How do you calculate implant battery life?

Divide usable capacity (mAh) by average current draw (mA), then multiply by a derating factor for end-of-life and self-discharge. With 1200 mAh, 0.035 mA draw, and 0.8 derating, runtime is about 27,429 hours (roughly 3.1 years).

Why apply a derating factor?

Nameplate capacity assumes ideal conditions. Real cells lose usable charge to self-discharge, end-of-life voltage cutoffs, and temperature. The 0.8 factor here trims the undated 34,286-hour figure down to a defensible 27,429 hours.

What is a good battery life for an implantable neurostimulator?

Primary-cell IPGs typically target 3-10 years depending on stimulation intensity; rechargeable units target 9-15 years to battery replacement. The example's ~3.1 years suits a high-duty therapy device.

Underrated vs derated runtime — which should I quote?

Quote the derated runtime (27,429 hr) in clinical and IFU contexts. The underrated 34,286 hr is the theoretical ceiling and is useful only as a sanity check, not a patient-facing claim.

How does current draw affect longevity?

Runtime is inversely proportional to average current. Doubling draw from 0.035 to 0.070 mA halves runtime. Reducing leakage and idle telemetry current is usually the cheapest way to add years.

Does this work for rechargeable implants?

It estimates time per charge cycle. For total device life, multiply by the number of cycles before capacity fade reaches your cutoff, accounting for charge-cycle degradation.

Implantable Electronics & Neurodevices calculator

Battery Life Estimate Calculator

Battery life estimate tells you how many hours an implanted pulse generator, cochlear processor, or neurostimulator will run before recharge or explant is required. Reliability engineers and product designers use it during cell selection and stimulation-parameter trade studies, where every microamp of leakage shortens the years between surgical replacements. Because an implant battery cannot be swapped without a procedure, an honest runtime number — derated for end-of-life voltage and self-discharge — directly drives clinical replacement scheduling and the longevity claims on a device's IFU.

What this calculator does

Estimate implantable device battery runtime from usable capacity, average current draw, and design derating.
Use it when an engineer needs a quick runtime check for a neurostimulator, implantable sensor, cochlear implant module, or rechargeable implant operating mode.
It divides usable battery capacity by average current draw, then multiplies by a derating factor to give a realistic runtime in hours.

Formula used

Estimated battery runtime = usable battery capacity ÷ average implant current draw × battery capacity derating factor
Underrated runtime = usable battery capacity ÷ average implant current draw

Inputs explained

Usable battery capacity:
Average implant current draw:
Battery capacity derating factor:

How to use the result

Use it during cell sizing, stimulation duty-cycle tuning, or when validating longevity claims for a primary-cell or rechargeable implant.
It assumes a constant average current; pulsed neurostimulation, telemetry bursts, and temperature-driven self-discharge can make real-world runtime diverge significantly.

Current U.S. benchmarks

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Common questions

How do you calculate implant battery life? Divide usable capacity (mAh) by average current draw (mA), then multiply by a derating factor for end-of-life and self-discharge. With 1200 mAh, 0.035 mA draw, and 0.8 derating, runtime is about 27,429 hours (roughly 3.1 years).
Why apply a derating factor? Nameplate capacity assumes ideal conditions. Real cells lose usable charge to self-discharge, end-of-life voltage cutoffs, and temperature. The 0.8 factor here trims the undated 34,286-hour figure down to a defensible 27,429 hours.
What is a good battery life for an implantable neurostimulator? Primary-cell IPGs typically target 3-10 years depending on stimulation intensity; rechargeable units target 9-15 years to battery replacement. The example's ~3.1 years suits a high-duty therapy device.
Underrated vs derated runtime — which should I quote? Quote the derated runtime (27,429 hr) in clinical and IFU contexts. The underrated 34,286 hr is the theoretical ceiling and is useful only as a sanity check, not a patient-facing claim.
How does current draw affect longevity? Runtime is inversely proportional to average current. Doubling draw from 0.035 to 0.070 mA halves runtime. Reducing leakage and idle telemetry current is usually the cheapest way to add years.

Last reviewed 2026-05-12.