If you’re looking to upgrade your Shovelhead’s charging system, choosing the best alternator upgrade kit is essential for reliable power and performance. The Heavy Duty Alternator Kit for Harley S&S, Ultima, TP Engineering 70-99 32 AMP stands out as the best overall for its durability and compatibility. The Painless 30700 Ultra High Amp Alternator Kit is a top choice for those seeking maximum output, while the Heavy Duty 32 Amp Alternator Charging System with HD One-Piece Rotor offers a solid balance of power and simplicity. These options highlight the key tradeoffs in this category—higher output often means increased complexity and cost. Keep reading for a detailed breakdown to find the best fit for your bike and riding style.
Key Takeaways
- The highest amperage kits deliver more power but may require more complex wiring and higher costs.
- Compatibility with different Shovelhead models varies, so checking fitment is critical before purchasing.
- Premium options tend to offer better build quality and longevity, but at a higher price point.
- Ease of installation varies; some kits include detailed instructions, making them more beginner-friendly.
- Balancing budget and performance is key—sometimes a mid-range kit offers the best value without sacrificing reliability.
| Heavy Duty Alternator Kit for Harley S&S, Ultima, TP Engineering 70-99 32 AMP |  | Best Overall for Classic Harley Big Twins | Compatibility: Harley Big Twin 1970-1999, S&S, Ultima, TP engines | Amperage: 32 AMP | Kit Includes: Chrome regulator, heavy-duty stator rotor, high-quality stator | VIEW LATEST PRICE | See Our Full Breakdown |
| Painless 30700 Ultra High Amp Alternator Kit |  | Best Value for High-Current Automotive Applications | Manufacturer: Painless Performance Products | Item Weight: 1.55 pounds | Dimensions: 12.5 x 7.5 x 2 inches | VIEW LATEST PRICE | See Our Full Breakdown |
| Painless Performance 30700 Ultra High Amp Alternator Kit (Up to 190 Amps) |  | Best for Demanding Electrical Needs and Custom Vehicles | Voltage: 12 Volts | Maximum Output: 190 Amps | Material: Aluminum, Copper, Steel | VIEW LATEST PRICE | See Our Full Breakdown |
| Heavy Duty 32 Amp Alternator Charging System with HD One-Piece Rotor for Harley Shovelhead & EVO Big Twin |  | Best for Classic Harley Shovelhead & EVO Big Twins | Compatibility: 1970-1984 Shovelhead, 1984-1999 EVO Big Twin | Ampere: 32 Amp | Rotor: One-piece, 12 magnet high-performance | VIEW LATEST PRICE | See Our Full Breakdown |
| Painless Performance Ford 3G Alternator Upgrade Kit |  | Best Universal Fit for Ford Enthusiasts | Fit Type: Universal | Part Number: 30831 | Weight: 1.5 pounds | VIEW LATEST PRICE | See Our Full Breakdown |
| Holdwell Black 17 Amp 12 Volt Alternator Generator Conversion Kit 32-0371 for Harley-Davidson |  | Best for Classic Harley Upgrades | Part Number: 32-0371 | Voltage: 12 Volt | Amperage: 17 Amp | VIEW LATEST PRICE | See Our Full Breakdown |
| 32 Amp Alternator Charging System for 1970-1984 Shovelhead & 1984-1999 EVO Big Twin Models |  | Best for Vintage Big Twins Needing More Power | Amperage: 32 Amp | Compatibility: 1970-1984 Shovelhead, 1984-1999 EVO Big Twin | Rotor Magnets: 12 short magnets | VIEW LATEST PRICE | See Our Full Breakdown |
More Details on Our Top Picks
Heavy Duty Alternator Kit for Harley S&S, Ultima, TP Engineering 70-99 32 AMP
This kit stands out for its robust construction tailored specifically for Harley Big Twins from 1970 to 1999, including S&S, Ultima, and TP engines. Compared with the Heavy Duty 32 Amp Alternator Charging System, it offers a more comprehensive upgrade with reinforced components and enclosed magnets, translating into better durability and performance for vintage models. However, it’s primarily suited to older Harley bikes, so newer models or those with EFI systems may find incompatible. Its heavy-duty stator and reinforced rotor deliver reliable power, making it ideal for riders seeking a long-lasting upgrade on classic bikes.
Pros:- Durable heavy-duty construction tailored for vintage Harley models
- Includes all essential components for a complete upgrade
- Reinforced rotor and enclosed magnets enhance longevity
- Compatible with a broad range of 1970-1999 Harley Big Twins
Cons:- Limited to older Harley models; incompatible with newer EFI bikes
- Installation requires some technical skill
Best for: Owners of Harley Big Twins from 1970-1999 looking to boost durability and reliability in their charging systems.
Not ideal for: Owners of newer Harley models or bikes with EFI, as this kit isn’t designed for modern electronic systems.
- Compatibility:Harley Big Twin 1970-1999, S&S, Ultima, TP engines
- Amperage:32 AMP
- Kit Includes:Chrome regulator, heavy-duty stator rotor, high-quality stator
- Features:Upgraded stator, reinforced spline area, enclosed magnets
- Installation:Requires technical knowledge
- Material:Chrome, heavy-duty components
Bottom line: This kit is the best choice for riders upgrading vintage Harley Big Twins seeking durability and a straightforward install.
Painless 30700 Ultra High Amp Alternator Kit
Designed for high-amp needs, the Painless 30700 kit provides a reliable wiring harness, fuse, and terminals capable of supporting demanding electrical loads. Compared with the Painless Performance 30700 (up to 190 amps) version, it offers a simplified package suitable for standard high-performance applications, but lacks the detailed wiring instructions of the higher-capacity model. It’s an excellent choice for those upgrading to a high-output alternator while maintaining straightforward compatibility, especially when paired with other reliable components. However, limited info on vehicle compatibility makes it less ideal for those outside typical automotive setups.
Pros:- High-quality wiring harness suited for high-amp systems
- Includes fuse and terminals for easy setup
- Reliable construction from a reputable brand
- Good value for supporting high electrical loads
Cons:- Limited compatibility details with specific vehicle models
- No detailed installation instructions included
Best for: Car enthusiasts upgrading high-current electrical systems with a focus on reliable wiring and affordability.
Not ideal for: Users needing detailed installation guidance or working on specialized or non-standard vehicles.
- Manufacturer:Painless Performance Products
- Item Weight:1.55 pounds
- Dimensions:12.5 x 7.5 x 2 inches
- Includes:Wire harness, fuse, terminals
- Compatibility:Automotive high-amp systems
- Material:Durable wiring
Bottom line: This kit is ideal for budget-conscious users upgrading high-amp automotive electrical systems requiring dependable wiring support.
Painless Performance 30700 Ultra High Amp Alternator Kit (Up to 190 Amps)
This version of the Painless 30700 delivers up to 190 amps, making it a robust upgrade for high-demand applications such as off-road lights, audio systems, or electric fans. Compared with the basic 30700 kit, it offers significantly higher output, suitable for vehicles with extensive electrical accessories. The included wiring and fuse ensure a safe, professional installation, though it demands solid wiring skills and precise setup. It’s overkill for standard vehicles but essential for builders with serious power requirements, especially when reliability is non-negotiable.
Pros:- Supports up to 190 amps, ideal for high-demand systems
- Includes comprehensive wiring and installation instructions
- Reliable and safe for demanding environments
- Suitable for off-road and custom builds
Cons:- Requires advanced wiring knowledge for proper installation
- Potentially excessive for normal vehicle needs
Best for: Off-road vehicle owners or custom builders needing maximum electrical capacity with professional-grade components.
Not ideal for: Casual drivers or those with standard electrical loads, as this setup may be more complex than necessary.
- Voltage:12 Volts
- Maximum Output:190 Amps
- Material:Aluminum, Copper, Steel
- Dimensions:12.5 x 7.5 x 2 inches
- Installation:Requires proper wiring knowledge
- Use Case:High-demand electrical systems
Bottom line: This high-output kit fits builders requiring maximum electrical capacity and professional-grade components for demanding applications.
Heavy Duty 32 Amp Alternator Charging System with HD One-Piece Rotor for Harley Shovelhead & EVO Big Twin
This upgrade offers a significant increase in charging capacity for Harley Shovelheads and EVO Big Twins from 1970-1984, providing a one-piece rotor with 12 magnets for enhanced performance. Compared with the Heavy Duty Alternator Kit for Harley 70-99, it is more specifically tailored for earlier models, emphasizing durability and ease of installation. Its chrome regulator adds aesthetic appeal, but it’s limited to vintage Harley setups without EFI. The high-quality rotor improves reliability, making it a smart choice for riders restoring or upgrading their vintage Harley engines.
Pros:- Increases charging capacity to 32 amps for vintage Harleys
- High-performance one-piece rotor with 12 magnets
- Chrome regulator adds style and corrosion resistance
- Designed for easy upgrade or custom build
Cons:- Limited to 1970-1984 Shovelhead and EVO Big Twins
- Installation may require some technical skills
Best for: Harley enthusiasts restoring or upgrading 1970-1984 Shovelhead and EVO Big Twin models needing increased reliability.
Not ideal for: Owners of newer Harley models with EFI or Twin Cam setups, as this kit isn’t compatible with modern systems.
- Compatibility:1970-1984 Shovelhead, 1984-1999 EVO Big Twin
- Ampere:32 Amp
- Rotor:One-piece, 12 magnet high-performance
- Regulator/Rectifier:Chrome plated
- Material:Chrome
- Features:Enhanced performance, durable construction
Bottom line: This kit is the best fit for owners of vintage Harley Shovelheads and EVOs seeking a reliable and stylish upgrade.
Painless Performance Ford 3G Alternator Upgrade Kit
This kit offers a straightforward upgrade path for Ford vehicles using the 3G alternator, providing a universal fit and all necessary components. Compared with specialized Harley or vintage Harley kits, it’s more versatile across different Ford models, but it lacks specific customization features for motorcycle applications. Its simplicity and inclusion of all parts make it appealing for DIYers, though limited instructions could pose a challenge for less experienced users. It’s a practical, no-frills solution for those needing a reliable upgrade on Ford vehicles.
Pros:- Universal fit across various Ford models
- Includes all necessary components for installation
- Simple, straightforward upgrade process
- Reliable and compatible with existing systems
Cons:- Limited detailed instructions for complex setups
- Compatibility may vary with specific vehicle configurations
Best for: Ford vehicle owners seeking an easy, universal upgrade for their 3G alternators without complex customization.
Not ideal for: Motorcycle or vintage Harley owners, as this kit isn’t tailored for bike-specific systems or vintage setups.
- Fit Type:Universal
- Part Number:30831
- Weight:1.5 pounds
- Dimensions:29.21 L x 5.334 H x 18.034 W centimeters
- Includes:Components for installation
- Application:Ford 3G alternator systems
Bottom line: This upgrade kit suits Ford owners looking for a reliable, easy-to-install solution for the 3G alternator upgrade.
Holdwell Black 17 Amp 12 Volt Alternator Generator Conversion Kit 32-0371 for Harley-Davidson
This kit stands out for offering a straightforward way to upgrade a wide range of Harley-Davidson models from 1936 to 1983, making it ideal for those restoring or maintaining vintage bikes. Compared with the 32 Amp Alternator Charging System, it provides a more modest 17 Amp output, which suits riders who prioritize reliability over high charging capacity. The inclusion of both alternator and regulator simplifies installation, but the need to drill bolt holes on some models adds a layer of complexity. Its compatibility with many early Harley models makes it a versatile choice, though it’s not suitable for newer bikes or those with mini batteries. The remote regulator mounting might be less convenient for some, and the limited 90-day warranty is shorter than premium options.
Pros:- Compatible with a broad range of vintage Harley models from 1936 to 1983
- Includes both alternator and regulator for a complete upgrade
- Easy to upgrade from original generator system
Cons:- Requires drilling of bolt holes on some models, which can complicate installation
- Regulator must be mounted remotely, adding clutter and complexity
- Limited to 17 Amp output, which may be insufficient for high-demand electrical setups
Best for: Owners of Harley models from 1936-1983 seeking a reliable, straightforward 12-volt upgrade.
Not ideal for: Riders with newer Harley models or those needing higher amperage capacity for accessories or lighting.
- Part Number:32-0371
- Voltage:12 Volt
- Amperage:17 Amp
- Compatibility:Harley-Davidson G 1936-1973, XL 1958-1982, FL 1941-1969, W 1936-1952
- Includes:Alternator, Regulator
- Warranty:90 days
Bottom line: This kit is best suited for vintage Harley owners wanting a simple, dependable 12-volt upgrade without high power demands.
32 Amp Alternator Charging System for 1970-1984 Shovelhead & 1984-1999 EVO Big Twin Models
This upgrade kit excels at boosting reliability and electrical capacity for vintage Harley Big Twins, especially compared to original setups that often struggle with modern electrical loads. With a 32 Amp output, it provides nearly double the power of the Holdwell kit, making it suitable for riders with additional accessories or upgraded lighting. Its chrome-plated components add a touch of style to the engine bay, while the fully encased magnet rotor enhances durability. However, it’s not compatible with Twin Cam or EFI models, limiting its versatility for riders with newer bikes. The kit is specifically designed for models from 1970-1984 Shovelhead and 1984-1999 EVO Big Twins, which could be a drawback for those with different engines. Compared to smaller capacity kits, this one offers a significant power boost, but at the cost of slightly increased complexity in installation.
Pros:- Doubles the electrical capacity compared to OEM systems
- Includes high-performance rotor and chrome regulator/rectifier for durability and style
- Easy to upgrade for vintage Harley-Davidson Big Twins
Cons:- Not compatible with Twin Cam or EFI models, limiting versatility
- Designed specifically for certain models, so not suitable for broader Harley range
- Installation may be slightly more involved due to larger components
Best for: Owners of vintage Harley Big Twins from 1970 to 1999 who need a reliable, higher-capacity charging system.
Not ideal for: Riders with Twin Cam, EFI, or newer Harley models, as this kit is incompatible with those systems.
- Amperage:32 Amp
- Compatibility:1970-1984 Shovelhead, 1984-1999 EVO Big Twin
- Rotor Magnets:12 short magnets
- Includes:Stator, Rotor, Regulator/Rectifier
- Material:Chrome plated
- Voltage:12 Volt
Bottom line: This kit makes the most sense for vintage Harley Big Twin owners seeking a straightforward, high-capacity upgrade for improved electrical reliability.
How We Picked
These products were evaluated based on their compatibility with Shovelhead models, power output, build quality, ease of installation, and overall value. Priority was given to kits that combine durability with straightforward wiring, ensuring both performance and user-friendliness. The ranking reflects a balance between higher amperage options and those that offer reliable longevity without excessive complexity or cost. We also considered customer reviews and industry reputation to ensure each kit performs well in real-world conditions.Factors to Consider When Choosing Best Alternator Upgrade Kit For Shovelhead
Choosing the right alternator upgrade kit for your Shovelhead involves several important considerations. Beyond just amperage, factors like compatibility, ease of installation, and build quality influence how well a kit will serve your needs over time. Understanding these elements can help you avoid common pitfalls like mismatched parts or overly complex wiring that leads to frustration. The right upgrade enhances your bike’s electrical system, ensuring reliable lighting, charging, and overall performance—especially on longer rides or in demanding conditions.Compatibility and Fitment
Ensuring the kit fits your specific Shovelhead model is crucial. Many kits specify years or engine types they support, so verify these details before purchasing. A mismatch can lead to installation issues or electrical incompatibilities that compromise performance. Some kits are designed for broad compatibility, while others are more targeted, so understanding your bike’s exact configuration will save time and money.
Amperage Output and Power Needs
The main reason for upgrading is usually to support additional electrical accessories or improve charging reliability. Kits range from modest 17-32 amps to high-output models exceeding 190 amps. Consider your typical electrical load and future needs—over-specifying can add unnecessary cost and complexity, while underestimating might leave you with insufficient power. Balance your current requirements with potential upgrades down the line.
Ease of Installation
Some kits come with comprehensive instructions and plug-and-play wiring, making installation straightforward even for less experienced users. Others may require custom wiring or modifications, which can extend installation time and increase difficulty. Reading reviews about installation experiences can help you choose a kit that matches your skill level and tools available.
Build Quality and Durability
High-quality components, such as sealed bearings and corrosion-resistant materials, ensure your upgrade lasts through many rides. Cheaper kits might save money upfront but could suffer from premature wear or failure. Investing in a well-made kit reduces the risk of electrical issues and saves money long-term.
Cost and Overall Value
While high-end kits often deliver superior performance and longevity, they come at a premium price. Conversely, budget options may meet basic needs but could require replacement sooner. Consider your riding style, budget, and performance expectations to find a kit that offers the best value without sacrificing essential quality.
Frequently Asked Questions
Will upgrading my alternator improve my bike’s electrical system?
Yes, upgrading to a higher-amp alternator can significantly enhance your bike’s electrical capacity. This allows for more accessories, brighter lighting, and more reliable charging, especially on long rides or when running multiple electrical devices. However, ensure the rest of your electrical system can handle the increased power to prevent potential issues.
Is it difficult to install an alternator upgrade kit myself?
Installation difficulty varies depending on the kit and your mechanical experience. Many kits are designed for straightforward installation with detailed instructions, making them suitable for DIY enthusiasts. More complex kits might require additional wiring or modifications, so assessing your skill level and available tools is important before proceeding.
Do I need to upgrade my entire charging system or just the alternator?
In most cases, upgrading the alternator alone provides a significant boost, but for optimal performance, you may also need to upgrade the voltage regulator or wiring to accommodate higher output. Compatibility between components is vital to prevent electrical issues—consult your bike’s specifications or a professional if unsure.
What amperage should I look for in an upgrade kit?
The ideal amperage depends on your electrical load. Standard Shovelheads typically need around 20-30 amps, but if you use many accessories or plan to upgrade lighting, a kit offering 50 amps or more might be beneficial. Balance your current needs with future plans, avoiding overkill that could increase costs unnecessarily.
Are high-amp alternator kits more prone to failure?
Higher-output alternators can generate more heat and require more robust components, which could impact longevity if not well-made. Choosing a reputable brand with quality materials reduces this risk. Proper installation and maintenance are also key to ensuring durability, regardless of the amperage rating.
Conclusion
For riders seeking a reliable, all-around upgrade, the Heavy Duty Alternator Kit for Harley S&S, Ultima, TP Engineering 70-99 32 AMP offers excellent durability and compatibility at a reasonable price, making it the best overall choice. Those needing maximum power for accessories or custom setups will find the Painless 30700 Ultra High Amp Alternator Kit ideal, despite its complexity and cost. Beginners or casual riders should consider kits with simpler wiring and clear instructions, like the Heavy Duty 32 Amp Alternator Charging System. Budget-conscious enthusiasts can opt for the Holdwell Black 17 Amp kit, which provides decent performance without breaking the bank. Ultimately, your choice hinges on your specific electrical needs, riding style, and comfort with installation complexity.
