The Lexus RX300 uses a standard 12-volt lead-acid automotive battery. In most US-market models, the correct size is commonly Group 24F or Group 35, depending on model year and equipment. Always confirm the exact specification by checking the owner's manual, the battery label, or a dealer with your VIN.
Common battery sizes for the RX300
Before listing common group sizes, note that the RX300's battery size can vary by year, trim, and regional specifications. The two most frequently seen options are Group 24F and Group 35.
- Group 24F: A common mid-size car battery with about 60-70 Ah and roughly 550-750 cold-cranking amps (CCA), depending on the exact brand and rating. Fits many 1990s-2000s Lexus/Toyota models with similar layouts.
- Group 35: A slightly larger physical size with comparable capacity; often used when the tray or wiring layout differs or in markets requiring higher CCA for cold starts.
Note: Some RX300s, particularly in different markets or with optional equipment, may use a different group size. Always verify the exact group size for your specific vehicle.
How to identify the right battery for your RX300
Before listing steps to identify the correct fit, gather your current battery information and VIN to confirm compatibility.
- Check the owner’s manual or battery label for the group size (for example, "Group 24F" or "Group 35").
- Inspect the top of the current battery for the stamped group size and CCA rating.
- Use your VIN to fetch exact battery specifications from Toyota/Lexus parts catalogs or by contacting a dealer.
- Measure the battery tray width, height, and the location of terminals to ensure you buy a battery that fits.
- Confirm the terminal arrangement (top-post or side-post) matches your RX300’s battery cables and clamps.
With the right data, you can purchase the correct battery and avoid fitment issues.
Replacement tips and maintenance
Before list, a note on safety and installation: replace in a dry, well-ventilated area; disconnect the negative terminal first; wear eye protection and gloves; follow torque specs when reinstalling.
- Disconnect the negative (-) battery terminal first, then the positive (+). Reconnect in reverse order.
- Clean corrosion on terminals with a baking soda solution and a wire brush, then apply a light layer of dielectric grease.
- Ensure the new battery has at least the same or higher CCA rating and the same group size as the original.
- Secure the battery with the retaining clamp to prevent vibrations and check the tray for any rust or damage.
- Recycle the old battery at an authorized facility; many auto shops offer free battery recycling.
Proper installation and maintenance help ensure reliable starting and electrical performance for the RX300.
Summary: The Lexus RX300 uses a 12-volt lead-acid battery, commonly Group 24F or Group 35, depending on year and market. Always verify with the owner's manual, battery label, or VIN-based catalogs, and follow correct installation practices to ensure compatibility and reliability.