# Optima YTS-2.1 · Classic car battery 6V 55Ah 765A

![Optima YTS-2.1 · Classic car battery 6V 55Ah 765A](https://bateriasonline.es/3885-home_default/optima-yts-2-1.jpg)

> Optima YTS-2.1 (ETN 818356000): 55 Ah classic car battery, 765 A (EN), 255×90×206 mm, positive terminal on the left, spiral AGM.

**Category:** [6V batteries for classic cars](https://bateriasonline.es/en/classic-car-batteries) → [Optima](https://bateriasonline.es/en/optima-batteries)

- **Canonical URL**: https://bateriasonline.es/en/optima-yts-2-1
- **Language**: en
- **Brand**: Optima
- **Reference**: BOL-OPTIMA-YTS-2.1
- **EAN**: 4016987124093
- **MPN**: YTS-2.1
- **Price**: 157,89 € (VAT incl., Spain)
- **Last updated**: 2026-10-27

## Technical specifications

| Feature | Value |
|---|---|
| Brand | Optima |
| Range | OPTIMA YELLOW TOP |
| Application | Classic cars |
| Technology | Spiral AGM |
| Voltage | 6 V |
| Capacity | 55 Ah |
| Cold cranking amps (EN) | 765 A |
| Length | 255 mm |
| Width | 90 mm |
| Height | 206 mm |
| Weight | 10.6 kg |
| Polarity | Positive terminal on the left |
| ETN code | 818356000 |

## Quick description

The Optima YTS-2.1 (ETN 818 356 000, also written 818356000) is a classic car battery (spiral AGM) with 6 V, 55 Ah and 765 A cold cranking current, measuring 255 × 90 × 206 mm, with the positive terminal on the left.

## Description

## The Optima YTS-2.1 at a glance

The Optima YTS-2.1 solves starting in a classic: voltage and size from another era with modern manufacturing, so the car starts at the first try again.
At 55 Ah it covers petrol compacts and small diesels, the best-selling format in Europe. The YTS-2.1 belongs to the Optima OPTIMA YELLOW TOP range. [See all Optima batteries](https://bateriasonline.es/en/optima-batteries)

## Optima YTS-2.1 vs RTS-2.1

How the YTS-2.1 compares with Optima batteries of similar size and capacity:

| Model | Capacity | Cold cranking (EN) | Dimensions (mm) | Positive | Weight |
|---|---|---|---|---|---|
| Optima YTS-2.1 (this one) | 55 Ah | 765 A | 255 × 90 × 206 | left | 10.6 kg |
| Optima RTS-2.1 | 50 Ah | 815 A | 254 × 90 × 203 | – | 8.9 kg |

- Optima RTS-2.1: 5 Ah less, 50 A more cranking power, a different case (254 × 90 × 203 mm).

## Optima YTS-2.1 codes and part numbers

Shops, garages and catalogues identify the YTS-2.1 with these codes:

| Commercial reference | YTS-2.1 |
|---|---|
| ETN code | 818356000 (also 818 356 000) |
| EAN | 4016987124093 |
| Base hold-down | B03 |
| Also known as | Optima 818356000 · Optima 818 356 000 |
| Not to be confused with | Optima RTS-2.1 (50 Ah, 815 A), Optima YTS-2.7 (38 Ah, 460 A) |

## Equivalents and alternatives to the Optima YTS-2.1

No other reference in the catalogue fully matches the dimensions and polarity of the YTS-2.1; you will find the closest ones among our [6V batteries for classic cars](https://bateriasonline.es/en/classic-car-batteries).

## What to look at before buying the YTS-2.1

- Measure the space: the YTS-2.1 takes up 255 × 90 × 206 mm.
- The YTS-2.1 has the positive terminal on the left: compare it with your current battery.
- Your current battery should say about 55 Ah; a little more is also fine.
- The YTS-2.1 delivers 765 A cold cranking (EN standard); do not go below what your original battery states.

## Inside the YTS-2.1: spiral AGM technology

Inside, the YTS-2.1 rolls its plates into cylindrical cells (spiral AGM). It is the basis of OPTIMA batteries.

## Frequently asked questions about the Optima YTS-2.1

### Optima YTS-2.1 or RTS-2.1?

Compared with the YTS-2.1, the Optima RTS-2.1 has 5 Ah less and 50 A more cranking power. If your current battery says 815 A or more, choose the RTS-2.1; if it says 765 A or less, the YTS-2.1 is enough. Mind the space: the RTS-2.1 measures 254 × 90 × 203 mm.

### What is the ETN code of the Optima YTS-2.1?

818356000, also written 818 356 000. The ETN (European Type Number) is printed on the label and used in parts catalogues.

### How much does the Optima YTS-2.1 weigh?

The YTS-2.1 weighs 10.6 kg. For reference, the Optima RTS-2.1 (50 Ah) weighs 8.9 kg.

### Which side is the positive terminal on the Optima YTS-2.1?

The YTS-2.1 has the positive terminal on the left, looking at the battery from its long side with the terminals closest to you.

### How do I preserve the battery of a classic I rarely drive?

With a maintenance charger connected whenever the car sleeps for more than two weeks. Avoid deep discharge: it is what shortens a lead battery's life most.

## More batteries to compare with the YTS-2.1

- [Other 6V batteries for classic cars](https://bateriasonline.es/en/classic-car-batteries)
- [More Optima models](https://bateriasonline.es/en/optima-batteries)

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