One Cell Per Record, Every Spec on Demand
Every 18650 build that goes wrong traces back to the same root cause: someone grabbed cells from a bag without knowing what grade they were, pulled cells with mismatched internal resistance into the same pack, or used a 10A continuous cell in a 25A application because the wrap color looked the same as something else. The cell is a commodity that looks identical on the outside and varies enormously on the inside—and that delta is where pack failures, thermal events, and underperforming builds come from.
This template takes the opposite approach. One entry per cell, every specification captured at the point of acquisition or testing, every cell's physical location mapped to the project or storage bag it lives in.
The Fields That Actually Determine Whether a Build Succeeds
Internal Resistance is the single most useful field in this template. Rated capacity and even Cell Grade are manufacturer claims; IR measured on an actual cell under your conditions is truth. The field records in milliohms. When you are building a parallel pack, filtered by Model Number and sorted by IR, you can hand-match cells to within 2mΩ of each other without any mental overhead.
Cell Grade—Low Drain, Mid Drain, High Drain—is the design-intent classification. A Samsung 30Q is high drain; a Panasonic NCR18650B is low drain. Pulling from a mixed stock without this field means you are doing the classification from memory, and memory fails when you have forty different cells across twelve bags.
Max Cont Current in amperes is the manufacturer's CDR (continuous discharge rating) for the specific cell. Rapid Charge Current and Charge Current capture the charge side—useful when you are configuring a charger or BMS and need to verify that your charge rate does not exceed the cell's CC limit. The Energy Storage field calculates automatically: 3.7V × Capacity(mAh) / 1000, giving watt-hours per cell. Useful when your project spec is in Wh rather than mAh.
Finding the Right Cell at 11 PM Before a Build Deadline
The Location field maps cells to twelve positions: two named projects (200W Project, 5000W Project) and Bags A through J. When you need three high-drain Molicell P28As for the 200W build at 11 PM, you filter by Manufacturer: Molicell, Cell Grade: High Drain, Location: 200W Project. The matching records show you exactly how many you have and what their individual IR values are. You grab them, the build proceeds.
Without this structure, Bag D is a mystery bag you dump onto the bench and sort by eye—cell by cell, wrap color by color, trying to remember if the orange-wrapped ones are P26As or P28As.
Wrap Color matters for visual inventory in hand. Nineteen options cover the standard rewrap palettes plus original manufacturer wraps. Combined with model number, wrap color resolves the physical identification problem that makes unmarked cell bins unusable.
Max Drain Tested and Capacity Tested are boolean flags, and both link to image fields for the actual test graph output from your analyzer. The difference between a stated 3000mAh and a tested 2850mAh across your stock is the kind of data that changes procurement decisions.
Cost in USD closes the financial side of the inventory—unit cost per cell, useful when you are calculating pack cost or comparing per-Wh economics across manufacturers.