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Use promotional code MMJ30 at checkout to receive 30% off the following categories: Select Brake Parts, Select Hi-Performance and Truck Accessories, Batteries, 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, Car Wash Accessories, Floor Mats, Lift Equipment, Hand Tools, Travel Accessories, Car Covers, Seat Covers, Wheel Covers, Body Repair, Collectibles and Apparel.

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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: 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 10/1/17.

Receive 25% Off Wagner branded brake parts with your online purchase. Use promotional code: WAGNER25.

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AGM Battery



AGM Battery

AGM (Absorbed Glass Mat) batteries are renowned for their ability to outlast regular leadacid batteries. AGM’s are completely spill and leak proof thanks to their absorbed glass mat construction. These car batteries are a new technology to the automotive world, a design that replaces conventional acid flooding of the battery cells with absorbent separators and cells held under compression. AGM reduces acid spilling in an accident, allows installation in virtually any location and, at odd angles, are famous for lasting up to two times longer than regular lead acid batteries.

What is a AGM Battery and how does it work

How Does it Work?

  • Glass mat separators are designed to wick the battery electrolyte between the series of battery plates.
  • Electrolyte is held in the glass mats, as opposed to freely flooding the plates. Very thin glass fibers are woven into a mat to increase surface area enough to hold sufficient electrolyte on the cells for their lifetime.
  • Electrolyte is distributed evenly across the active plate material.
  • It contains only enough liquid to keep the absorbed mat wet with the electrolyte, and is known as a safe non-spilling battery.

How is it Made?

  • Plates and separators are compressed prior to insertion into the case, allowing them to be held tightly - a technique that lends to vibration resistance.
  • The glass mat plates allow for the even distribution of electrolyte over the entire surface area of its adjacent lead plate, due to its ability to hold acid.
  • This maximization of electrolyte-to-plate coverage enables these batteries to far exceed the performance of conventional flooded lead acid batteries.
  • The plates in an AGM battery may be any shape: flat, bent or rolled.
  • AGM batteries, both deep cycle and starting, can be built in a conventional rectangular case or other design.

Why Does it Fail?

  • As with all batteries, the active material eventually wears out.
  • Gradual capacity decline over time means more predictable replacement intervals.
  • Overcharging. AGM is more sensitive to being overcharged, which will shorten life.
  • Keeping battery in an extended discharged state
  • Must be stored in charged condition.

What are the Symptoms of Failure?

  • A change in the sound of the starter (decrease in cranking speed) is the best indicator of impending failure.
  • A 12 volt battery should be between 13.2 -13.8 volts at rest. When the battery can’t hold a charge, they are getting close to dying.
  • Best to test the complete starting, charging system with the battery to determine battery state-of-health.

What are the Implications of Failure?

  • Complete failure most frequently results in a no-start condition.
  • The alternator is designed to replenish the battery. A battery that is failing can damage an alternator if not replaced when required.

How Difficult is the Install?

Difficulty Rating:


  • Installation difficulty varies by vehicle

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