Finding correct USB-C charging module for 12.8v 3ah Battery

[leon123]

Hello, I am very new to this forum and hope someone of you could help me with my project.
Just to make clear from the beginning, I am a programmer and don't know very much about circuits and electronics.
My project idea is to make a portable digital frame, with a battery that can be charged.
The software part is not a problem, but I struggle to find the right hardware parts, so my project can run from a battery and I can charge it by using a USB-C cable. This is my very first hardware project. I attached a document with a rough scheme of the hardware components and how I believe it should all work together.

The question is as followed:
I need to find a correct USB-C charging module, so I can charge my 12.8v 3a Battery pack. I thought of something like a TC4056A charger module (a picture is also attached). But I think that it will be not enough to charge my 12.8v Battery. I wanted it to be able to work and charge at the same time like a phone, without a switch. I looked up on the internet but could not find a fitting module.
I was hoping one of you could help me find a fitting module for that purpose (the Battery pack already has a BMS).

Thank you in advance

 

[rjenkinsgb]

As far as I can find no one is selling any multi-cell USB charging modules.
All present ones are for a single cell, voltage-wise, at least - several cells in parallel is possible, or required for high current units.

The only way I can see with off-the-shelf parts is to use a single cell (parallel cells) and step the voltage up with a boost regulator to what you need from that.

It may then work using a module for a high power "power bank" as the charge side?
eg. one of the boards in this listing - they are supposedly capable of drawing 18W or more from a suitable USB C power unit.

Pardon our interruption...

Note that there are lots of HDMI-input displays that can run just from 5V, which would simplify things a lot; you could just use the USB 5V out from such a power bank module.

From a quick check these all appear to be 5V:

TFT LCD Display Module Touch Screen

BuyDisplay is the factory store of Eastrising who is a leading Manufacturer of TFT LCD display based in China. Our TFT display modules are sold throughout the world. EastRising offers a wide product range of TFT display modules product line which is from small to medium sizes such as 0.96 inch...

www.buydisplay.com

 

[leon123]

Does it mean I could just use the input of the Powerbank module to charge my battery and the output to power the rest of my device? Would it work at the same time?
I have an other Boost regulator so it should technically work. With the 5v output.

 

[Nigel Goodwin]

Does it mean I could just use the input of the Powerbank module to charge my battery and the output to power the rest of my device? Would it work at the same time?
I have an other Boost regulator so it should technically work. With the 5v output.

You probably need to design, build, and program your own system - it's not easy to charge while the battery is also in use, as the charger needs to monitor both voltage and current, and in this case the current is going to both system and battery.

 

[rjenkinsgb]

That should work, with one that supports charge and discharge simultaneously - the first one in that ebay listing says it does.

 

[leon123]

You probably need to design, build, and program your own system - it's not easy to charge while the battery is also in use, as the charger needs to monitor both voltage and current, and in this case the current is going to both system and battery.

Thank you so much for the quick reply.
Sadly I don’t have much knowledge of how to do this stuff. I only have three weeks for this, so maybe there is an other way of doing it? If not, I would be grateful if you could help me getting started and tell me what i need to know to achieve my goal. Maybe you know good books or websites for this purpose where I could also learn it.

 

[leon123]

That should work, with one that supports charge and discharge simultaneously - the first one in that ebay listing says it does.

Ah perfect, thank you very much!
As I understand, the output voltage of the module should be higher than the one of my battery. So 12v wouldn't be enough, am I correct?
I have also read about a bidirectional buck-boost converter. Could I technically use this to increase output voltage of the first module for my battery?

 

[rjenkinsgb]

As I understand, the output voltage of the module should be higher than the one of my battery. So 12v wouldn't be enough, am I correct?

No - that powerbank module IS the battery connection; use matched single cells in parallel, connected to its battery terminals , then it manages the battery charge and discharge.

Just use the 5V out to feed your devices or the boost converter to run a 12V screen.

There are no off-the-shelf parts to use a multi-cell battery in the application you need, with USB charging.

 

[leon123]

Ok so I'll use 1s4p 3.7v battery.
The Data sheet of the controller says, Power-supply: 12v, >2A. If I use the 5v out to feed it, wouldn't I loose current if I boost it to 12v, and does it even matter? (Output of Module: 5V 3.1A)
If not, then could I also use the Type-C TC4056A charger module?