Schumacher 12 Volt Battery Charger Instructions

Schumacher brand battery chargers are highly regarded by automotive repair professionals and home-based enthusiasts alike. The reputation this brand enjoys has been earned over the years by the reliable and capable character of the products. Many different models of chargers are available, with features that meet any needs anticipated. Small models can provide a slow charge to bring a battery up to par, while larger models can jump-start most cars and trucks in short order. The information and instructions provided in company produced literature is well researched and complete.

Things You'll Need

  • Protective eyewear
  • Wire brush
  • Ensure all vehicle electrical devices are turned off to avoid arcing at the battery. Observe battery polarity and determine if the negative post is grounded to the chassis. Negative-grounded systems are most common in passenger vehicles produced in recent times. Connect the positive battery charger lead to the positive, ungrounded battery post.

  • Connect the negative battery charger lead to a ground source on the car chassis or engine block. Avoid grounding to fuel lines or fuel delivery devices such as carburetors or throttle bodies. Clean any rust or corrosion from the grounding site selected with a wire brush, if necessary.

    Unpainted studs or screws on the engine block are good grounding sites.
    Unpainted studs or screws on the engine block are good grounding sites.
  • Plug in the AC power cord of the charger into a 120VAC electrical outlet and observe the charger indicator(s). Some models display battery voltage on a meter. The meter display can be analog or digital, depending on the model. Select the charging rate recommended by the manufacturer, for models equipped with this feature.

  • Monitor LED indicators on chargers that display an amber light for charging in progress. A green light will signify charging is complete. Unplug the AC power cord when charging is complete, or if a red LED illuminates. A red LED indicates internal battery problems. Seek professional testing to determine exact battery condition. Remove the charger leads after the power cord is unplugged.