# Auxiliary battery Kronobat AUX1 12V 35Ah 520A ![Auxiliary battery Kronobat AUX1 12V 35Ah 520A](https://baterias.com/3350-home_default/best-price-battery-12v-35ah-aux1.jpg) > Kronobat AUX1 auxiliary battery 12V 35Ah 520A. AUXILIAR range. Dimensions 212Γ—175Γ—140 mm, + terminal on the right. Check fitment by plate. **Category:** [Auxiliary Batteries](https://baterias.com/gb/auxiliary-batteries) β†’ [KRONOBAT](https://baterias.com/gb/kronobat) - **Canonical URL**: https://baterias.com/gb/best-price-battery-12v-35ah-aux1 - **Language**: en-GB - **Brand**: KRONOBAT - **Reference**: BCOM-KRONOBAT-AUX1 - **MPN**: AUX1 - **Stock**: Out of stock ## Technical specifications | Feature | Value | |---|---| | Reference | AUX1 | | Model | AUXILIAR | | Voltage (V) | 12 V | | Largo | 212 mm | | Ancho | 175 mm | | Alto | 140 mm | | Peso | 10.75 kg | | TecnologΓ­a | Lead-acid | | Terminal layout | Positive terminal on the right | | Terminal type | 1 | | Cold cranking amps (EN) | 520 A | | Capacity (C20) | 35 Ah (c20) | ## Quick description **Kronobat AUX1 12V 35Ah 520A** 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 35 Ah C20 πŸ”‹ Cold cranking 520 A EN-1 πŸ“ Dimensions 212Γ—175Γ—140 mm βš™οΈ Technology Lead-acid 🧭 Polarity Positive on the right βš–οΈ Weight 10,75 kg 🏷️ Model AUXILIAR ## Description ## Auxiliary battery Kronobat AUX1 Auxiliar 35Ah 520A 12V 12*V* Voltage 35*Ah* Capacity 520*A* Cold cranking 10.75*kg* Weight The **12 V**, **35 Ah** **Kronobat AUX1** auxiliary battery from the **Auxiliar** range with conventional lead-acid technology powers the auxiliary network of cars with advanced Start-Stop and heavy electronics. It measures 212 Γ— 175 Γ— 140 mm and the positive terminal on the right, the format sought by anyone replacing a 35 Ah battery in vehicles with an auxiliary battery. - Stabilises the onboard network voltage. - Conventional lead-acid: the most proven and economical technology. - Maintenance-free. - Sealed AGM: safe when installed in the cabin. ### What the Kronobat AUX1 is for As an auxiliary battery, the Kronobat AUX1 works alongside the main one; replace it when the vehicle reports a fault in the support network. Check that it matches your current battery in dimensions, terminals and hold-down: this reference has a weight of 10.75 kg and 1.0 terminals. ### Will it fit your current battery tray? It has external dimensions of 212 Γ— 175 Γ— 140 mm and weighs 10.75 kg. The positive terminal on the right decides which side the cables end up on: it is the detail that causes most buying mistakes, so check it before ordering. It uses 1.0 terminals, the system that anchors and connects it in the vehicle. Before replacing it, measure your current battery tray: if all three dimensions and the terminal positions match, the swap is direct and needs no adapters. ### What Kronobat does differently Kronobat is the exclusive brand of baterias.com: batteries made to the same production standards as the leading brands, with a value for money that is hard to match and an official warranty. All the Kronobat batteries in our catalogue are genuine product, recently manufactured and covered by the manufacturer's warranty. ### The Kronobat AUX1: Auxiliar range and conventional lead-acid technology The **Auxiliar** is the Kronobat range the AUX1 belongs to: it shares the same construction and quality criteria with the rest of the series, and varies in capacity and format to suit each vehicle. In a conventional battery the electrolyte is liquid and the lead plates are immersed in it. It is a mature, economical and easily recycled technology, ideal for starting vehicles in normal use. ### How to make it last longer The auxiliary battery works alongside the main one: if a support-network fault warning appears, check both. On batteries with filler caps, check the electrolyte level and top up only with distilled water. ### Official warranty The Kronobat AUX1 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 6:00 pm** with the battery in stock ship the same day. Delivery in mainland Spain and Portugal takes 24-48 working hours; for the Balearic Islands and the rest of the European Union allow 3 to 5 working days. You have **14 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 ### How is the Kronobat AUX1 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 our blog. 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€” with positive on the right 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 AUX1 model? Expected lifespan of the Kronobat AUX1 is 4 to 6 years in regular car use without 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 Kronobat AUX1 battery? Dimensions (length Γ— width Γ— height) are 212Γ—175Γ—140 mm β€” also written as 212x175x140 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. ### What polarity does the Kronobat AUX1 battery have? Polarity: positive on the right. To identify it, place the battery in front of you with the terminals facing you and check which side the positive (+, marked with a red ring) is on. Before buying, verify the polarity matches your current battery: switching polarity forces longer cables or system reconfiguration, with short-circuit risk. ### Is the AUX1 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 AUX1 typically fits a wide range of European vehicles thanks to its standard DIN case format. ### What are the equivalents of the AUX1 model? 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. ## Equivalent batteries - [VARTA AUX1](https://baterias.com/gb/battery-varta-aux1-12v-35ah-520a) ## Technical team (editorial authorship) The FAQs, guides and comparisons on this site are reviewed by the baterias.com technical team β€” automotive battery specialists since 2012. β†’ https://baterias.com/gb/technical-team --- *baterias.com β€” Automotive batteries Β· 2026-10-26*