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What kind of battery is in a Lexus RX 350?

The Lexus RX 350, the gasoline-powered member of the RX lineup, uses a conventional 12-volt battery to start the engine and run electronics. It does not contain a high-voltage traction battery—the kind used in hybrids like the RX 450h. If you have a hybrid RX 450h, that model carries a separate high-voltage pack for propulsion.

Understanding the RX 350’s 12-volt battery

Here are the core facts about the 12-volt battery used in most RX 350 models and how it differs from the hybrid system.

The RX 350 relies on a 12-volt lead-acid battery to power starting, lighting, and the vehicle’s electronics.

In newer Lexus models, including many RX 350 trims, the 12-volt battery is typically an Absorbent Glass Mat (AGM) type, which is more resistant to vibration and provides better cold-weather performance than traditional flooded batteries.

The high-voltage battery pack that powers electric motors is not present in the RX 350; it’s a feature of the hybrid RX 450h/450hL models.

Location: the 12-volt battery sits in the engine bay under the hood and is connected to the regular charging system via the alternator and the vehicle’s power management system.

Replacing or maintaining the 12-volt battery is similar to other modern vehicles; many RX 350 owners replace the battery about every 4–6 years on average, depending on climate and usage. Signs of deterioration include slow cranking, dim lights, or warning messages on the dashboard.

RX 350 vs RX 450h: battery systems compared

To understand how the RX 350 compares with its hybrid sibling, it helps to contrast the battery systems used in the two configurations.

RX 350: uses a 12-volt lead-acid battery that powers starting and on-board electronics; no traction motor power from this battery.

RX 450h: uses a high-voltage traction battery (typically nickel-metal hydride in older models, with newer variants potentially using lithium-ion), providing propulsion via electric motors and assisting the gasoline engine.

Voltage and pack size: 12V for the RX 350 vs hundreds of volts (generally around 200–300V) for the hybrid pack.

Operation: the RX 350 relies on the alternator to recharge the 12V battery; the hybrid uses regenerative braking and the hybrid battery to store energy and assist starting.

The main takeaway is that the RX 350’s battery is a conventional 12-volt unit, while the RX 450h carries a separate high-voltage pack for hybrid operation.

Battery care and maintenance tips

Keep the vehicle’s battery healthy with these practical tips tailored to the RX 350’s 12-volt system.

Inspect the battery and connections for corrosion, and keep the terminal clamps tight and clean.

Replace with the recommended AGM 12-volt battery when replacing, if the vehicle’s manual calls for AGM.

Avoid prolonged deep discharges; if the car sits unused for extended periods, consider using a battery maintainer.

Have the charging system (alternator, belt) checked if you experience slow starts or electrical issues.

With proper maintenance, the RX 350’s 12-volt battery can provide reliable performance across many years and miles, while the hybrid model maintains its separate high-voltage battery for its electric drive.

Summary

The RX 350 uses a standard 12-volt lead-acid battery (commonly AGM) for starting and electrical systems, not a high-voltage traction battery. The high-voltage battery is present only in the RX 450h hybrid version, which powers the electric motors and supports the gasoline engine. For most drivers, normal maintenance and monitoring of the 12-volt battery will keep the vehicle starting reliably, while hybrid versions require attention to a separate HV pack.

Does Lexus require a special battery?

Lexus vehicles use various battery types, tailored to meet the specific needs of its diverse lineup. Learning about these batteries can help you make informed decisions regarding maintenance and replacement.

What kind of battery does a Lexus RX350 take?

A Lexus RX350 typically uses a 12V lead-acid battery, most commonly in BCI Group Size 24F. However, some model years may also use other sizes, such as the 35, so it's best to confirm the correct fit for your specific year by using an online battery finder or checking the existing battery. The choice between different battery types, like traditional flooded or absorbed glass mat (AGM), depends on factors like climate and accessory power needs, with AGM generally offering premium performance, according to AutoZone.com and Interstate Batteries.

Key information

Common group size: 24F
Other possible group sizes: 35
Battery type: 12V lead-acid
Best practice: Use an online battery finder or check your current battery for the exact specifications for your vehicle's year and trim.

Choosing a battery

Confirm the group size: Use an online tool or check your existing battery to ensure you buy the correct physical size (like 24F or 35) for your RX350.
Consider battery type:
- Flooded vs. AGM: Flooded batteries are standard, while Absorbed Glass Mat (AGM) batteries can offer better performance and are maintenance-free.
- Climate: AGM batteries are often recommended for those in more extreme climates.
Check other specifications: Look at the Cold Cranking Amperage (CCA), Cranking Amperage, and Reserve Capacity to match your vehicle's needs.
Check with your dealer: As Bell Lexus North Scottsdale notes, using a genuine Lexus battery is a great way to ensure the vehicle receives power according to manufacturer specifications.

What battery does Lexus recommend?

Lexus uses different battery types depending on the model: a 12-volt lead-acid battery for gasoline-only vehicles, and a high-voltage nickel-metal hydride (NiMH) battery for hybrid models. Newer models with start-stop technology may use AGM (Absorbed Glass Mat) or EFB (Enhanced Flooded Battery) lead-acid batteries.

Gasoline and hybrid models

Gasoline Models: Use a standard 12-volt lead-acid battery. Aftermarket options include flooded and AGM types, and some models with start-stop technology may use EFB batteries.
Hybrid Models: Use a high-voltage nickel-metal hydride (NiMH) battery to assist the gasoline engine, which is separate from the standard 12-volt starting battery.

Battery replacement specifics

For 12V batteries: It is important to match the group size and specifications (like CCA - Cold Cranking Amps) of the original battery when replacing it, says AutoZone.
Genuine batteries: Lexus offers genuine replacement batteries that are designed to meet the specific requirements of each model, notes this Lexus video.

Key takeaways

The type of battery depends on whether the vehicle is a standard gasoline, hybrid, or has start-stop technology.
For a 12-volt battery replacement, match the original specifications for best performance, according to this Reddit post.

How much does it cost to replace the battery in a Lexus RX350?

A standard Lexus RX 350 battery replacement typically costs between $150 and $400, while a dealership replacement can be higher, sometimes up to $800. The price can vary based on the battery's quality, brand, and where you have the service done (independent mechanic vs. dealership). For a hybrid RX 450h, the cost for a hybrid battery is much higher, ranging from approximately $2,000 to $8,000.

Standard battery

Independent Mechanic/Auto Parts Store: $150–$400. This is a typical range for both the battery and labor costs combined.
Dealership: $550–$800. Dealerships may charge more, as they often use premium, OEM-specified parts and may have higher labor rates.

Hybrid battery

Total Cost: $2,000–$8,000. Hybrid battery replacements are significantly more expensive due to the larger size and advanced technology of the battery.
Factors: The exact price can depend on the model year and specific battery required, with some estimates for older models reaching as high as $7,000 or more at a Lexus dealer.

What can influence the price?

Battery quality: Premium or specialty batteries, such as those from brands like Optima or Duralast Platinum, will cost more than basic options.
Labor: Some services may have separate costs for the battery itself and the labor to install it, which can vary by location and the complexity of the replacement.
Taxes and other fees: These will be added to the total cost.

Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.