# Fulmen FK508 · Start-Stop battery 12V 50Ah 800A

![Fulmen FK508 · Start-Stop battery 12V 50Ah 800A](https://bateriasonline.es/2643-home_default/fulmen-fk508.jpg)

> Fulmen FK508: 50 Ah Start-Stop battery, 800 A (EN), 260×173×206 mm, AGM. Equivalent to Exide EK508 and Tudor TK508. Ask for a no-obligation quote.

**Category:** [Start-Stop batteries (AGM and EFB)](https://bateriasonline.es/en/start-stop-batteries-agm-efb) → [Fulmen](https://bateriasonline.es/en/fulmen-batteries)

- **Canonical URL**: https://bateriasonline.es/en/fulmen-fk508
- **Language**: en
- **Brand**: Fulmen
- **Reference**: BOL-FULMEN-FK508
- **EAN**: 3661024046442
- **MPN**: FK508
- **Last updated**: 2026-10-27

## Technical specifications

| Feature | Value |
|---|---|
| Brand | Fulmen |
| Range | FULMEN AGM |
| Application | Start-Stop cars |
| Technology | AGM |
| Voltage | 12 V |
| Capacity | 50 Ah |
| Cold cranking amps (EN) | 800 A |
| Length | 260 mm |
| Width | 173 mm |
| Height | 206 mm |
| Weight | 17.5 kg |
| Terminal layout | 9 |

## Quick description

Fulmen FK508: Start-Stop battery (AGM) with 12 V, 50 Ah and 800 A cold cranking current, measuring 260 × 173 × 206 mm.

## Description

## Where the Fulmen FK508 fits

The Fulmen FK508 is a battery for cars with Start-Stop: it withstands many more starting and partial-discharge cycles than a conventional battery and powers the electronics every time the engine stops at the lights. It takes repeated discharges without losing capacity the way a conventional battery would.
At 50 Ah it covers petrol compacts and small diesels, the best-selling format in Europe. The FK508 belongs to the Fulmen FULMEN AGM range. [The full range of Fulmen batteries](https://bateriasonline.es/en/fulmen-batteries)

## Fulmen FK508 vs FK600 and FK620: differences

What sets the FK508 apart from its neighbours in the Fulmen range:

| Model | Capacity | Cold cranking (EN) | Dimensions (mm) | Weight |
|---|---|---|---|---|
| Fulmen FK508 (this one) | 50 Ah | 800 A | 260 × 173 × 206 | 17.5 kg |
| Fulmen FK600 | 60 Ah | 680 A | 242 × 175 × 190 | 17.9 kg |
| Fulmen FK620 | 62 Ah | 680 A | 242 × 175 × 190 | 17.9 kg |

- Fulmen FK600: 10 Ah more, 120 A less cranking power, a different case (242 × 175 × 190 mm).
- Fulmen FK620: 12 Ah more, 120 A less cranking power, a different case (242 × 175 × 190 mm).

## Fulmen FK508 codes and part numbers

Look for any of these FK508 codes on your current battery or in the manufacturer's catalogue:

| Commercial reference | FK508 |
|---|---|
| EAN | 3661024046442 |

## Equivalents and alternatives to the Fulmen FK508

As the FK508 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) |
|---|---|---|---|---|
| Exide EK508 | AGM | 50 Ah | 800 A | 260 × 173 × 206 |
| Tudor TK508 | AGM | 50 Ah | 800 A | 260 × 173 × 206 |
| Deta DK508 | AGM | 50 Ah | 800 A | 260 × 173 × 206 |

## Check this before ordering the Fulmen FK508

- Length, width and height of the FK508: 260 × 173 × 206 mm.
- With 50 Ah, the FK508 replaces an original battery of that capacity or slightly less.
- Check the EN amps on your battery: if it says 800 A or less, the FK508 covers your engine.
- The FK508 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.

## What it means that the FK508 is AGM

The FK508 is AGM: the electrolyte is absorbed in glass fibre mats, so it is sealed and spill-proof. Being sealed, the FK508 can be fitted in the boot or under a seat with no risk of spills.

## Frequently asked questions about the Fulmen FK508

### Fulmen FK508 or FK600?

Compared with the FK508, the Fulmen FK600 has 10 Ah more and 120 A less cranking power. The FK508 cranks harder; the FK600 is only a good option if your original battery says 680 A or less. Mind the space: the FK600 measures 242 × 175 × 190 mm.

### Can the Fulmen FK508 be used in a car with Start-Stop?

Yes. As an AGM battery, the FK508 handles automatic engine stop and brake energy recovery, and it can replace an EFB of the same size.

### How much does the Fulmen FK508 weigh?

The FK508 weighs 17.5 kg. For reference, the Fulmen FK600 (60 Ah) weighs 17.9 kg.

### Which battery is equivalent to the Fulmen FK508?

Only other AGM batteries with its dimensions and polarity: Exide EK508, Tudor TK508 and Deta DK508. Neither an EFB nor a conventional battery replaces the FK508.

### Which charger does the Fulmen FK508 need?

A charger with an AGM mode that limits voltage to about 14.4-14.7 V. Never an old unregulated charger: overcharging dries out an AGM beyond repair.

## More batteries to compare with the FK508

- [Other start-Stop batteries (AGM and EFB)](https://bateriasonline.es/en/start-stop-batteries-agm-efb)
- [More Fulmen models](https://bateriasonline.es/en/fulmen-batteries)
- [Exide EK508](https://bateriasonline.es/en/exide-ek508) · 50 Ah, 800 A, 260×173×206 mm
- [Tudor TK508](https://bateriasonline.es/en/tudor-tk508) · 50 Ah, 800 A, 260×173×206 mm

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