input on idea/project 2x li batteries to usb converter

[sphinx]

i would like to make a usb converter with a battery pack of 2x li batteries in parallel and to transform that down to 5v with an output 2-4 amps with charging and protection on batteries like over and low
voltage overcurrent protection. charging and output ports i would prefer separate.

any input on ic's to use. i have looked on some manufacturer and this topic is a bit over my knowledge soft out
when finished i will share scematics and pcb made in altium 19

regards.

and a big thanks to all uploaders

[CocaCola]

Not to discourage your plans, but have you looked at over the counter options?  You likely won't get the 4a output (unless you Y adapter two not shared ports) but there are a ton of 18650 USB full-featured battery bank cases out there for cheap...

[sphinx]

the ones i got have 5 x 18650 batteries in paralell i have looked at some and mmost of those i looked at seems to be batteries in parallel with an output of 3.7volts transformed to 5volts

no worries about discouraging my plans, since it just an idea i got.
and i want to do some playing with altium on rainy days.

[sphinx]

sadly the post company in sweden has added extra costs to packages on chinese packets so not so cheap to order from china anymore.
i am moving to croatia shortly and i need to find out if it is possible to get cheap stuf from there instead.

looks like croatia has the same as sweden adding extra costs but i need to look how much extra that is since sweden adds 75 sek minimum and the tax on that

[pickit2]

sadly the post company in sweden has added extra costs to packages on chinese packets so not so cheap to order from china anymore.

Items from China on ebay has an option to add postage, so it's not sent by China Packet Post.
I don't know if it's all sellers but from Hong Kong I get post in about 4 days. with tracking.
I keep the orders small as they get though without having a tax placed on them.
if its going to get taxed, have it sent via one of the main firms like DHL they only add the tax not a handling fee as well.
some sellers also state the value is higher than what you paid, I have stopped using them.