Best Alternator For 6.7 Cummins: Top 6 Picks

Have you ever experienced the inconvenience of your vehicle’s battery suddenly dying while driving? In such cases, the alternator is usually the culprit – responsible for charging the car’s battery. If your battery dies, it could indicate a faulty alternator.

The 6.7 Cummins alternator poses another significant issue, it struggles to handle high-performance upgrades, such as aftermarket audio systems or off-road lighting. This leads to premature wear and tear, eventually resulting in complete failure.

To avoid these problems, investing in a high-quality alternator capable of handling your vehicle’s specific requirements and any additional electrical components you may have installed is essential.

When selecting an alternator, ensure the output amperage is sufficient to power your vehicle. Higher amperage output is preferred for vehicles with many electrical components. Choosing an alternator suitable for your vehicle’s size and weight is also crucial to ensure optimal performance and efficiency.

Quality and durability are crucial factors to consider when selecting an alternator. The alternator must withstand harsh conditions to function correctly.

Choosing the wrong alternator can make your life more difficult. If you’re seeking a 6.7 Cummins alternator replacement, you’re in luck! As someone experienced in purchasing alternators for the 6.7 Cummins engine, I’m happy to share my insights with you.

Top 6.7 Cummins Alternator Picks

Please note that Prices and Availability Are Subject To Change

Best Alternator For 6.7 Cummins

What Types of Alternators Are Available For 6.7 Cummins?

Based on applications, there are two types of alternators for your 6.7 Cummins Ram diesel engine. These are brushed and brushless alternators. Brushless alternators are better compared to brushed alternators.

Brushless Alternator Vs Brushed Alternator

Brushed Alternator

A brushed alternator uses a set of brushes to transmit electrical power from the stationary part of the alternator (stator) to the rotating part (rotor). As the rotor rotates, the brushes make contact with the slip rings, allowing electrical current to flow and generate the necessary energy. However, this contact can cause wear and tear on the brushes, requiring them to be replaced periodically.

Brushless Alternator

Brushless alternators, on the other hand, use a digital controller to regulate the electrical output. It eliminates the need for brushes, resulting in lower maintenance and a longer lifespan. Brushless alternators also tend to be more efficient and produce less electrical noise.

In general, brushless alternators are becoming more common in modern vehicles due to their increased efficiency and reliability. However, brushed alternators may still be used in some older vehicles or in applications where cost is a primary concern.

What Amp Alternator Do You Need For 6.7 Cummins?

A 6.7 Cummins engine typically requires an alternator with at least 120 amps of output. However, the specific amp rating you need will depend on your vehicle and the accessories you have installed. The more electronic accessories you use in your vehicle, you will need amperage output.

But there is a way to determine the exact amperage output needed for your vehicle. To follow this procedure, you will need a multimeter.

Connect the multimeter to the battery with the car’s engine turned off. Then turn on your electrical components one by one and measure the readings. After checking all of the components, add them up.

Your alternator amperage should be 50% more than your total amperage output. If you are considering adding more electrical components, here is a chart for which components draw how much current.

ComponentsCurrent Draw
Power windows15-20
Dash lights2-4
Air conditioning19-22
Audio amplifiers15-250+
HEI ignition10-12
Electric water pump18-25
Electric fuel pump8-10
Air suspension compressors20-50

Knowing that higher amperage output doesn’t hurt your car is important. The higher amperage your alternator provides, the better your charging system will be.

When Should You Upgrade Your 6.7 Cummins Alternator?

As a seasoned 6.7 Cummins owner, The first and most obvious sign that it’s time to upgrade your alternator is if you’re experiencing electrical issues. If you’re noticing that your lights are flickering or dimming or having trouble starting your engine, it could be a sign that your battery is not charging correctly. The underlying cause can be that the alternator is failing. 

You should also consider a 6.7 Cummins alternator upgrade if you have added additional electrical components to your truck. Electrical components like a high-performance stereo system, off-road lights, or a winch will draw more power from your electrical system. Your current alternator may not keep up with the increased demand, meaning it’s time to upgrade to a higher-output alternator.

Another thing to remember is the age of your current alternator. Alternators have a lifespan of around 100,000 miles. So, if your current alternator has passed that milestone, it’s a good idea to consider upgrading to a newer, more reliable alternator. When left unchecked, a failing alternator can cause significant damage to your engine.

Best Alternators for 6.7 Cummins Engines

From my experience, I have made a list of 6 different alternators for your 6.7 Cummins. These alternators have different features that can set your 6.7 Cummins charging system for a long time.

DB Electrical ABO0396

DB Electrical’s alternator for your 6.7 Cummins could be an ideal choice if you are looking for one that will last you a long time and does not require a high amperage output.


The DB Electrical ABO0396 is a powerful and reliable alternator that can provide up to 136 amps of power at 12 volts. It weighs 16.33 pounds and measures 10.1 x 7.4 x 7.2 inches, making it a compact and easy-to-install option for your 6.7 Ram Cummins.

The ABO0396 features a clockwise rotation and an internal fan, which helps to keep it cool during operation. It also has an SC8 pulley class and an external regulator. Additionally, it has a clock of 10 and comes with a 1-year warranty from DB Electrical.

It will surely provide you with great value for what it costs. 

Heat Resistance

The DB electrical alternator uses high-temperature epoxy and grease, which is designed to withstand extreme heat. I have used this alternator for years without having any problems. This alternator was one of my favorites as it’s fantastic for heavy-duty use.


Performance-wise, I did not even notice I had replaced my alternator. This alternator was made exactly as the 6.7 Cummins diesel engine stock alternator. That’s why it can replicate its performance precisely as it was, if not better.


This alternator from DB Electrical is made for 6.7 Cummins; you do not have to worry about installation. This alternator is designed to be a perfect fit for your 6.7 Cummins. You can integrate this into your car with no problem at all.


If you are looking for an alternator that will last you a long time and also doesn’t put stress on your pocket, this is the one for you. This alternator is one of the cheapest alternators that have a high value.

Sinister Diesel High Output Alternator SD-6.7CALT07-01-2

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The DB Electricals alternator is a budget-friendly option with low amp output. But if you need high amp output and are not reluctant to spend money, the Sinister Diesel’s alternator is for you.

The Sinister Diesel High Output Alternator is considered the best 6.7 Cummins alternator, especially for power-hungry electrical systems. A whooping 320 Amp output will surely cover all of your electrical needs. 


I am very impressed with the Sinister Diesel High Output Alternator SD-6.7CALT07-01-2. I have to say this is a masterpiece of an alternator. With a powerful 320 amp output, this alternator is designed to provide ample power to your vehicle’s electrical system. 

Its price may be a bit high, but it’s well worth the money. Also, Sinister Diesel provides a one-year warranty with the product.

High Output 

If you’re looking for a high-output alternator to take your 6.7 Cummins diesel to the next level, I highly recommend the Sinister Diesel High Output Alternator. I’ve seen first-hand the difference this 320 amp alternator can make. With its impressive power output, you can transform your diesel engine into a true powerhouse that will leave others in the dust.

High-Temperature Resistance 

I can’t stress enough how important it is to have an alternator that can handle the high amount of heat generated by a high-output engine. That’s why I always recommend the Sinister Diesel High Output Alternator to anyone looking for a reliable and durable option. 

With upgraded bearings that can withstand extreme heat, this alternator can last for a long time without any issues. I’ve personally seen this alternator in action and can attest to its quality and performance.


As a truck owner who values durability and longevity, I have to say that this alternator is truly impressive in its construction. The chassis made of cast aluminum is a major advantage as it’s lightweight and corrosion-resistant. This means that the alternator won’t add unnecessary weight to the engine and won’t rust away over time.

But what’s even more impressive is the powder-coated finish that gives the alternator an added layer of protection against wear and tear. With this finish, the alternator can handle all the tough conditions of a vehicle’s engine without breaking down or suffering any damage.


One feature of the Sinister Diesel High Output Alternator that I really appreciate is its upgraded high-output regulator. This means that the alternator has a robust system that can regulate the electricity it produces. Making sure that the battery gets the right amount of charge to keep the car running smoothly.

LActrical High Output Custom Alternator

My first recommended alternator was budget-friendly, and the second one had high power output. This alternator from LActrical has got it both; a high amp alternator at a pocket-friendly price.

Please note that Prices and Availability Are Subject To Change


I consider the LActrical to be a reliable brand, and its custom LA11239HO300A is a dependable alternator for 6.7 Dodge Cummins. Weighing 18 pounds, this alternator is designed to provide a high output of 300 amps at 14 volts.

The LActrical High Output Custom Alternator boasts an 8-groove clutch pulley for efficient operation, and an internal fan to prevent overheating. As a cherry on top, it also uses an electric regulator to maintain consistent voltage output. 

High Amp Output

Not as high as the Sinister Diesel, but this LActrical alternator also packs quite a punch.  It is designed to deliver an incredible 300Amp output with its custom-made 6-Phase Hairpin Technology. That means you can easily count on it to handle even the most demanding electrical systems. 

Plus, all that power is packed into a compact and durable package, making it an excellent choice for those who want top-notch performance without sacrificing space or durability.

Unique Design

I can vouch that the LActrical High Output Custom Alternator is one of the best-designed alternators on the market today. The “Precision Balanced Low-Mass Rotor” is a key feature that allows the alternator to operate smoothly and quietly at shaft speeds up to 20,000+ RPM. This innovative design provides reliable power to the vehicle’s electrical system without any hiccups or interruptions.

What’s more, the low-mass rotor also helps to reduce the load on the engine, making it operate more efficiently. This is a huge advantage for anyone who wants to improve their vehicle’s fuel efficiency and save money on gas. 

And thanks to the precision balancing of the rotor, the alternator operates without any vibrations, which can harm other vehicle components. 

Quality Material

LActrical always prioritizes quality, so their alternators are made from premium state-of-the-art materials. Made to endure the harshest of conditions, and qualified to tackle higher RPMs.  

If you want the same features with a lower amperage output, you can opt for the LActrical Alternator For Dodge Ram 2500 3500 Pickup Truck Cummins... * (#ad)

Gladiator New Alternator 4022170C91 

Now, all my previous suggestions had one distinctive feature. But the Galdiator’s new alternator is a bit unique. From a decent amperage to a sturdy construction, the Gladiator’s 200 amp alternator has it all.


The Gladiator New Alternator 4022170C91 is a solid and reliable option, in my opinion. This alternator is engineered to maintain a consistent 200-amp output at a voltage of 12 volts. Its compact design resulted in a dimension of 9.5 by 8.5 by 5.8 inches, with a weight of 19 pounds.

The alternator also includes a one-year warranty, which offers reassurance and guarantees coverage in case of any possible faults or problems.


The Gladiator New 12 Volt 200 Amp Alternator is designed to withstand even the harshest conditions with its rugged construction. Its heavy-duty housing shields the internal components, ensuring dependable performance for an extended period. Whether you’re navigating off-road terrains or enduring extreme weather conditions, this alternator tough enough to last through them all.


For those who are not used to replacing alternators, installing the Gladiator New 12 Volt 200 Amp is a breeze. It’s designed to directly replace your stock alternator, so there’s no need for complicated modifications or adjustments. 

Plus, with its compact size and lightweight construction, this alternator won’t add unnecessary bulk or weight to your vehicle.

Everything in One

The Gladiator New alternator is the “Jack of all trades”. It is low on price, is strong enough to last through harsh weather, has a compact design, and has a decent amp output. It’s a trendy choice among top mechanics and experts. Also, it’s designed to meet the performance standard of your stock alternator.

The Gladiator 4022170C91 is a significant case alternator, ideal for your 6.7 Cummins. However, if you want a small case alternator, you can choose the New 200 Amp Alternator with Plug for Freightliner with Caterpillar,... * (#ad). This alternator is slightly smaller (‎9 x 9 x 6.5 inches) and slightly lighter (18 pounds). Other than this, these two alternators have the same materials and features.

Factors to Consider When Selecting an Alternator For 6.7 Cummins Engine

When buying an alternator for your 6.7 Cummins engine, there are several factors to ensure you get the best value for your money. Here are some of the critical things to remember:


One of the most important factors to consider is the size of the alternator. A larger alternator will typically have a higher output capacity and be more durable, but it may also be heavier and more challenging to install. Consider your specific needs and the space available in your engine compartment to determine the right size.

So, does it matter what size alternator I need?

Yes, it does. You want to ensure that the alternator you choose can handle the power requirements of your vehicle. If the alternator is too small, it may not be able to keep up with the demands of your electrical system, which could lead to issues with your battery or other components.

There are two types of alternators based on size: small and large. For your 6.7 Cummins diesel, large case alternators are ideal. For reference, a large case alternator has a 4 inches gap between the two mounts. And a small case has approximately 3.25 inches.

Maximum Output Capacity

The maximum output capacity of the alternator is another important consideration. This will determine how much power the alternator can generate and how well it can keep up with the demands of your electrical system. Look for an alternator with a high output capacity to ensure your vehicle has the power to operate efficiently.


Apart from the power output, the efficiency of the alternator is also measured in different types of losses, like mechanical loss and copper loss. These losses can prevent the alternator from reaching its full potential.

Although inevitable, these losses can be kept to a bare minimum by using high-quality materials and engineering. So, when purchasing a high-output alternator, always go with the most reliable brand and not be intimidated by prices.   

Lifespan and Durability

An alternator for your 6.7 Cummins should last you for at least 300,000 miles. But this depends on how well you have been taking care of your electrical system. 

However, if you are getting a low-quality alternator, you are just setting your truck to fail. To choose a quality alternator, here are some things to look for:

  • Look for alternators that use high-quality materials, such as copper or aluminum for the windings and steel or aluminum for the housing.
  • Look for alternators that have design features that promote durability and reliability. This can include features such as internal cooling fans, heavy-duty bearings, and high-strength drive pulleys.
  • Look for alternators that meet or exceed OEM standards.

Alternator Pulley Ratio

The pulley ratio of your alternator will determine how much power it generates at different engine speeds. The pulley ratio is determined by the ratio of the crankshaft pulley diameter and the alternator pulley diameter. So, for example, if your crankshaft pulley diameter is 6 inches and the alternator pulley diameter is 3 inches, then you have a pulley ratio of 2:1.

Now, the pulley ratio decides how fast your alternator will spin, and you should consider this based on your engine use. Here is a table explaining which ratio is suitable for you-

UsagePulley Ratio
Street use3:1
Drag racing1.75:1
Circle racing1:1

Also, you can calculate the alternator RPM from the pulley ratio. An alternator RPM should never exceed over 18000.

The formula for calculating alternator RPM is RPM = Pulley Ratio x Highest Engine RPM 

Power Requirements

If you did not already know, the alternator voltage and the battery voltage should match. For example, if your truck uses a 12v battery, you also must get a 12v alternator. Running a 14v (or more) voltage alternator with a 12v battery will simply damage the battery. That’s because the alternator will overcharge it.

On the contrary, running a 12v alternator with a 14v battery will leave the battery undercharged, which will kill the battery over time. 

Heat Resistance

Alternators are primarily affected by heat due to the fact that heat increases electrical resistance, which means parts and devices have to work harder in order to produce the same amount of power. Additionally, excess heat puts strain on electrical components, mechanical parts, and lubricants.

An alternator produces a lot of heat, especially when fully loaded. As an alternator warms up, it typically loses 10 percent of its efficiency. Not to mention it absorbs heat from the engine as well. Over time, this strain can reduce the life of belts or bearings.

That’s why choosing an alternator with heat-resistant properties is a must unless you want to keep replacing yours once yearly. So, before purchasing an alternator, check to ensure the alternator uses these components-

  • Copper and aluminum windings
  • Epoxy resin
  • Bearings made of temperature-resistant materials (ceramic bearings)
  • Heat-resistant coating or paint
  • Wires designed for high-temperature use

Mount Type

One of the things that is easy to overlook is the mount type. Your 6.7 Dodge Ram Cummins usually have a pad mount or a J180 mount. So, choose your alternator based on the mount on your engine.

So, with this, I conclude my list of best alternators for 6.7 Cummins. Let me know what you’d pick for your 6.7 Cummins Dodge diesel engine. Also, let me know what you think about my list. 


In conclusion, choosing the best alternator for your 6.7 Cummins engine can greatly enhance the performance and reliability of your vehicle’s electrical system. With so many great options available on the market, it’s important to weigh your specific needs and budget when making a decision. Whether you prioritize efficiency, durability, or affordability, there’s a top-quality alternator out there to suit your unique requirements. By selecting one of our top 6 picks, you can feel confident that you’re investing in a reliable and high-performance alternator that will keep your 6.7 Cummins running smoothly for years to come.


How many amps should an alternator have for a Cummins engine?

The amount of amps an alternator should have for a Cummins engine depends on the type and size of the engine, as well as any added electrical accessories. Generally speaking, a 6.7 Cummins engine requires an alternator with at least 180 amps of output capacity. For an optimal charging system, it is recommended to use an alternator with 200-220 amps for this engine.

Last Updated on April 23, 2024 by Rifen

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