If you’ve ever tried to buy a replacement car battery and been hit with codes like 652AGM or 646P, you’re not alone. Battery size codes can feel confusing — but they’re one of the fastest ways to make sure you get the correct fit, correct terminal layout, and the right performance for your vehicle.
This guide explains common battery size codes, including 616P, 615P, 618P, 628P, 646P, 649P, 658P, 668P and their AGM variants, what these codes generally mean, how to choose the right one, and what to check before you buy — so you avoid common issues like “it doesn’t fit”, “the terminals are on the wrong side”, or “the battery dies too quickly”.
Why battery size codes matter (and why “any battery will do” is a myth)
Choosing the wrong battery size can cause real problems, like:
- The battery doesn’t physically fit the tray or clamp
- Terminal layout is wrong (leads don’t reach / risk of shorting)
- Not enough cold cranking power (CCA) → slow starts, especially in winter
- Wrong technology for your vehicle (especially with Stop/Start systems)
- Shorter battery life and repeat replacements
If you’re searching things like:
- “which car battery size do I need”
- “652AGM battery”
- “668P battery”
- “AGM vs normal car battery”
- “car battery replacement near me”
…then you’re in exactly the right place.
Understanding the code: what do “P”, “AGM”, and “PS” usually mean?
Battery codes (like 652AGM) are commonly used in South African battery catalogues to group batteries by case size + terminal layout + specs range. While the exact meaning can vary slightly by supplier catalogue, here’s how these labels are typically used:
What does “AGM” mean on a battery?
AGM stands for Absorbent Glass Mat. It is a distinct battery technology that may be specified for some vehicles. Confirm the exact vehicle requirement before choosing it.
- Stop/Start vehicles
- Cars with high electrical load (multiple computers, sensors, infotainment)
- Vehicles that do lots of short trips
- Better resistance to vibration and deep cycling than standard flooded batteries
What does “P” mean on a battery size (e.g., 646P, 668P)?
In many catalogues, the letter (like P) is used to indicate a specific terminal orientation/polarity layout for that battery case type. This matters because even if two batteries are “the same size”, the positive and negative terminal positions can differ.
Quick takeaway: If your current battery says 646P, replacing it with a different terminal layout can cause fitment and safety issues.
What does “PS” mean (e.g., 652PS)?
“PS” is often used as a catalogue marker for a variant in the same size family, sometimes linked to application type or spec differences. Because “PS” labeling can differ between catalogues, it’s best to match what’s currently in your vehicle or confirm using your vehicle details.
Battery size codes covered in this guide
This guide covers the following battery size codes:
- 616P
- 615P
- 618P
- 628P
- 646P
- 646AGM
- 612AGM
- 652PS
- 652AGM
- 668P
- 668AGM
- 658P
- 658AGM
- 649P
If you searched any of these (example: “652AGM battery near me”, “658P car battery”, “646AGM battery”), this post is built to help you choose correctly.
How to choose the correct battery size (step-by-step checklist)
Before buying a replacement battery, check these 7 critical items:
1) Match the existing battery code (best starting point)
If your current battery label shows 668P, then start by replacing with 668P (or the correct approved equivalent).
2) Confirm battery type: Standard vs AGM
- If your vehicle has Stop/Start, confirm the manufacturer-specified battery technology for the exact model.
- Do not change from AGM to standard without authoritative vehicle specifications.
- Do not change from standard to AGM without confirming compatibility, fitment, and specifications.
3) Check terminal position (polarity/layout)
This is where “P” variants matter. Wrong layout can mean:
- Cables don’t reach
- Terminals can contact metal parts (dangerous)
- Installation becomes a hack-job (and reliability drops)
4) Check the hold-down/clamp type and tray length
Even “almost the same size” can fail because:
- the clamp doesn’t align
- the battery is too tall
- the battery moves (vibration kills batteries)
5) Check CCA (Cold Cranking Amps)
CCA is the battery’s starting power. Too low = slow starts and strain on the starter.
6) Check Ah (Amp-hour) capacity
Ah relates to how long the battery can support electrical demand. Too low can lead to repeated flat batteries.
7) Vehicle electronics & coding
Some vehicles require battery registration/coding after replacement. If your vehicle is sensitive, correct spec matters even more.
Quick guidance on each battery size code
Below is practical, buyer-friendly guidance for each code. (Exact Ah/CCA varies by model variant — always confirm your required spec.)
615P battery
Often used where a compact battery with correct terminal layout is required. Key checks:
- Terminal layout match
- Adequate CCA for your engine size
616P battery
Commonly chosen when a slightly different fitment/spec range is needed from closely-related sizes. Key checks:
- Tray fit
- Clamp alignment
- Cable reach
618P battery
A popular size family in many passenger vehicle applications. Key checks:
- Correct terminal orientation (“P”)
- Compare CCA/Ah to your current battery
628P battery
Often selected where more starting power/capacity is required than smaller case options. Key checks:
- Physical size (length/height)
- CCA matching your engine needs
646P battery
A widely searched size code. Key checks:
- Terminal layout match
- Proper clamp fit (very important)
646AGM battery
An AGM-labelled option in the 646 size family. Confirm the exact vehicle requirement and fitment. Key checks:
- Confirm Stop/Start battery requirements for the exact vehicle
- AGM suitability for your charging system
- Correct fitment vs 646P
612AGM battery
An AGM-labelled option in the 612 size family. Confirm the exact vehicle requirement and fitment. Key checks:
- Confirm the required battery technology before replacement
- Correct terminal layout + tray fit
652PS battery
A variant in the 652 family. Key checks:
- Match the exact code if it’s currently installed
- Confirm terminal layout and clamp type
- Confirm required CCA/Ah
652AGM battery
An AGM-labelled option in the 652 size family. Confirm the exact vehicle requirement and fitment. Key checks:
- For Stop/Start vehicles, confirm the manufacturer-specified technology
- Ensure the correct fitment and spec range
668P battery
A highly searched battery size in many catalogues. Key checks:
- Terminal layout match
- CCA sufficient for your engine
- Tray fit and clamp alignment
668AGM battery
An AGM-labelled option in the 668 size family. Confirm the exact vehicle requirement and fitment. Key checks:
- Confirm whether AGM is required for the exact vehicle
- Do not change battery technology without confirming vehicle requirements
- Confirm spec range and fitment
658P battery
A common size family for customers searching by code. Key checks:
- Exact fitment
- Terminal layout
- Compare Ah/CCA to your existing battery
658AGM battery
An AGM-labelled option in the 658 size family. Confirm the exact vehicle requirement and fitment. Key checks:
- Confirm Stop/Start battery requirements for the exact vehicle
- Confirm the required electrical specification
- Correct fitment
649P battery
A battery size code where correct polarity and layout are critical. Key checks:
- Terminal orientation (“P”)
- Clamp/tray fit
Frequently asked questions
Can I choose a battery from the size code alone?
No. The size code is only one part of fitment. Confirm the vehicle specification, battery dimensions, terminal layout, technology, and electrical requirements before replacement.
Can I replace an AGM battery with a standard battery?
Do not change battery technology based on a general online guide. Follow the vehicle manufacturer’s specification or other authoritative vehicle information for the exact model.
What details should I provide when I call?
Provide the exact location, vehicle make, model, year, engine details, current battery label if visible, and the symptoms you noticed.
What if the battery keeps going flat?
A repeat no-start problem can have more than one cause. Battery Near Me tests the battery first. If replacement is not indicated, the test result helps you decide on the next step.
Need mobile battery help in Cape Town?
Battery Near Me provides 24/7 mobile battery testing and replacement for cars and trucks in the Cape Town service area. We target arrival in 30–60 minutes, depending on location, traffic, and team availability. Read about mobile car battery replacement, mobile truck battery replacement, or request a current quote. Call 074 347 9479.