# Car battery Optima RTU-3.7 12V 44Ah 730A AGM ![Car battery Optima RTU-3.7 12V 44Ah 730A AGM](https://baterias.com/3833-home_default/battery-optima-red-top-rtu-37-8022-255-12v-44ah.jpg) > Optima RTU-3.7 car battery 12V 44Ah 730A AGM. RED TOP range. Dimensions 237×172×197 mm, + terminal on the left. 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-rtu-37-8022-255-12v-44ah - **Language**: en-GB - **Brand**: OPTIMA - **Reference**: BCOM-OPTIMA-RTU-3.7 - **EAN**: 4016987113561 - **MPN**: RTU-3.7 - **Price**: 187,30 € - **Stock**: In stock ## Technical specifications | Feature | Value | |---|---| | Brand | OPTIMA | | Reference | RTU-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 | 4016987113561 | | Terminal layout | Positive terminal on the left | | Terminal type | 1 & 21 | | Hold down | B1 | | Cold cranking amps (EN) | 730 A | | Capacity (C20) | 44 Ah (c20) | | ETN | 8222550008882 | ## Quick description **Optima RTU-3.7 12V 44Ah 730A** is a passenger car battery with factory-guaranteed cranking power and extended service life. OEM quality at white-label prices: calcium-silver grids, low self-discharge and compatible with all modern electrical systems. ## 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 left ⚖️ Weight 15,7 kg 🏷️ Model OPTIMA RED TOP ## Description ## Car battery Optima RTU-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 RTU-3.7** from the **Red Top** range is a starter battery built for passenger cars with conventional starting, without a Start-Stop system. It replaces the original battery without adaptation in cars with a 237 × 172 × 168 mm format: same 44 Ah capacity and the positive terminal on the left. - Direct replacement for the original battery in size and terminals. - Original-equipment build quality without the dealership price. - Spiral cells: maximum vibration resistance and very powerful cranking. - Reliable cold starts, even after weeks without driving. ### Dimensions, polarity and mounting The Optima RTU-3.7 is made in the 237 × 172 × 168 mm format and weighs 15.60 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 B1 hold-down and 1 & 21 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. ### Vehicles compatible with the Optima RTU-3.7 This battery appears as compatible in more than 37 vehicles from manufacturers such as Chevrolet, Buick, Ford, GMC, Saturn and Toyota. For anyone who needs to replace the **battery in their Chevrolet** or Buick, this Optima RTU-3.7 reproduces the original specifications. ### The Optima RTU-3.7: Red Top range and spiral-cell AGM technology Within the Optima catalogue, the **Red Top** series groups the references designed for this use. The RTU-3.7 is the 44 Ah model of that family, with the same performance as its siblings in other sizes. 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. ### What Optima does differently 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. We guarantee that every Optima arrives new, charged and with the manufacturer's full warranty. ### Warranty and coverage The Optima RTU-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. ### Care and maintenance Avoid leaving lights or accessories on with the engine off: most batteries fail not through defects but through repeated deep discharges. Keep the terminals clean and tight, and check that the resting voltage does not drop below 12.4 V: below that it is time to recharge. ### Delivery times and returns Order **before 6:00 pm** with stock available and it leaves today: mainland Spain and Portugal receive it in 24-48 working hours, the islands and the rest of the EU in 3 to 5 days. You have **14 days** to return it if it has not been installed, with free collection on the mainland, and shipment tracking by email. ## Frequently asked questions ### Is the Optima RTU-3.7 an AGM battery and what are the benefits of AGM? Yes. The RTU-3.7 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 RTU-3.7 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 fit the RTU-3.7 model in my car? 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 (−) 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 — with positive on the left 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 does this battery last? Expected lifespan of the Optima RTU-3.7 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 Optima RTU-3.7 battery? Dimensions (length × width × height) are 237×172×197 mm — also written as 237x172x197 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. ### On which side is the positive of the RTU-3.7 model? Polarity: positive on the left. 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. ### What ETN and EAN codes does the Optima RTU-3.7 battery have? The manufacturer reference (MPN) is RTU-3.7 and its ETN code is 8222550008882 (short form 822 255 000), the European identifier used in spare-part catalogues. The EAN-13 barcode is 4016987113561. 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 RTU-3.7 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 10:00–13:30 and 16:40–18:00 (Spanish time, CET)). The RTU-3.7 fits 37 verified vehicle versions in our database. ### What are the equivalents of the RTU-3.7 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 — 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. ### When do I need an AGM battery like this one? 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 RTU-3.7 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 RTU-3.7 ships factory-charged at 80-90% so you can use it straight after fitting. ## Compatible vehicles This battery fits 37 vehicles. 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