# OPTIMA RED TOP batteries

> OPTIMA Red Top pure-cranking AGM SpiralCell: restomods, hot-rods, European V8s. 38-75 Ah, 730-1000 A CCA. RT R 3.7, RT S 4.2, RT 34. 24h delivery.

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## Description

**OPTIMA Red Top batteries** are the pure-cranking AGM SpiralCell variant of the OPTIMA range: no deep-cycle capability, built to deliver the brand's highest cold-cranking amps (CCA) peak. 38-75 Ah, CCA 730-1000 A, across the RT R 3.7, RT S 4.2, RT R 5.0 and RT 34 models.
Ideal for American classic restomods, hot-rods, high-performance European V8s and tuning projects with no heavy auxiliary loads, where the only thing that matters is starting the engine with maximum reliability.

## OPTIMA Red Top: pure cranking, no deep cycle

The Red Top series is the **cranking-only** variant of OPTIMA's SpiralCell technology: spiral-wound lead plates delivering a far higher CCA peak than a conventional lead-acid battery of the same size, but with no deep-cycle capability.
That's why it's the go-to choice for modified cars whose engine demands a reliable start with high compression and zero margin for error.

### What projects the Red Top is built for

- American classic restorations and **restomods**.
- **Hot-rods** and show cars.
- High-performance **European V8s** (BMW M and similar).
- Classic American pick-ups with large-displacement engines.

### Compatibility and how to choose your OPTIMA Red Top

RT R 3.7 (44 Ah, 730 A) for compacts, RT S 4.2 and RT R 5.0 (50 Ah, 815 A) for European V8s and hot-rods, RT 34 (55 Ah, 875 A) for classic pick-ups. With HiFi audio, a winch or a motorhome use [Yellow Top](/gb/batteries-optima-yellow-top); for boats, the marine [Blue Top](/gb/batteries-optima-blue-top). Check fitment with our [comparator](/gb/comparator) or your [number plate](/gb/battery-finder-by-plate).

## Frequently asked questions about OPTIMA Red Top

### **Is the Red Top suitable for deep cycling?**

No: it delivers very high CCA peaks but isn't designed for repeated deep discharges. That's what the Yellow Top series is for.

### **What's the difference between RT S 4.2 and RT R 5.0?**

They share Ah and CCA; only terminal layout and case shape change to fit different vehicle bays.

### **Will it fit my classic or restomod car?**

It depends on tray dimensions and terminal polarity; use the comparator or tell us your make and model.

### **How long does an OPTIMA Red Top last?**

Used correctly (no deep discharges) it typically outlasts a conventional lead-acid battery thanks to the SpiralCell build, more resistant to vibration and heat.

Catalogue curated by our technical team. **11,760 Trustpilot reviews · 4.5/5**. 24h mainland delivery, free 14-day returns.

## Products in this category

| Product | Brand | Price |
|---|---|---|
| [Car battery Optima RTC-4.2 12V 50Ah 815A AGM](https://baterias.com/gb/battery-optima-red-top-rtc-42-8001-287-12v-50ah) | OPTIMA | 185,80 € |
| [Car battery Optima RTS-4.2 12V 50Ah 815A AGM](https://baterias.com/gb/battery-optima-red-top-rts-42-8002-250-12v-50ah) | OPTIMA | 187,40 € |
| [Car battery Optima RTS-2.1 6V 50Ah 815A AGM](https://baterias.com/gb/battery-optima-red-top-rts-21-8010-355-12v-50ah) | OPTIMA | 163,60 € |
| [Car battery Optima RTU-4.2 12V 50Ah 815A AGM](https://baterias.com/gb/battery-optima-red-top-rtu-42-8004-250-12v-50ah) | OPTIMA | 185,80 € |
| [Car battery Optima RTU-3.7 12V 44Ah 730A AGM](https://baterias.com/gb/battery-optima-red-top-rtu-37-8022-255-12v-44ah) | OPTIMA | 187,30 € |
| [Car battery Optima RTR-3.7 12V 44Ah 730A AGM](https://baterias.com/gb/battery-optima-red-top-rtr-37-8035-255-12v-44ah) | OPTIMA | 191,90 € |
| [Car battery Optima RTR-4.2 12V 50Ah 815A AGM](https://baterias.com/gb/battery-optima-red-top-rtr-42-8003-251-12v-50ah) | OPTIMA | 209,90 € |
| [Car battery Optima RTF-4.2 12V 50Ah 815A AGM](https://baterias.com/gb/battery-optima-red-top-rtf-42-8078-209-12v-50ah) | OPTIMA | 204,95 € |
| [Car battery Optima RTS-3.7 12V 44Ah 730A AGM](https://baterias.com/gb/battery-optima-red-top-rts-37-8020-255-12v-44ah) | OPTIMA | 190,80 € |

## Technical team (editorial authorship)

The FAQs, guides and comparisons on this site are reviewed by the baterias.com technical team — over 25 years of experience validating automotive batteries.

→ https://baterias.com/gb/technical-team

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*baterias.com — Automotive batteries · 2026-09-25*