Fullriver FT438-U1 · Marine battery 12V 35Ah 438A AGM
Specifications
| Brand | FULLRIVER |
|---|---|
| Part number | FT438-U1 |
| Voltage (V) | 12 |
| Capacity (C20) | 35 |
| Cold cranking amps (EN) | 438 |
| Technology | AGM |
| Length | 196.00 cm |
| Width | 131.00 cm |
| Height | 192.00 cm |
Fullriver FT438-U1 12V 35Ah 438A is a marine battery, vibration- and deep-discharge resistant, suitable both for outboard engine starting and for onboard auxiliary services (navigation lights, GPS, sonar, fridge). Sealed and maintenance-free.
Why this marine battery?
- Marine designbuilt for boat swell and vibration
- Dual functionstarts the engine and powers onboard services
- Sealed and safemaintenance-free even when the boat rolls

Marine battery Fullriver FT438-U1 Full Throttle Series 35Ah 438A 12V
The Fullriver FT438-U1 marine battery offers 12 V, 35 Ah and 438 A of cold cranking current (EN) from the Full Throttle Series range with AGM technology, designed for motor and sailing boats, both for engine starting and onboard services. Its 196 × 131 × 192 mm make it the exact replacement for the 35 Ah battery fitted as standard to many boats.
- Ready for starting outboard and inboard engines.
- AGM: faster recharging and better cycle resistance than a conventional battery.
- Resistant to humidity and salt air.
- Sealed: no spills or gases in the locker.
What the Fullriver FT438-U1 is for
With 35 Ah, the Fullriver FT438-U1 covers motor and sailing boats, both for engine starting and onboard services. At the end of the season, charge it fully before winter storage. Check that it matches your current battery in dimensions, terminals and hold-down: this reference has a weight of 11.30 kg and M6 + TP26 (SAE) terminals.
Will it fit your current battery tray?
In terms of format, the Fullriver FT438-U1 measures 196 × 131 × 192 mm (length × width × height) and weighs 11.30 kg. It uses M6 + TP26 (SAE) 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.
Why choose Fullriver batteries
With its own plants and a catalogue focused on high-performance AGM, Fullriver is a familiar brand in power wheelchairs, boats and photovoltaic systems that need thousands of cycles. At baterias.com we work directly with the manufacturer or its official distributor: real stock, brand-new product and official warranty.
The Fullriver FT438-U1: Full Throttle Series range and AGM technology
Within the Fullriver catalogue, the Full Throttle Series series groups the references designed for this use. The FT438-U1 is the 35 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.
How to make it last longer
As a service battery, avoid routine discharges below 50% to extend its cycle life. Protect the terminals with dielectric grease and check the fixing: vibration and swell loosen connections.
Warranty and coverage
The Fullriver FT438-U1 comes with the manufacturer's official warranty against manufacturing defects. Deep discharge from winter lay-up without charging is not covered.
Shipping, delivery 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.
Data sheet
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BrandFULLRIVER
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ReferenceFT438-U1
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ModelFull Throttle Series
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Voltage (V)12
-
Length196.00 cm
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Width131.00 cm
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Height192.00 cm
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Weight11.30 Kgs
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TechnologyAGM
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EAN810233030633
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Terminal typeM6 + TP26 (SAE)
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Cold cranking amps (EN)438
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Capacity (C20)35
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Case typeU1
Specific References
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UPC810233030633
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MPNFT438-U1
Recommended accessories
Frequently asked questions
Is the Fullriver FT438-U1 an AGM battery and what are the benefits of AGM?
Yes. The FT438-U1 from Fullriver 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 boats with advanced Start-Stop and regenerative braking. Expected lifespan: 5-8 years under normal conditions.
How do I change this battery step by step?
In most boats 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 — match the polarity shown on the product sheet; 6) connect the positive (+) first, then the negative (−). On boats 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 Fullriver FT438-U1 is 5 to 8 years in mild-climate boat 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 FT438-U1 model?
Dimensions (length × width × height) are 196×131×192 mm — also written as 196x131x192 mm — following the European DIN standard. Always measure the space in your boat before buying: even one extra millimetre can prevent the hold-down clamp from closing. The height shown includes the terminals.
Will the Fullriver FT438-U1 battery fit my boat?
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 FT438-U1 typically fits a wide range of European vehicles thanks to its standard DIN case format.
Which batteries are equivalent to the Fullriver FT438-U1?
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 boats. See the "Equivalents" section to view recommended options at the same performance level.
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