# Varta AUX1 · Auxiliary battery 12V 35Ah 520A

![Varta AUX1 · Auxiliary battery 12V 35Ah 520A](https://bateriasonline.es/1140-home_default/varta-aux1.jpg)

> Varta AUX1 (ETN 535106052): 35 Ah auxiliary battery, 520 A (EN), 212×175×140 mm, positive terminal on the right. Equivalent to Kronobat AUX1.

**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-aux1
- **Language**: en
- **Brand**: Varta
- **Reference**: BOL-VARTA-AUX1
- **EAN**: 4016987167816
- **MPN**: AUX1
- **Price**: 144,55 € (VAT incl., Spain)
- **Last updated**: 2026-10-27

## Technical specifications

| Feature | Value |
|---|---|
| Brand | Varta |
| Range | VARTA Dynamic AUX |
| Application | Auxiliary and back-up use |
| Technology | Lead-acid |
| Voltage | 12 V |
| Capacity | 35 Ah |
| Cold cranking amps (EN) | 520 A |
| Length | 212 mm |
| Width | 175 mm |
| Height | 140 mm |
| Weight | 10.3 kg |
| Polarity | Positive terminal on the right |
| ETN code | 535106052 |

## Quick description

The Varta AUX1 (ETN 535 106 052, also written 535106052) is an auxiliary battery with 12 V, 35 Ah and 520 A cold cranking current, measuring 212 × 175 × 140 mm, with the positive terminal on the right.

## Description

## The Varta AUX1 at a glance

The Varta AUX1 is an auxiliary vehicle battery: it powers back-up functions such as Start-Stop, electric steering or the emergency system while the main battery starts the engine. Without it, Start-Stop or back-up warnings appear on the dashboard.
Varta lists the AUX1 in its Dynamic AUX line. [See all Varta batteries](https://bateriasonline.es/en/varta-batteries)

## Inside the AUX1: lead-acid technology

The AUX1 is a conventional lead-acid battery, with plates immersed in liquid electrolyte. Avoid leaving them discharged, as they sulphate, and charge them with a charger that cuts off or switches to maintenance when finished.

## Varta AUX1 vs A10: differences

How the AUX1 compares with Varta batteries of similar size and capacity:

| Model | Capacity | Cold cranking (EN) | Dimensions (mm) | Positive | Weight |
|---|---|---|---|---|---|
| Varta AUX1 (this one) | 35 Ah | 520 A | 212 × 175 × 140 | right | 10.3 kg |
| Varta A10 | 40 Ah | 420 A | 175 × 175 × 190 | right | 12.19 kg |

- Varta A10: 5 Ah more, 100 A less cranking power, a different case (175 × 175 × 190 mm), AGM technology.

## Equivalents and alternatives to the Varta AUX1

Same dimensions and polarity as the AUX1, with similar capacity and cranking power; as a conventional battery, the AUX1 can also be replaced by an EFB or AGM of the same size if you want more cycles.

| Model | Technology | Capacity | Cold cranking (EN) | Dimensions (mm) |
|---|---|---|---|---|
| Kronobat AUX1 | Lead-acid | 35 Ah | 520 A | 212 × 175 × 140 |

## Varta AUX1 codes and part numbers

The AUX1 is listed under these codes on labels, in garages and in catalogues:

| Commercial reference | AUX1 |
|---|---|
| ETN code | 535106052 (also 535 106 052) |
| EAN | 4016987167816 |
| Case size according to Varta | POB |
| Base hold-down | B13 |
| Also known as | Varta 535106052 · Varta 535 106 052 |
| Not to be confused with | Varta AUX14 (13 Ah, 200 A, positive terminal on the left), Varta AUX9 (9 Ah, 130 A, positive terminal on the left) |

## What to look at before buying the AUX1

- The AUX1 delivers 520 A cold cranking (EN standard); do not go below what your original battery states.
- Your current battery should say about 35 Ah; a little more is also fine.
- With the terminals facing you, the positive terminal of the AUX1 is on the right.
- The AUX1 needs 212 × 175 × 140 mm of space: measure it with the hold-down clamp in place.

## Frequently asked questions about the Varta AUX1

### Varta AUX1 or A10?

Compared with the AUX1, the Varta A10 has 5 Ah more, 100 A less cranking power and AGM technology. The AUX1 cranks harder; the A10 is only a good option if your original battery says 420 A or less. Mind the space: the A10 measures 175 × 175 × 190 mm.

### What does the code 535 106 052 on the Varta AUX1 mean?

It is its ETN (European Type Number), also written 535106052. The first three digits (535) encode voltage and capacity: 12 V and 35 Ah (5xx = under 100 Ah, 6xx = 100 to 199 Ah, 7xx = 200 Ah or more). The middle group (106) identifies the specific model within that capacity, and the last three digits (052) multiplied by 10 give the cold cranking current: 520 A.

### How much does the Varta AUX1 weigh?

The AUX1 weighs 10.3 kg. For reference, the Varta A10 (40 Ah) weighs 12.19 kg.

### Which battery is equivalent to the Varta AUX1?

With the same dimensions, polarity and similar capacity you have the Kronobat AUX1. As the AUX1 is a conventional battery, an EFB or AGM of the same size also works.

### Which side is the positive terminal on the Varta AUX1?

The AUX1 has the positive terminal on the right, looking at the battery from its long side with the terminals closest to you.

### Is the auxiliary battery replaced together with the main one?

Not necessarily, but they usually age together. If the main battery is over five years old, check the auxiliary one too.

## Keep comparing: alternatives to the AUX1

- [All auxiliary batteries (back-up and in-vehicle service)](https://bateriasonline.es/en/auxiliary-backup-batteries)
- [More Varta models](https://bateriasonline.es/en/varta-batteries)
- [Kronobat AUX1](https://bateriasonline.es/en/kronobat-aux1) · 35 Ah, 520 A, 212×175×140 mm

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