USB PowerBank GP302 gives 8v at startup for 1-2 seconds ?!?!?!

[Lizerd]

Hi all.
I bought a GP Portabel PowerBank GP302 12000 mAh and I wanted to check the capacity on the unit.
And I noticed that it gives a voltage Spike 8v at startup. Brand New.

I have an Zendure A4 powerpack and that one works just fine with the same test setup. So there is no problem with the electric load.
And there is no change if I use 100mA or 1A load.

I did a video of the problem.
https://youtu.be/GIKHLfaEOWw

I do not know if this is within USB specifications or if it's defect?
I haven't used it with any of my electronics.
I am not so sure I like  to connected to my Sony tablet ?

toughs ?

Anyone

[Zbig]

This might be some Accucell-6 quirk. I think it ramps up the load smoothly at startup (at least I think mine does) and chances are, there's some voltage being coupled from it before it actually starts to draw any current. Have you tried with some passive load?

[Lizerd]

I am going to test it tomorrow with an passive load and an oscilloscope.
But I guess it will show the same thing.
Because the load function in the Accucell has worked fine before and it behaves just fine with the Zendure A4 with the same setup.     

[Christopher]

Yep, try a 10R power resistor and try again

[Zbig]

I am going to test it tomorrow with an passive load and an oscilloscope.
But I guess it will show the same thing.
Because the load function in the Accucell has worked fine before and it behaves just fine with the Zendure A4 with the same setup.   

May be. Or maybe the Zendure pack has some output protection that clamps the voltage down when > 5V.

[Lizerd]

I will make a extra cable that has a TVS or Zener to clamp the voltage. So I can feel safe to use it with my camera and tablet.

[Zbig]

What I meant was, perhaps there's a protection that happens to clamp whatever stray voltage gets there from the Accucell (dis)charger.