Newbie Designing Circuit for Battery charging/external power for GoPro

[Rob Andrew]

Hi there everyone, Hopefully someone can see this and help me out just a little bit here...

I'm in the process of finding a solution to gaining external power for a GoPro, mounted on a helmet. The idea is to film for multiple hours, but my only solurion is external power. (External to the camera, that is)
I have a 3.7V, 6000mAh battery which I am using to power it. However, this battery will need access to a charging point from mains (Via Type C USB) but will also need the ability to charge the GoPro (Via a female USB jack) as well as overcharge protection. Basically creating my own small power bank.
The Major issue is I have no expertise in this subject at all. I don't know what conponents I need or where to get them from. I need help from somewhere to understand what conponents I need for this. Main questions are:
What size resistors/conponents will I need to create overcharge protection from mains power to this battery.
How to represent USB ports on a schematic/how to draw a schematic

Thats all for now. Thank you for reading

 

[Musicmanager]

Hi Rob

Firstly, in your rugby playing days you were one of my heroes !!

Questions .. .. ..

What size is the 3.7v 6000mAh battery .. 18650 ?
What are the details of the battery in the GoPro ?

There is a charging module TP4056 that would charge the battery from a 5v 1amp USB although it would take a while, but it does have overcharge protection built in.

More info needed

MM

 

[audioguru]

If the battery has a size of 18650 then it is fake. The maximum mAh rating of a real one is about 4000mAh.
You need a protection circuit that senses the battery voltage and disconnects it when the voltage drops to about 3.0V.
You need a proper charger circuit that detects a full charge then shuts off.

 

[Rob Andrew]

Thank you for the replies guys, wasn't sure I would get one...
Sadly I'm not the Rugby player people think I am! Although it's always fun to pretend!
The GoPro battery is a 3.85v li-ion 1220mAh battery at 4.7Wh. I understand the voltage is different between the battery I intend on using and this one, but I've been told its to small of a difference to matter.
The new battery size I believe is 135178, at least that's the detail I've been given. Dimensions are roughly 70mmX50mmx12mm. The battery (Lipo) has two wires (Red and black) running off it. I was hoping to connect it straight to a circuit board I could place on top of it. Then run charging connections to and from there. I don't mind about charging times.
Hopefully this is coming across clearly. If any more info is needed please let me know

 

[audioguru]

An ordinary Li-PO battery is 4.20V when fully charged and when its charging current has reduced to about 1/20th its mAh rating. Yours is pretty large. Most radio controlled toys have a charger.

 

[Rob Andrew]

....understood. but I afraid this doesn't help me create a connection I need between my camera and the battery.
The camera has a standard USB 2.0 male socket leading from it. My battery has a black and red wire leading from it. I need a connection that can charge the battery, as well as connect said battery to the camera. I'm assuming a small circuitboard will do the trick. But I need advice on what should go on said circuitboard to make this happen.

 

[audioguru]

USB is 5V, not the reducing 3.8V or 4.2V from a lithium battery. You need a Power Bank.
A Power Bank has a lithium battery plus a charger circuit with a 5V USB input jack.
It also has a voltage stepup converter in it and has one or two 5V USB output jacks. Its output is always 5V until the battery voltage is low and it is disconnected.

 

[Pommie]

If it's a standard LiPo battery then you might be able to substitute the larger battery for the current one and use the GoPro's charging circuit.

Mike.

 

[Rob Andrew]

If it's a standard LiPo battery then you might be able to substitute the larger battery for the current one and use the GoPro's charging circuit.

Mike.

Thank you for the suggestion, Could you please reiterate and expand on this? The GoPro does come with the ability to bypass their battery circuit, which is what I'm planning on doing (just removing the battery and wiring a larger one via the Type C input)