# Optima RTC-4.2 · Car battery 12V 50Ah 815A

![Optima RTC-4.2 · Car battery 12V 50Ah 815A](https://bateriasonline.es/3851-home_default/optima-rtc-4-2.jpg)

> Optima RTC-4.2 (ETN 801287000): 50 Ah car battery, 815 A (EN), 254×175×200 mm, spiral AGM. Equivalent to Optima RTR-4.2 and Optima RTS-4.2.

**Category:** [Car batteries](https://bateriasonline.es/en/car-batteries) → [Optima](https://bateriasonline.es/en/optima-batteries)

- **Canonical URL**: https://bateriasonline.es/en/optima-rtc-4-2
- **Language**: en
- **Brand**: Optima
- **Reference**: BOL-OPTIMA-RTC-4.2
- **EAN**: 4016987113455
- **MPN**: RTC-4.2
- **Price**: 181,81 € (VAT incl., Spain)
- **Last updated**: 2026-10-27

## Technical specifications

| Feature | Value |
|---|---|
| Brand | Optima |
| Range | OPTIMA RED TOP |
| Application | Cars |
| Technology | Spiral AGM |
| Voltage | 12 V |
| Capacity | 50 Ah |
| Cold cranking amps (EN) | 815 A |
| Length | 254 mm |
| Width | 175 mm |
| Height | 200 mm |
| Weight | 18.5 kg |
| Terminal layout | 8 |
| ETN code | 801287000 |

## Quick description

The Optima RTC-4.2 (ETN 801 287 000, also written 801287000) is a car battery (spiral AGM) with 12 V, 50 Ah and 815 A cold cranking current, measuring 254 × 175 × 200 mm.

## Description

## Where the Optima RTC-4.2 fits

The Optima RTC-4.2 is a starter battery for cars without Start-Stop: it delivers the current the starter motor needs and then powers lights, control units and audio with the engine off. If your car has no Start-Stop and had a 50 Ah battery, the RTC-4.2 is a direct replacement.
At 50 Ah it covers petrol compacts and small diesels, the best-selling format in Europe. The RTC-4.2 belongs to the Optima OPTIMA RED TOP range. [See all Optima batteries](https://bateriasonline.es/en/optima-batteries)

## Optima RTC-4.2 vs RTR-3.7 and RTS-3.7: differences

Torn between the RTC-4.2 and another similar Optima? This is what changes:

| Model | Capacity | Cold cranking (EN) | Dimensions (mm) | Weight |
|---|---|---|---|---|
| Optima RTC-4.2 (this one) | 50 Ah | 815 A | 254 × 175 × 200 | 18.5 kg |
| Optima RTR-3.7 | 44 Ah | 730 A | 237 × 172 × 197 | 15.6 kg |
| Optima RTS-3.7 | 44 Ah | 730 A | 237 × 172 × 197 | 15.6 kg |

- Optima RTR-3.7: 6 Ah less, 85 A less cranking power, a different case (237 × 172 × 197 mm).
- Optima RTS-3.7: 6 Ah less, 85 A less cranking power, a different case (237 × 172 × 197 mm).

## Optima RTC-4.2 codes and part numbers

Look for any of these RTC-4.2 codes on your current battery or in the manufacturer's catalogue:

| Commercial reference | RTC-4.2 |
|---|---|
| ETN code | 801287000 (also 801 287 000) |
| EAN | 4016987113455 |
| Case size according to Optima | 34C (BCI) |
| Base hold-down | B00 |
| Also known as | Optima 801287000 · Optima 801 287 000 |
| Not to be confused with | Optima RTF-4.2 (50 Ah, 815 A, positive terminal on the left), Optima RTR-4.2 (50 Ah, 815 A, positive terminal on the right), Optima RTS-4.2 (50 Ah, 815 A, positive terminal on the left) |

## Equivalents and alternatives to the Optima RTC-4.2

As the RTC-4.2 is an AGM battery, we only list other AGM batteries with its dimensions and polarity: neither an EFB nor a conventional battery can replace it.

| Model | Technology | Capacity | Cold cranking (EN) | Dimensions (mm) |
|---|---|---|---|---|
| Optima RTR-4.2 | Spiral AGM | 50 Ah | 815 A | 254 × 175 × 200 |
| Optima RTS-4.2 | Spiral AGM | 50 Ah | 815 A | 254 × 175 × 200 |
| Optima RTU-4.2 | Spiral AGM | 50 Ah | 815 A | 254 × 175 × 200 |

## Before ordering the RTC-4.2, check this

- The RTC-4.2 needs 254 × 175 × 200 mm of space: measure it with the hold-down clamp in place.
- With 50 Ah, the RTC-4.2 replaces an original battery of that capacity or slightly less.
- Cold cranking: 815 A (EN), equal to or higher than the original.
- The RTC-4.2 is AGM: it replaces an AGM or an EFB of the same size. You can swap an EFB for an AGM, but not an AGM for an EFB.

## Inside the RTC-4.2: spiral AGM technology

The RTC-4.2 is a spiral-cell AGM battery. Perfect for 4x4s, marine use and vehicles with lots of electronics.

## Frequently asked questions about the Optima RTC-4.2

### Optima RTC-4.2 or RTR-3.7?

Compared with the RTC-4.2, the Optima RTR-3.7 has 6 Ah less and 85 A less cranking power. The RTC-4.2 cranks harder; the RTR-3.7 is only a good option if your original battery says 730 A or less. Mind the space: the RTR-3.7 measures 237 × 172 × 197 mm.

### What is the ETN code of the Optima RTC-4.2?

801287000, also written 801 287 000. The ETN (European Type Number) is printed on the label and used in parts catalogues.

### Can the Optima RTC-4.2 be used in a car with Start-Stop?

Yes. As an AGM battery, the RTC-4.2 handles automatic engine stop and brake energy recovery, and it can replace an EFB of the same size.

### How much does the Optima RTC-4.2 weigh?

The RTC-4.2 weighs 18.5 kg. For reference, the Optima RTR-3.7 (44 Ah) weighs 15.6 kg.

### Which battery is equivalent to the Optima RTC-4.2?

Only other AGM batteries with its dimensions and polarity: Optima RTR-4.2, Optima RTS-4.2 and Optima RTU-4.2. Neither an EFB nor a conventional battery replaces the RTC-4.2.

### How long does a car battery like the Optima RTC-4.2 last?

Between 4 and 6 years in normal use. Very short trips, extreme heat and leaving the car parked for weeks without starting it shorten its life.

## More batteries to compare with the RTC-4.2

- [More car batteries](https://bateriasonline.es/en/car-batteries)
- [The whole Optima range](https://bateriasonline.es/en/optima-batteries)
- [Optima RTR-4.2](https://bateriasonline.es/en/optima-rtr-4-2) · 50 Ah, 815 A, 254×175×200 mm
- [Optima RTS-4.2](https://bateriasonline.es/en/optima-rts-4-2) · 50 Ah, 815 A, 254×175×200 mm

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*bateriasonline.es — Batteries and accessories · 2026-11-10*