Anyone here use any of these cheap Chinese step up circuits?

>>1102052
5V to 5V is 2A. Any higher voltage is less than 2A. 3V to anything else is less than 2A. 5V to anything else than 5V is less than 2A.

No experience with them per se, but they probably work as advertised.

>>1102052
Just check the datasheet...
E.g. here you lazyass: https://www.olimex.com/Products/Breadboarding/BB-PWR-3608/resources/MT3608.pdf

> Anyone here use any of these cheap Chinese step up circuits?
Yes.
They just pack ordinary chips plus all passive stuff on a PCB and try to sell that.
It's often better than what you'd design in for even twice the price.

> Can it really do 2A 5v output?
No, check the datasheet for details.

>How inefficient are they?
Check the datasheet for details. 80÷95%, depending on conditions. Chinese passive components (e.g. a cheap inductor) can decrease that.

> How hot do they get?
Check the datasheet for details. Depends on use conditions.

> Can I limit the output current to improve efficiency?
Check the datasheet for details. There's a plot, you'll see where's the peek efficiency.

>>1102368
Yes but how to limit output so device doesn't draw more than, for example, 1A?

Also could I replace the inductor with one from an atx psu or laptop charger for better efficiency?

>>1102499
> power bank
> limit output [current]
No USB device will draw more than 0.5A unless it negotiates so or unless you explicitly allow it by short-circuiting D+ and D-.

>could I replace the inductor with one from an atx psu or laptop charger for better efficiency
If you find inductor of same (or intentionally other) inductance and similar footprint, check its datasheet, see if its other parameters are better, recalculate the values for capacitors, replace the capacitors – ten yes, you'll increase efficiency.
Yet it's equivalent to DIY'ing such a PCB.

Google the fuck up!

>>1102052
>Check the datasheet.
>Check the datasheet.
>Check the datasheet.
>Check the datasheet.

Really, before you do anything with any part or ask any questions, CHECK THE DATASHEET. If it doesn't provide one or it's not easy to get to, that's a red flag.

Again.

>Check the datasheet.

>>1102052
Last one I bought is functional now.

When I first plugged it in, there was no voltage. In fact, a component started smoking and burning, and all of a sudden it worked again. it still works to this day.

Chinks reused to even give me a partial refund since it was "self correcting".

I have one, stgepped up 3.7v li-po to power up 12v led stripe, worked, but got hot after a moment (was about 1m of white led stripe ~60 leds, so i assume 600 mA). besides that it works well.