Step-by-Step BMW i3 120Ah Module Replacement: Save Money & Boost Range

Introduction: The High Cost of BMW i3 Battery Failures

“My 2018 BMW i3’s range dropped from 150 miles to 90 miles in a year. The dealer quoted $12,000 for a replacement battery—but I found a better solution.”
—Michael T., BMW i3 Owner, Austin, TX

If you own a BMW i3 with a 120Ah battery pack, you’ve likely faced:

• 🔋 Sudden range loss (after just 3-4 years)
• 💸 Dealer replacement costs ($8,000–$15,000+)
• 🚫 Limited DIY options (due to BMW’s proprietary battery design)

But what if you could replace failing modules yourself—for a fraction of the cost?

BMW’s 120Ah battery (used in 2017–2022 i3 models) consists of 12 modules (6 in the front, 6 in the rear). When one or two modules degrade, the entire pack suffers.

Instead of replacing the whole battery, you can:
✅ Swap just the faulty modules (saving $5,000–$10,000)
✅ Restore range to near-factory levels (120–140 miles)
✅ Do it yourself or with a local shop (no dealer markup)

CNS BATTERY’s 120Ah replacement modules make this possible—OEM-grade quality, plug-and-play compatibility, and a 2-year warranty.

Step-by-Step BMW i3 120Ah Module Replacement Guide

1. Diagnose the Problem

Before replacing modules, confirm which ones are failing:

• 🔍 Use an OBD-II scanner (like BimmerCode) to check for “Cell Imbalance” or “Low Voltage” errors.
• 📊 Monitor individual module voltages (a healthy module reads 3.6–3.8V; a failing one drops below 3.4V).
• 🚨 If more than 2 modules are bad, consider a full pack replacement.

2. Gather Tools & Parts

You’ll need:

• 🔧 New 120Ah replacement modules (CNS BATTERY offers OEM-grade cells)
• 🔩 Torque wrench (for battery pack bolts)
• 🧤 Insulated gloves (safety first!)
• 💻 BMW ISTA/D software (for BMS recalibration)

3. Remove the Old Battery Pack

1. Disconnect the 12V battery (under the hood).
2. Remove the rear seat (exposes the battery access panel).
3. Unbolt the battery pack (10mm socket required).
4. Disconnect the HV cables (use insulated tools!).

4. Swap the Faulty Modules

1. Open the battery pack (pry off the plastic cover).
2. Identify the bad modules (marked by low voltage or swelling).
3. Unbolt & remove the modules (4 bolts per module).
4. Install new CNS BATTERY modules (ensure proper alignment).

5. Reassemble & Recalibrate

1. Rebolt the battery pack (torque to 12 Nm).
2. Reconnect HV cables (double-check polarity!).
3. Use ISTA/D to recalibrate the BMS (this restores accurate range readings).
4. Test-drive (monitor for errors).

Why Choose CNS BATTERY’s 120Ah Replacement Modules?

1. OEM-Grade Quality

• CATL cells (same supplier as BMW’s original batteries)
• No refurbished or degraded cells (all brand-new)
• Strict QC testing (each module is individually checked)

2. Cost Savings

• 50–70% cheaper than dealer replacements
• No core charge (keep your old modules)
• Free shipping (on orders over $500)

3. Warranty & Support

• 24-month/80,000km warranty (better than most dealers)
• Free tech support (chat, phone, or email)
• Compatibility guaranteed (or your money back)

4. DIY-Friendly

• Plug-and-play design (no soldering or special tools)
• Detailed installation guides (videos + PDFs)
• Community forum access (learn from other i3 owners)

FAQs: BMW i3 120Ah Module Replacement

Q1: How long do replacement modules last?

Our 120Ah modules have a 8–10 year lifespan (same as OEM) when properly maintained.

Q2: Can I replace just one module?

Yes—but if two or more are failing, we recommend replacing all weak modules at once for balanced performance.

Q3: Do I need special software to recalibrate the BMS?

Yes—BMW’s ISTA/D or a similar tool is required. We provide free installation guides.

Q4: Will this void my BMW warranty?

No—if done correctly, module replacement does not affect your vehicle warranty.

Q5: What if the new modules don’t work?

30-day money-back guarantee + free replacement if any issues arise.

Restore Your BMW i3’s Range Today

Don’t pay dealer prices for a full battery replacement.

✅ Replace just the failing modules (save $5,000–$10,000)
✅ OEM-grade CATL cells (same quality as BMW’s originals)
✅ 2-year warranty + free tech support (peace of mind)

👉 https://cnsbattery.com/ev-battery-home/ev-battery-contact/ 👈

Drive farther, spend less—with CNS BATTERY. 🚗💨