Cordless angle grinder

The **cordless angle grinder** is a portable angle grinder designed to perform straight, cross and angle cuts, or roughing and polishing tasks on various materials such as metal, stone, ceramics and concrete. Unlike corded grinders, this type of angle grinder operates using rechargeable batteries, providing greater freedom of movement and versatility, making it ideal for construction work, light carpentry and DIY .

Their ergonomic design makes them easy to operate with one hand. Cordless angle grinders have gained popularity due to their portability and ease of use. They are characterized by their mobility, lightness, and versatility, especially in places without access to the electrical grid. They use lithium-ion batteries, usually 12 V, 18 V, or 20 V.

## History

The angle grinder was invented in 1954 by the German company _Ackermann + Schmitt_ ( _FLEX-Elektrowerkzeuge GmbH_ ) in Steinheim an der Murr

## Characteristics

- It uses a circular abrasive disc that rotates at high speed, with different diameters (usually 115 mm, 125 mm or 150 mm).

- It works with lithium-ion batteries, usually 18 V, 20 V or 36 V.

- Includes auxiliary handle, disc guard and shaft locking system.

- Some models incorporate a _brushless_ motor for greater efficiency.
- Power: between 1200 and 2000 W.
- Disc diameter: 115–150 mm.
- Cutting depth: up to 65 mm at 90°.

### Advantages

- Greater freedom of movement than cable ones
- Less weight and size.
- Ideal for quick cuts on site or outdoors.

### Limitations

- Lower autonomy and power than wired models.
- They require recharging or additional batteries for extended work.

## Battery types

Cordless angle grinders are rated by battery voltage, which determines their power and runtime.

### 10–12 V

Compact and lightweight models, suitable for precision work or light cutting.

- **Bosch GWS 12V-76**
- **Makita CP100DZ**

### 14.4 V

Less common today, but still present in mid-ranges.

- **Makita DGA452Z** (compatible with 14.4V and 18V batteries)

### 18–21 V

Professional range. High power for demanding jobs.

- **Bosch GWS 18V-10**
- **Makita DGA513Z**
- **DeWalt DCG405N**
- **Einhell TE-AG 18 Li**
- **Worx WX800**

### 28–36 V

Industrial models for intensive tasks and larger diameter discs.

- **Milwaukee M28 CAG125X**
- **Makita DGA900Z**

## Comparison between market models

They started with small, low-power radials, but today they cover a very wide range.
|Brand|Model|Voltage|Motor|Max RPM|Disc diameter|Electronic brake|Kickback|Approx. weight.|Observations|
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|**Bosch**|GWS 18V-LI|18 V|4 poles|11,000|115 mm|No|No|2.3 kg|Equivalent to 800 W wired|
|**Bosch**|GWS 12V-76|12 V|Brushless|19,500|76 mm|No|No|0.5 kg|Ultra compact|
|**Bosch**|GWX 18V-15 PSC|18 V|BITURBO|11,000|125 mm|Yeah|Yeah|2.7 kg|X-LOCK, speed control|
|**Makita**|DGA452|18 V|With brushes|11,000|115 mm|No|No|2.3 kg|Classic LXT model|
|**Makita**|DGA513Z|18 V|Brushless|8,500|125 mm|Yeah|Yeah|2.5 kg|Cruise control, AVT|
|**Makita**|DGA900Z|36 V|Brushless|7,800|230 mm|Yeah|Yeah|5.4 kg|Double battery, industrial use|
|**DeWalt**|DCG405N|18 V|Brushless|9,000|125 mm|Yeah|Yeah|1.74 kg|XR, compact and powerful|
|**DeWalt**|DCG418|54 V|Brushless|9,000|125 mm|Yeah|Yeah|2.2 kg|FLEXVOLT, high performance|
|**Einhell**|TE-AG 18/115 Li|18 V|With brushes|8,500|115 mm|No|No|1.2 kg|Light, economical|
|**Einhell**|AXXIO 18/125|18 V|Brushless|8,500|125 mm|No|Yeah|1.4 kg|Professional, PurePower engine|
|**Worx**|WX800|20 V|Brushless|8,600|115 mm|Yeah|Yeah|1.9 kg|Compact, PowerShare|
|**Worx**|WX812L|20 V|Brushless|8,500|115 mm|Yeah|Yeah|1.8 kg|Nitro, anti-kickback|
|Brand|Model|Voltage|Disc diameter|Max cut at 90°|
| --- | --- | --- | --- | --- |
|Makita|HS301DSAE|12 V|85 mm|25 mm|
|Bosch|GKS 18V-57|18 V|165 mm|57 mm|
|DeWalt|DCS570N|18 V|184 mm|64 mm|
|Metabo|KS 18 LTX 66 BL|18 V|165 mm|66 mm|

### Technical notes

- Max RPM : No-load speed. The higher the speed, the more efficient it is at fine cutting.
- Electronic brake : Stops the disc when the trigger is released, improving safety.
- Kickback control : Detects blockages and shuts off the tool to prevent kickback.
- BITURBO / FLEXVOLT / XGT : Technologies that increase performance in high-end models.

## Disc table for cordless grinders (76–125 mm)

|Diameter (mm)|Usual compatibility|Available disc types|Common applications|
| --- | --- | --- | --- |
|**76 mm**|Compact mini grinders|Fine cut, multi-material, metal|Light repairs, automotive|
|**85 mm**|Bosch GWS 12V, Makita 12V|Cutting metal, ceramic, diamond|Electrical installations, plumbing|
|**100 mm**|Some 12–14.4 V|Cutting, roughing, turbo diamond|Ceramic cutting, DIY|
|**115 mm**|Standard in 18 V|All types: cutting, roughing, diamond, flap|Construction, renovations, carpentry|
|**125 mm**|Standard in 18–21 V|All types + special discs (brush, polishing)|Professional work, metallurgy, masonry|

## 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.  Typically, a battery regulator is a device built into the battery pack that performs battery balancing.  Most modern cordless drills use lithium-ion batteries which offer:

- Higher energy density.
- Less weight.
- Absence of memory effect.
- Fast charging and long 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, smart BMS|
|Makita|BL1021B|12V|2.0|External|CXT Series, Compact|
|Makita|BL1850B|18V|5.0|Internal|LXT Series, with charge indicator|
|Makita|BL4040|40V|4.0|Internal|XGT Series, Battery-Machine Digital 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 3.7 V cell subgroups connected in series. Each subgroup can be made up of one or more cells in parallel, which increases the capacity (Ah) of the pack.
|Nominal voltage|Number of 3.7V subgroups in series|Example of models|BMS|Comment|
| --- | --- | --- | --- | --- |
|3.7 V|1|USB Power Banks|Not required|The cells are in parallel; a 3.7 V → 5 V DC-DC converter is used.|
|10.8–12 V|3|Black&Decker BL1510, Makita BL1013, Bosch BAT411 (PS31)|External|2 intermediate sockets for BMS on the charger|
|14,4–16 V|4|Makita BL1415G|External|3 intermediate sockets; BMS normally 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's wiring allows the BMS (internal or located in the charger) to monitor and balance the state of charge of each group of cells. This balancing is essential in series configurations, since the cells do not balance themselves automatically as they do in parallel. Some low-cost designs use diodes to limit cell imbalance, although this technique offers limited protection and may reduce the battery's lifespan.

## Power packs => % Charge vs. Volt

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

## Applications

- Cutting of wooden boards, MDF, plywood.
- Cutting metal profiles with suitable discs.
- Cutting of plastics and synthetic materials.
- Installation, assembly and renovation work.

## Security

Hand-held radial saws include protection systems such as:

- Adjustable disc guard.
- Safety switch.
- Non-slip grip.
- Cutting guides and cutting line blowers.

## Related pages

- Angle grinder