Cordless drill

Makita_18v_electric_drill

A cordless drill or battery drill is a portable power tool that operates on rechargeable batteries, usually lithium-ion technology. Its cordless design allows great freedom of movement, making it ideal for DIY, carpentry, assembly and professional use on construction sites.

Features

Type according voltage

Cordless drills are classified by battery voltage, which determines their power and autonomy.

10–12V

Compact, lightweight models suitable for household or precision tasks.

14.4V

Balance between power and size. Still present in mid-ranges.

18–21 V

Professional range. High power for demanding jobs.

28V

Less common models aimed at industrial or high-performance tasks.

Technical comparison between models

They started out as low-power electric screwdrivers, but today they fill a very wide range.

Brand Model Volts Engine Max. torque Max RPM Percussion Drill chuck Drilling capacity (Wood / Metal / Bricks)
Bosch GSB 18V-55 18V Brushless 55 Nm 1,800 Yes 13 mm 35mm / 13mm / 13mm
Bosch GSR 18V-110 C 18V Brushless 110 Nm 2,100 No 13 mm 82mm / 13mm / —
Bosch GSR 1800-LI 18V With brushes 34 Nm 1,300 No 10mm 29mm / 10mm / —
Bosch PS31 12V With brushes 30 Nm 1,300 No 10mm 19mm / 10mm / —
Makita DHP453RFE 18V With brushes 42 Nm 1,300 Yes 13 mm 36mm / 13mm / 13mm
Makita DF331DSAE 12V With brushes 30 Nm 1,700 No 10mm 21mm / 10mm / —
Makita HP347D 14.4V With brushes 34 Nm 1,400 Yes 10mm 25mm / 10mm / 10mm
DeWalt DCD796D2 18V Brushless 70 Nm 2,000 Yes 13 mm 38mm / 13mm / 13mm
DeWalt DCD710D2 10.8V With brushes 24 Nm 1,500 No 10mm 20mm / 10mm / —
Einhell TE-CD 18 Li-i 18V Brushless 60 Nm 1,800 Yes 13 mm 38mm / 13mm / 13mm
Worx WX375 20V Brushless 60 Nm 1,600 Yes 13 mm 40mm / 13mm / 13mm

Battery pack technology

Battery packs require battery balancing, which is a technique that maximizes a battery's ability to have all of its energy available for use and increases battery longevity. The battery regulator is typically a device built into the battery pack that performs battery balancing. Most modern cordless drills use lithium-ion batteries that offer:

Manufacturer Model Voltage Capacity (Ah) BMS type Observations
Bosch PBA 12V 2.5Ah 12V 2.5 External Home use, Power for All system
Bosch GBA 18V 5.0Ah 18V 5.0 Internal Professional, CoolPack technology
Bosch ProCORE 18V 8.0Ah 18V 8.0 Internal High energy density, intelligent BMS
Makita BL1021B 12V 2.0 External CXT series, compact
Makita BL1850B 18V 5.0 Internal LXT series, with load indicator
Makita BL4040 40V 4.0 Internal XGT series, digital battery-machine communication
DeWalt DCB124 12V 3.0 External XR Compact, light professional use
DeWalt DCB184 18V 5.0 Internal XR Li-Ion, compatible with the entire 18V range
DeWalt DCB546 18V / 54V 6.0 Internal FLEXVOLT, dual voltage, smart BMS

Internal architecture of battery packs

The nominal voltage of a battery pack is determined by the number of 3.7V cell subgroups connected in series. Each subgroup can consist of one or more cells in parallel, which increases the capacity (Ah) of the pack

Structural typology according to voltage
Rated voltage No. of 3.7V subgroups in series Example of models BMS Comment
3.7V 1 USB Power Banks Not required The cells are in parallel; a 3.7 V → 5 V DC-DC converter is used
10.8–12V 3 Black&Decker BL1510, Makita BL1013, Bosch BAT411 (PS31) External 2 intermediate sockets for BMS on the charger
14.4–16V 4 Makita BL1415G External 3 intermediate sockets; BMS usually in the charger
18–21 V 5 Makita BL1850B, Bosch SM31 (GSR 1800-LI) Internal 4 intermediate sockets; with integrated BMS

The presence of intermediate taps in the pack connection allows the BMS (internal or located in the charger) to monitor and balance the state of charge of each group of cells. This balance is essential in series configurations, since the cells do not automatically balance as they do in parallel. Some low-cost designs use diodes to limit the imbalance between cells, although this technique offers limited protection and can reduce the useful life of the set.

Power packs => % charge vs. Volts

Loading 3.7V pack 10.1 V pack 14.8V pack 18V pack 21 V-pack
100% 4.2V 12.6V 16.8V 21.0V 25.2V
75% 3.9V 11.7V 15.6V 19.5V 23.1V
50% 3.7V 10.8V 14.4V 18.0V 21.0V
25% 3.5V 10.0V 13.2V 16.5V 18.9V

Applications

Security

References

  1. ↑ "Optimot. Consultes lingüístiques". Llengua catalana (in Catalan). Retrieved 2025-07-30.
  2. ↑ Magazines, Hearst (1989). Popular Mechanics. Hearst Magazines. Retrieved 2025-07-30.
  3. ↑ "PS31N Taladros/atornilladores de 12 V máx". Boschtools. Retrieved 2025-07-28.
  4. ↑ "Taladros a batería: Comparativa BOSCH, MAKITA y DEWALT". Blog Bricovel (in Spanish). 2018-06-10. Retrieved 2025-07-30.
  5. ↑ Inc, Active Interest Media (2005). Old-House Journal. Active Interest Media, Inc. Retrieved 2025-07-30. {{cite book}}: |last= has generic name (help)
  6. ↑ Wen, Sihua (2009). "Cell balancing buys extra run time and battery life" (PDF). Analog Applications Journal.
  7. ↑ "Battery Management and Monitoring Systems BMS". www.mpoweruk.com. Archived from the original on 2023-10-15. Retrieved 2024-01-12.
  8. ↑ Diao, Weiping; et al. (2017). "Active battery cell equalization based on residual available energy maximization". Applied Energy. 210: 690–698. doi:10.1016/j.apenergy.2017.07.137. {{cite journal}}: Explicit use of et al. in: |last= (help)
  9. ↑ "Cell Balancing Design Guidelines" (PDF). Retrieved 2025-07-30.
  10. ↑ "What is Battery Balancing and Does Your System Need It?". Cadence System Analysis. 2022-09-07. Retrieved 2025-07-30.

Bibliography

Other websites