The Complete Guide to Choosing and Using Cordless Angle Grinders

Have you ever struggled with a corded angle grinder while trying to cut or grind metal or masonry? The cord constantly gets in the way, limiting your working radius and mobility. Plus, finding a nearby electrical outlet isn’t always convenient.

Cordless angle grinders solve these problems and offer greater ease of use and flexibility for DIY, automotive, construction and industrial applications.

In this comprehensive guide, we’ll cover everything you need to know about cordless angle grinders – from key features to look for, top models on the market, and tips for safe operation.

What is a Cordless Angle Grinder?

An angle grinder is a versatile handheld power tool used for cutting, grinding, sanding, and polishing metal, concrete, tile and other hard materials.

Cordless models run on rechargeable lithium-ion battery packs, giving you the freedom to move around your workspace without being tethered by a power cord. The compact size and lightweight design also makes them easier to handle for prolonged periods.

Cordless angle grinders provide the convenience of portable operation combined with the power to perform tough jobs like:

• Cutting and grinding metal
• Smoothing welds
• Removing mortar
• Grinding concrete surfaces
• Sanding rusted areas
• Sharpening blades
• Polishing metal

Compared to corded grinders, cordless models offer exceptional mobility and safety since there are no cords to trip over or get tangled up while working. However, corded grinders tend to be a bit more powerful for very heavy duty use.

Key Features to Look for in a Cordless Angle Grinder

With many cordless angle grinder models available from brands like DeWalt, Makita and Milwaukee, how do you choose the right one? Here are the most important features to consider:

Battery Voltage and Power

Higher battery voltage translates into more power and torque from the motor. This enables faster material removal, especially for thick metal.

18 volt batteries are suitable for light DIY use, while 20V to 24V offers a good balance of power and portability. For intensive industrial use, 36V to 60V grinders provide the highest cutting and grinding performance.

Look at the motor wattage rating too – 350-450Watts is decent for typical home use, while 600W+ is best for heavy duty applications.

Battery Capacity

The battery’s amp-hour (Ah) rating determines how long it will run on a single charge. Standard batteries are around 2 to 5 Ah, but high capacity 8Ah+ batteries allow extended use. Larger batteries do add bulk and weight, so consider your runtime needs.

Quick change battery packs allow you to easily swap in a fresh pack when one runs out of juice. This minimizes downtime on bigger jobs.

Size and Ergonomics

Since you’ll be gripping and handling the grinder for long periods, comfort is essential.

Look for a model with a slim, ergonomic handle that minimizes hand fatigue. The grip size should fit your hand nicely too. Compact and lightweight grinders are easier to control.

However, don’t sacrifice power just for smaller size. Ensure there is enough grip area for proper leverage and handling safety.

Variable Speed Trigger

The best cordless angle grinders allow you to vary the disc rotation speed based on the material and operation:

• Lower speeds for polishing and finishing work
• Higher speeds for aggressive grinding and cutting

Electronic triggers offer precise speed control. Dial or multi-mode speed selectors are convenient too.

Electric Brake

An electric brake brings the spinning disc to a faster stop when you release the trigger. This makes cordless grinders much safer to use, preventing potential injuries from an out of control spinning disc.

Safety Features

Since grinders rotate at very high RPMs, safety should be a top consideration.

Look for additional features like:

• Paddle or sliding switch to prevent accidental start-up
• Lock-off button when storing tool
• Non-slip grip design
• Barrier guard for added protection

Proper protective gear like an ANSI approved face shield is a must too!

Top 5 Cordless Angle Grinders

Now that you know what features to look for, here are my top recommendations for the best cordless angle grinders currently available:

1. Milwaukee 2780-20 M18 Fuel Grinder

If you’re looking for no-compromise power and performance, Milwaukee’s heavy duty M18 Fuel grinder is a top choice.

Some key features:

• Brushless motor delivers maximum power and speed
• RedLithiumTM battery provides superior run time, up to 2x more cuts per charge
• Just 5.1 lbs for great handling comfort
• 4-mode adjustable speed for optimized cutting and grinding
• E-brake and paddle switch for safety

With the power to grind even stainless steel quickly, this grinder is ideal for intensive use by metal workers, plumbers and automotive shops. But it doesn’t come cheap.

Average Price: $160

2. DEWALT DCG413B 20V Max Grinder

The DeWalt DCG413B is a very popular and highly rated cordless grinder known for its relentless power and premium battery life.

Notable features:

• High efficiency brushless motor stays cool under heavy loads
• 5Ah lithium ion battery for longest runtime in its class
• Weighs only 5.5 lbs for comfortable all day use
• Low profile jam-pot gear case – best in class durability
• Paddle switch with brake for safety

This rugged, well-balanced grinder can handle just about any DIY or professional job you throw at it. DEWALT’s 3-year warranty provides peace of mind too.

Average Price: $179

3. Makita XAG04Z 18V LXT Grinder

For a compact grinder packed with innovative features, Makita’s 18V LXT model is a top contender.

Key advantages:

• Star Protection communication technology – prevents overloading by controlling RPM based on load
• Rapid Optimum Charger – charges battery in just 22 minutes!
• Weighs only 5 lbs with battery for reduced fatigue
• Slim soft grip handle provides exceptional comfort and control
• Fast braking for improved safety

If you need a highly portable grinder for occasional use, this Makita is a great choice. The rapid charger minimizes downtime.

Average Price: $139

4. PORTER-CABLE PCC761B 20V MAX Grinder

The Porter Cable PCC761B is designed to deliver high performance and durability in a compact size.

Notable features:

• At only 5 lbs, great for extended overhead use
• 2-speed gear box allows matching speed to application
• Optimized handle size and shape for superior balance and control
• Fuel gauge displays battery charge level
• Spindle lock makes wheel changes fast and easy

This rugged, no-nonsense grinder gets the job done without breaking the bank. A great choice for value-conscious buyers.

Average Price: $112

5. BLACK+DECKER BDCAG700K 20V MAX Grinder

For light duty DIY use on a budget, the Black & Decker BDCAG700K provides decent power at an affordable price.

Key features:

• Automatic spindle lock for quick and easy wheel changes
• 2-position side assist handle prevents wheel slipping during sideways grinding
• Battery charge level indicator
• Solid performance for light home use
• Typically costs under $100

While it can’t replace a heavy duty model for day long work, this BLACK+DECKER gets basic jobs done without costing a fortune.

Average Price: $99

Frequently Asked Questions about Cordless Angle Grinders

Here are answers to some common questions about choosing and using cordless angle grinders:

How long will a fully charged battery last?

Runtime depends on the battery amp rating, motor strength and your workload. Light use may get 20 to 40 minutes of cutting or grinding per charge. High capacity 5-6Ah batteries provide 30 to 60 minutes of run time. Plan on having 1 or 2 spare batteries for extended jobs.

Can I use a cordless grinder for heavy duty work?

Yes, good quality 18V to 20V models with high Ah lithium batteries can handle most DIY and professional use, including heavy stock removal. Select a grinder with higher voltage (36V – 60V) for intensive industrial use and extreme demands.

Should I run the battery all the way down before recharging?

It’s best not to wait until the battery is completely drained, which can damage lithium-ion cells over time. However, these batteries have no “memory effect” so you don’t need to fully discharge before recharging like old Ni-Cd batteries. Just charge when the indicator shows a low state of charge.

How long will a battery last before needing replacement?

With proper care and storage, expect around 500 charge cycles, or 3 to 5 years of typical use before significant capacity loss. High quality lithium batteries degrade slower than cheaper ones. Extreme temperatures also reduce battery lifespan.

Is it safe to use an extension cord with my corded grinder?

It’s not recommended to use extension cords with corded grinders, since the extra cord length causes power loss and risk of overheating. For full power delivery, use a grinder with an adequately long stock power cord. Or use a cordless grinder where an outlet is not conveniently located.

What safety gear should I use with my grinder?

Always wear ANSI approved eye protection to guard against debris, along with a face shield for full facial coverage. Use a NIOSH approved dust mask to avoid inhaling fine particles. Leather gloves and long sleeves provide protection from sparks and sharp edges.

Get the Right Cordless Grinder for the Job

Cordless angle grinders provide outstanding versatility for metalworking, construction, automotive repair, and home renovation projects. Their portable convenience makes work areas more accessible compared to corded models.

When selecting your grinder, match the power and capacity to your typical workload. Ergonomics are important too for safe control and comfort during use. Invest in a quality model from a leading brand and it will provide years of reliable service.

Always use proper precautions like eye shields, gloves and dust masks to prevent injuries while grinding.

With the right grinder, you can power through all sorts of demanding cutting, grinding and finishing jobs with greater freedom, productivity and safety!