Overkill Solar BMS Series - Building a Battery Pack with Overkill Solar BMS; Safety Precautions for Battery Pack Assembly; Gathering Components for Battery Pack

1. Introduction
1.1 What is a BMS
A battery management system, or BMS, is an electronic device that protects and manages rechargeable
battery cells.
2. How to Build a Battery Pack
2.1 Safety Precautions
● Keep metal tools away from exposed terminals
● Wear safety glasses
● Battery cells and electronics can overheat and cause fires or release toxic smoke, if they are
misconfigured or used incorrectly. Always keep a Class C fire extinguisher near the battery system,
and ensure that those around it are properly trained to use it.
● Ensure that the all electrical connections are screwed down tight and are not loose
● Battery systems are not a toy. Never let unsupervised children or pets near the battery system.
● Do not connect anything but the BMS’s B- cable to the cell negative BC0 terminal (the one exception
being the BC0 balance wire). The load negative must be wired to the BMS’s C- lead.
● Do not purposely short-circuit the battery pack
● Do not accidentally short-circuit the battery pack
● Do not submerge the battery pack
● Do not purposely connect the battery pack to a load that dissipates more than the BMS is rated to
handle.
2.2 Planning
2.2.1 Gather Components
● Battery cells (we recommend the Overkill Solar 100Ah LiFePO4 cells, which are the perfect size for our
BMS modules). We also give very detailed diagrams, mechanical drawings, bill-of-materials, and BMS
configuration parameters to ensure a smoother DIY experience.
● Bus bars (used to link the battery cells together. While it’s possible to use stranded insulated wire and
ring terminals, this is considered bad practice, and is arguably more expensive). The easiest approach is
to purchase properly-sized bus bars with your battery cells (Overkill Solar’s 100 Ah LiFePO4 cells
include bus bars). If you purchased other batteries that did not come with bus bars, they may be made
from copper bar or pipe; see Appendix F.2.
● The Overkill Solar BMS, which ships with the following items:
○ Balancing lead
○ Temperature sensors
○ 2-pin cable for external switch
○ Quick-start guide
○ Bluetooth module and cable (optional)