Battery knowledge · Charging and discharging
Constant-power charging
Charging with a fixed-power stage, so current falls as voltage rises because current equals power divided by voltage. In a CP-CV protocol, a constant-voltage stage follows when the voltage limit is reached. A power rating alone does not establish that a charger implements this sequence. [1]
- Abbreviation
- CP-CV
Example
Interpretation & limits
- This arithmetic illustrates P = VI; these voltages are not recommendations for a lithium-ion cell.
Explore the graph
See which quantity is held constant, when the phase changes and how charging ends.
Power holds at 16.25 W during CP. Current falls as voltage rises (I = P/V). At the example 4.15 V threshold, CV begins: voltage stays fixed while current and power taper.
P = VI; I = P/V
Illustrative model. Positive current charges the cell. Time is normalized; selected thresholds are not cell-specific recommendations. The voltage trace ends at termination; post-stop relaxation is excluded.
Use in Lemonergy
Design protocol or analysis tool
Program constant power
Positive power magnitude and explicit direction define CP.
Equation or tool to use
- Charge at constant power
Programs power
Inputs & settings
- mode: cp
- w / s
This overview identifies the components to use. Follow the example in Lemonergy for their connections and settings.
Example. 2 kW at 100 V implies 20 A; at 120 V it implies about 16.7 A.
Observe. Current follows I = P/V.
This is CP only, not a combined CP–CV controller. CC and CP cannot share a protocol.
Open Design → Protocol bench →References & further reading
Technical references
- Lithium-ion battery fast charging: A review
Anna Tomaszewska et al. · eTransportation · 2019
Technical reference · CC-CV and alternative charging protocols, transport limitations, degradation and thermal implications; results depend on cell and test conditions. Software behavior is documented separately in Lemonergy block references.