Taken from my reddit post here: https://www.reddit.com/r/fightsticks/comments/dm83zj/got_a_wireless_fighting_board_use_a_proper_battery/
The batteries sold by FocusAttack for use with the Wireless Fighting Board are TRASH.
They are labeled as 1800mah, but this is FALSE. These are the same cheap Chinese Dualshock 3 replacement batteries that have been floating around the internet for YEARS. There is no way a battery of this size is 1800mah – especially since the official Dualshock 3 battery is the exact same size and only ~570mah.
To make matters worse, these cheap replacement batteries are often old stock, so they don’t hold charge well and are already half dead before you even start using them.
The Brook WFB uses any standard 3.7v li-ion battery pack. These are pretty easily found online, but I use ones from adafruit:
2500mah, works great. High capacity. Only issue you may encounter is that due to the high capacity your PS4 might give you a low battery warning too early. Otherwise they are 100% functional and way better than the trash being sold by FocusAttack.
If you REALLY wanna go crazy you can even try using this even HIGHER capacity one from Adafruit – but I haven’t tried it yet:
Brook WFB uses Dualshock 3/4 wiring config, which is opposite from most of the batteries you can find online. You will need to take the red and black wires in the connector and swap them before using them with the WFB. See below picture:
DO NOT LET THE RED AND BLACK WIRES TOUCH. REMOVE ONE WIRE, TAPE THE END, AND THEN REMOVE THE OTHER.