charging is inefficient. You can expect to loose 20% or more of your power in the charging process in good conditions. This will be worse outside an optimal temp range or using longer cables, Etc. So, assuming voltage is the same, the best case scenario is likely 8 charges on the 50k mAh pack.

You also have to look at how the bank is designed. Lithium batteries do not like deep discharges or full recharges. A bank designed to give you the most power possible will have a short useful life before capacity starts to drop. You need to know if the advertised capacity is total theoretical or total available. If you bank was designed for maximum power supply, then after 500 charging cycles the pack will have less than 80% of its original capacity and the degradation will be faster if you store it fully charged, store it at higher temperatures, or charge it fast. Even in optimal conditions, lithium batteries degrade with time.

Anyway, good luck. Not really answering your question, but might be helpful in setting expectations.

 

[Marbles]

The Biolite Charge 80 PD is rated 20,000 mAh and 74 Wh.

74x0.8/18.5=3.2, so should get roughly 3.2 charges under optimal conditions.

Now, factor in cold temps and it probably looks more like 74x0.6/18.5=2.4 charges.

It does sound like your power banks are not giving as much as would be expected.

Fast charging is less efficient, so power loss will be greater as well if using it.

This looks to be a decent article. https://justinsimoni.com/buying-a-p...acity_Deprecation_From_The_Loss_of_Efficiency