# Varta A10 · Auxiliary battery 12V 40Ah 420A

![Varta A10 · Auxiliary battery 12V 40Ah 420A](https://bateriasonline.es/1554-home_default/varta-a10.jpg)

> Varta A10 (ETN 540901042): 40 Ah auxiliary battery, 420 A (EN), 175×175×190 mm, positive terminal on the right, L0 case, AGM.

**Category:** [Auxiliary batteries (back-up and in-vehicle service)](https://bateriasonline.es/en/auxiliary-backup-batteries) → [Varta](https://bateriasonline.es/en/varta-batteries)

- **Canonical URL**: https://bateriasonline.es/en/varta-a10
- **Language**: en
- **Brand**: Varta
- **Reference**: BOL-VARTA-A10
- **EAN**: 4016987168752
- **MPN**: A10
- **Price**: 103,21 € (VAT incl., Spain)
- **Last updated**: 2026-11-07

## Technical specifications

| Feature | Value |
|---|---|
| Brand | Varta |
| Range | VARTA Dynamic AGM |
| Application | Auxiliary and back-up use |
| Technology | AGM |
| Voltage | 12 V |
| Capacity | 40 Ah |
| Cold cranking amps (EN) | 420 A |
| Length | 175 mm |
| Width | 175 mm |
| Height | 190 mm |
| Weight | 12.19 kg |
| Polarity | Positive terminal on the right |
| Case size | L0 (175 × 175 × 190 mm) |
| ETN code | 540901042 |

## Quick description

The Varta A10 (ETN 540 901 042, also written A 10 or 540901042) is an auxiliary battery (AGM) with 12 V, 40 Ah and 420 A cold cranking current, case size L0 (175 × 175 × 190 mm), with the positive terminal on the right.

## Description

## Who the Varta A10 is for

The Varta A10 is the second battery fitted in many modern cars. Without it, Start-Stop or back-up warnings appear on the dashboard.
In the Varta catalogue, the A10 belongs to the Dynamic AGM line. [More Varta batteries](https://bateriasonline.es/en/varta-batteries)

## Equivalents and alternatives to the Varta A10

We have no other battery with exactly the dimensions and polarity of the A10. Browse the rest of our [auxiliary batteries (back-up and in-vehicle service)](https://bateriasonline.es/en/auxiliary-backup-batteries) to compare close options.

## AGM technology in the A10

Inside, the A10 has glass fibre separators (AGM) that hold the electrolyte. The A10 needs a charger with an AGM mode that does not exceed 14.7 V.

## Check this before ordering the Varta A10

- Measure the space: the A10 takes up 175 × 175 × 190 mm (European case size L0).
- Polarity of the A10: positive terminal on the right (if yours has it on the other side, the cables will not reach).
- Capacity of the A10: 40 Ah; the same as your current battery or slightly more is fine.
- Cold cranking: 420 A (EN), equal to or higher than the original.

## Part numbers and codes for the Varta A10

This is how the Varta A10 appears on the label and in parts catalogues:

| Commercial reference | A10 (A 10) |
|---|---|
| ETN code | 540901042 (also 540 901 042) |
| EAN | 4016987168752 |
| Case size (EN) | L0 |
| Case size according to Varta | L0 / H3 |
| Base hold-down | B13 |
| Also known as | Varta A 10 · Varta 540901042 · Varta 540 901 042 |
| Not to be confused with | Varta A17 (41 Ah, 360 A), Varta F10 (88 Ah, 680 A), Varta A13 (40 Ah, 330 A) |

## Frequently asked questions about the Varta A10

### What does the code 540 901 042 on the Varta A10 mean?

It is its ETN (European Type Number), also written 540901042. The first three digits (540) encode voltage and capacity: 12 V and 40 Ah (5xx = under 100 Ah, 6xx = 100 to 199 Ah, 7xx = 200 Ah or more). The middle group (901) identifies the specific model within that capacity, and the last three digits (042) multiplied by 10 give the cold cranking current: 420 A.

### How much does the Varta A10 weigh?

12.19 kg, with 40 Ah of capacity.

### What case size is the Varta A10?

Case size L0: 175 × 175 × 190 mm (Varta lists it as L0 / H3). The A10 fits any standard L0 battery tray.

### What is the cold cranking current of the Varta A10?

420 A to the EN standard, with 40 Ah capacity.

### Which side is the positive terminal on the Varta A10?

On the A10, the positive terminal is on the right with the terminals facing you: compare it with your current battery, because with reversed polarity the cables will not reach.

### What warnings does the car give when the auxiliary battery fails?

Typically Start-Stop unavailable, back-up battery fault or emergency call system fault. The car still starts, but those functions are disabled.

## Other options if you are unsure about the A10

- [All auxiliary batteries (back-up and in-vehicle service)](https://bateriasonline.es/en/auxiliary-backup-batteries)
- [Full Varta catalogue](https://bateriasonline.es/en/varta-batteries)
- [Exide EK500](https://bateriasonline.es/en/exide-ek500) · 50 Ah, 570 A, 207×175×190 mm

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