How to Connect Battery Cables

by Jesse Vibbert

Many situations require you to connect a battery cable. Three such examples follow.

Replacing the Battery Cables on Your Vehicles

Wrench

Remove the old cables from your battery by loosening the bolts on both cable ends with a wrench. Take both cables off the battery posts, starting with the negative cable.

Disconnect the negative cable from the engine block. Remove the positive cable from the solenoid, relay or starter.

Wire brush for cleaning battery posts

Clean both battery posts with a wire brush. Connect the positive cable to the solenoid, relay or starter. Connect the other end to the battery post and tighten both ends with a wrench. Connect the negative battery cable to the engine block where you took it off. Connect the other end to the negative post on the battery and tighten both ends with a wrench.

Connecting Jumper Cables

Connecting jumper cables

Clean both cables on the battery with a wire brush to get a good connection.

Hook up to the positive (+) post on the battery first.

Connect one end of the jumper cables to the positive (+) side of the dead battery. Always start with the positive (+) cable. Connect the other end of the jumper cable to the positive (+) side of the fully charged battery.

Negative sign

Connect the negative (-) side of the jumper cables to the fully charged battery first. Connect the other end of the jumper cable to the engine. Locate an unpainted bolt or nut and place the other end of the jumper cable on it, being sure the bolt or nut is free of grease and dirt. This will let you start your vehicle.

Connecting the Second Battery in the Vehicle

Connect a second battery in parallel with the first battery, i.e., hook the negative (-) post from the first battery to the negative (-) post on the second battery first. Hook the positive (+) post from the first battery to the positive (+) post on the second battery.

Remove the nut from the negative (-) cable and take the cable off the battery. Take the nut off the positive (+) cable end and place the eyelet of the new cable on the bolt, then replace the nut and tighten with a wrench. Place the other end of the cable on the positive (+) post on the second battery, tighten with a wrench.

Connect one cable end to the negative (-) post of the second battery and tighten with a wrench. Place the other end with the eyelet on the negative (-) cable end bolt on the first battery and replace the nut. Reconnect the cable to the first battery and tighten nut with a wrench.

Tip

  • check Unhook the negative (-) battery cable first to prevent a short circuit.

Warning

  • close Wear your safety goggles and rubber gloves when you work on, or around, batteries.

Items you will need

About the Author

Jesse Vibbert has been a master mechanic and has worked in automotive and truck parts stores for 40 years. He has recently written articles about automotive repair for various websites.

Photo Credits

  • photo_camera the powerful engine image by kuhar from Fotolia.com