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.

Calculator Electronics Updated Apr 23, 2026
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How to Use
  1. Enter cell capacity, charge rate (C-rate), and starting SOC.
  2. Tool estimates CC phase duration, CV phase duration, and total charge time.
Input
mAh
C (e.g. 1 = 1C)
%
C (e.g. 0.1 = C/10)
Presets
Charge Profile
CC Time
—
CV Time
—
Total
—
CC End SOC
—%

Show Work

Enter values.

Formulas

Charge current
I = Cap · C-rate
1C for 3350 mAh = 3.35 A.
CC end SOC
~70-80%
Voltage reaches 4.2 V.
CC duration
(SOC_cc − SOC_start) · Cap / I
Hours.
CV duration
~45-60 min at 1C
Weak function of C-rate.
Total
CC + CV
Battery is "full" when current tapers to cutoff.
Temperature
Slows below 10°C
Cold cells accept charge more slowly.

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.

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.

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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