What Is a 24 85 17 Battery and How Does It Work?
What is a 24 85 17 battery? A 24 85 17 battery is a lead-acid automotive battery commonly used in vehicles like BMW, Mercedes-Benz, and Audi. It delivers 85 Ah (ampere-hours) of capacity and 800 CCA (cold cranking amps), designed for reliable performance in start-stop systems and high-demand electronics. Its dimensions (typically 278mm x 175mm x 190mm) ensure compatibility with European luxury cars.
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What Vehicles Are Compatible with a 24 85 17 Battery?
The 24 85 17 battery is engineered for European luxury vehicles, including BMW 3/5/7 Series, Mercedes-Benz C/E/S-Class, and Audi A4/A6 models. Compatibility depends on terminal placement (reverse polarity in some models), battery tray size, and voltage requirements. Always consult your vehicle manual or use an online compatibility checker to confirm fitment.
How Does the 24 85 17 Battery Compare to Other Models?
Unlike standard batteries, the 24 85 17 features enhanced cycle durability for start-stop technology and deeper discharge recovery. Compared to Group 48 batteries, it offers higher CCA and a modular design for compact spaces. Its absorbent glass mat (AGM) variant provides spill-proof operation, outperforming traditional flooded batteries in vibration resistance and lifespan (up to 6-8 years).
AGM batteries in the 24 85 17 category excel in vehicles with regenerative braking systems, as they handle frequent charge-discharge cycles better than EFB (Enhanced Flooded Battery) alternatives. For example, while EFB batteries offer 30,000 cycles, AGM variants can withstand up to 50,000 cycles. The table below highlights key differences:
| Feature | Group 48 | 24 85 17 AGM | 24 85 17 EFB |
|---|---|---|---|
| CCA Rating | 700 A | 800 A | 760 A |
| Cycle Life | 4-5 years | 6-8 years | 5-6 years |
| Technology | Flooded | AGM | EFB |
What Are the Key Specifications of the 24 85 17 Battery?
- Capacity: 85 Ah
- CCA: 800 amps
- Dimensions: 278mm (L) x 175mm (W) x 190mm (H)
- Terminal Type: DIN posts
- Technology: AGM or EFB (Enhanced Flooded Battery)
How Do You Replace a 24 85 17 Battery Safely?
- Turn off the engine and disconnect the negative terminal first.
- Remove the battery hold-down clamp and lift the old battery.
- Clean corrosion from terminals with baking soda and water.
- Install the new battery, securing it with the clamp.
- Reconnect terminals (positive first), then register the battery via OBD-II to reset the vehicle’s power management system.
How Does Temperature Affect the 24 85 17 Battery’s Performance?
Cold weather reduces CCA efficiency by 30-50%, increasing start-up strain. Heat accelerates fluid evaporation and plate corrosion. Store the battery at 50-80°F (10-27°C) for optimal longevity. Use insulated battery blankets in sub-freezing climates.
In extreme cold, the battery’s chemical reactions slow down, requiring nearly twice the energy to start the engine. Conversely, high temperatures above 95°F (35°C) can cause sulfation, permanently reducing capacity. The table below shows performance changes across temperature ranges:
| Temperature | Effect on Capacity | Effect on CCA |
|---|---|---|
| 32°F (0°C) | -20% | -40% |
| 77°F (25°C) | 100% | 100% |
| 104°F (40°C) | +12% (temporary) | -15% |
Can the 24 85 17 Battery Be Recycled?
Yes. Lead-acid batteries are 99% recyclable. Return old units to retailers or certified recycling centers. AGM batteries contain reusable lead plates and polypropylene cases. Improper disposal risks heavy metal contamination and legal penalties under EPA regulations.
“The 24 85 17 represents a shift toward modular, high-efficiency power sources for advanced vehicle systems,” says Dr. Lars Weber, automotive engineer. “AGM technology reduces sulfation and offers 3x faster recharge rates compared to conventional batteries. However, proper BMS calibration remains critical—many premature failures stem from incorrect registration, not manufacturing defects.”
FAQs
- Can I use a 24 85 17 battery in a non-European car?
- Only if the dimensions, terminal alignment, and CCA meet the vehicle’s requirements. Consult a mechanic first.
- How often should I test my 24 85 17 battery?
- Test voltage every 6 months using a multimeter. Professional load testing is recommended annually.
- Why does my new 24 85 17 battery drain quickly?
- Parasitic drains (e.g., faulty alternator, aftermarket accessories) or improper BMS registration are common culprits.