If you’re looking to upgrade the stock alternator in your vehicle to power more electronics and accessories, JS Alternators and Mechman are two popular high output alternator brands to consider.
But which one is better for your needs? This comprehensive guide examines the key differences between JS Alternators and Mechman alternators.
Brief Comparison Table
| Feature | JS Alternators | Mechman Alternators |
| Max Amp Output | 400 Amps | 620 Amps |
| Price (300 Amps) | $349 | $450 |
| Warranty Length | 1 year (extendable) | 1 year (extendable to 3 years) |
| Quality | Very Good | Excellent |
| Applications | Mainstream domestic vehicles | 600+ vehicle applications including diesel & marine |
| Country of Origin | USA | USA |
Overview Of JS Alternators
Founded in 1996, JS Alternators is a U.S.-based company focusing exclusively on manufacturing high-performance alternators. Their alternators deliver 25% to 40% more charging power than stock alternators.
Some key things to know about JS Alternators:
- Available for most vehicle makes and models
- Offered in various amperage configurations from 200 amps to 400 amps
- Features unique regulator and stator upgrades for improved performance
- Manufactured in the U.S. with high quality components
- Comes with a 1-year unlimited mileage warranty
Overview Of Mechman Alternators
Around since 1999, Mechman is one of the original players in high output alternators. They’re known for making alternators that offer up to 50% more electrical power than stock units.
Here are some notable Mechman alternator features:
- Hundreds of direct-fit applications for popular vehicles
- Numerous winding configurations from 270 amps up to 620 amps
- Uses upgraded DEKA batteries and Balmar regulators
- Assembled in the U.S. using global sourced components
- Comes standard with a 1-year or optional 3-year warranty
Key Difference – Maximum Potential Output
One of the biggest deciding factors between these two brands comes down to peak amperage rating.
Mechman alternators can produce up to 620 amps of output. This makes them capable of running more high-powered electronics without losing voltage at idle. Mechman uses custom windings and advanced regulators to achieve these ultra-high outputs.
In comparison, the highest amp alternator JS Alternators offers is 400 amps. While their 400 amp model is powerful, it doesn’t match the max performance of Mechman’s line-topping 620 amp alternator.
So if you need an alternator exceeding 400 amps, Mechman is the only choice. But JS Alternators still offers decent amp outputs at a more affordable price point.
Construction Quality
Both Mechman and JS Alternators build their high output alternators using high grade components to optimize durability and longevity.
JS Alternators uses 100% new components, including upgraded copper wound stators and thick dual ball bearing rotors. Their strict quality control allows each unit to handle high temperatures and RPMs without issue.
Mechman also features copper windings, robust rotors, as well as aircraft-grade aluminum housings to resist corrosion. During construction, their alternators undergo rigorous testing to verify performance.
So in terms of construction quality, both brands are fairly even and a clear cut above factory alternators. Just note – Mechman does offer more customization like chrome plating and anodized coloring options.
Pricing Differences
Due to the higher max amperages and degree of customization, Mechman alternators typically cost $100 to $250 more than comparable JS Alternator models.
For example, a 300 amp Mechman alternator sells for around $450 USD. A 280 amp JS Alternator goes for approximately $349 USD.
Labor costs for installation are similar between both brands as they use mostly factory mounting points. Just check wiring requirements carefully, as the alternator outputs affect gauge needs.
If squeezed for budget, JS Alternators still impress. But expect to pay more for the peak performance that Mechman achieves.
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Vehicle Application Support
JS Alternators and Mechman produce direct fit alternators for a wide range of popular vehicle makes and models:
Supported By Both Brands:
- Ford F-150, F-250, F-350
- Chevy Silverado, GMC Sierra
- Dodge Ram
- Jeep Wrangler, Cherokee
Extra Mechman Applications:
- Toyota Tacoma, Tundra
- Nissan Titan
- Diesel trucks
- Marine engines
Mechman supports over 600 applications spanning diesel trucks, marine vessels, exotic cars, and more. JS Alternators has a narrower catalog focused on mainstream cars and trucks.
Included Warranties
The alternator warranty is an important consideration before purchasing, as it protects against early failures.
JS Alternators come standard with a 1-year unlimited mileage warranty. Additional 2 year and 4 year warranties can be added for a small fee at time of purchase.
Comparatively, Mechman alternators include a 1-year unlimited mileage warranty out of the box, with the option to pay extra for a 3-year unlimited mileage extended warranty.
So base JS Alternator warranties match Mechman’s standard 1-year warranty. But only Mechman gives the option to extend coverage to 3 years for added peace of mind.
Also watch the video about Mechman Alternators!
Ease Of Installation
Due to the direct factory fitment, both Mechman and JS Alternators can be installed easily without modifications by experienced installers. The main steps involve:
- Disconnect negative battery terminal
- Remove belts/mounting bolts to remove old alternator
- Install new alternator using existing brackets/bolts
- Connect wiring harnesses as per diagram
- Re-install belts and recheck alignments
- Reconnect battery and test operation
No specialty tools are required. Just expect slightly more time if needing to upgrade alternator charging wires. If DIYing, a background in electrical work is highly recommended.
Customer Reviews
Happy customers praise both brands for delivering noticeable improvements in charging capacity compared to old units.
- JS Alternators earn consistent 4+ star ratings, with users commenting on their powerful performance and quality construction.
- Mechman alternators also rate highly, with fans calling them a “night and day difference” that’s “worth every penny.” Complaints about Mechman’s customer service are rare.
Negative reviews for both mostly cite premature failures likely caused by botched installations. As long as your alternator is sized appropriately and wired correctly, it should perform reliably for years.
FAQs
Yes, JS Alternators is considered one of the leading high output alternator brands. They offer well-built alternators with excellent durability and charging capacity.
JS Alternators are designed and manufactured in the USA, with headquarters located in Nebraska.
Most Mechman alternators can handle at least 8,000 RPM continuously. Some models are rated for 10,000+ RPM. Always verify your max RPM based on chosen winding configuration.
No. But the alternator output must be properly matched to the vehicle’s electrical system. Exceeding fuse/wire ratings risks fire hazards. Upsizing wires is often required to support added loads.
Yes. Alternators output more current at higher engine RPMs. Idle speeds only generate about 25-40% of total amp capacity. Faster spinning makes them charge batteries faster.
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Conclusion
For those seeking maximum amperage outputs exceeding 400 amps, Mechman is the top choice. Their 620 amp models truly push the limits of alternator performance. But you’ll pay over $100+ more than comparable JS Alternators models.
JS Alternators deliver slightly lower peak performance up to 400 amps. However, their 100% new construction still provides noticeable charging improvements over stock units at more wallet-friendly pricing.
Overall, Mechman leads in peak power and application variety. Yet JS Alternators shouldn’t be underestimated either – their robust 400 amp alternators suit most upgrade needs at greater value. Just size your prospective unit based on your vehicle’s demands.