How to Find the Right Battery for Your Car
Buying a battery for the wrong car is an expensive mistake. It may not fit the tray, the terminals may be on the wrong side, or it may not have enough power to start the engine reliably. A short checklist can help you get it right the first time.
Short version: start with the old battery's label and your manual, then match the size code, terminal side, capacity and starting power. Measure the tray if you are unsure.
Step 1: read the old battery
Take a clear photo of the label on your current battery. Note:
- The size code, such as NS40 or 55B24
- The capacity (Ah) and cold-cranking amps (CCA)
- Which side the positive terminal is on
- Whether it is a standard, EFB or AGM type
See how to read a car battery label for what each marking means.
Step 2: check your manual
The owner's manual or the fitment guide of the seller will list the recommended battery for your car's make, model, engine and year. Do not rely only on the old battery, since a previous owner may have fitted the wrong one.
Step 3: match the engine
As a rough guide, the bigger the engine, the more power the battery needs.
| Vehicle | Typical capacity (rough guide) |
|---|---|
| Small petrol cars | 32 to 45 Ah |
| Family cars and saloons | 45 to 65 Ah |
| Large cars and SUVs | 60 to 80 Ah |
| Diesel pickups and 4x4s | 70 to 100 Ah or more |
These are only rough ranges. Always follow your vehicle's specification.
Step 4: check the physical fit
- Measure the length, width and height of the tray and compare them with the new battery.
- Check the terminal position (L or R) and terminal type. See car battery size codes explained.
- Check that the hold-down bracket will fit.
Step 5: check the type
If your car has a start-stop system or many electrical features, it may need an EFB or AGM battery. A standard battery in such a car will wear out quickly. Replace like with like.
Step 6: check freshness and quality
- Look at the date code and choose a fresh battery.
- Ask for the warranty terms in writing.
- Check that the battery looks and feels genuine. See how to spot fake, refurbished or old-stock tyres and batteries.
Step 7: confirm that the old battery is the problem
Do not replace the battery if the problem is the alternator or a drain. Test it first. See how to test a car battery and car won't start: battery or starter?
Common mistakes
- Buying by price alone
- Choosing the wrong terminal side
- Choosing a battery with less capacity or starting power than the original
- Ignoring the date code
- Leaving the old battery behind. Take it to a recycler.
After buying
Fit it carefully, following how to replace a car battery safely, and keep the receipt and warranty.