High Output Alternators

Why upgrade to a High Output Alternator?

The alternator can be the backbone of a charging system.  With a high output alternator, every minute that the engine is running can be utilized for maximum charging capabilities.  High Output alternators provide:


  • 2-3 times the charging current of a factory alternator
  • as much as 5 times the output of a factory alternator with a dual alternator setup
  • reduced fuel consumption due to higher efficiency charging

Our Suppliers

American Power Systems

  • highest output small case alternators
  • 28V & 56V applications
  • highest output large case with internal rectifier

Mark Grasser DC Solutions

  • lower cost 12V small case high output alternators
  • available with remote rectifier for improved heat dissipation & higher performance
  • custom pulley kits for all alternator upgrades

American Power Systems, Inc

Why Choose America Power Systems?

Compact and lightweight. APS high output alternators pack more power into a smaller, lighter case. Clients often are surprised to learn how much power we can fit into the stock alternator position. APS alternators can double or triple a vehicle’s OEM output. With a dual alternator solution, we can provide as much as five times more power.

High efficiency. Most APS alternators are rated as highly efficient, which denotes efficiency of 80 percent or greater. High efficiency units require less energy from the vehicle’s engine and therefore consume less fuel. Therefore, these units cost less to operate and contribute to less engine wear than other options.

Self-cooling. APS high output alternators self-cool with singular or dual internal fans and high-performance heat sinks, allowing the user to work these units hard without overheating or causing damage to other equipment.

Tested, proven durability. With over 2,000 vehicles currently in the field and 18,000 test miles logged at the Nevada Automotive Test Center, our high output alternators withstand the harshest environments to deliver stable, dependable power.

Check out this blog post by APS on the alternators installed on the solo ocean racing yacht Hugo Boss.  http://www.americanpowerinc.com/aps-blog/hot-yacht-aps-marine-alternators-power-stellar-performance/


Small Case HPI

Highest output alternators for the stock position


Model Voltage Rating Weight
HPI-255-EXT-14 14V 255A 17lb
HPI-360-EXT-14 14V 360A 17lb
HPI-185-EXT-28 28V 185A 17lb
HPI-160-EXT-56V 56V 160A 17lb

Large Case Alternators

APS- Large case alternators

Model Voltage Rating Weight
AP-42i-270 14V 270A 16lb
AP-42i-160 28V 160A 16lb
55i-300 28V 300A 32lb

Mark Grasser DC Power Solutions

Why Choose Mark Grasser DC Solutions?

Mark Grasser DC Solutions is a family-owned company located in Kenosha, WI, specializing in marine equipment, such as high output alternators & custom pulley kits. The business was founded by Mark Grasser who has extensive experience in engineering and design and has worked in the boating industry since 1973. MGDC Solutions provides custom solutions for many applications. 


MGDC Alternators

Mark Grasser DC Solutions Alternators

All models are available with 1″ foot mount, 2″ foot mount, 1.7″ and 3.14″ saddle mount, 4″ J180 mount, or pad mounts


Model Voltage Rating Case
12V100A 12V 100A small
12V140A 12V 140A small
12V160A w/ optional Remote Rectifier 12V 160A small
12V180A w/ Remote Rectifier 12V 180A small
12V 220A w/ Remote Rectifier 12V 220A small
12V 250A w/optional Remote Rectifier 12V 250A large J180


Remote Rectifier

MGDC marine alternators

Mark Grasser DC Solutions Remote Rectifier

More than 50% of the heat created by an alternator comes from the rectifier.  Removing the rectifier from the alternator significantly improves heat dissipation from the alternator.  This drastically improves the performance of the alternator.


Custom Serpentine Pulley Kits

MGDC marine alternators

Mark Grasser DC Solutions Custom Pulley Kits

It is highly recommended to upgrade to a serpentine pulley kit and higher pulley ratio when upgrading your alternator.  MGDC solutions provides custom pulley kit solutions for alternators in the stock position as well as secondary alternators.  He has a vast library of kits already in production, but with pictures & measurements, he can also design a kit specifically for your application.

Other things to think about…


Heat Management

The biggest challenge when upgrading to a high output alternator is managing the heat created while charging. Enough space and forced air flow in the engine room can help to keep the temperature down but in the case that it is getting dangerously hot, a properly mounted temp sensor with a smart regulator programmed to dial back appropriately are a must for safety.  Additionally, some alternators are available with the MGDC remote rectifier which physically removes the rectifier diodes from the alternator allowing better cooling within the alternator. 

Installation Can be Tricky

Each alternator & pulley kit upgrade should be viewed as a custom job.  There are minor differences between engine models by year, variations in installations, and engine compartment differences that make each upgrade a unique situation.  Even with the best measurements & fabrication, the installation will require some tweaking & testing for proper operation. Check out this customer blog with a helpful & thorough explanation of the entire upgrade and installation process.

Upgrading to a Serpentine Pulley Kit

When upgrading to a high output alternator, it is necessary to upgrade to a serpentine belt pulley kit.  A serpentine belt provides better surface contact to the pulleys which allows for better power transfer from the engine to the alternator, less vibration & a longer lasting system.  MGDC Solutions custom kits are available for many engine types & are designed to improve lower RPM charging & achieve faster charging times.


Alternator Regulators

An alternator regulator is necessary to adjust the voltage coming out of your alternator to the level that your battery bank needs. A regulator is also necessary to protect your engine and alternator by making adjustments according to environmental conditions. Choosing the best alternator regulator will ensure that you get the most out of your charge cycle. The most advanced regulators, such as the AP500, are also capable of interfacing with the engine so that the alternator is always charging at peak efficiency. Learn More.  Additionally, OPE has developed a web browser interface for the AP500 which allows users to easily access the most advanced programming & monitoring options. Check out the OPE Tether.

Ready to design or purchase your system?