# Auxiliary battery Deta DK091 12V 9Ah 120A AGM ![Auxiliary battery Deta DK091 12V 9Ah 120A AGM](https://baterias.com/3618-home_default/battery-deta-dk091-12v-9ah-120a.jpg) > Deta DK091 auxiliary battery 12V 9Ah 120A AGM. Start-Stop Auxiliary range. Dimensions 150Γ—90Γ—105 mm, + terminal on the left. Check fitment by plate. **Category:** [Auxiliary Batteries](https://baterias.com/gb/auxiliary-batteries) β†’ [Deta](https://baterias.com/gb/deta) - **Canonical URL**: https://baterias.com/gb/battery-deta-dk091-12v-9ah-120a - **Language**: en-GB - **Brand**: Deta - **Reference**: BCOM-DETA-DK091 - **EAN**: 3661024026338 - **MPN**: DK091 - **Stock**: Out of stock ## Technical specifications | Feature | Value | |---|---| | Brand | DETA | | Reference | DK091 | | Model | DETA Start-Stop Auxiliary | | Voltage (V) | 12 V | | Largo | 150 mm | | Ancho | 90 mm | | Alto | 105 mm | | Peso | 3.1 kg | | TecnologΓ­a | AGM | | EAN | 3661024026338 | | Terminal layout | Positive terminal on the left | | Terminal type | M12 | | Hold down | B00 | | Cold cranking amps (EN) | 120 A | | Capacity (C20) | 9 Ah (c20) | | Case type | C54 | ## Quick description **Deta DK091 12V 9Ah 120A** is an auxiliary battery: it supports the Start-Stop system and on-board electronics during stops, without draining the main battery. ### Why this auxiliary battery? - **Designed for Start-Stop** built for the intensive cycling of modern cars - **2 to 3 times longer life** vs fitting a cheap conventional battery - **Fast recovery** recharges in minutes once the engine is running πŸ”Œ Voltage 12 V ⚑ Capacity 9 Ah C20 πŸ”‹ Cold cranking 120 A EN-1 πŸ“ Dimensions 150Γ—90Γ—105 mm βš™οΈ Technology AGM 🧭 Polarity Positive on the left βš–οΈ Weight 3,1 kg 🏷️ Model DETA Start-Stop Auxiliary ## Description ## Auxiliary battery Deta DK091 Start-Stop Auxiliary 9Ah 120A 12V 12*V* Voltage 9*Ah* Capacity 120*A* Cold cranking 3.10*kg* Weight The **12 V**, **9 Ah** **Deta DK091** auxiliary battery from the **Start-Stop Auxiliary** range with AGM technology powers the auxiliary network of cars with advanced Start-Stop and heavy electronics. It replaces the original battery without adaptation in vehicles with an auxiliary battery with a 150 Γ— 90 Γ— 105 mm format: same 9 Ah capacity and the positive terminal on the left. - AGM technology: absorbed electrolyte, no spills, can be mounted at an angle. - Stabilises the onboard network voltage. - Sealed AGM: safe when installed in the cabin. - Maintenance-free. ### What the Deta DK091 is for With 9 Ah, the Deta DK091 is the direct replacement for the original auxiliary battery in the auxiliary network of cars with advanced Start-Stop and heavy electronics. Check that it matches your current battery in dimensions, terminals and hold-down: this reference has a weight of 3.10 kg, M12 terminals and B00 hold-down. ### Will it fit your current battery tray? In terms of format, the Deta DK091 measures 150 Γ— 90 Γ— 105 mm (length Γ— width Γ— height) and weighs 3.10 kg. The positive terminal on the left decides which side the cables end up on: it is the detail that causes most buying mistakes, so check it before ordering. It uses a B00 hold-down and M12 terminals, the system that anchors and connects it in the vehicle. For a direct replacement, the current battery tray must accept these dimensions and the same terminal layout; otherwise adapters will be needed or the hold-down will change. ### Why choose Deta batteries Deta is the German brand of the Exide group: batteries built with original-equipment technology and a very complete range for cars, Start-Stop, trucks, motorcycles and leisure. We guarantee that every Deta arrives new, charged and with the manufacturer's full warranty. ### The Deta DK091: Start-Stop Auxiliary range and AGM technology Within the Deta catalogue, the **Start-Stop Auxiliary** series groups the references designed for this use. The DK091 is the 9 Ah model of that family, with the same performance as its siblings in other sizes. In an AGM battery the electrolyte is absorbed in glass-fibre separators: there is no free liquid, it cannot spill and it can be mounted at an angle. That construction lowers internal resistance, speeds up recharging and multiplies cycle life compared with a conventional battery. ### Usage and maintenance tips Charge with a charger that has an AGM mode: it limits the voltage and protects the glass-fibre separators. Replace it with the same technology and capacity as the original. ### Official warranty The Deta DK091 comes with the **manufacturer's official warranty** against manufacturing defects. If it fails through a defect within the warranty period, we replace it at no cost to you. ### Delivery times and returns Orders placed **before [[ks:cutoff]]** with the battery in stock ship the same day. Delivery in mainland Spain and Portugal takes 24-48 working hours; for the Balearic and Canary Islands and the rest of the European Union allow 3 to 5 working days. You have **[[ks:return_days]] days** to return an unused battery; in mainland Spain and Portugal collection is free. We email you the tracking number as soon as the parcel ships. ## Frequently asked questions ### Is the DK091 model AGM? What does this technology offer? Yes. The DK091 from Deta uses AGM (Absorbent Glass Mat) technology: a sealed lead-acid battery where the electrolyte is absorbed in a glass-fibre mat. It withstands more charge/discharge cycles than a conventional one, handles heat better and is the required technology for cars with advanced Start-Stop and regenerative braking. Expected lifespan: 5-8 years under normal conditions. ### Is this battery compatible with Start-Stop systems? Yes. As AGM technology it is designed for Start-Stop vehicles. AGM batteries support advanced Start-Stop and regenerative braking thanks to their higher cycle count. EFB is recommended for basic Start-Stop; AGM is recommended when regenerative braking is also present, thanks to its higher cycle capability. It works straight out of the box β€” on most modern vehicles registering the battery via OBD is recommended so the alternator automatically applies the optimal charging profile. ### How is the Deta DK091 battery installed in the vehicle? In most cars it fits in 15-30 minutes with a 10 mm wrench; if the battery is under the seat or in the boot the time can double. See the step-by-step guide on this page. Quick summary: 1) switch off the engine and remove the key; 2) locate the original battery (engine bay, boot or under seat); 3) disconnect the negative (βˆ’) terminal first, then the positive (+); 4) loosen the hold-down clamp and remove the old battery; 5) fit the new one in the same orientation β€” match the polarity shown on the product sheet; 6) connect the positive (+) first, then the negative (βˆ’). On cars with Start-Stop or BMS, register the battery via OBD so the alternator applies the correct charging profile. ### What is the service life of the DK091 model? Expected lifespan of the Deta DK091 is 5 to 8 years in mild-climate car use with Start-Stop. In cold regions it drops slightly due to cold-start stress; in very hot regions it also drops because of electrolyte evaporation. To extend its life: avoid deep discharges (headlights on with engine off), have the alternator checked yearly, and keep the battery clean and properly secured. ### What are the dimensions of the Deta DK091 battery? Dimensions (length Γ— width Γ— height) are 150Γ—90Γ—105 mm β€” also written as 150x90x105 mm β€” following the European DIN standard. Always measure the space in your car before buying: even one extra millimetre can prevent the hold-down clamp from closing. The height shown includes the terminals. ### Is the DK091 valid for my vehicle? Three options to confirm: 1) enter your number plate in the finder (DGT/DVLA/KBA auto-detect your model and engine); 2) check the "Compatible vehicles" tab on this page, where we list every vehicle verified by our technical team; 3) if you cannot find your model, message us on WhatsApp with brand, model, engine and year β€” we reply during business hours (Mon–Fri 10:00–13:30 and 16:40–18:00 (Spanish time, CET)). The DK091 typically fits a wide range of European vehicles thanks to its standard DIN case format. ### Which interchangeable batteries are there for this one? Directly interchangeable batteries (same dimensions, same polarity, same Ah and CCA) are the OEM equivalents from leading brands: Bosch, Tudor, Exide and, depending on the model, Banner or Yuasa. Exact equivalence depends on technology β€” an EFB cannot be replaced with a conventional battery in Start-Stop cars. See the "Equivalents" section to view recommended options at the same performance level. ### What advantages does the Deta DK091 AGM battery offer over an EFB? AGM (Absorbent Glass Mat) technology uses absorbent fibreglass that retains the electrolyte, eliminating leaks and allowing up to 3Γ— more charge/discharge cycles than a conventional battery. It is the recommended option when the car has advanced Start-Stop with regenerative braking (BMW EfficientDynamics, Mercedes Eco, Audi MHEV, Land Rover ECO, Volvo i-Stop). Withstands tilted positions, high vibration and extreme temperatures better than EFB. The Deta DK091 is fully original and meets European EN 50342-6 standards for advanced Start-Stop. ### Is there anything to do after replacing a Start-Stop battery? On most cars it is not strictly necessary β€” the alternator detects the new battery and adapts the charge automatically. It is recommended to register the battery via OBD so that the alternator applies the optimal charging profile from the first minute and extends the battery life as much as possible (especially on brands with sophisticated BMS: BMW, Mercedes, Audi, Volvo, Land Rover). Any workshop with an OBD scanner (~10-15 € labour) does it in 5 minutes. DIY apps: VCDS / Carista (VAG), Bimmercode (BMW), iCarsoft. If you do not register, the car will still start correctly β€” the alternator just takes a few days to adjust the profile. The Deta DK091 ships factory-charged at 80-90% so you can use it straight after fitting. ## Equivalent batteries - [TUDOR TK091](https://baterias.com/gb/battery-tudor-tk091-9ah-120a) - [EXIDE EK091](https://baterias.com/gb/battery-exide-ek091-12v-9ah-120a) ## Technical team (editorial authorship) The FAQs, guides and comparisons on this site are reviewed by the baterias.com technical team β€” over 25 years of experience validating automotive batteries. β†’ https://baterias.com/gb/technical-team --- *baterias.com β€” Automotive batteries Β· 2026-09-30*