Anyone else hate their Fatshark batteries? I have two of the newer style ones and they both are horrible. Really high internal resistance, IR, from the start. So I finally got around to creating an 18650 version of the fatshark battery mods. Why 18650? While they are Lithium Ion they are listed at a 4.2 max. They are readily available. They are cheap. What more could you ask for? In a slightly bigger package I am cramming 3400mah versus 1800mah… and a better IR.

So let’s get started, what do you need?

• 2x 18650 cells (I used Panasonic NCR18650B)
• 1x 2.1mm Barrel Plug 
• 1x Balance Plug JST-XH**
• 3x Balance Terminals**
• 3x colored 26 awg wire
• 1x 2S Battery Balance LED

** When you buy from DigiKey I suggest ordering more. I also suggest ordering some 2S, 3S, 4S and higher plugs so that you save on shipping.

Once you have that you need to wire it so that it looks like this:

While the wire color doesn’t matter, generally positive is red and negative is black. I didn’t use “purple” but I used white. White doesn’t show up so well in the image. I still charge it with my normal lipo charger (as a Lithium Ion though). Balance plug should still be used. Soldering to batteries is dangerous and only do so at your own risk. I roughed up the terminals on the batteries with some sand paper to help the solder grab better. Only touch the battery with the soldering iron for as little time as possible. It is dangerous.

Below are the images of mine as I created it:

After I was done with the wiring and positive it was working correctly I closed it up with some hot glue. Since it was such a big thing the glue hardened by the time I was done so I just used a heat gun to quickly heat it up and then push it closed firmly… heating it up may not have been the safest thing to do… but I survived. Honestly it was a pretty simple build and so far after one day of flying it is still reporting 100% charged. So I am pleased at this point.