# Car battery Optima RTR-3.7 Red Top 12V 44Ah 730A AGM ![Car battery Optima RTR-3.7 Red Top 12V 44Ah 730A AGM](https://baterias.com/3817-home_default/battery-optima-red-top-rtr-37-8035-255-12v-44ah.jpg) > Optima RTR-3.7 car battery 12V 44Ah 730A AGM. RED TOP range. Dimensions 237×172×197 mm, + terminal on the right. 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-rtr-37-8035-255-12v-44ah - **Language**: en-GB - **Brand**: OPTIMA - **Reference**: BCOM-OPTIMA-RTR-3.7 - **EAN**: 4016987113578 - **MPN**: RTR-3.7 - **Price**: 191,90 € (VAT incl., Spain) - **Last updated**: 2026-10-28 - **Stock**: In stock ## Technical specifications | Feature | Value | |---|---| | Brand | OPTIMA | | Reference | RTR-3.7 | | Model | OPTIMA RED TOP | | Voltage (V) | 12 V | | Largo | 237 mm | | Ancho | 172 mm | | Alto | 168 mm | | Peso | 15.6 kg | | Tecnología | AGM ESPIRAL | | EAN | 4016987113578 | | Terminal layout | Positive terminal on the right | | Terminal type | 1 | | Hold down | B1 | | Cold cranking amps (EN) | 730 A | | Capacity (C20) | 44 Ah (c20) | | ETN | 8352550008882 | ## Quick description **Optima RTR-3.7 12V 44Ah 730A** is a ready-to-use passenger car battery, sealed and maintenance-free. Delivers the cranking amps the engine needs in cold weather and keeps stable voltage for modern car loads (ECU, sensors, climate control, infotainment). ## 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 12 V ⚡ Capacity 44 Ah C20 🔋 Cold cranking 730 A EN-1 📏 Dimensions 237×172×197 mm ⚙️ Technology AGM ESPIRAL 🧭 Polarity Positive on the right ⚖️ Weight 15,6 kg 🏷️ Model OPTIMA RED TOP ## Description ## Car battery Optima RTR-3.7 Red Top 44Ah 730A 12V 12*V* Voltage 44*Ah* Capacity 730*A* Cold cranking 15.60*kg* Weight With **44 Ah** at **12 V** and **730 A** of cold cranking current (EN), the **Optima RTR-3.7** from the **Red Top** range is a starter battery built for passenger cars with conventional starting, without a Start-Stop system. It measures 237 × 172 × 168 mm and the positive terminal on the right, the format sought by anyone replacing a 44 Ah battery in cars. - Reliable cold starts, even after weeks without driving. - Spiral cells: maximum vibration resistance and very powerful cranking. - Original-equipment build quality without the dealership price. - Direct replacement for the original battery in size and terminals. ### What the Optima RTR-3.7 is for Designed for passenger cars with conventional starting, without a Start-Stop system, the Optima RTR-3.7 is the direct replacement when your vehicle uses a 44 Ah battery of this format. Before buying, compare dimensions, terminals and capacity with the battery you are replacing. Check that it matches your current battery in dimensions, terminals and hold-down: this reference has a weight of 15.60 kg, 1 terminals and B1 hold-down. ### The Optima RTR-3.7: Red Top range and spiral-cell AGM technology The RTR-3.7 is part of the Optima **Red Top** range. Choosing the right reference within the series comes down to capacity, dimensions and terminals: technology and quality are common to the whole family. In a spiral-cell battery the electrolyte is absorbed and the plates are wound under pressure. That lets it deliver very high current peaks, recharge quickly and be mounted in any position. ### Will it fit your current battery tray? The Optima RTR-3.7 is made in the 237 × 172 × 168 mm format and weighs 15.60 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 a B1 hold-down and 1 terminals, the system that anchors and connects it in the vehicle. Checking the three dimensions and the terminal position before buying avoids the most common mistake when replacing a battery. ### Optima: the maker behind the RTR-3.7 The Optima Red, Yellow and Blue Top are references for high-performance starting, deep cycling and marine use respectively, all with the characteristic six spiral-cell design. At baterias.com we work directly with the manufacturer or its official distributor: real stock, brand-new product and official warranty. ### Usage and maintenance tips In normal daily use the alternator keeps the battery charged; if the car stands for weeks, a maintenance charge once a month prevents deep discharge. Avoid leaving lights or accessories on with the engine off: most batteries fail not through defects but through repeated deep discharges. ### Warranty and coverage The Optima RTR-3.7 comes with the **manufacturer's official warranty** against manufacturing defects; the exact period is stated in the brand's conditions. If it fails through a defect within the period, we replace it free of charge. ### When you get it and how to return it Same-day dispatch from our warehouse for in-stock orders placed **before 6:00 pm**: 24-48 working hours in mainland Spain and Portugal, 3 to 5 days in the islands and the rest of Europe. Returns are accepted for **14 days** if the battery has not been used (free collection on the Iberian mainland). You will receive tracking by email. ## Frequently asked questions ### Is the Optima RTR-3.7 an AGM battery and what are the benefits of AGM? Yes. The Optima RTR-3.7 is AGM (Absorbent Glass Mat): sealed lead-acid, with the electrolyte absorbed in glass fibre. Its advantages: more charge/discharge cycles than a conventional battery and better heat tolerance. It is also required in cars with advanced Start-Stop and regenerative braking. ### Is the RTR-3.7 model suitable for Start-Stop cars? Yes. It is a AGM battery of 44 Ah, designed for vehicles with Start-Stop. AGM batteries support advanced Start-Stop and regenerative braking thanks to their higher cycle count. Registering it via OBD is advisable on most modern cars (the alternator then applies the optimum profile), but it works from the start. As a rule: EFB for basic Start-Stop, AGM when there is also regenerative braking (more cycles); in any case, what the car manufacturer specifies. ### How do I fit the RTR-3.7 model in my car? Tool: a 10 mm spanner. Time: 15-30 minutes on almost every car, and up to double if the battery is not under the bonnet but in the boot or under a seat. Before you start, check the car handbook: the manufacturer's procedure always comes first. Our full step-by-step guide is on the blog. The right order: engine off and key out; disconnect the negative (−) first, then the positive (+); release the hold-down clamp, lift out the old battery and seat the new one in the same position (positive on the right), keeping the polarity; reconnect the positive (+) first and the negative (−) last. ### What is the service life of the RTR-3.7 model? Estimated lifespan of the Optima RTR-3.7: 5 to 8 years in mild-climate car use with Start-Stop. Treat it as an approximate guide, as every case is different. Actual lifespan varies with climate (cold starts, heat evaporating the electrolyte), with usage and short journeys, with the condition of the alternator and charging system, with power draw while parked and with maintenance; the type of car and Start-Stop also count. ### What are the measurements of the RTR-3.7 model? Check the room available in your car, because a single millimetre too much can stop the clamp from closing. Its dimensions are 237×172×197 mm, also written 237x172x197 mm; the height already includes the terminals. ### On which side is the positive of the RTR-3.7 model? The RTR-3.7 has the positive on the right: that is its polarity. If your current battery has its positive on the other side, this one is not suitable without longer cables or a reconfigured system (short-circuit risk). Face the battery with its terminals nearest you and see which side the positive post (+, red ring) is on. ### Under which reference is the Optima RTR-3.7 listed in catalogues? Parts catalogues list it under ETN 835 255 000 (in full, 8352550008882); the manufacturer's reference is RTR-3.7 and its EAN-13 is 4016987113578. It belongs to the OPTIMA RED TOP range. Any of the three works for getting a quote or comparing prices without mix-ups. ### Does this battery fit my car? The quickest way is to enter your number plate in the finder: DGT/DVLA/KBA detect model and engine. You can also look at the "Compatible vehicles" tab, verified by our technical team, or send us make, model, engine and year on WhatsApp; we answer during business hours (Mon–Fri 10:00–13:30 and 16:30–18:00 (Spanish time, CET)). According to our data, 2 verified vehicle versions are compatible with the RTR-3.7. Always cross-check with what the car manufacturer states in the owner's handbook. ### What are the equivalents of the RTR-3.7 model? Technology matters too: in Start-Stop cars, an EFB cannot be replaced with a conventional battery. The options at the same level are in the "Equivalents" section of this page. A direct equivalent needs what this RTR-3.7 offers: 237×172×197 mm, positive on the right, the same Ah and CCA and AGM technology. ### Optima RTR-3.7 or Optima YTR-3.7: which one to choose? It is the bigger sister of the RTR-3.7 in the same Optima range. Compared with the RTR-3.7 it has 4 Ah more and 70 A of cold cranking less. It costs 11,90 € more. If the tray takes the size, extra reserve never hurts; for a daily-driven petrol car the extra is not needed. ### What advantages does the Optima RTR-3.7 AGM battery offer over an EFB? Cold cranking current (EN) of the Optima RTR-3.7: 730 A. In an AGM (Absorbent Glass Mat) battery the electrolyte is held in a glass-fibre mat: no spills, and many more charge/discharge cycles than a conventional battery. Compared with an EFB it resists tilted positions, heavy vibration and extreme temperatures better, and it is the recommended option where there is regenerative braking (BMW EfficientDynamics, Mercedes Eco, Audi MHEV, Land Rover ECO, Volvo i-Stop). ### Is there anything to do after replacing a Start-Stop battery? On most cars it is not strictly necessary: the alternator detects the new battery and adapts the charge by itself. It is advisable, though, to register it via OBD so the optimum profile applies from the first minute and the battery lasts as long as possible, especially on brands with sophisticated BMS (BMW, Mercedes, Audi, Volvo, Land Rover). Without registration the car starts normally; the alternator simply takes a few days to adjust the profile. To do it yourself: VCDS or Carista on VAG, Bimmercode on BMW, iCarsoft. At a workshop with an OBD scanner it takes minutes. ## Compatible vehicles The Optima RTR-3.7 fits 2 vehicles, including the GEO Prizm Saloon 1.6 (78 kW / 106 CV) (1992–1997) and GEO Prizm Saloon 1.6 (76 kW / 103 CV) (1990–1992). | Make | Model | Engine | Years | |---|---|---|---| | GEO | Prizm Saloon | [1.6 (78 kW / 106 CV)](https://baterias.com/gb/car-batteries/geo/prizm-saloon/16-78-kw-106cv) | 1992–1997 | | GEO | Prizm Saloon | [1.6 (76 kW / 103 CV)](https://baterias.com/gb/car-batteries/geo/prizm-saloon/16-76-kw-103cv) | 1990–1992 | ## Equivalent batteries - [OPTIMA YTR-3.7](https://baterias.com/gb/battery-optima-yellow-top-ytr-37-8040-222-12v-48ah) ## Technical team (editorial authorship) The FAQs, guides and comparisons on this site are reviewed by the baterias.com technical team — automotive battery specialists since 2012. → https://baterias.com/gb/technical-team --- *baterias.com — Automotive batteries · 2026-11-12*