# Car battery Optima RTR-4.2 12V 50Ah 815A AGM

![Car battery Optima RTR-4.2 12V 50Ah 815A AGM](https://baterias.com/3821-home_default/battery-optima-red-top-rtr-42-8003-251-12v-50ah.jpg)

> Optima RTR-4.2 car battery 12V 50Ah 815A AGM. RED TOP range. Dimensions 254×175×200 mm, + terminal on the right. Check fitment by plate.

**Category:** [Car Batteries](https://baterias.com/gb/car-batteries) → [OPTIMA](https://baterias.com/gb/optima)

- **Canonical URL**: https://baterias.com/gb/battery-optima-red-top-rtr-42-8003-251-12v-50ah
- **Language**: en-GB
- **Brand**: OPTIMA
- **Reference**: BCOM-OPTIMA-RTR-4.2
- **EAN**: 4016987113479
- **MPN**: RTR-4.2
- **Price**: 209,90 €
- **Stock**: In stock

## Technical specifications

| Feature | Value |
|---|---|
| Brand | OPTIMA |
| Reference | RTR-4.2 |
| Model | OPTIMA RED TOP |
| Voltage (V) | 12 V |
| Largo | 254 mm |
| Ancho | 172 mm |
| Alto | 173 mm |
| Peso | 18 kg |
| Tecnología | AGM ESPIRAL |
| EAN | 4016987113479 |
| Terminal layout | Positive terminal on the right |
| Terminal type | 1 |
| Hold down | B11 |
| Cold cranking amps (EN) | 815 A |
| Capacity (C20) | 50 Ah (c20) |
| ETN | 8032510008882 |

## Quick description

**Optima RTR-4.2 12V 50Ah 815A** is a starter battery with OEM-equivalent quality, designed for modern passenger cars. Delivers reliable cold-cranks even after weeks of inactivity and supports stable auxiliary loads (lights, climate control, infotainment).

### Why this car battery?

- **Original-equipment quality** without dealership prices
- **Lasts 4 to 6 years** buy once instead of twice
- **Real human tech support** if you have any doubts before buying

🔌 Voltage
12 V

⚡ Capacity
50 Ah C20

🔋 Cold cranking
815 A EN-1

📏 Dimensions
254×175×200 mm

⚙️ Technology
AGM ESPIRAL

🧭 Polarity
Positive on the right

⚖️ Weight
18 kg

🏷️ Model
OPTIMA RED TOP

## Description

## Car battery Optima RTR-4.2 Red Top 50Ah 815A 12V

12*V* Voltage
50*Ah* Capacity
815*A* Cold cranking
18*kg* Weight

With **50 Ah** at **12 V** and **815 A** of cold cranking current (EN), the **Optima RTR-4.2** from the **Red Top** range is a starter battery built for passenger cars with conventional starting, without a Start-Stop system. Measuring 254 × 172 × 173 mm and the positive terminal on the right, it is the direct replacement for cars fitted from the factory with a 50 Ah battery of this format.
- Low self-discharge: copes with long stops without losing charge.
- Designed to last several years under normal daily use.
- Spiral AGM construction, sealed and mountable in any position.
- Stable voltage for the vehicle electronics (ECU, sensors, climate control).

### Vehicles compatible with the Optima RTR-4.2

This battery appears as compatible in more than 37 vehicles from manufacturers such as Ford and Chevrolet. If you are looking for a **battery for a Ford** or Chevrolet with these dimensions, the RTR-4.2 is one of the usual replacement references. In our database it is cross-referenced against 2 original-equipment part numbers, which gives an idea of its real coverage.

### Dimensions, polarity and mounting

In terms of format, the Optima RTR-4.2 measures 254 × 172 × 173 mm (length × width × height) and weighs 18 kg. The positive terminal on the right decides which side the cables end up on: it is the detail that causes most buying mistakes, so check it before ordering. It uses a B11 hold-down and 1 terminals, the system that anchors and connects it in the vehicle. Checking the three dimensions and the terminal position before buying avoids the most common mistake when replacing a battery.

### Optima: the maker behind the RTR-4.2

Optima makes spiral-cell (SpiralCell) AGM batteries with pure lead: maximum vibration resistance, very powerful cranking and a durability recognised in 4x4, motorsport, marine and car audio. All the Optima batteries in our catalogue are genuine product, recently manufactured and covered by the manufacturer's warranty.

### The Optima RTR-4.2: Red Top range and spiral-cell AGM technology

The RTR-4.2 is part of the Optima **Red Top** range. Choosing the right reference within the series comes down to capacity, dimensions and terminals: technology and quality are common to the whole family.
Spiral AGM construction winds the plates into cylindrical pure-lead cells: maximum active surface, extreme vibration resistance and cranking current far above a battery of the same size.

### Usage and maintenance tips

Charge with a voltage-controlled AGM charger; a fully discharged pure-lead battery may need a specific charger to recover. In normal daily use the alternator keeps the battery charged; if the car stands for weeks, a maintenance charge once a month prevents deep discharge.

### Warranty and coverage

The Optima RTR-4.2 comes with the **manufacturer's official warranty** against manufacturing defects; the exact period is stated in the brand's conditions. If it fails through a defect within the period, we replace it free of charge.

### When you get it and how to return it

Orders placed **before [[ks:cutoff]]** with the battery in stock ship the same day. Delivery in mainland Spain and Portugal takes 24-48 working hours; for the Balearic and Canary Islands and the rest of the European Union allow 3 to 5 working days. You have **[[ks:return_days]] days** to return an unused battery; in mainland Spain and Portugal collection is free. We email you the tracking number as soon as the parcel ships.

## Frequently asked questions

### Is the Optima RTR-4.2 an AGM battery and what are the benefits of AGM?

Yes. The RTR-4.2 from Optima uses AGM (Absorbent Glass Mat) technology: a sealed lead-acid battery where the electrolyte is absorbed in a glass-fibre mat. It withstands more charge/discharge cycles than a conventional one, handles heat better and is the required technology for cars with advanced Start-Stop and regenerative braking. Expected lifespan: 5-8 years under normal conditions.

### Is the Optima RTR-4.2 battery suitable for Start-Stop?

Yes. As AGM technology it is designed for Start-Stop vehicles. AGM batteries support advanced Start-Stop and regenerative braking thanks to their higher cycle count. EFB is recommended for basic Start-Stop; AGM is recommended when regenerative braking is also present, thanks to its higher cycle capability. It works straight out of the box — on most modern vehicles registering the battery via OBD is recommended so the alternator automatically applies the optimal charging profile.

### How is the Optima RTR-4.2 battery installed in the vehicle?

In most cars it fits in 15-30 minutes with a 10 mm wrench; if the battery is under the seat or in the boot the time can double. See the step-by-step guide on this page. Quick summary: 1) switch off the engine and remove the key; 2) locate the original battery (engine bay, boot or under seat); 3) disconnect the negative (−) terminal first, then the positive (+); 4) loosen the hold-down clamp and remove the old battery; 5) fit the new one in the same orientation — match the polarity shown on the product sheet; 6) connect the positive (+) first, then the negative (−). On cars with Start-Stop or BMS, register the battery via OBD so the alternator applies the correct charging profile.

### What is the service life of the RTR-4.2 model?

Expected lifespan of the Optima RTR-4.2 is 5 to 8 years in mild-climate car use with Start-Stop. In cold regions it drops slightly due to cold-start stress; in very hot regions it also drops because of electrolyte evaporation. To extend its life: avoid deep discharges (headlights on with engine off), have the alternator checked yearly, and keep the battery clean and properly secured.

### What size is this battery?

Dimensions (length × width × height) are 254×175×200 mm — also written as 254x175x200 mm — following the European DIN standard. Always measure the space in your car before buying: even one extra millimetre can prevent the hold-down clamp from closing. The height shown includes the terminals.

### Under which reference is the Optima RTR-4.2 listed in catalogues?

The manufacturer reference (MPN) is RTR-4.2 and its ETN code is 8032510008882 (short form 803 251 000), the European identifier used in spare-part catalogues. The EAN-13 barcode is 4016987113479. It belongs to the OPTIMA RED TOP range. Any of these codes identifies exactly this battery when requesting quotes or comparing prices.

### Does this battery fit my car?

Three options to confirm: 1) enter your number plate in the finder (DGT/DVLA/KBA auto-detect your model and engine); 2) check the "Compatible vehicles" tab on this page, where we list every vehicle verified by our technical team; 3) if you cannot find your model, message us on WhatsApp with brand, model, engine and year — we reply during business hours (Mon–Fri 10:00–13:30 and 16:40–18:00 (Spanish time, CET)). The RTR-4.2 fits 37 verified vehicle versions in our database.

### What are the equivalents of the RTR-4.2 model?

Directly interchangeable batteries (same dimensions, same polarity, same Ah and CCA) are the OEM equivalents from leading brands: Bosch, Tudor, Exide and, depending on the model, Banner or Yuasa. Exact equivalence depends on technology — an EFB cannot be replaced with a conventional battery in Start-Stop cars. See the "Equivalents" section to view recommended options at the same performance level.

### What advantages does the Optima RTR-4.2 AGM battery offer over an EFB?

AGM (Absorbent Glass Mat) technology uses absorbent fibreglass that retains the electrolyte, eliminating leaks and allowing up to 3× more charge/discharge cycles than a conventional battery. It is the recommended option when the car has advanced Start-Stop with regenerative braking (BMW EfficientDynamics, Mercedes Eco, Audi MHEV, Land Rover ECO, Volvo i-Stop). Withstands tilted positions, high vibration and extreme temperatures better than EFB. The Optima RTR-4.2 is fully original and meets European EN 50342-6 standards for advanced Start-Stop.

### Is there anything to do after replacing a Start-Stop battery?

On most cars it is not strictly necessary — the alternator detects the new battery and adapts the charge automatically. It is recommended to register the battery via OBD so that the alternator applies the optimal charging profile from the first minute and extends the battery life as much as possible (especially on brands with sophisticated BMS: BMW, Mercedes, Audi, Volvo, Land Rover). Any workshop with an OBD scanner (~10-15 € labour) does it in 5 minutes. DIY apps: VCDS / Carista (VAG), Bimmercode (BMW), iCarsoft. If you do not register, the car will still start correctly — the alternator just takes a few days to adjust the profile. The Optima RTR-4.2 ships factory-charged at 80-90% so you can use it straight after fitting.


## Compatible vehicles

This battery fits 37 vehicles. Most searched:

- [FORD F-150 Crew Cab Pickup (2014)](https://baterias.com/gb/car-batteries/ford/f-150-crew-cab-pickup)
- [FORD F-150 Standard Cab Pickup (2008)](https://baterias.com/gb/car-batteries/ford/f-150-standard-cab-pickup)
- [FORD F-150 Extended Cab Pickup (2014)](https://baterias.com/gb/car-batteries/ford/f-150-extended-cab-pickup)
- [CHEVROLET SUBURBAN 1500 SUV (1993)](https://baterias.com/gb/car-batteries/chevrolet/suburban-1500-suv)
- [CHEVROLET TAHOE (GMT900) (2007)](https://baterias.com/gb/car-batteries/chevrolet/tahoe-gmt900)
- [CHEVROLET SILVERADO 2500 Crew Cab Pickup (2006)](https://baterias.com/gb/car-batteries/chevrolet/silverado-2500-crew-cab-pickup)

## Reviews

- **Average rating**: 4.8 / 5 (33 reviews)

## 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 · 2026-09-30*