Power bank is not super fast charger

[Eslam3030]

I just purchased 20000mah samsung 25w power bank for my mobile note 20 ultra and wishing to charge with it super fast charging but I discovered that it starts the charging in super fast mode for some minutes then fast mode to the end.

Is that normal?

[Tech-Savvy]

That's normal ig

[Tech-Savvy]

Could you say me at what percentage did it change?

[Eslam3030]

This is a real case:
The phone is shutting down, and the battery percentage is 17%.
Battery bank charged it From 17% : 100% at about 1 hour.
About only 6 mins of them was at super fast mode.
By disconnecting and connecting the cable multiple times, we can get the super fast mode for 1 min or 2 mins then it switches back to fast charge.

I can not define the problem

[Tech-Savvy]

If you don't face problem with Samsung official 25w cable charging
Then the problem is in your power bank

[Eslam3030]

I do not have samsung cable now.
I am using another brand.
I ordered anker cable 100w to be tested with the power bank to see.
Regardless the text (fast or super fast)
Is the 1 hour charging duration makes sense??

[Tech-Savvy]

Nope, you misunderstood it
I said try charging your device in a power outlet with original superfast adapter
If it shows no problem
Then your powerbank will be the problem
If it shows problem in that it might be with the phone
It's best to consult Samsung regarding the phone

[Eslam3030]

Yes, maybe the problem in the power bank.
But also may be the cable loss and overheating loss derate the output current to a safe limit for the power bank. However, the wall adapter has no problem as it is an infinite source, so whatever the derating, it will supply the super fast charge power.