My wife ask me to fix her battery pack for her head led lamp because it was no longer charging. When I open it up, inside was a 2 cells (18650) li-ion with a protection board and JST-XH connector.  A light bulb went off, it is similar to a Fatshark battery pack.  I figure I fix my wife's LED light and make a tutorial out of it. There will a few that you will need to alter to make it work with your Fatshark, but I will point it out.

Things you need.
2 18650 li-ion cells
2S Protection Board
Nickel tabs
Red and Black silicone wire preferred.  22 gauge is enough.
3 pins JST-XH connector
PVC or some other kind of shrink wrap
2.1mm x 5.5mm barrel connector

Li-ion 2S overcharge protection circuit. Just Goggle "18650 2S Protection Board"  There are a lot of design, but I like the one picture below.  If you buy a different design, you will have to figure out you own wiring.
https://www.amazon.com/Li-ion-Lithium-Ba...B01N9GRHRX



JST-XH 3 pins connector.  Although my photo is a two pins, you will need a 3 pins for the Fatshark.  The red and black wire will be on the outside.  There will be no wire connected in the middle pin.  Don't mix up where the red and black wires go. It is important you connect as shown  



Go ahead and solder JST connector wires to the board.  On my board, it is labeled p+ and p-.



Nickel Solder Tab (cut to the following)
https://www.amazon.com/Kastar-commercial...ay&sr=8-14



2 li-ion 18650 cells.  Buy from a good source.  There is a lot of counterfeits.  If the weigh per cell is not over 40g, then you have a fake.



I used double side foam tape to keep the two cells together.  Arrange in the configuration in the photo below.



I spot welded small tab to the large tab.  If you want to make a spot welder, you can check out my tutorial.  You can also just solder.
https://intofpv.com/t-mot-spot-weld-with...er-control



I solder the tab to the balance pad on the board.



If you did it correctly, the T tab will bend over on to cells end.



Make sure that the board line up with the cells, so the B+ and B- is on the same side as the cells end.  I use a piece of tape to hold the board in place. I will remove it after I am done welding. 



Once everything lines up, cut the extra nickel tab away and spot solder into place.





Now you will solder the barrel connector.  There are two places you can solder the barrel connector to.



First location



Second Location



I put some electrical tape over the battery ends and shrink wrap the packs.  The pack below is missing the barrel connector, but as I mentioned above, this was for something else.



To charge your battery, you will use non-balance charge settings on your charger. Connect barrel connector to the charger. Don't use the JST-XH.

Nice tut thanks.

Just one thing to add
Don't u use insulator paper on positive side to prevent nickel touching negative side (Short)???

Keep it up !!!

Regards

Great tutorial and write up 

Nice one! thanks Voodoo!

(21-Mar-2019, 10:13 AM)Darozas Wrote: Nice tut thanks.

Just one thing to add
Don't u use insulator paper on positive side to prevent nickel touching negative side (Short)???

Keep it up !!!

Regards

You can use installation paper underneath the nickel on the positive. But the only way you can get a short if the installation (green wrap) of the battery rips.