Updated: June 2026
Calculate battery watt-hours and estimated runtime
For cordless tools, voltage and amp-hours are not the whole story. Buyers need to estimate how long a tool can work under load and which battery pack belongs in a retail kit.
Formula
Watt-hours = voltage x amp-hours. A 20V 5.0Ah pack is roughly 100Wh. Runtime depends on the tool load. A drill under light use draws far less than an angle grinder cutting steel.
Common battery pack choices
| Battery pack | Estimated energy | Recommended kit |
|---|---|---|
| 20V 2.0Ah | 40Wh | Entry retail drill kit |
| 20V 4.0Ah | 80Wh | Pro drill/driver kit |
| 20V 5.0Ah | 100Wh | Contractor kit and grinder bundle |
| 40V 4.0Ah | 160Wh | Heavy-duty outdoor and construction tools |
FAQ
Should every tool kit use the largest battery?
No. Larger batteries increase perceived value but also weight and cost. For retail shelves, 2.0Ah and 4.0Ah kits often convert better than overbuilt bundles.
Why does the same battery run differently on different tools?
Runtime depends on motor load, gear ratio, material resistance and user behavior. This is why distributors should match battery capacity to the main application.
Can VoltForge recommend a kit battery size?
Yes. Send the tool list, expected retail price and target user. We will recommend battery capacity, charger type and bundle structure.
Related buyer resources
Need help choosing a battery platform?
Send your tool list and target retail price. We will recommend a battery and charger configuration.