Autel MaxiBAS BTMS OBD2 Memory Saver for 12V Vehicles — OBD-II plug-in battery backup, polarity & surge protection

The 2026 Autel MaxiBAS BTMS OBD2 Memory Saver maintains a vehicle's electronic settings while you remove or replace a 12V battery.

The Autel MaxiBAS BTMS is a purpose-built OBD2 memory preserver that supplies temporary power to a vehicle’s control units during battery service. Designed for 12V systems in cars from 1996 onward, it attaches to the vehicle’s OBD-II port and to a 12V backup battery via battery clips, protecting stored adaptations, window and throttle positions, radio presets, and other module data that can be lost when the main battery is disconnected.

How does the MaxiBAS BTMS prevent data loss during battery replacement?

By routing power from a separate 12V backup battery into the vehicle’s OBD-II port, the MaxiBAS BTMS keeps critical modules energized while the primary battery is removed. The device monitors voltage and will not pass power if the backup battery is too weak or improperly connected, protecting both the vehicle and the backup source.

• Plugs into the vehicle OBD-II port for direct module power sustaining.
• Connects to a 12V backup battery with red (positive) and black (negative) clips.
• LED indicators show connection success and sufficient backup voltage (three-green lights >10V).
• Built-in polarity detection stops flow on reverse connection to avoid damage.

Which vehicles and situations is the Autel memory saver compatible with?

The MaxiBAS BTMS is compatible with nearly all 12V OBD-II equipped vehicles commonly made since 1996. It’s intended for use during routine battery replacement or any service where the vehicle’s battery must be disconnected and stored module data must be preserved.

• Works with OBD-II 12V cars, light trucks, and SUVs from 1996 onward.
• Ideal for dealerships, independent shops, and DIY home mechanics.
• Useful when replacing batteries, swapping battery cables, or performing electrical work.
• Two battery clips fit standard 12V backup battery terminals for universal compatibility.

What safety and diagnostic features are built into the unit?

The device includes a small voltmeter and three LED indicators to help you verify backup battery health and proper connection before starting work. Polarity-reverse protection and surge protection are integrated to reduce the risk of electrical damage when attaching the backup battery or connecting to the vehicle.

• Three-LED status lights: connection, adequate voltage (>10V), and low voltage warning.
• Detects reverse polarity and automatically blocks current flow if clips are reversed.
• Surge protection limits transient spikes that could affect vehicle electronics.
• Simple four-step procedure for safe use and reliable memory retention.

How do you use the MaxiBAS BTMS step-by-step?

Operation is straightforward: test the backup battery, power off the vehicle, plug the MaxiBAS into the OBD-II port, attach the clips to the backup battery, then proceed to remove or replace the vehicle battery. The LED lights guide you through voltage and connection confirmation so you can work with confidence.

• Step 1: Test backup battery—three green LEDs indicate sufficient voltage (≥10V).
• Step 2: Turn off and secure the vehicle ignition to a powered-off state.
• Step 3: Insert OBD-II connector and attach red/black clips to backup battery terminals.
• Step 4: Replace or service battery while modules remain powered; disconnect after finishing.

Who this is for: The Autel MaxiBAS BTMS is aimed at professional technicians, garage owners, and informed DIYers who regularly change batteries or perform electrical work on 12V vehicles and need to avoid reprogramming or losing stored vehicle settings. It’s especially valuable in shops that service modern vehicles with multiple electronic control units where saved positions and adaptive values are important to preserve. Backed by surge protection, a built-in voltmeter, polarity safeguards, and a 1-year warranty, the MaxiBAS BTMS provides a practical, low-complexity solution to prevent electronic memory loss during battery service.