We’ll Help You Find the Best Milwaukee M18 Battery for Your Job
It’s a simple concept—every M18 Milwaukee RedLithium battery works in any M18 or M18 Fuel tool. But there are a lot of pack sizes to choose from. And what’s the deal with High Output and Forge? In this article, I’ll walk you through each M18 battery to help you compare the power, capacity, and weight. Better still, I’ll help you sort out which battery to use when.
Milwaukee M18 Battery Comparison: Standard, High Demand, High Output, and Forge
Before we start comparing these batteries in detail, let’s start by sorting out the designations.
Milwaukee’s standard M18 batteries form the baseline power source for the system. Using 18650 lithium cells and traditional connection methods, they’re well-built and reliable for years of service.
Milwaukee High Demand batteries were the first advancement beyond their standard packs. This initial upgrade provides a 35% power boost while running up to 60% cooler and uses 18650 cells with some pack upgrades.
These batteries are now all discontinued, but there are still plenty of them in service, including some among our own crew.
Read
Milwaukee Battery Warranty Guide
The High Output Upgrade
M18 High Output batteries are a more comprehensive upgrade with 21700 cells and new battery electronics. They can deliver up to 50% more power than standard packs while running up to 50% cooler.
But there’s a catch. In order to get that much extra power, the tool has to have an upgraded electronics package as well. Standard tools still get a boost, but we can feel a more significant difference when we use tools specifically optimized for High Output batteries and switch between standard and H.O. packs.
High Output technology opened up advancements in charging as well. Specifically, they can charge much faster. However, you need an upgraded charger to take advantage. Milwaukee Rapid Chargers boost any battery’s charge time over the standard charger, but H.O. packs have legitimately impressive charge rates on a Super Charger.
Most of these batteries are now discontinued in favor of Forge technology. We still have quite a few of them in service in our shop, and there are a ton of them in the field across the trades.
Forging Ahead
M18 Forge batteries offer the newest and best battery technology Milwaukee offers. Some packs, like the 6.0 Ah Forge, use pouch cell technology. Others, such as the 12.0 Ah Forge, use upgraded cylindrical cells with a tabless connection design.
Read
Power Tool Tech: Pouch Cell vs Tabless Cell Battery Technology
Either way, the result is higher power delivery, faster charging, and longer service life, even compared to the High Output packs. This has enabled Milwaukee’s product development teams to pursue more powerful tools and develop some of the fastest chargers we’ve seen.
A Quick Note About “P”
“P” stands for parallel in a battery designation. 18V and 20V Max batteries use sets of five lithium-ion cells. These get series, or “S”, connections to give the battery the sum of their voltages. Each cell contributes 3.6V, so the set of five delivers 18 volts: 3.6 x 5 = 18V.
In a basic compact battery, each of those cells has two amp-hours of capacity. Using the series connections above, the voltage increases, but not the capacity. So, those five cells make an 18V, 2.0 Ah battery.
When you connect multiple sets with parallel connections, the amp hours increase while leaving the voltage steady. If a single five-cell set is 2.0 Ah, two sets of those same cells make a 4.0 Ah battery.
When we talk about a 1P pack, it means there’s one set of 5 cells. 2P is two sets and 3P is three sets. So a 1P compact pack uses a total of 5 cells, a 2P pack has 10 cells, and a 3P pack has 15.
Read
Power Tool Battery Voltage vs Amp Hours: What’s the Relationship?
Milwaukee M18 Battery Comparison Chart
Lately, Milwaukee has been reclassifying its M18 batteries as PWR2, PWR3, PWR4, and PWR5. This refers to the relative power levels provided by the battery, with the only current PWR5 battery being the Forge HD12.0 pack.
| Battery | Model | Amp-Hours | Watt-Hours* | PWR |
|---|---|---|---|---|
| CP2.0 | 48-11-1820 | 2.0 Ah | 36 Wh | PWR2 |
| XC3.0 | 48-11-1828 | 3.0 Ah | 54 Wh | PWR2 |
| CP3.0 | 48-11-1835 | 3.0 Ah | 54 Wh | PWR2 |
| XC4.0 | 48-11-1840 | 4.0 Ah | 72 Wh | PWR2 |
| XC5.0 | 48-11-1850 | 5.0 Ah | 90 Wh | PWR2 |
| H.O. XC6.0 | 48-11-1865 | 6.0 Ah | 108 Wh | PWR3 |
| FORGE XC6.0 | 48-11-1861 | 6.0 Ah | 108 Wh | PWR4 |
| FORGE XC8.0 | 48-11-1881 | 8.0 Ah | 144 Wh | PWR4 |
| FORGE HD12.0 | 48-11-1813 | 12.0 Ah | 216 Wh | PWR5 |
Every Milwaukee M18 Battery and When to Use Them
Milwaukee M18 RedLithium CP2.0 Battery
- Model: 48-11-1820
- Power Rating: PWR2
- Amp-hours: 2.0
- Watt-hours: 36 Wh
- Lithium-ion cells: 18650
- Weight: 1.1 lb
- Price: $119
Milwaukee’s M18 2.0 Ah battery is the current standard compact 1P pack. It uses standard technology and is the lightest on the M18 system.
When to Use it
- Compact Tools
- Light to Medium-Duty Applications
- Low-volume Applications
Example Tool Pairings
- 2953 M18 Fuel Impact Driver
- 2761 M18 Fuel Surge
- 3693-22CX M18 Brushless Compact Drill/Impact Driver
- 2836 M18 Fuel Oscillating Multi-tool
Rated at PWR2, this battery produces similar power to the 2P 5.0 Ah pack, so it’s not a big drop in performance when you use it.
The bigger consideration is capacity. At just 36 Wh, you might be able to drill 1/8-inch holes in lumber all day, but you’re going to chew through it quickly if you’re roughing in with a 2 9/16-inch self-feed bit.
We love this battery because it keeps our compact tools lighter and with a smaller footprint than using the 5.0 Ah battery. However, we shy away from it for heavier loads or higher volume work.
Milwaukee M18 RedLithium XC3.0 Extended Capacity Battery
- Model: 48-11-1828
- Power Rating: PWR2
- Amp-hours: 3.0
- Watt-hours: 54 Wh
- Lithium-ion cells: 18650
- Weight: 1.69 lbs
- Price: $129
The Milwaukee M18 3.0 XC battery was the original 2P extended-capacity pack, and you still find it in some kits as well as individually. It uses standard technology.
When to Use it
- Compact to Mid-size Tools
- Light to Medium-Duty Applications
- Low-volume Applications
Example Tool Pairings
- 3701 M18 Rotary Laser
- 2676 M18 Force Logic 10-ton Knockout Tool
- 2695 M18 4-Piece Combo (and other brushed motor combos)
This is a pack that’s likely on its way out. When it’s time to replace yours, we recommend upgrading in one of two ways.
The High Output CP3.0 has the same price, capacity, and performance rating in a much more compact package.
You could also upgrade to the XC5.0 pack and increase your runtime by 67% while only increasing the weight by about two ounces.
Milwaukee M18 RedLithium High Output CP3.0 Battery
- Model: 48-11-1835
- Power Rating: PWR2
- Amp-hours: 3.0
- Watt-hours: 54 Wh
- Lithium-ion cells: 21700
- Weight: 1.33 lb
- Price: $129
The 3.0 Ah High Output battery is Milwaukee’s most advanced 1P compact battery pack. It uses larger 21700 size lithium-ion cells with advanced RedLink electronics to deliver better performance and faster charging than other compact packs.
When to Use it
- Compact to Mid-size Tools
- Light to Medium-Duty Applications
- Low-volume Applications
Example Tool Pairings
- 2829 M18 Fuel Compact Bandsaw
- 3311 M18 Fuel Overhead Rotary Hammer
- 2909 M18 Fuel Coil Roofing Nailer
- 2843 M18 Fuel Fencing Stapler
If you’re looking for a balance between the size of the CP2.0 and the capacity XC5.0, this is your battery. You get 50% higher capacity than the CP2.0 and a much smaller size that’s nearly 1/2 a pound lighter than the XC5.0.
Plus, you get a bump in performance (even though all three of these packs have a PWR2 rating), and it’s only $10 more than the CP2.0.
Milwaukee M18 RedLithium XC4.0 Battery
- Model: 48-11-1840
- Power Rating: PWR2
- Amp-hours:4.0
- Watt-Hours: 72 Wh
- Lithium-ion cells: 18650
- Weight: 1.72 lbs
- Price: $139
Milwaukee’s M18 4.0 Ah battery took over for the XC3.0 as the premium 2P pack for a while, but tends to move out of the way in favor of the 5.0 Ah pack when you’re looking for a standard pack with higher capacity.
When to Use it
- Mid-size Tools
- Light to Medium+ Duty Applications
- Medium to High-volume Applications
Example Tool Pairings
- 2666 M18 Brushless High-Torque Impact Wrench
- 3693-24CX M18 4-Tool Combo
This is another battery that’s likely ready to retire. While it is available, it’s on even fewer combo kits than the XC3.0 pack. It’s been a solid workhorse, so there’s no need to get rid of the ones you have. It just didn’t seem to have quite as much time in the sun before Milwaukee developed the 5.0 Ah pack as the primary 2P battery.
If it’s time to replace yours, though, the XC5.0 is the way to go. It offers 25% more runtime and only costs $20 more. Since it’s also the standard extended-capacity battery, you’ll find it in many kits and combos if you need to upgrade other tools as well.
Milwaukee M18 RedLithium XC5.0 Battery
- Model: 48-11-1850
- Power Rating: PWR2
- Amp-hours:4.0
- Watt-hours: 90 Wh
- Lithium-ion cells: 18650
- Weight: 1.8 lbs
- Price: $169
The Milwaukee M18 5.0 Ah battery is probably the most popular battery in the entire line and certainly the go-to 2P pack. It has the highest capacity among Milwaukee’s standard technology options.
When to Use it
- Mid-size Tools
- Light to Medium+ Duty Applications
- Medium to High-volume Applications
Example Tool Pairings
- 2904 M18 Fuel Hammer Drill
- 2733 M18 Fuel 7 1/4-inch Miter Saw
- 2877 M18 Force Logic Dieless Crimper
- 2744 M18 Fuel Framing Nailer
- 2821 M18 Fuel Sawzall
This is Milwaukee’s do-anything pack. You can put it on your M18 drills and impact drivers to get better runtime, power mid-range M18 Fuel products like rotary hammers and saws, and much, much more.
This carries the same PWR2 rating as the CP2.0 battery and forms the perfect one-two punch with it. Use the CP2.0 when you want the lowest weight and most compact size, then step up to the XC5.0 when you need longer runtime. In fact, you’ll see that exact battery combination in several popular combo kits.
Milwaukee RedLithium High Output XC6.0 Battery
- Model: 48-11-1865
- Power Rating: PWR3
- Amp-hours: 6.0
- Watt hours: 108 Wh
- Lithium-ion cells: 21700
- Weight: 2.3 lbs
- Price: $199
Milwaukee’s 6.0 Ah High Output battery is the only current model left in the High Output line. It’s also the only one that carries a PWR3 power level designation. Stepping up in performance from the previous packs we discussed, it’s your gateway power source for high-performance tools.
When to Use it
- Mid-size Tools
- Medium to Heavy-duty Applications
- Medium to High-volume Applications
Example Tool Pairings
- 2883 M18 Fuel 5-inch Angle Grinder
- 3008 M18 Brushless Telescoping Pole Pruner
- 2912 M18 Fuel 1-inch SDS-Plus Rotary Hammer
- 2684 M18 Fuel Random Orbital Polisher
Even though this is a 2P pack, it’s 1/2 a pound heavier than the 5.0 Ah, so we prefer it on tools that are already beefier than your basic drills and impact drivers. It’s a solid choice for outdoor power equipment, mid-range rotary hammers, small angle grinders, polishers, and others with a medium-size power appetite.
While this is a solid battery to use if you have it, I recommend upgrading to the 6.0 Ah Forge pack when it’s time to replace it. Not only are you stepping up to PWR4, but the Forge battery is currently $50 less, making it an easy decision.
Milwaukee M18 RedLithium Forge XC6.0 Battery
- Model: 48-11-1861
- Power Level: PWR4
- Amp-hours: 6.0
- Watt hours: 108 Wh
- Lithium-ion cells: Stacked pouch-style
- Weight: 2.07 lbs
- Price: $149
The 6.0 AH Forge pack is your entry into Milwaukee’s most advanced battery technology. As such, it has advantages in performance, charging, and service life over standard, High Output, and High Demand options.
When to Use it
- Mid-size Tools
- Medium to Heavy-duty Applications
- Medium to High-volume Applications
Example Tool Pairings
The Forge 6.0 Ah pack seems destined to replace the High Output 6.0 Ah battery as the gatekeeper to Milwaukee’s advanced battery technology. It’s a solid choice for the same range of tools, but offers a performance boost, the fastest charging times, and longer service life.
We’re not seeing this battery in many kits at the moment, but it’s a real upgrade over the High Output XC6.0 when it’s time to replace those. So, grab this one to pair with outdoor power equipment like hedge trimmers and pruners that aren’t as power-hungry, as well as those mid-size concrete, automotive, and general construction tools.
Milwaukee M18 RedLithium Forge XC8.0 Battery
- Model: 48-11-1881
- Power Level: PWR4
- Amp-hours: 8.0
- Watt hours: 144 Wh
- Lithium-ion cells: Tabless cells
- Weight: 2.38 lbs
- Price: $229
The Forge XC8.0 pack has the same power rating as the Forge XC6.0 but uses a different cell technology. Whereas the 6.0 has a pouch cell design, the 8.0 features cylindrical cells with tabless connections.
When to Use it
- Mid to Large-size Tools
- Medium to Heavy-duty Applications
- Medium to High-volume Applications
Example Tool Pairings
- 2927 M18 Fuel Ringer Roll Groover
- 2827 M18 Fuel Dual Battery 20-inch Chainsaw
- 3670 M18 Fuel 6-inch Angle Grinder
The Forge 8.0 Ah battery has become the cornerstone of Milwaukee’s handheld OPE lineup. Filling the gap between the smaller size of the 6.0 Ah and the capacity of the 12.0 Ah, it’s just right for most single and dual-battery chainsaws, trimmers, blowers, and others.
While it’s capable of running larger products, such as the backpack blower or self-propelled lawn mower, those really need the higher capacity of the 12.0 Ah Forge for the best overall experience.
Of course, this is a smart choice for a number of other power tools as well. If you’re feeling short on runtime with a 6.0 Ah Forge, the 8.0 Ah offers 33% more. If you’re working with larger rotary hammers, circular saws, or Sawzalls, you can shave some weight when you’re not as concerned about conserving runtime.
Milwaukee RedLithium Forge HD12.0 Battery
- Model: 48-11-1813
- Power Level: PWR5
- Amp-hours: 12.0
- Watt hours: 216 Wh
- Lithium-ion cells: Tabless cells
- Weight: 3.3 lbs
- Price: $279
The Forge HD12.0 is the 3P version of the 8.0 Ah Forge and uses the same tabless design. In addition to its higher capacity, it’s steps up in performance as the only battery Milwaukee designates with the PWR5 label.
When to Use it
- Large-size Tools
- Heavy-duty Applications
- High-volume Applications
Example Tool Pairings
- 3009 M18 Fuel Backpack Blower
- 2869 M18 Fuel 1-inch D-Handle Impact Wrench
- 3036 M18 Fuel Snow Blower
- 2834 M18 Fuel 7 1/4-inch Circular Saw
When you need the highest power level and the greatest capacity, the Forge HD12.0 is your battery. From the 12-inch miter saw and 8 1/4-inch table saw to the backpack blower and snowblower, as well as the most power-hungry saws and rotary hammers, it powers Milwaukee’s highest-performing tools to give Pros the runtime they need.
This is the largest and heaviest battery on the M18 system, so it’s not the pack you want to use unless you really need it. Don’t be intimidated by it, though. For the tools Milwaukee kits this battery with, you can be sure they’ve considered how it affects the ergonomics and that it’s not going to work against you.
However, if you decide to run your M18 Compact Brushless Drill and Impact Driver with it, well, that’s on you.
Discontinued Milwaukee M18 Batteries
The following Milwaukee batteries may be available at selected retailers, but are considered discontinued by Milwaukee Tool. Note, these models are still subject to and eligible for the Milwaukee Tool battery warranty policy.
Milwaukee M18 RedLithium Compact Battery *DISCONTINUED*
- Model: 48-11-1815
- Amp-hours: 1.5
- Watt-hours: 27 Wh
- Lithium-ion cells: 18650
- Weight: 0.95 lb
Milwaukee’s 1.5 Ah compact battery has been around for a while and is largely set aside in favor of the 2.0 Ah pack.
If you happen to come across these 1P packs, they’re a lightweight battery that works best on light-duty tasks and with compact tools. Think screwdriving, light drilling, and punch list projects. If you’re a DIYer looking at Milwaukee as a step up, these are an excellent choice.
Milwaukee M18 RedLithium XC6.0 Battery *DISCONTINUED*
- Model: 48-11-1860
- Amp-hours: 6.0
- Watt-hours: 108 Wh
- Lithium-ion cells: 18650
- Weight: 1.6 lbs
The 2P 6.0 Ah battery struggled to gain traction across the board, primarily because of cell reliability (an issue with the cell manufacturers, not the power tool brands). Many manufacturers, including Milwaukee, stick with the 5.0 Ah pack as their go-to and the current 6.0 Ah packs use advanced battery technology.
If you still have some of these and they’re working, keep on using them until they reach the end of their service life.
Milwaukee M18 RedLithium High Output XC8.0 Battery *DISCONTINUED*
- Model: 48-11-1880
- Amp-hours: 8.0
- Watt hours: 144 Wh
- Lithium-ion cells: 21700
- Weight: 2.33 lbs
When you take the original 6.0 Ah battery and swap its cells for the higher-density 21700s, you get the Milwaukee 8.0 Ah High Output battery. When it launched, it was the most advanced 2P pack available.
With the size increase, we like this as a battery mainly for the M18 Fuel products that can step up in performance with a High Output battery.
It’s certainly capable of working in other tools—rotary hammers and miter saws are others we can recommend. It definitely throws smaller tools out of balance when you move up to this pack, though.
Milwaukee M18 High Demand 9.0 Battery *DISCONTINUED*
- Model: 48-11-1890
- Amp-hours: 9.0
- Watt hours: 162 Wh
- Lithium-ion cells: 18650
- Weight: 2.4 lbs
Milwaukee’s 9.0 Ah High Demand battery served as the foundational power source on the brand’s OPE line and a handful of other tools. It doesn’t benefit from the same power delivery and cooler runtimes as the High Output packs, so it does its best work when you need sustained power instead of quicker, more powerful bursts.
Save for the products like M18 Fuel SDS-Max that need the higher power delivery of High Output or Forge packs, this 3P pack can be a go-to battery for other rotary hammers, OPE, Hole Hawgs, 7 1/4-inch circular saws, and miter saws.
Milwaukee M18 High Output HD12.0 Battery *DISCONTINUED*
- Model: 48-11-1812
- Amp-hours: 12.0
- Watt hours: 216 Wh
- Lithium-ion cells: 21700
- Weight: 3.4 lbs
When it came to the most power and runtime available, Milwaukee’s 12.0 Ah High Output battery was the cream of the crop when it launched. It packs a massive 216 watt-hours across its 15 lithium-ion cells, giving you outstanding capacity.
For the newest, most powerful tools, it’s a solid choice that we still use. You can find it kitted with Milwaukee’s M18 Fuel chainsaw, 2732 circular saw, Super Sawzall, SDS-Max rotary hammers, table saw, and 9-inch angle grinder.
For products like lighting that you don’t need to carry constantly, this battery delivers the best runtime. It’s also a boost to tools like the Switch Tank if you don’t mind the extra battery weight.
Milwaukee M18 Battery Chargers
Milwaukee M18 & M12 Multi-Voltage Charger
- Model: 48-59-1812
- Charging amps (12/18V): 3.0 (Max DC)
- Price: $89
Milwaukee’s 48-59-1812 is their basic charger, charges both M18 and M12 batteries, and comes with many of their tools.
Milwaukee M18 & M12 Rapid Charger
- Model: 48-59-1808
- Charging amps (12V/18V): 4.5/6.0 (Max DC)
- Price: $119
The Milwaukee Rapid Charger boosts charging times significantly across the board. Expect an average of 40% faster charging compared to the standard M12 & M18 Multi-Voltage Charger.
Milwaukee M18/M12 Vehicle Charger
- Model: 48-59-1810
- Charging amps (12/18V): 2.5 (Max DC)
- Price: $149
When you need to charge batteries on the go, the Milwaukee M18/M12 Vehicle Charger is your best bet. Its 2.5 amps charge a little slower than the standard charger, but you don’t need an AC plug to run this one.
Milwaukee M18 Dual Bay Rapid Charger
- Model: 48-59-1802
- Charging amps (18V): 2.5 (Max DC)
- Price: $149
The advantage of the Milwaukee M18 Dual Bay Rapid Charger is that it charges two M18 batteries at the same time. That’s similar to running two Rapid chargers side-by-side. With this charger, you can charge two Forge HD12.0 batteries in just 130 minutes. A standard charger would take 231 minutes to do the same task.
Milwaukee M18 and M12 Gangbox 4-Port Rapid Charger
- Model: 48-59-1804
- Charging amps): 3.5
- Price: $349
The Milwaukee M18 and M12 Gangbox 4-Port Rapid Charger charges any combination of two M18 or two M12 batteries simultaneously—with a total capacity of 4 M18 and 2 M12 batteries (note that when charging an M12 battery, the adjacent M18 battery port must be empty).
The system charges with the speed of a pair of Rapid Chargers. Like the Rapid Charger, you can charge two Forge HD12.0 batteries in just 130 minutes. Compare this to the 48-59-1806 Six Pack Sequential Charger, which takes 482 minutes to charge a pair of Forge HD12.0 batteries.
Milwaukee M18 Dual Bay Simultaneous Super Charger
- Model: 48-59-1815
- Charging amps: 4.0
- Price: $249
The advantage of the Milwaukee M18 Dual Bay Simultaneous Charger is in the name. It charges two M18 batteries at the same time. It also charges much more quickly than either the standard or Rapid chargers. For example, you can charge two Forge HD12.0 batteries in just 45 minutes. A Rapid Charger would take 130 minutes to do the same task.
Milwaukee M18 PACKOUT 6-Port Daisy Chain Rapid Charger
- Model: 48-59-1817
- Charging amps: 3.5A
- Price: $369
For those wanting an on-site charging solution, the Milwaukee M18 Six Bay Daisy Chain Rapid Charger charges two batteries at the same time while it works sequentially around the six available bays (note that it charges one battery per side, so place your pack accordingly for best results).
One of the main advantages is Milwaukee Packout compatibility. On the jobsite, this lets you bring along up to six batteries while easily facilitating recharging, provided you can access a 120V outlet. Even better, you can daisy chain up to 10 of these on a single 15A circuit—perfect for creating a custom charging wall in your tool crib.
Milwaukee M18 Six Pack Sequential Charger
- Model: 48-59-1806
- Charging amps: 2.5A
- Price: $149
Milwaukee’s Six-Pack Charger can handle up to 6 batteries at once, but it’s going to charge them one at a time. It’s a great option to make sure all your batteries get charged overnight. On the job site, you don’t have to worry about remembering to switch out packs. Once one is done, it moves on to the next.
Milwaukee M18 & M12 Rapid Charge Station
- Model: 48-59-1807
- Charging amps (12/18V): 4.5/6.0 (Max DC)
- Price: $279
Milwaukee’s Rapid Charge Station takes a turn away from the Six Pack’s obsession with M18 and returns to a multi-voltage platform. It holds up to 3 M18 packs and 3 M12 packs at once. The big difference is that it can charge up to 3 batteries at once and charge them up to 40% faster. If your crew is using multiple Milwaukee cordless tools on site, this is the charger that keeps them working all day.
Discontinued Milwaukee M18 Battery Chargers
Milwaukee M18 & M12 Super Charger *DISCONTINUED
- Model: 48-59-1811
- Charging amps (12/18V): 4.5/13.5 (Max DC)
The Super Charger opened up a new level in Milwaukee’s charging lineup, giving the High Output batteries lightning-fast charge cycles. For batteries that don’t have the High-Output designation, the Super Charger reverts to Rapid Charger times.
