# Help making DIY USB-C computer power bank

#### -live wire-

Joined Dec 22, 2017
897
I have a computer that uses USB-C charging (the charger says "130W", but the standard is 100W max). While it has acceptable battery life, a power bank for it would be useful. It is much more practical than trying to find a wall outlet and looking for an extension cord. And there may not even be an outlet!

So, here are the requirements for it:
1) not thicker than about 1-1.25" total

2) uses 12 of these cells or something similar (to get 150Wh+)

3) can easily handle 100W on the USB-C port and 2 x 5V 2A for normal USB ports

4) 80%+ efficient in discharging at full load

5) removable cells (so I can put them in other things)

6) safe!

It would also be nice if it was 12S, for maximum efficiency and no parallel issues.

If someone could direct me to somewhere I could get the following, that would be great.
I will need but can't find:
1) A 12S BMS that can handle at least 5A, ideally 10A, discharge (more room for inefficiencies and multiple loads). Under $25 and < 1 inch thick. All I could find was this sketchy one. 2) A buck converter for the USB-C port that is under 1 inch thick and rated 200W, can handle input voltages of up to 60V. Ideally under$20.

3) A UBS-C port! I could cut open a cable like this, but it would be bigger and less desirable. It must be able to handle the 5A at 20V max.

And how do you get it to recognize that it is a charger that is 20V and can supply 5A? What is the USB-C interface thing? Do I need a certain chip or something?

#### -live wire-

Joined Dec 22, 2017
897
Could someone respond?

#### spinnaker

Joined Oct 29, 2009
7,837
First off you posted just a couple of hours ago and you are already pleading for an answer. Obnoxious behavior like that is enough to turn anyone off.

Or maybe no one wants to tell you how to burn your house down? Buy a proper charger and forget about trying to build your own. You will never satisfy requirement if you need to ask.

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#### shortbus

Joined Sep 30, 2009
7,080
Could someone respond?
To add to what Spinnaker said, you never listen to the advice you get anyway. People end up getting tired of trying to steer you in the right direction.