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30% Off Online Orders of Select Hard Parts. Enter Promo Code MMJ30 in Cart.

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Receive Up To 30% Off Your Online Purchase Of Select Parts And Accessories
Use promotional code MMJ30 at checkout to receive 30% off the following categories: Select Brake Parts, Select Hi-Performance and Truck Accessories, Batteries, Paint, Splash Guards, Select Ventvisors & Bug Shields, Springs & Spacers, Water Pumps, Belts, A/C Parts, Starters, Alternators, Fuel Pumps, Radiators, Radiator Fans, Thermostats, Caps & Clamps, Clutches, Spark Plugs, Plug Wires, CV Axles, Battery Chargers & Booster Cables, OE Locks, Rack & Pinons, Window Motors, RainX Wipers, Appearance Chemicals, Floor Mats, Lift Equipment, Hand Tools, Travel Accessories, Car Covers, Seat Covers, Wheel Covers, Body Repair, Collectibles and Apparel.

Use promotional code MMJ20 at checkout to receive 20% off the following categories: Ignition, Shocks & Struts, Chassis, Jumpstarts, Air Filters, Oil Filters, Bearings & Seals, Engine Parts, Wash Accessories, Outdoor Lifestyle, Towing, Mini Air Compressors, Tire Repair Accessories, Mufflers, Grease/Oil, Additive Chemicals, P/S Pumps, Cooling Product, Timing Belts, Specialty Tools, Radiator Hose, Motor Mounts, Mirrors, Lug Nuts, Sealants/Adhesives, Fuel Filters, P/S Hoses, Gas Cans, Oil Change Accessories, Help, Wiper Motors, Loaner Tools, Air Compressors, Horns, Books, Distributors, Sun Control and Exhaust Adapters.

Use promotional code MMJ15 at checkout to receive 15% off the following categories: Test Equipment, Power Tools, Emergency Supplies, Electronics and Stereo & Accessories (MAP pricing Exclusions).

Offers not valid in combination with any other discounts, promotions or items already on sale. Not valid on gift cards, special orders, installed merchandise, commercial or fleet purchases. Those products that are included in these offers will be displayed in product search results and product detail pages. Excludes the following brands: WeatherTech, Champion, Powerstop, Razor, Traxxas, Superchips, Hypertech, Edge, Bully Dog, Diablo, Edelbrock, Holley, NOS, Proform, Specialty Auto, Autometer, Accel, K&N, Kenwood, Pioneer, Sony, Thule, Thule Karrite, JVC, Flowmaster, Hurst, B&M, MSD, Moog, Wagner, Philips and BBK Performance. Valid online until 11:59 PM EST on 11/22/17.

Receive 10% Off Wagner branded brake parts with your online purchase. Use promotional code: WAGNER10.

Receive 20% Off Select Champion branded products with your online purchase. Use promotional code: CHAMP20.

Receive 10% Off Select FelPro branded products with your online purchase. Use promotional code: FELPRO10.

Free Shipping on Orders Over $50 or in-store pickup


Nearly every factory-standard accessory in your car is powered by your vehicle’s battery. Sometimes, however, you need a little more juice, which is exactly what an auxiliary car battery will provide.

Auxiliary batteries have been installed in vehicles for several decades, particularly those powered by diesel engines and used for recreation. The introduction of hybrid vehicles has also increased the need for auxiliary batteries. And today, aux batteries are gaining traction with car owners whose engines are driven by unleaded gasoline as well. In fact, some manufacturers factory install auxiliary batteries in unleaded gas powered cars.

So what are aux car batteries?

In an unleaded gas powered vehicle, aux batteries are a second 12 volt car battery designed to take some of the strain away from the main one. They are used for multiple applications, including the job of running non-standard accessories installed in cars. Some common uses for aux batteries include:
  • Powering a high performance aftermarket audio system like those installed to enter competitions
  • Providing electricity to run tailgating gear, including televisions, stereos, and cooking appliances
  • Outfitting your car to power camping gear, such as lights, heating elements, and cooking appliances

Hybrid vehicles, which are still gaining popularity amongst new car buyers, have drivetrains powered by high voltage traction batteries. As a means of reducing stress on the traction battery, hybrid cars rely on auxiliary 12 volt batteries. Because of the 12 volt auxiliary car battery, the isolated high voltage battery is not subjected to the normal drain that occurs when a vehicle isn’t running. This includes the computer and its internal “keep-alive” memory, clock, and related settings that all draw a small amount of current when the vehicle is off. Additionally, the 12 volt auxiliary car battery keeps all of the accessories such as lighting, safety, and entertainment systems powered up when the engine is not running.

Speak with a Pep Boys certified technician today to see if your current auxiliary car battery needs replacing or if having one installed can benefit you.