Raspberry Pi Battery Life Calculator

Electrical Calculator

Battery capacity

Capacity unit

Battery nominal voltage

Series count

Parallel count

Raspberry Pi voltage

Active current mA

Idle current mA

Active duty cycle %

Accessory current mA

Accessory voltage

Converter efficiency %

Usable capacity %

Battery health %

Temperature factor %

Reserve capacity %

Load safety margin %

Target runtime hours

Example Data Table

Project	Battery	Voltage	Average Load	Efficiency	Estimated Use
Remote sensor	10000 mAh	3.7 V	3.2 W	88%	Short field test
Camera logger	20000 mAh	3.7 V	5.5 W	90%	Outdoor monitoring
Robot controller	6 Ah	7.4 V	8.0 W	85%	Mobile testing
Kiosk display	120 Wh	12 V	10.5 W	92%	Backup operation

Formula Used

Pack voltage: Battery voltage × series count.

Raw energy for mAh: Capacity Ah × pack voltage.

Raw energy for Wh: Wh rating × series count × parallel count.

Average Pi current: Active current × duty cycle + idle current × idle cycle.

Load power: Pi power + accessory power, then add safety margin.

Usable output energy: Raw Wh × usable capacity × health × temperature factor × reserve factor × converter efficiency.

Battery life: Usable output energy ÷ adjusted load power.

Required Wh: Target hours × adjusted load power ÷ all derating factors.

How to Use This Calculator

Enter the battery capacity and choose mAh, Ah, or Wh.
Enter the nominal battery voltage and pack series count.
Add the parallel count for larger battery banks.
Enter active and idle current for the Raspberry Pi board.
Set the duty cycle based on actual project behavior.
Add accessory current for hats, screens, sensors, or fans.
Set converter efficiency, usable capacity, health, and reserve.
Click calculate to see runtime and target capacity needs.

Raspberry Pi Battery Planning Guide

A Raspberry Pi can run from many battery types. Common choices include USB power banks, lithium ion packs, LiFePO4 packs, and sealed lead acid batteries. Each option behaves differently under load. A runtime estimate should consider energy, not only capacity. A 10,000 mAh bank at 3.7 volts stores far less energy than a 10,000 mAh pack at 12 volts.

Key Factors

Current draw changes during every project. The board may idle at a low current. It can rise during WiFi traffic, camera capture, USB storage access, or heavy processor work. Sensors, fans, screens, relays, and hats also add drain. This calculator separates active and idle current. It also includes accessory power. That gives a better average load.

Losses and Real Capacity

No converter is perfect. A boost or buck module wastes energy as heat. Battery ratings are also tested under ideal conditions. Cold weather, aged cells, high discharge rates, and voltage cutoff reduce usable energy. The reserve field keeps some capacity unused. This protects lithium cells and prevents sudden shutdowns. The safety margin adds extra load allowance. Use it when current readings are uncertain.

Better Measurement

The best input comes from a USB power meter or inline ammeter. Measure the board while it performs its normal task. Record idle current and peak active current. Then estimate the duty cycle. A camera trap may sleep most of the time. A kiosk may run near active load all day. Remote projects should include the worst expected network and sensor activity.

Design Tips

Choose a battery with more runtime than the exact result. Add overhead for startup peaks and converter heat. Keep wires short and sized correctly. Use a stable regulated supply. Raspberry Pi boards can become unstable when voltage sags. For outdoor systems, place the battery in a suitable enclosure. Consider solar charging only after knowing daily watt hour demand.

Using Results

Runtime estimates are planning values. They are not guarantees. Real tests matter. Run the project for several hours. Compare measured runtime with the calculator result. Then adjust efficiency, reserve, or current values. This creates a practical model for repeatable portable power design. Document results before sealing the final case and wiring harness.

FAQs

1. Why does mAh alone give poor runtime estimates?

mAh depends on voltage. A 10,000 mAh battery at 3.7 volts stores different energy than one at 12 volts. Watt hours give a better comparison.

2. What current should I enter for my Raspberry Pi?

Use measured current when possible. A USB power meter is helpful. Enter active current during normal work and idle current during low activity.

3. What is converter efficiency?

It is the percentage of battery energy delivered after voltage conversion. Boost and buck converters lose energy as heat. Typical values are 80% to 95%.

4. Should I include accessories?

Yes. Screens, cameras, USB drives, fans, sensors, and relay boards can drain large amounts of power. Add them for realistic runtime results.

5. What does reserve capacity mean?

Reserve capacity is energy intentionally left unused. It protects batteries, allows safe shutdown, and helps prevent sudden voltage drop during operation.

6. Why add a safety margin?

Current can spike during startup, wireless use, storage writes, or processor load. A safety margin reduces the risk of undersized battery planning.

7. Can this calculator size a solar system?

It helps estimate daily watt hour demand. Solar sizing also needs sun hours, charge controller losses, weather allowance, and battery recharge targets.

8. Are the results guaranteed?

No. They are estimates. Battery age, temperature, cable loss, converter quality, and workload changes can affect actual runtime. Field testing is recommended.