Battery Building Tools

13 free calculators for planning, building, and validating lithium battery packs.

Browse supplies
Step 1

Plan & Design

Start here. Figure out what you need to build.

Pack Planner

Figure out what size pack you need for your application. Enter your requirements and get a recommended cell configuration.

Plan your pack

3D Battery Pack Designer

Plan your pack in 3D. See how many cells fit, visualize the layout, and get exact dimensions.

Design your pack

Powerwall Planner

Plan an entire off-grid power system for your home. Solar, battery, inverter sizing all in one place.

Plan your powerwall

Car Audio Calculator

Going lithium for car audio? Calculate your battery requirements and plan the switch.

Plan your car audio
Step 2

Build & Match

You've got cells. Sort them, match them, pick your BMS.

Pack Builder

Balance your cells into even series groups based on capacity and internal resistance. Paste your cell data and get an optimized layout.

Build your pack

BMS Picker

Find the right Battery Management System for your build. Match your cell count, chemistry, and current requirements.

Find your BMS
Step 3

Analyze & Validate

Test your cells. Check your math. Catch problems before they become expensive.

Cell Resistance Estimator

Measure internal resistance and calculate max safe current. Test cells before using them in builds.

Test your cells

Wire Resistance Calculator

Calculate wire resistance, voltage drop, and power loss. Size your wires correctly for high-current applications.

Calculate wire specs

Pack Design Validator

Get a pass/warning/fail verdict on overcurrent risk, thermal risk, BMS mismatches, and more.

Validate your design

Runtime Simulator

Simulate real-world runtime under actual load conditions, duty cycles, and ambient temperatures.

Simulate your runtime

Thermal & Layout Visualizer

Visualize heat distribution and layout risks. Identify hotspots, spacing issues, and nickel strip bottlenecks.

Check thermal risks

Cost vs Performance Optimizer

Compare cell types and configurations. Optimize cost per kWh, cost per cycle, weight, and safety margins.

Optimize your build
Step 4

Safety

The last step before you power on. Don't skip this.

Safety Checklist Generator

Generate a custom pre-flight safety checklist covering fuse locations, disconnect requirements, pre-charge circuits, fire mitigation, and transport safety.

Generate your checklist

Essential Tools & Supplies

Our curated list of the best DIY battery building tools across every category. Spot welders, testers, safety gear, and more.

Browse supplies