Free battery tools · Estimate, don’t guess

Silicon-Carbon Lock Capacity Calculator

Enter a nominal capacity in mAh, choose a charge-lock target (80%, 85%, or custom), and estimate usable mAh, Wh, and rough minutes to that lock. Compare against labeled example phone presets. This is an estimator — lock behavior differs by vendor and OS version.

01 / Enter battery & lock

Honest estimate only. Manufacturers publish nominal mAh under their own test conditions. Charge-lock (“optimized charging”) targets and real usable energy vary by brand, firmware, temperature, and age. Numbers here are not official lab results.

Picking a preset fills nominal capacity, voltage, and a common lock target. You can edit any field afterward.

Use the rated mAh from the phone or battery label. Positive decimals allowed; no unit suffix.

Typical Li-ion / Si-C packs use ~3.8–3.87 V. Default 3.85 V.

Charger or phone peak wattage for a rough time estimate.

Lock target is the share of nominal capacity you allow the phone to charge to.

Values are calculated on your device. This tool does not upload or save your inputs. Refreshing or switching languages clears them. The site uses Google Analytics for page visits.

02 / Results & comparison

Enter a nominal capacity, then calculate.

Lock achievement rate —
Estimated usable capacity —
Estimated usable energy —
Rough time to lock target — 



Example presets only — not official lab tests. Charge minutes reuse your entered wattage for every row so you can compare capacity, not marketing claims.




Includes inputs, derived usable mAh / Wh, lock rate, and the rough charge-time estimate.


















What does “lock capacity” mean here?


Many phones offer an optimized or limited charge (often around 80%) to reduce time spent at full charge and slow battery wear. This tool treats the lock target as a percentage of the published nominal mAh and estimates usable capacity and energy under that cap.






How is lock achievement rate calculated?


    

  1. Usable mAh = nominal mAh × lock% ÷ 100
    2. 

  2. Usable Wh = (usable mAh ÷ 1000) × voltage
    3. 

  3. Lock achievement rate = usable mAh ÷ nominal mAh × 100% (equals the lock target when usable is defined that way)
    4. 

  4. Rough minutes ≈ (usable Wh ÷ charge power W ÷ 0.9) × 60
    5. 







Why mention silicon-carbon batteries?


Recent phones advertise silicon-carbon (Si-C) anodes for higher energy density at a given pack size. Nominal mAh still comes from the manufacturer’s rating. This page does not claim a special Si-C formula — it helps you translate that rating into a lock-limited usable estimate.






Are the phone presets accurate?


No. They are labeled example capacity bands for comparison only. Real devices differ by SKU, region, firmware, and measurement method. Prefer the mAh printed for your exact model.






Why is charge time only a rough estimate?


Real charging curves are not constant wattage. Phones taper current near the top of charge, and efficiency depends on temperature and cable. The 90% efficiency factor is a simple disclosure, not a lab constant.






Are my numbers uploaded?


No. Calculation runs in your browser. Inputs are not stored in localStorage or sent to a server. The site uses Google Analytics for page visits only.