Research-based advice, not a hands-on Six3X test. Affiliate links are not active. Our methodology and disclosure.
Capacity is not a complete performance score
Amp-hours describe battery capacity, while voltage and working conditions must also be considered when estimating cordless drill runtime, as explained by Lowe’s drill buying guide. Do not turn a single Ah figure into a promise about how long an unspecified job will run.
Our recommendation is to write down the exact battery supplied with every kit. “Battery included” is not enough information for a meaningful comparison when the capacity, physical size, and manufacturer’s intended application differ.
Use watt-hours to make the arithmetic visible
For a straightforward nominal-voltage comparison, multiply volts by amp-hours to calculate watt-hours; for example, Bosch lists its 18V, 4Ah pack at 72Wh in Bosch’s battery specification. The arithmetic is 18 × 4 = 72.
At that same nominal voltage, an illustrative 2Ah pack corresponds to 36Wh, but a nominal energy calculation is not a measured count of holes or screws. Use the number to understand the pack, not to manufacture a runtime claim.
Why larger packs can change more than runtime
Bosch claims both twice the runtime and 60% more power for its specified CORE18V 4Ah battery compared with its BAT612 18V 2Ah battery in Bosch’s battery specification. That is a manufacturer’s comparison of named packs, not evidence that every 4Ah battery improves every tool by the same amount.
We recommend checking the battery the manufacturer used for any advertised performance claim. When comparing two tools, record whether the claim was made with a pack you intend to buy or with an additional battery outside your budget.
Balance capacity against the way you work
Our preference for intermittent household drilling is to evaluate a comfortable compact pack first, while pricing a second compatible pack if interruptions are inconvenient. For sustained work, compare the manufacturer’s recommended higher-capacity options against the weight and size you can comfortably handle.
Charging time depends on both battery size and charger capability, and runtime is also influenced by the material, temperature, and use pattern, according to Lowe’s drill buying guide. A second pack and a suitable charger may be more useful to your workflow than a single large pack chosen without considering recharge time.
Check the platform and charging instructions
Makita says batteries must be used within the appropriate platform and advises using genuine batteries and chargers in Makita’s official FAQ. Our recommendation is to reject a shopping comparison that does not identify the compatible charger or relies on altered batteries.
- Before ordering: record battery model, nominal voltage, capacity, and tool compatibility.
- Before comparing value: include the charger and any second pack you need.
- Before use: follow the exact battery, charger, and tool instructions.
For example, Makita advises stopping and charging when useful tool performance diminishes rather than continuing to discharge the battery in Makita’s official FAQ. These buying notes are not a substitute for your model’s operating manual.
Read our voltage guide and bare-tool versus kit worksheet before deciding how much battery to buy.