Li-ion CC/CV Charge Profile Calculator
Compute constant-current (CC) and constant-voltage (CV) charge phase durations and total charge time for a Li-ion cell.
How to Use
- Enter cell capacity, charge rate (C-rate), and starting SOC.
- Tool estimates CC phase duration, CV phase duration, and total charge time.
Show Work
Formulas
History of CC/CV Charging
The constant-current / constant-voltage charge profile was developed at Bell Labs and Sony in the late 1980s alongside lithium-ion commercialization (Sony released the first Li-ion cell in 1991). Unlike lead-acid's float profile, Li-ion needed strict voltage control to prevent thermal runaway. Modern charger ICs (TP4056, BQ25895, MAX77860) implement adaptive CC/CV with thermal feedback and JEITA-compliant temperature limits. USB-PD 3.0+ adds PPS (Programmable Power Supply) for cell-voltage-tracking charge across the cable.
About This Calculator
Enter cell capacity, charge C-rate, starting SOC (from OCV calculation), and termination current (fraction of C). The tool estimates CC phase duration (bringing SOC from start to ~75% when voltage hits 4.2 V), CV phase duration (~45 min at 1C tapering to termination), and total time.
Actual CC/CV switchover depends on cell impedance, temperature, and age. For production chargers, use a dedicated IC (TP4056, BQ25895) that implements accurate CC/CV with thermal protection. Everything runs client-side.
About the Li-ion CC/CV Charge Profile Calculator
Li-ion CC/CV Charge Profile Calculator is a quick, free tool for electronics and circuit design. It works in your browser and keeps everything on your device. Compute constant-current (CC) and constant-voltage (CV) charge phase durations and total charge time for a Li-ion cell.
How it works
Enter your figures and the result appears instantly, updating the moment you change anything. There is no submit button and nothing to wait for, so it is easy to try a few what-if numbers and compare the results. Just check each box holds the kind of value it expects.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
CC/CV profile?
Li-ion charge proceeds in two phases: constant current (CC) until voltage reaches 4.2 V (~70-80% SOC), then constant voltage (CV) at 4.2 V while current tapers to cutoff (~C/10). Total time = CC + CV phases.
Fast charging?
1C charge rate: ~1 hour to 80%, 2-2.5 hours total. Higher rates (2-3C) compress CC phase but CV phase doesn\'t shrink much. Fastest-possible charge is limited by cell internal impedance and temperature rise.
Termination?
CV phase ends when charge current tapers to C/10 (10% of 1C current). Some chargers terminate earlier (C/20) for longer pack life, later (C/5) for shorter charge times.
How do I use the Li-ion CC/CV Charge Profile Calculator?
Simply type your numbers and read the result, which refreshes the instant you change something. There is nothing to submit and nothing to wait for.
Does it cost anything or need an account?
No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.
Is anything I type uploaded?
No. The tool works entirely on your device, so the values you enter never leave your browser.
Common Use Cases
USB 5V/2A Charger
3350 mAh cell: ~1.7 hours CC + ~30 min CV = ~2 hours total.
Fast USB-PD
2C on PD 20W: CC phase 30 min but CV still 30 min = 1 hour total.
Trickle Charging
0.1C slow charge: 10+ hours CC, 1 hour CV. Gentlest on cell life.
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