Some sellers on Amazon are selling smaller than typical size while stating the ah is same as competition. Is this possible? They stated because of their superior (insert marketing language) tech so it’s smaller. By directly addressing it I am wonder if such tech exist to make lithium battery smaller?
Eg.
T-CORE Power Bank The Smallest and Lightest 10000mAh External Battery Ultra-Compact High-Speed Charging Technology Portable Charger for iPhone, Samsung Galaxy and More Amazon.com
Looking at some of the negative Amazon reviews of this:
https://www.amazon.com/dp/B09VP41M71
It looks like the actual capacity is only about 6000mAh, and people complain that the charger is extremely heavy (and maybe overly thick.)
I don’t know the answer to your questions, though.
I thought they only deliver about 70% of nameplate. In general, I would be suspicious of anything significantly smaller than others of similar rating. Look for a Romoss or Jackery at a good price/coupon and I think you will get what you paid for.
Most powerbanks I’ve owned are 18650-cell based, the only way to increase the energy density I suspect would be to use Li-po pouch cells. If claims seem to be too good to be true, they probably are.
You can normally guesstimate the cell capacity inside the power bank, if it’s using 6x18650 cells, then 3500mah X 6 = 21,000 mAh.
Someone at TLF tested many powerbanks:
How do you know its not a LiPo?
Ya. Like 70%-ish. Somewhere around there.
Theyre definitely using lipo. Not many powerbanks use 18650s anymore. Very rare to find one that does unless youre seeking it out
More like 50-60% in reality.
It’s not like they’re lying though, a 10000 mAh power bank usually does have that capacity … but transforming that to USB-voltage and then back to battery charging voltage in the target device eats up almost half of it.
But 18650 is still safer than Li-Po pouch by a long shot. Since it can contain the pressure and have some safety built into the cell instead of relying 100% on the protection circuit to do the job. That’s why you don’t see EVs with Li-Po pouches because catastrophic failures would be a lot more common.
Depends on the devices. The most efficient boost / buck charging circuit would retain 90% of the energy instead of wasting it as heat.
You cant hold that against the power bank tho. But ya, true, and efficiency is going to swing depending on 5he power bank’s SOC and the device’s SOC and even the length of the cord or the temperature in the room.
Im revising my answer lol. Efficiency is somewhere between 1% and 99% depending on where and when and how its measured.
Depends on the application. They both have their strengths. One isnt universally safer than the other. There are EVs using pouch cells.