Batteries

Battery Capacity Fade Calculator

Enter values for Battery Capacity Fade that describe the same case, then use remaining capacity as a check rather than a design approval.

Set up the Battery Capacity Fade case

Keep Battery Capacity Fade units and measurement conditions consistent before comparing remaining capacity.

Scope of the remaining capacity result

Battery Capacity Fade turns the visible entries into remaining capacity. It works best as a comparison tool where each run has a clear measurement basis.

Battery Capacity Fade depends on battery chemistry, state of charge, temperature, age, and the discharge or charge rate.

Source notes for Battery Capacity Fade

Collect Initial capacity, and Capacity fade from the same operating case before reading remaining capacity.

Initial capacity: Enter initial capacity in Ah. Default shown: 100 Ah.
Capacity fade: Enter capacity fade in %. Default shown: 18%.

Interpreting Battery Capacity Fade

The result card gives a comparison point for Battery Capacity Fade. Equipment ratings, safety margins, and manufacturer limits still need their own check.

Formula notes for Battery Capacity Fade

remaining = initial × (1 − fade)

Only the entries shown on Battery Capacity Fade feed remaining capacity. If another correction factor matters, keep it in the notes or make a separate run.

Boundaries for remaining capacity

Fade is not always linear with time or cycles.

Aging and capacity fade
Manufacturer test conditions
Bms cutoffs

If this answer becomes an input to Battery Self-Discharge, copy the value with its units and source note attached.

Operating notes for Battery Capacity Fade

Battery Capacity Fade has a direct equation, so the short answer can look more certain than it is. Keep capacity fade and capacity fade tied to the same case before using remaining capacity.

A pack or cell value that looks exact can still shift under a different discharge rate or BMS cutoff.

Do not round toward a limit; apply margin after calculation.
Save the baseline before testing a high or low case.

Where assumptions enter Battery Capacity Fade

Battery Capacity Fade should be read with chemistry and state-of-charge notes. The same amp-hour value can represent a different usable-energy case at another discharge rate.

When remaining capacity becomes an input to another worksheet, copy the value only after the units and source condition have been verified.

Before copying remaining capacity

Attach chemistry, state of charge, temperature, and the test condition used for the Battery Capacity Fade entry.

If a later Battery Capacity Fade run changes only capacity fade, label it as sensitivity work. Several changed conditions deserve a new baseline.