🔧 Battery - Replacement

Replacing the battery on your Focus is a beginner-friendly job, but it must be done carefully because the battery is heavy and contains acid. You’ll remove the old 12-volt battery, install a matching replacement, then reset the battery monitoring system so the charging system knows a new battery is installed.

Difficulty Level: Beginner | Estimated Time: 30-45 minutes

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⚠️ Safety & Precautions

• ⚠️ Wear safety glasses and gloves because battery acid can burn skin and eyes.
• ⚠️ Always remove the negative cable first and install it last to reduce spark risk.
• ⚠️ Do not let metal tools touch both battery terminals at the same time.
• ⚠️ Keep flames, cigarettes, and sparks away from the battery.
• ⚠️ The battery is heavy; lift with both hands and keep it upright.
• ⚠️ Battery disconnect is required for this repair.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 13mm socket
• 3/8-inch ratchet
• 3/8-inch extension 6-inch
• Battery terminal puller (specialty)
• Battery terminal cleaning brush
• Battery carrier strap
• OBD-II scan tool with Ford BMS reset function (specialty)
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 12-volt battery, Group 96R - Qty: 1
• Battery terminal protectant spray - Qty: 1
• Battery terminal anti-corrosion washers - Qty: 2

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📋 Before You Begin

• Park your Focus on level ground and set the parking brake.
• Turn the ignition off and remove the key.
• Open the hood and wait at least 2 minutes before disconnecting the battery.
• Make sure the replacement battery matches the original size, terminal position, and rating.
• A battery monitoring system reset is required after installation. “BMS” means Battery Monitoring System; it helps the alternator charge the battery correctly.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Locate the Battery

• Open the hood and locate the battery on the driver-side front area of the engine bay.
• Use your hands to remove or lift any plastic battery cover if equipped.
• Take a photo before disconnecting anything.

Step 2: Disconnect the Negative Cable

• Find the negative terminal marked with a minus sign.
• Use a 10mm socket, 3/8-inch ratchet, and 3/8-inch extension 6-inch to loosen the negative terminal clamp nut.
• Twist the cable gently and lift it off the battery post.
• If it is stuck, use a battery terminal puller. A terminal puller safely lifts the clamp without bending or breaking it.
• Move the negative cable away from the battery so it cannot spring back and touch the post.

Step 3: Disconnect the Positive Cable

• Open the red protective cover over the positive terminal.
• Use a 10mm socket and 3/8-inch ratchet to loosen the positive terminal clamp nut.
• Lift the positive cable off the battery post.
• If needed, use the battery terminal puller to remove it safely.

Step 4: Remove the Battery Hold-Down

• Look near the lower edge of the battery for the hold-down bracket. This bracket locks the battery in place.
• Use a 13mm socket, 3/8-inch ratchet, and 3/8-inch extension 6-inch to remove the hold-down bolt.
• Remove the hold-down bracket and set it aside.

Step 5: Remove the Old Battery

• Attach a battery carrier strap if the battery does not have a built-in handle.
• Lift the battery straight up and out with both hands.
• Keep the battery upright at all times.
• Set it on the ground carefully, away from children, pets, and tools.

Step 6: Clean the Battery Tray and Terminals

• Inspect the battery tray for corrosion, cracks, or loose parts.
• Use a battery terminal cleaning brush to clean the inside of both cable clamps.
• Install battery terminal anti-corrosion washers on the new battery posts if supplied.
• Clean metal gives better starting power.

Step 7: Install the New Battery

• Use the battery carrier strap to lower the new battery into the tray.
• Make sure the positive and negative posts are in the same positions as the original battery.
• Reinstall the hold-down bracket.
• Use a 13mm socket, 3/8-inch ratchet, and 3/8-inch extension 6-inch to tighten the hold-down bolt.
• Torque to 8-10 Nm (71-89 in-lbs)

Step 8: Connect the Positive Cable First

• Push the positive cable fully down onto the positive battery post.
• Use a 10mm socket and 3/8-inch ratchet to tighten the terminal clamp nut.
• Torque to 5-6 Nm (44-53 in-lbs)
• Close the red protective cover over the positive terminal.

Step 9: Connect the Negative Cable Last

• Push the negative cable fully down onto the negative battery post.
• Use a 10mm socket and 3/8-inch ratchet to tighten the terminal clamp nut.
• Torque to 5-6 Nm (44-53 in-lbs)
• Spray both terminals lightly with battery terminal protectant spray.

Step 10: Reset the Battery Monitoring System

• Connect an OBD-II scan tool with Ford BMS reset function to the diagnostic port under the driver-side lower dash.
• Turn the ignition on without starting the engine.
• On the scan tool, select Ford > Focus > Body Control Module > Battery Monitoring System Reset.
• Follow the scan tool prompts until the reset is complete.
• Turn the ignition off for 30 seconds, then start the engine.

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✅ After Repair

• Start your Focus and make sure it cranks normally.
• Check that the battery warning light turns off after the engine starts.
• Reset the clock, radio presets, and one-touch window functions if needed.
• For the driver window, hold the switch down until fully open, then hold it up until fully closed, and keep holding for 2 seconds.
• Recycle the old battery at a parts store, battery shop, or recycling center. Do not throw it in the trash.

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💰 DIY vs Shop Cost

Shop Cost: $220-$380 (parts + labor)

DIY Cost: $140-$240 (parts only)

You Save: $80-$140 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.5-1.0 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.