2013-2015 BMW X1 L6 3.0L High Output Alternator
Many in-stock orders ship within 1-2 business days, but timing varies by item. Custom, built-to-order, oversized, special-order and supplier-direct products may need extra processing time. Free shipping applies to qualifying orders over $99 in the contiguous US. Approved returns may be subject to a restocking fee.
Most products are covered by the manufacturer's warranty against defects. Damage from over-powering or improper installation isn't covered — we'll help coordinate any valid claim.
Tell us your vehicle, subwoofers and electrical setup and our team will help you match the right gear. Reach out before you buy.
Installation Instructions
Important: A Big 3 wiring upgrade is required for all high output alternators — factory wiring isn't rated for 250A+ output.
Before you start: Batteries fully charged, vehicle off and engine cool. Wear eye protection and remove loose jewelry.
Remove the old unit: Disconnect the negative battery cable, then the alternator wiring. Note the belt routing, remove the belt, then remove the bracket bolts and the factory alternator.
Install the new alternator: Mount it (factory bolts usually work) — hand-thread first, then torque to spec. Fit a serpentine belt about 0.5–1" shorter unless otherwise specified and confirm it's aligned in all pulley grooves.
Grounding: Clean all contact surfaces to bare metal and apply a corrosion inhibitor. On uni-body vehicles, ground to the thickest sub-frame metal and add ground cables if charging voltage is low. Keep wiring at least 12" from heat sources.
Regulator / plug: Factory plug — snap the harness into the regulator. Pigtail (single-wire) — excite wire (L) to a 7–15V ignition source, sense wire (S) to the alternator positive. Self-exciting (one-wire) — no plug; connect only B+ and ground (a battery light may appear). A dash volt gauge is recommended.
Finish: Complete the Big 3 upgrade, reconnect the negative terminal, start the vehicle, and confirm 13.5–14.8V at the battery.
Big 3 Wiring Installation
The Big 3 upgrade replaces the three main cables with 1/0 100% OFC (oxygen-free copper) wire: (1) alternator positive → battery positive, (2) engine/alternator ground → chassis, and (3) battery negative → chassis. Required for all high output alternators.
Before you start: Charge the batteries, vehicle off and cool, eye protection on. Disconnect the negative battery cable first.
Install: Run the upgraded positive cable from the alternator positive to the battery positive. Add an upgraded ground from the engine/alternator bracket to the frame, and another from the battery negative to the frame. Clean every contact point to bare metal and apply a corrosion inhibitor. Crimp and heat-shrink the lugs, then torque firmly.
Finish: Reconnect the negative terminal last. Two kit types are offered — Universal (most common) and Polaris Slingshot (longer positive cable for trunk-mounted batteries). Check the measurements for your vehicle before buying.
Fitment:
This is a direct fit high-output alternator aftermarket replacement for 2013-2015 BMW X1 3.0L 250-320-370-400 amp High Output Alternator. Being a direct fit, aftermarket alternator replacement fits directly into your stock alternator location.
Plug:
This high-output alternator comes with a factory style plug so that your OEM plug will plug directly into the alternator.
NOTE: If you require charging at a certain voltage setpoint, we offer a selection of different voltage regulators that you will need to purchase with the alternator for it to be installed. View our Regulator Options Here.
Pulley:
This alternator also comes with a smaller pulley, which causes it to spin faster than a larger pulley. This can help the alternator produce its maximum output. With a smaller pulley, it is required to install a 1/2" - 1" shorter belt.
See this Blog Article for assistance in finding the correct shorter belt.
Big 3 Wiring:
When Upgrading to a High-Output Alternator, it is required to upgrade your wiring with the Big 3 Wiring Upgrade Kit. It is recommended to use 1/0 100% copper wires for the upgrade. Our Big 3 Wiring Upgrade Kit is 10% off with a purchase of a JS Alternator; use code BIG3DISCOUNT at checkout.
