Cordless 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 
 It works without a cable, powered by a rechargeable battery.
 Allows drilling, screwing and has percussion in some models
 Includes automatic or manual chuck.
 It has multiple torque positions.
 They usually incorporate an LED light, charge indicator and carrying case.

 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.

 Bosch PS31 10-12V 
 Bosch GSR 12V-15
 Makita DF331DSAE
 Black+Decker BDCHD12S1

 14.4V 
Balance between power and size. Still present in mid-ranges.

 Bosch GSR 1440-LI
 Makita HP347D
 Makita DF347DWE
 Makita BL1430B (compatible battery)

 18–21 V 
Professional range. High power for demanding jobs.

 Bosch GSR 1800-LI
 Bosch GSB 18V-21
 Makita DHP453RFE
 DeWalt DCD776C3-QW
 Einhell TE-CD 18 Li-i
 Worx WX375 20V

 28V 
Less common models aimed at industrial or high-performance tasks.

 Some Milwaukee and DeWalt models in industrial ranges.

 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: 

 Greater energy density.
 Less weight.
 Absence of memory defect.
 Fast charging and extended battery life.

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 
 Furniture assembly.
 Installation of shelves, curtains, supports.
 Drilling in wood, metal, plastic and masonry (models with percussion).

 Security 
 Ergonomic and non-slip handle.
 Overload and overheating protection.
 Electronic brake on some models.
 LED light for dark areas.

 References 

 Bibliography 
 Bell, Brian. Farm Machinery. Old Pond Books, 2010-02-12. ISBN 978-1-910456-23-1. 
 Peterson, Chris. Black & Decker Readymade Home Furniture: Easy Building Projects Made from Off-the-Shelf Items. Cool Springs Press, 2018-12-25. ISBN 978-0-7603-6162-7. 

 Other websites 



Category:Construction