Our top pick for the best 4-1/2″ cordless angle grinder is the DeWalt DCG412B 20V MAX 4-1/2” angle grinder for its moderate price and well rounded capabilities. Need something that has the power of a corded grinder, this isn’t the only option on our list so browse our buyer’s guide and learn what features to look for. If you know what you require in a grinder, jump right into our reviews.
If you haven’t been in the market for new power tools in past few years you may be shocked to see how popular cordless or battery power tools have become. For those of us who are aware, it hasn’t made it any easier when selecting the best 4 ½” cordless grinder as there numerous choices.
With the advances in battery technology, cordless power tools are now dominating both the professional market and the do-it-yourself-er weekend warrior. This has opened the flood gates for many tool manufacturers to put out their own model of battery powered angle grinder. Not only are the putting out their own models, they are updating them as fast as battery technology improves to take full advantage of the improvements.
It’s often hard to determine marketing gimmick from the actual performance features that matter but I hope to help with that. I have put together a thorough guide to help you understand what features actually matter in a cordless grinder. I have used battery powered grinders in everything from masonry work to general carpentry and have experienced what features are better in certain circumstance. This is important and you should keep in mind how you think you will use the angle grinder most when making your choice.
Aside from my own experience with grinders as a home welder among other uses, I also sought input from a family member who owns and operates a cabinet shop as well as a large home remodeling business and they have experience with every major brand of cordless drills, saws, and grinders. Together we came up with a list of the best cordless angle grinders and what makes them so great.
How To Choose: A Guide to Cordless Angle Grinders
There are many uses for angle grinder and you should keep that in my when reading the guide. You will learn what to look for when choosing a cordless grinder, whether you should go for power or battery performance, and what applications may be best for certain features.
For most heavy users like metalworkers, welders, concrete workers, fabricators, and other heavy grinder users I would only recommend a cordless grinder as a complement to a really good corded angle grinder that would be used as a primary.
Typically, every battery powered grinder comes with a side handle, a guard, and the wheel attachment wrench. Beyond that, each angle grinder have difference that range from the minute details to huge differences in battery performance or grinder power. First I will go over the performance features and close with accessories features to look for.
Battery Powered Angle Grinders: Performance Attributes
Cordless Grinder Motor
The power rating for the motors in cordless grinders are largely all the same. One area they may differ is in durability and the popularity of a brand is a good indicator of this as the manufacturer will have a large loyal following of people who continue to buy their tools. There will be the occasional lemon but most manufacturers will promptly replace the defective tools as to not tarnish their reputation.
There is one thing to look out for however and that is the motor type. Brushed motors used to be the most common motor type found in cordless power tools but more and more manufactures have switched over to the more efficient brushless motors.
- BRUSHLESS MOTORS: Uses a permanent magnet external rotor and three phases of driving coils. Another electronic device senses the position of the rotor and the associated drive electronics. When the coils are activated one after another by the speed controller it provides the torque to the shaft connected to the motor.
These motors are highly efficient and are usually smaller while maintaining the same power as brushed motors, but they cost more to manufacture than brushed motors as well as add to components costs in the products that use them. These motors require less maintenance since they do not have brushes and have better heat dissipation which means longer useful life.
- BRUSHED MOTORS: Has a rotating set of wire coils called which acts as an electromagnet with two poles. A mechanical rotary switch reverses the direction of the electric current, so that the poles of the electromagnet push and pull against the permanent magnets on the outside of the motor. As the poles of the armature electromagnet pass the poles of the permanent magnets, the commutator reverses the polarity of the armature electromagnet. During the instant of switching polarity, inertia keeps the classical motor going in the proper direction.
These motors are cheaper but they typically require periodic maintenance, the speed/torque is moderately flat, and at higher speeds the brush friction increases, reducing the useful torque. These motors also have poor heat dissipation due to the internal rotor construction.
Brushless motors are up to 90% efficient compared to DC brushed motors which are only about 80% efficient. The better efficiency in the brushless motor means more of the total power used by the motor is turned into rotational force and less is lost as heat energy.
Cordless Grinder RPM
The RPM or rotations per minute of a grinder is one aspect of an angle grinder’s performance. Higher RPM will usually allow for the user to work quicker as the higher RPMs will make quick work of the job at hand. A high RPM motor is great for cutting material and will be bogged down less due to the built up inertia of the high RPMs. That said, more RPMs will mean more battery will be used to operate at higher a RPM.
How you intend to use the angle grinder will best determine whether you should go for a high RPM grinder capable of shearing through steel rebar or speedily cleaning a rusty piece of metal you are prepping for a welding project. You may not need a high RPM but instead a long battery life capable of lasting all day on a carpentry job with minimal down time due to charging batteries.
One great thin you will find on some higher end models is a variable speed setting. This will give you the best of both worlds where you can toggle the higher RPM only when need saving much of the battery for extended use.
Cordless Grinder Battery
Arguably one of the most important aspects of any cordless tool, the battery is the tools power source and without a quality battery that maintains a good charge you can’t be productive. You probably aren’t aware but the battery is usually the single most expensive component of a battery powered angle grinder and better batteries are the reason why the best cordless angle grinders are more expensive. Lithium Ion batteries are definitely better than NiCad but they are more expensive. They will charge faster, have better capacity, and last longer.
Believe it or not, the 18V vs 20V battery rating is in part, one of those marketing gimmicks. Batteries have two voltage ratings, a nominal and max. For power tool batteries the nominal rating is 3.6 volts and the maximum rating is 4 volts. When you multiply that times the number of cells in the battery, which is 5, respectively you get 18V and 20V.
Sometimes companies choose to market the nominal rating and other times they use good marketing and label the 20V max rating. To further clarify, Li-Ion batteries have a higher voltage rating when fully charges, this being 4 volts, but discharges down as soon as you start using it. In the U.S., manufacturers like Bosch, Milwaukee, Ridgid, Ryobi, and Makita are all running on an 18V battery platform, DeWalt and Porter-Cable run on their 20V Max systems.
Now that I have cleared that up, when it comes to the different brands, you really get what you pay for in terms of batteries. The higher quality brands are sourcing higher quality components. A battery is only as good as the cells that make up the battery pack and it costs more for high quality cells that are going to last longer, have better discharge rates, and be less prone to dying altogether.
Last thing to look at in a battery pack is the Ah rating or Amp hour rating. This is a measurement of how much use you can expect to get out the battery under normal conditions and use. Typically they will range from 2Ah up to 5Ah in cordless power tools but for grinding I recommend a 4Ah to 5Ah pack. The later are usually marketed as extended use and are good for taking on the job-site if you don’t want to worry about having to take a charger everywhere you go.
Battery Powered Angle Grinders: Features and Accessories
The features and accessories of a cordless angle grinder may not affect the performance but they can definitely make using the grinder more convenient, safe, and versatile. Whether it’s 4.5 inch angle grinder being capable of also handling 5 inch discs with no modifications or a handle that can be relocated, this versatility will definitely be appreciated when using your grinder.
Some grinders will have movable hand grip that can be re-positioned by simply unscrewing it and relocating it. Typically grinders will have handle positions on either side for ambidextrous use. Some grinders will have a third location for positioning the handle on the back/top of the grinder which provides optimal positioning options for the user.
Grinder Wheel and Guard
When selector your grinder note the size of the arbor nut and spindle size. This will determine what size discs will fit on your new grinder. Nothing is more frustrating than getting to the store and forgetting the size or returning home with the wrong size spindle holes on your new discs.
The angle grinder guard offers some protection from particles flying off the wheel at high speeds. Some grinders now have quick release mechanisms on the guard so they can be re-positioned easily without the use of a tool. This is very convenient and will save time and frustration.
If you haven’t already learned this about electronic components, heat will break down components. This can lead to premature failure and at the least reduce the life of motor. Manufacturers will often design heat syncs into the design to dissipate heat better to keep the unit cool. Look for grinders that specifically mention the improved heat dissipation as this will improve the life and performance of the motors.
The Best Cordless Angle Grinders – Top 5 Reviews
Now that you have a good idea of what to look for in a grinder you should be able to select the best battery powered angle grinder to suit your needs. Everyone will use their grinder differently and a mason will not use a grinder like a welder will and that goes for any other tradesman. Pick the grinder that works for you and your needs not the one that has worked best for someone else.
That said, I have already researched the top angle grinders and used quite few of these myself. There are actually quite a few great ones out there with differing features. One final thought is if you have already invested in a particular brand and already have compatible batteries than I will make it easy for you, pick the grinder of my list that is compatible with your batteries. Otherwise, just pick the one that has the features you desire and get back to work!
Keep an eye on whether your purchase comes with a battery or not.
DeWalt is one of the most recognized and trusted power tool brands on the market so it should be no surprise they are my top choice in cordless angle grinder. I use this model and I can say without a doubt it is the best 4-1/2″ cordless angle grinder for just about any job. It has a 7,000 RPM rating which is a nice balance of power and extended use of battery capacity. It is priced well enough for weekend warriors but it is good enough for professionals.
Whether you are doing light masonry work, carpentry, or plumbing it will tackle just about anything. It seems to get about 10-20 minutes of constant grinding per charge depending on the material you are working with. It also has a quick-change wheel release as well as a tool free guard adjustment which is extremely convenient and quicker to get the job done.
The only thing that would make this grinder better would be a variable speed feature but for the price it isn’t something I’d expect. I have used this particular grinder to cut galvanized pipe, red house bricks, and cinder blocks and it has yet give me a reason to be disappointed. I have never had any issues finding a variety of wheels to use on the 5/8th arbor either.
I expect to get even more years out of this grinder but if not I would certainly buy it again based on my experience with it so far. If you want a grinder that is time tested from a trusted brand, this DeWalt cordless angle grinder is great choice.
If you want the best on a budget Porter Cable will not let you down. This is one of the best cheap cordless angle grinders on the market and I can attest to the quality of Porter Cable cordless tools. I own and still use regularly, a complete set of their cordless tools for over 8 years now, and whats most remarkable is the original two batteries are still good.
Porter Cable has built a reputation for offering affordable power tools and cheaper prices than the competition without sacrificing quality or power. At this price even if you had a failure out of warranty you could repurchase and still come in cheaper than most models. If you already own a different brand of cordless tools and batteries I also recommend the RYOBI P421 18V CORDLESS ANGLE GRINDER or the HITACHI CORDLESS ANGLE GRINDER as a comparable grinder based on price and great performance.
Perfect for the DIY’er as it is affordable and very capable of handling any home project. Some users have commented how it can go head to head with a DeWalt and keep up but others have stated it doesn’t have quite as much torque but I would expect this and that would only affect really heavy load on the motor. The 8,500 RPM rating makes it great for cutting just about anything and would also work well well with wire wheels to clean up corroded metal quickly.
This lightweight but portable grinder also wins on battery use as it will give you about 10-15 minutes of continuous use depending on the material and use. Another great feature on the Porter Cable angle grinder that not many others feature is a 3-position handle which makes using the grinding in difficult positions a lot more convenient. Overall a grinder worth a try if this is the price range you are looking at or already own Porter Cable batteries.
Makita power tools is another respected brand that has been around for a very long time and their reputation for great tools is well deserved. My grandfather was a loyalist who only purchased and used Makita for his HVAC business. He always referenced their reliability when giving his reasoning. The cordless tools by Makita are every bit as good as DeWalt both in performance and features.
Makita uses a brushless motor in this grinder as well as automatic speed change technology that can adjust both speed and torque during operation. These two features combine make for outstanding battery performance and probably one of the best on this list. This angle grinder is ideal if you are demanding on your tools and will be cutting and grinding a variety of materials.
The Makita XAG03Z cordless grinder is an absolutely job site worthy grinder and professionals should certainly consider this grinder for their tool box. This would probably be the only cordless grinder you buy as it will last years before needing a replacement. If you a Milwaukee Tool fan and really like this grinder but already own Milwaukee tools and batteries the MILWAUKEE M18 FUEL is a very comparable angle grinder although starting fresh the Makita is probably the way to go.
If you haven’t bought a cordless grinder yet because you don’t want to lose the power of corded, this is the best and most powerful cordless grinder on the market and is a must have for professionals and industrial job sites needing a comparable corded grinder alternative. Everything about the DeWalt 60V MAX has been designed to provide optimal power to the user.
This angle grinder has a brushless motor, operates at 9,000 RPM, and can accommodate 4-1/2″ to 6″ wheels. With the power and battery size this makes it the best angle grinder for metal. Not only is it the best metal grinder, it can also make quick work of concrete and masonry materials. Where a lot of the grinders on this list will not last long cutting and grinding metal and concrete, the DeWalt will work those materials long after the other will need a recharge.
It is also important to point out the safety features on this angle grinder since we are all concerned with job safety these days. It has a kickback brake that engages when a pinch, stall, or bind-up is sensed and the electronic brake engages with maximum force to quickly stop the wheel and shut the grinder off. It also has a brake to slow the wheel quickly after a stop so you aren’t waiting around to put the grinder down safely because the wheel is still spinning.
User after user is impressed with how much power this grinder can offer. It feels every bit as powerful as a comparable corded grinder and professionals can finally be confident a cordless power tool can offer up as much power as a corded tool. The only word of caution when considering this angle grinder is the charge time for the batteries. These batteries have some much power and capacity they do take longer to charge than the 20V 5Ah batteries so you may want purchase several to minimize downtime.
If you are already familiar with Metabo you probably know them for having some of the best corded grinders on the market. Well know for their quality and German engineering, this cordless grinder is every bit as good as the corded line. It’s compact and sleek design is very comfortable to work with. The Metabo also features a water resistant motor which makes it a great angle grinder for plumbers.
If you are a Metabo fanboy and already own a few Metabo cordless tools this would be a great addition to your collection. If you are new to Metabo this is definitely worth a look as it is a very quality 4-1/2″ grinder at a very affordable price. It also has an very interesting feature that allows the battery to swivel making it great for working in confined or awkward spaces.
Best Cordless Angle Grinders Comparison
|Grinder Image||Cordless Grinder||RPM||Max Disc Size||Switch||Price|
|DEWALT DCG412B 20V MAX||7000||5"||Trigger||$$|
|PORTER CABLE PCC761B 20V MAX||8500||4.5"||Trigger||$|
|MAKITA XAG03Z 18V||8500||4.5"||Paddle-Lock||$$|
|DEWALT DCG414B 60V MAX||9000||6.5"||Trigger With Lock||$$$|
|METABO W18 LTX 18V||8000||4.5"||Paddle-Lock||$$|
|MILWAUKEE M18 FUEL||8500||5"||Paddle-Lock||$$$|
|RYOBI P421 18V||6500||4.5"||Trigger||$|
I hope you found the list and guide useful. I’d love to hear what others think and if there are any grinders not on my list I should try out!