BXT-99RT4-A Battery
The BXT 99RT4 A is a genuine original equipment (OE) automotive battery engineered and manufactured under Ford Motorcraft premium Tested Tough MAX product line. Found under the hoods of numerous Ford, Lincoln, and Mercury vehicles, this specialized battery provides dependable cold-weather starting power, durable vibration resistance, and extended reserve capacity. In automotive parts nomenclature, the BXT designation stands for "Battery eXtreme Tested" (or Battery eXtra Technology), representing Motorcraft premium lead-calcium alloy grid engineering backed by extensive cold cranking capabilities and long factory warranties.
Motorcraft Part Number Decoded: BXT Full Form, Chemistry, and Group Sizes
Decoding the alphanumeric product code BXT-99RT4-A reveals precise manufacturing and engineering specifications. The prefix "BXT" designates the top-tier Motorcraft Tested Tough MAX series, distinguished from baseline BXL (Tested Tough PLUS) units by having higher plate counts and longer free replacement warranties. The number "99" identifies the manufacturer specific series code, "R" signifies a reversed terminal post orientation, "T4" corresponds to the Battery Council International (BCI) Group T4 (or European DIN LB1) physical casing dimensions, and the suffix "A" denotes the active revision generation.
Automotive battery group size T4 is specifically engineered for compact and sub-compact engine bays where vertical hood clearance is constrained. Measuring 8.2 inches in length, 6.9 inches in width, and a low-profile 5.5 inches in height, the BXT-99RT4-A features recessed top-post terminals that prevent accidental short-circuits against metallic hood underside bracing while delivering robust cranking amperage.
The following technical specifications summarize the electrical output, battery group sizing, and casing dimensions of the BXT-99RT4-A.
| Specification Parameter | Technical Metric / Rating | Measurement Standard | Significance to Vehicle Starting & Electronics |
|---|---|---|---|
| BCI Group Size | Group T4 (DIN LB1 / LN1 low profile) | Battery Council International | Ensures exact physical fit in Ford OEM battery trays |
| Cold Cranking Amperage (CCA) | 470 CCA | SAE J537 @ 0°F (-18°C) | Guarantees rapid engine turnover in sub-zero winter climates |
| Cranking Amperage (CA / MCA) | 590 CA | Tested @ 32°F (0°C) | Starting amperage available in mild operating temperatures |
| Reserve Capacity (RC) | 70 Minutes | SAE test @ 25 Amp discharge | Emergency run-time for electronics if alternator fails |
| Nominal Voltage | 12.0 Volts DC | 6 internal lead-acid cells | Standard passenger automotive electrical architecture |
| Terminal Configuration | Type Top Post (Reversed Terminals) | SAE standard tapered posts | Positive post on right side with terminals facing front |
| Weight | 26.8 lbs (12.16 kg) | Filled with liquid electrolyte | Heavy-duty lead plate structure for vibration damping |
Electrical Specifications: Cold Cranking Amps, Reserve Capacity, and BCI Group T4
The internal architecture of the Motorcraft BXT-99RT4-A utilizes advanced lead-calcium-tin alloy grid technology. By incorporating calcium into the positive and negative lead plates, Motorcraft engineers substantially reduce internal water decomposition and gassing during high-voltage alternator charging. This maintenance-free design eliminates the traditional need to periodically pry open cell caps to replenish distilled water, while maximizing resistance to grid corrosion caused by intense engine bay heat.
Terminal post orientation is a crucial detail when replacing automotive batteries. The "R" in BXT-99RT4 indicates reversed terminal polarity compared to standard BCI layouts. In the T4-R layout, when looking at the battery with the terminals closest to you, the positive terminal is positioned on the right side and the negative terminal is on the left. Attempting to install a non-reversed battery forces battery cables to stretch across hot engine components or may cause catastrophic reverse-polarity damage to vehicle Engine Control Units (ECU).
The BXT-99RT4-A is factory specified across various Ford Motor Company platforms requiring compact T4 footprints.
| Vehicle Make & Model | Model Year Span | Engine Configurations | OEM Replacement Part Number | Mounting Bracket Type |
|---|---|---|---|---|
| Ford Fiesta | 2011 to 2019 | 1.6L Ti-VCT I4 / 1.6L EcoBoost ST | BXT-99RT4-A / BAGM-99RT4-A | Base clamp bottom lip bracket |
| Ford Focus | 2012 to 2018 (Select trims) | 2.0L Duratec / 1.0L EcoBoost | BXT-99RT4-A / BXT-96R | Engine compartment battery box strap |
| Ford Transit Connect | 2014 to 2018 (Select) | 1.6L EcoBoost / 2.5L I4 | BXT-99RT4-A | Top-hold crossbar mount |
| Lincoln MKZ / Crossover | Select model years | Compact auxiliary 12V tray | BXT-99RT4-A | Enclosed trunk/cabin tray with vent |
Vehicle Fitment Across Ford Models, Terminal Orientation, and Maintenance Tips
Modern vehicles equipped with the BXT-99RT4-A frequently feature Battery Monitoring Systems (BMS). When a new battery is installed, the vehicle body control module must be digitally reset using an OBD-II diagnostic scan tool or a specific dashboard button sequence. Resetting the BMS calibrates the alternator charging algorithm to the fresh internal resistance of a new battery, preventing overcharging and extending battery life.
Proper maintenance practices safeguard battery longevity and starting reliability. Technicians recommend inspecting terminal posts every six months for greenish-white lead sulfate buildup. Cleaning terminals with a wire brush and a mixture of baking soda and warm water neutralizes acidic deposits, followed by an application of dielectric grease or protective petroleum jelly to repel atmospheric moisture.
Warranty coverage for the Motorcraft Tested Tough MAX series typically includes a thirty-six-month free replacement period, followed by prorated warranty protection up to eighty-four or one hundred months. Purchasing genuine Motorcraft batteries through Ford authorized dealerships or certified parts distributors guarantees warranty tracking through vehicle identification numbers (VIN).
How to Replace and Install a Motorcraft BXT-99RT4-A Battery in 5 Steps
Follow this automotive procedure to safely remove an old battery and install a new BXT-99RT4-A without electrical damage.
Turn Off Ignition and Wear Eye Protection
Switch off the vehicle engine, remove the key fob, engage parking brake, and put on safety glasses and chemical-resistant gloves.
Disconnect Negative Terminal First
Use a 10 mm wrench to loosen the black negative terminal clamp nut, twist gently, and pull it away to break electrical ground safely.
Disconnect Positive Terminal and Remove Hold-Down
Remove the red positive terminal clamp, unbolt the battery hold-down clamp bracket, and lift the old 27-lb battery out of the tray.
Clean Tray and Seat New BXT-99RT4-A
Clear debris from the battery tray, lower the new BXT-99RT4-A into position with terminals matching cable orientation, and secure the hold-down bracket.
Connect Positive Terminal First, Then Negative
Attach and torque the red positive clamp first, followed by the black negative clamp, apply protective spray, and reset the vehicle BMS sensor.
Frequently Asked Questions (8 Questions Answered)
Q1: What does BXT stand for in Motorcraft batteries?
BXT stands for "Battery eXtreme Tested" (or Battery eXtra Technology), representing Motorcraft top-tier Tested Tough MAX battery line with higher CCA ratings and longer warranties.
Q2: What are the cold cranking amps of the BXT-99RT4-A?
The Motorcraft BXT-99RT4-A delivers 470 Cold Cranking Amps (CCA) tested at 0 degrees Fahrenheit, and 590 Cranking Amps at 32 degrees Fahrenheit.
Q3: What group size is the BXT-99RT4-A battery?
The BXT-99RT4-A belongs to BCI Group T4 (equivalent to European DIN LB1), a low-profile compact battery size measuring approximately 8.2 x 6.9 x 5.5 inches.
Q4: What does the R mean in BXT-99RT4-A?
The "R" signifies reversed terminal post polarity, meaning the positive terminal is on the right side when viewing the battery with terminals forward.
Q5: What vehicles use the Motorcraft BXT-99RT4-A battery?
It is commonly used in compact Ford vehicles, notably the Ford Fiesta (2011-2019), select Ford Focus models, Transit Connect vans, and compact Lincoln trims.
Q6: Do you need to reset the BMS after installing a BXT-99RT4-A?
Yes, modern Ford vehicles utilize a Battery Monitoring System (BMS) that should be reset using a scan tool or manual sequence to adjust alternator charging rates.
Q7: What is the warranty on a Motorcraft BXT-99RT4-A battery?
Motorcraft Tested Tough MAX batteries generally feature a 36-month free replacement warranty, followed by prorated coverage up to 84 or 100 months through Ford dealers.
Q8: Can you use an AGM battery instead of the BXT-99RT4-A?
Yes, Ford offers the BAGM-99RT4-A as an Absorbent Glass Mat (AGM) upgrade, which provides superior cycling resistance for vehicles with start-stop technology.
Final Thoughts & Key Takeaways
In conclusion, understanding bxt-99rt4-a battery provides essential clarity, practical strategies, and actionable advice. By incorporating these foundational insights, adhering to verified safety guidelines, and following structured best practices, you ensure reliable, long-term outcomes while preventing common mistakes. Stay informed, consult certified professionals when needed, and maintain consistent quality care.