# Car battery Optima RTS-2.1 6V 50Ah 815A AGM ![Car battery Optima RTS-2.1 6V 50Ah 815A AGM](https://baterias.com/837-home_default/battery-optima-red-top-rts-21-8010-355-12v-50ah.jpg) > Optima RTS-2.1 car battery 6V 50Ah 815A AGM. RED TOP range. Dimensions 254×90×203 mm. Check fitment by plate. **Category:** [Car Batteries](https://baterias.com/gb/car-batteries) → [OPTIMA](https://baterias.com/gb/optima) - **Canonical URL**: https://baterias.com/gb/battery-optima-red-top-rts-21-8010-355-12v-50ah - **Language**: en-GB - **Brand**: OPTIMA - **Reference**: BCOM-OPTIMA-RTS-2.1 - **EAN**: 4016987113516 - **MPN**: RTS-2.1 - **Price**: 163,60 € - **Stock**: Out of stock ## Technical specifications | Feature | Value | |---|---| | Brand | OPTIMA | | Reference | RTS-2.1 | | Model | OPTIMA RED TOP | | Voltaje | 6 V | | Largo | 252 mm | | Ancho | 90 mm | | Alto | 185 mm | | Peso | 8.9 kg | | Tecnología | AGM ESPIRAL | | EAN | 4016987113516 | | Scheme | 8 | | Terminal | 1 | | Subjection | B11 | | Arranque en frío CCA EN | 815 A | | Capacidad C20 (Ah) | 50 Ah (c20) | | ETN | 8103550008882 | ## Quick description **Optima RTS-2.1 6V 50Ah 815A** is a battery designed for classic and vintage vehicles. It holds steady voltage in older 6 V systems, starts reliably after long spells parked in the garage and keeps the engine bay looking original. ### Why this car battery? - **Original-equipment quality** without dealership prices - **Lasts 4 to 6 years** buy once instead of twice - **Real human tech support** if you have any doubts before buying 🔌 Voltage 6 V ⚡ Capacity 50 Ah C20 🔋 Cold cranking 815 A EN-1 📏 Dimensions 254×90×203 mm ⚙️ Technology AGM ESPIRAL ⚖️ Weight 8,9 kg 🏷️ Model OPTIMA RED TOP ## Description ## Battery Optima Red Top RTS 2.1 50Ah 815A 6V The Battery OPTIMA RTS-2.1 50Ah 815A 6V RED TOP belongs to the Optima Redotop batteries range This high -end battery incorporates Spiracell (cells with spiral structure inside that enhances the performance of the batteries) created by OptimIn those applications where starting power is priority such as trucks, all -terrain vehicles, agricultural and construction machinery, emergency vehicles, generators and trams. They are batteries that last up to three times more and is up to 15 times more resistant to vibrations than other batteries.It is designed to spill -proof.And offers rapid recharge capacity to recover tension in a short time for short driving cycles. This battery is incredibly robust.Its power and durability are characteristics in which you can fully trust because it is designed to always offer the maximum starting power and, therefore, a reliable commissioning of the vehicle. ### Ideal for: - Start applications - Agricultural machines - Construction vehicles - Emergency vehicles - Generators - Trams ### Battery advantages and characteristics OPTIMA RTS-2.1 50Ah 815A 6V - Long useful life.Lasts up to three times more than conventional flat plates batteries - Constant performance - Greater power.More power during the first one, two, five and ten seconds of the starting process compared to similar lead-acid batteries. - Perfect for seasonal uses.If it is fully charged, it may not be used for a period of up to 12 months at room temperature (or lower) and yet start a car. - x15 times more resistant to vibrations than standard lead-acid batteries - Free of mantenimient - It can be installed almost in any position ### How to find the right battery for your vehicle or device? Optimal AGM AGM batteries are not comparable to any other battery in the world.Its Spi-Dpiell technology is among the most advanced lead-acid battery technologies available in the market. If you are not sure what cover color is better under your hood, do not hesitate to contact us and we will be happy to advise you. ### Why choose an optimal battery? If you look for the maximum possible power or a battery to work in the toughest working conditions.Do not hesitate, choose an optima battery ### OPTIMA - LEADING BRAND IN THE SECTOR With a 40 -year history of technological innovation and engineering, Optima® products offer unstoppable power for extreme enthusiasts and other people who require the final source of energy. In the 1970s, Optima Batteries presented the first main maintenanceless lead batteries for commercial and military use and the first high-performance AGM automotive batteries, but optimal innovation did not stop there.Optima the industry revolutionized with the introduction of its exclusive Spiord Technology® that grants certain key benefits such as: - Incredibly high starter characteristics in a small battery - Up to 15 times more resistance to vibrations than a conventional battery - Have a higher life cycle compared to traditional batteries If you want additional information about Battery Optima Red Top RTS 2.1, you can download the product's technical sheet at the following link: [ Download technical sheet Optima Red Top RTS 2.1 50Ah 815A 6V](/fichastecnicas/data-sheet-battery-optima-rts-2_1-50ah-815a-6v-en.pdf) ## Frequently asked questions ### Is this battery AGM? What is it for? Yes. The RTS-2.1 from Optima 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 the Optima RTS-2.1 battery suitable for Start-Stop? 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 — on most modern vehicles registering the battery via OBD is recommended so the alternator automatically applies the optimal charging profile. ### How do I check that the Optima RTS-2.1 battery fits my vehicle? Three ways: 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 for the RTS-2.1; 3) if you cannot find your model, message us on WhatsApp with brand, model, engine and year — we reply during business hours (Mon–Fri 9:00–18:00 CET). ### How is the Optima RTS-2.1 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 (−) 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 — match the polarity shown on the product sheet; 6) connect the positive (+) first, then the negative (−). On cars with Start-Stop or BMS, register the battery via OBD so the alternator applies the correct charging profile. ### How many years of warranty does the RTS-2.1 model cover? This battery includes 2 years of official manufacturer warranty against manufacturing defects. Coverage includes cell breakdowns, internal short-circuits and abnormal capacity decreases. Wear from misuse (prolonged overcharging, wrong charger or faulty alternator) is not covered. Once the defect is verified by technical inspection, we replace the RTS-2.1 at no cost. ### How long does Optima RTS-2.1 delivery take? In mainland Spain and Portugal it arrives in 24 h if you order before 17:00 and the battery is in stock — it leaves the same day and arrives the next business day. Afternoon or weekend orders ship the next business day. For Balearics, Canaries and other EU destinations, allow 2-5 days. Shipping cost is calculated in the cart based on destination and service (standard, express, cash on delivery). Tracking number is sent by email + SMS as soon as the parcel ships. ### Can I return the Optima RTS-2.1 battery if it doesn't fit or doesn't work? Yes. You have 14 days from delivery to return it. In mainland Spain and Portugal returns are FREE — we cover the return shipping cost via prepaid label. In other EU countries the return shipping cost is the customer's. It must arrive in its original packaging with no signs of installation. If it was defective, the warranty covers replacement even after the 14-day period. ### What is the price of the RTS-2.1 model? The current price at baterias.com is 163,60 € (VAT included; 135,21 € excl. VAT), updated every 24 hours. The applicable VAT may vary with the destination country and is confirmed in the cart. Shipping cost is calculated in the cart based on destination and chosen service (standard, express, cash on delivery). ### Where do I find the RTS-2.1 model online? At baterias.com — authorised distributor with real stock, 24h delivery in mainland Spain and Portugal if you order before 17:00, and full manufacturer warranty. Shipping cost is calculated in the cart based on destination and chosen service (standard, express, cash on delivery). Secure payment by card, Bizum, PayPal or bank transfer. If you choose at-home installation, our technician will take the used battery and dispose of it through an authorised collection point. ### How long does the Optima RTS-2.1 battery last? Expected lifespan of the Optima RTS-2.1 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 measurements of the RTS-2.1 model? Dimensions (length × width × height) are 254×90×203 mm — also written as 254x90x203 mm — 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. ### How much does the Optima RTS-2.1 battery weigh? It weighs 8,9 kg. Most of the weight is lead. If you plan to fit it yourself, use gloves and a carrying strap (AGM batteries are slightly heavier than conventional due to the absorbent glass-mat fibre). ### How many Ah and CCA does this battery have? Nominal capacity 50 Ah[?cca: and [cold-cranking amps 815 A]] at 6 V. Ah measure the total energy available (autonomy); CCA (also written A in cold or EN under the European standard) measure the instantaneous power to crank the starter motor. A battery with more CCA starts better in winter; one with more Ah keeps accessories on for longer. ### Under which reference is the Optima RTS-2.1 listed in catalogues? The manufacturer reference (MPN) is RTS-2.1 and its ETN code is 8103550008882 (short form 810 355 000), the European identifier used in spare-part catalogues. The EAN-13 barcode is 4016987113516. It belongs to the OPTIMA RED TOP range. Any of these codes identifies exactly this battery when requesting quotes or comparing prices. ### Will the Optima RTS-2.1 battery fit my car? 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 — we reply during business hours (Mon–Fri 9:00–18:00 CET). The RTS-2.1 typically fits a wide range of European vehicles thanks to its standard DIN case format. ### Which batteries are equivalent to the Optima RTS-2.1? 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 — 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. ### Is this battery a better choice than another equivalent? This battery and its equivalents from Bosch, Tudor or Exide are technically comparable: same dimensions, same voltage and same capacity. The differences are warranty (Varta and Bosch: 2 years; Tudor and Exide: 2 years on the equivalent line), manufacturing plant (Varta and Bosch share origin in the Clarios Group; Tudor and Exide belong to Exide Technologies) and price. For private use any of these brands will give 4-6 years of life. Compare them in the "Equivalents" section. ### What reviews does the RTS-2.1 model have? The average rating of the Optima RTS-2.1 on baterias.com is 4.82/5 from 26 verified customer reviews. The product rating, when available, is shown on the product page next to the stars. You can also check our public Trustpilot profile at shop level (4.5/5 from 11,561+ verified reviews). Most-praised points: reliable cold start, lifespan above 5 years and fast delivery; most common complaints mention BMS-equipped cars that need OBD registration after fitting. ### What advantages does the Optima RTS-2.1 AGM battery offer over an EFB? AGM (Absorbent Glass Mat) technology uses absorbent fibreglass that retains the electrolyte, eliminating leaks and allowing up to 3× 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 Optima RTS-2.1 is fully original and meets European EN 50342-6 standards for advanced Start-Stop. ### Will my car recognise the new battery automatically? On most cars it is not strictly necessary — 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 — the alternator just takes a few days to adjust the profile. The Optima RTS-2.1 ships factory-charged at 80-90% so you can use it straight after fitting. ## Reviews - **Average rating**: 4.82 / 5 (26 reviews) ## Technical team (editorial authorship) The FAQs, guides and comparisons on this site are reviewed by the baterias.com technical team — over 25 years of experience validating automotive batteries. → https://baterias.com/gb/technical-team --- *baterias.com — Automotive batteries · 2026-09-11*