Battery knowledge · Capacity, energy, power and ratings
Usable capacity
The part of a cell’s capacity that a system actually lets it use, after the BMS reserves margins at the top and bottom of the state-of-charge window. An electric-car pack may use 90–95 % of its gross capacity. [1]
- Also called
- available capacity
Example
Charge balance and state of charge
From 20% SOC, ideal full charge takes 48 min. Integration stops at 100%.
Current is positive into the cell. Constant capacity and 100% charge efficiency; no CC-CV taper.
Explore the graph
SOC rises with accumulated charge; depth of discharge falls by the same amount.
From 20% SOC, ideal full charge takes 48 min. Integration stops at 100%.
SOC = SOC₀ + ∫ I_charge dt / Q; DOD = 1 − SOC
Illustrative model. Current is positive into the cell. Constant capacity and 100% charge efficiency; no CC-CV taper.
Use in Lemonergy
Separate nameplate ratings from test results.
This is a reference concept. No executable Lemonergy block has been verified for this term.
References & further reading
Technical references
- Battery Test Manual For Electric Vehicles, Revision 3
Jon P. Christopherson · Idaho National Laboratory · 2015
Technical reference · Performance characterization, pulse resistance/power, life testing and reference performance tests; historical 2015 edition.
Further reading on this topic
These sources provide broader context; they are not presented as citations for every statement in this entry.
- The International System of Units (SI), 9th edition
Bureau International des Poids et Mesures · 2026
Topic background · Definitions of SI units and coherent derived units; 2026 revision.