5AH 26650 4S2P 4.6Ah Battery Cassette LiFePO4

thingiverse

WARNING: Lithium batteries can spontaneously combust or overheat, releasing a massive amount of energy that can melt objects and destroy devices. Use this information at your own risk, as it is a personal account of what was done, not a suggestion to replicate these actions. A custom battery cassette was built to retrofit a Profoto Acute B, originally equipped with a PB cell, to Li for under $650, which is the cost charged by Profoto for their battery. The cassette is held together with two screws and plenty of kapton tape, necessary because the original cassette frame is metal, exposing the PCB on both sides and inside where it fits. This build was completed for approximately $100. 25560 cells can be purchased in various chemistries. LiFePo4 delivered comparable voltage to the original PB cell. A different cell made by Nitecor was initially considered, but 3.7V cells combined to make 16V were thought to increase the risk of catastrophic failure. A battery balance and protection PCB is required. The specifications for this board can be found at https://www.batteryspace.com/pcbpcmfor128vlifepo4pack4inseries.aspx Instructions on how to wire it are available at http://www.batteryspace.com/prod-specs/pcb_wiring.pdf The 26650 cells used in this build were purchased from all-battery.com. A123 cells with the same capacity can be bought for double the price, but reviews indicate they may hold up well.