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TUDOR AUXILIARY Batteries

Tudor Auxiliary batteries are AGM back-up batteries for premium cars with a twin-battery layout: a main 12V battery cranks the engine, while the auxiliary unit supports Start-Stop and the on-board electronics whenever the engine is off. Tudor is the European-built brand of the Exide Group, and this range covers 12 to 20 Ah.

It is the usual auxiliary battery for Mercedes, BMW and Audi models fitted with a second battery, including 48V mild-hybrids. A direct counterpart to the VARTA Dynamic SLI Aux, it requires OBD coding after replacement.

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TUDOR

Auxiliary battery Tudor TK143 12V 14Ah 80A AGM

12V

14Ah

80A

AGM

150 × 100 × 100 mm

€53.10 VAT incl.

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TUDOR

Auxiliary battery Tudor TK151 12V 15Ah 200A AGM

12V

15Ah

200A

AGM

150 × 90 × 145 mm

€64.95 VAT incl.

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TUDOR

Auxiliary battery Tudor TK111 12V 11Ah 150A AGM

12V

11Ah

150A

AGM

150 × 90 × 130 mm

€169.70 VAT incl.

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TUDOR

Auxiliary battery Tudor TK091 12V 9Ah 120A AGM

12V

9Ah

120A

AGM

150 × 90 × 105 mm

€61.70 VAT incl.

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Showing 1-4 of 4 item(s)

Frequently asked questions

What is the difference between the main and the auxiliary battery?

The main battery cranks the engine; the Tudor Auxiliary, at 12 to 20 Ah, backs up Start-Stop and the electronics while the engine is off. They are different batteries and not interchangeable.

Does the auxiliary battery need OBD coding?

Yes. On Mercedes, BMW and Audi, OBD coding is mandatory after replacement so the energy management system applies the correct charging curve to the new battery.

Is it equivalent to the VARTA Dynamic SLI Aux?

Yes. The Tudor Auxiliary range is the direct counterpart of the VARTA Dynamic SLI Aux: same AGM technology and same applications, built in Europe by the Exide Group.

How long does an auxiliary AGM battery last?

Under normal use, an auxiliary AGM battery typically lasts 4 to 6 years. It needs no maintenance, but replace it as soon as the dashboard warns you, to avoid overworking the main battery.

Tudor auxiliary AGM battery: reliable back-up for your second battery

Many recent Mercedes, BMW and Audi models run two batteries: the main one handles engine starting, while the auxiliary battery keeps Start-Stop, the electric parking brake and other systems powered when the engine is off. The Tudor Auxiliary range does that job with sealed, maintenance-free AGM technology, safe to mount inside the cabin or boot with no risk of leaks.

When the auxiliary battery wears out, the dashboard usually shows an auxiliary battery malfunction warning and Start-Stop stops working, even though the car still starts normally.

Models in the Tudor Auxiliary range

Tudor TX12 (12 Ah): auxiliary battery for Mercedes E-Class W213 and BMW 5 Series.
Tudor TX13 (13 Ah): designed for Mercedes S-Class and BMW 7 Series.
Tudor TX20 (20 Ah): back-up battery for 48V mild-hybrid systems.

Compatibility: choosing the right auxiliary battery

Find the exact model your car uses in our battery comparator or look it up with the battery finder by number plate. After fitting, OBD coding is mandatory so the charging management recognises the new battery.

Catalogue curated by our technical team. 12,445 Trustpilot reviews · 4.5/5. 24-48 h delivery in mainland Spain and Portugal (orders before 6:00 pm); 14-day returns with free collection on the Iberian mainland.

TUDOR AUXILIARY Batteries

Frequently asked questions

Tudor auxiliary AGM battery: reliable back-up for your second battery

Models in the Tudor Auxiliary range

Compatibility: choosing the right auxiliary battery

Best sellers in TUDOR AUXILIARY Batteries