TITAN 12V 230Ah Underseat Lithium Leisure Battery

12.8V | 230Ah | 2,944Wh

Real achievable capacity - up to 245Ah

315mm long x 280mm wide x 188mm high

The 230Ah Underseat, in short

Our answer to the under-seat battery. 2,944Wh of real, usable energy at 12.8V, packed into a low, wide metal case that fits in the space nobody else can use: under a driver or passenger seat base, under a bench seat, in a low locker or beneath a bed frame. 188mm tall, so it clears seat boxes and locker lids that a taller industrial pack never could, and every connection is on the front face so it can sit hard against a wall on three sides.

• 2,944Wh usable, up to 245Ah in practice
• 250A continuous BMS discharge, 300A peak
• 188mm tall - fits where a standard tall pack will not
• All connections on the front face: M8 terminals, two comms ports, built-in on/off
• Metal case, 25kg - replaces 143kg of lead-acid for the same usable Wh
• Native Victron CANBUS, RS485 and NMEA2000 on request
• Built-in heater mat, safe charging down to -30°C
• Lifetime, transferable warranty

Same cells, same custom BMS and same 250A output as our standard 230Ah. The only thing that changes is the shape of the box it lives in. Happy mounted on its base, on its side or on its end, just not inverted (upside down). Free tie-down strap kit included with every metal-cased battery.

Will it fit your vehicle?

The cell chemistry

All TITAN batteries use lithium iron phosphate (LiFePO4) prismatic cells - the most thermally and chemically stable lithium chemistry available. No cobalt, no nickel, no off-gassing, no acid. The trade-off is a slightly lower cell voltage (3.2V per cell, 4 cells = 12.8V) and lower energy density than the NMC cells used in EVs. In return, you get lifespans that make NMC look disposable: 3,000 to 25,000 cycles depending on use, against NMC's 1,000 to 2,500.

LiFePO4 is now widely considered safer than lead-acid. Cells can be installed in any orientation (upright is optimum), contain no liquid electrolyte, and are fully recyclable.

Cycle life you won't outlive

A cycle is one full discharge plus one full recharge. Count scales with how deep you take each discharge:

• 100% DoD - 3,000 cycles (8.2 years at one cycle a day)
• 80% DoD - 6,000 cycles
• 50% DoD - 12,000 cycles (over 30 years daily use)
• 30% DoD - 15,000+ cycles

For reference, the best lead-acid gel battery tops out at 350-400 cycles at 80% DoD. A TITAN at the same depth gives 6,000 - roughly 15x the service life.

Prismatic, not cylindrical

Our cells are long, flat prisms that fill the rectangular case end to end. Cylindrical cells leave gaps between every cell and are much harder to repair (lots of spot welding), so we pay the extra cost for prismatic and pass the capacity gain back to you. The aluminium cell casing also disperses heat evenly: even at full 250A BMS allowance we measured peak cell temperatures around 45°C, well inside spec (thermal runaway territory doesn't start until around 100°C). Heater mats also work better with prismatic cells - every cell sits against the heating element, rather than only the outer ring of a cylindrical pack.

Capacity, without the weight

Five and a half times the usable capacity of lead-acid

Matching this 230Ah in lead-acid means five and a half Exide ER550 115Ah batteries paralleled up to 630Ah. One TITAN 230Ah Underseat replaces the lot, and does it in a space you probably already have.

We quote capacity in Wh (Watt-hours) because Ah on its own ignores chemistry. TITAN lithium delivers 100% of rated capacity. Gel manages around 90%, AGM 75%, flooded lead-acid 60%. Factor that in and a TITAN 230Ah has more than double the real-world capacity of a lead-acid battery on the same label rating.

25kg. Not 143kg.

There isn't a single lead-acid battery that comes close to this capacity. The honest comparison is five and a half ER550-class leisure batteries paralleled together to match the usable Wh - that's 143kg of lead-acid sitting in your install. One TITAN Underseat does it in 25kg. A 118kg saving matters on a motorhome's drive-axle plate, at the ferry scales, and at the pump. Under a seat, it also puts that weight low down and inboard rather than in a rear locker.

99% electrically efficient

Almost every watt you put in comes back out. A great partner for solar - no wasted incoming charge - and happy to accept very high charge currents: 0 to 95% in under two hours at 100A+.

The TITAN BMS

The battery management system is the circuit board between the cells and the terminals. It's the difference between a lithium battery that lasts 15 years and one that self-destructs in two. Most brands fit an off-the-shelf board with generic parameters. We don't.

Matched, not off-the-shelf

Our BMS is custom, with parameters tuned to the exact cell spec we use. That lets us run the cells right up to their real safe working limits without compromising protection. It's also how we pull an extra 5-10% usable capacity out of every cell (a 230Ah can show as 245Ah fully charged). We can't guarantee the bonus capacity batch to batch, but the BMS re-maps its 100% reading automatically so the app always shows what you actually have.

11 protections, all self-resetting

Over-discharge, over-voltage, under-voltage, over-current, short-circuit, over-temperature, under-temperature, cell balance faults and more. All protections are temporary - they either self-reset or clear the moment the battery is put back on charge. The 250A continuous allowance on this model (280A for 5 seconds, 300A for 1 second) is class-leading thanks to premium MOSFETs, oversized heat sinks and properly sized internal cabling.

Dual active and passive cell balancing

Passive balancing is cheap: cells bleed off to each other and that's it. Active balancing actively moves energy between cells, protecting the weakest cell from doing all the work. Most brands pick one. We run both - passive for small voltage deltas, active for larger ones. Keeps the BMS's own power draw low while still giving you the full benefit of active balancing. It's automatic, most active when charging above 3.4V per cell, and takes full effect between 90-100% SOC.

Self-heating, safely charging down to -30°C

Lithium cannot be charged below 0°C without cell damage. Our built-in heater mat wraps the internal pack and kicks in automatically at around 2°C whenever there's an incoming charge current. It draws from the charger first, and if the charger can't keep up, pulls up to 3.6A from the battery itself to get cell temperature to 10°C before routing charge back to the cells. Expect roughly 20 extra minutes on your charge time in the cold. Discharge is unaffected and works down to -20°C.

Automatic and user hibernation

A fully discharged lithium battery left for months can be a lithium battery that doesn't come back. Two hibernation modes keep that from happening:

• Automatic: triggers after several days of inactivity at low SOC. The battery stops outputting, but retains enough headroom to last around 6 months before any cell risk. Wakes up the moment you put it on charge or open the app.
• User: triggered by the on/off control built into the front face of the case, so there is no separate cable to fit, store or lose. The BMS stays awake, but charge and discharge are disabled. Perfect for winter storage - stops parasitic loads from draining the battery over a season off the road.

Handles high inrush currents

Inverters, water pumps, motor movers and compressors can pull 1,000A+ for a microsecond on start-up. Many BMSs read that as a short circuit and trip. Ours is tuned to ride those spikes without nuisance shutdowns, so start-up loads behave the way they did on your old lead-acid.

Inverter and device communication

Two comms ports on the front face let the battery talk to compatible inverters, chargers and GX devices. Defaults to Victron CANBUS (VE.CAN and BMS.CAN) and is compatible with Victron DVCC out of the box. RS485 and NMEA2000 are supported, and the data mode can be switched to other brands or protocols on request - flag it in the order notes and our engineers will set it before dispatch.

Known working with:

• Victron GX devices (default) - CAN
• Growatt - CAN
• Sacolar - CAN
• Goodwe - CAN
• Voltronic Power - RS485
• Sofar - CAN
• Sorotec - CAN or RS485
• Deye / SunSynk - CAN or RS485
• Solis - CAN
• Luxpower - CAN
• Pylon Tech - CAN or RS485
• Sol-Ark - CAN
• SRNE - RS485
• MUST - CAN
• SMA - CAN
• MEGAREVO - CAN
• MPP Sola - RS485
• TBB Power - CAN
• Senergy - CAN
• Schneider Electric - CAN
• Aiswei - CAN
• SMK - RS485
• Foxess - CAN
• SunGrow - CAN

Cable kits for every protocol are stocked on our store.

Fitment and installation

Measure the void, not the old battery

Under-seat spaces are made by the converter, not the chassis manufacturer, so they vary. Check 315mm long x 280mm wide x 188mm high against your seat base or locker, and allow room for the cables to approach the front face. Up to eight can be paralleled for 1,840Ah, and up to four in series for 48V systems.

Double-check your charger. TITAN batteries accept AGM or "Sealed" modes if your charger does not have a dedicated lithium preset. Aim for a maximum charge voltage of 14.4V.

Compatible with split-charge relays and DC-DC chargers out of the box. These are deep-cycle leisure batteries for running equipment - not engine-starting batteries.

Terminals

High-performance copper M8 terminals on the front face, positioned alongside the comms ports and the on/off control so all cabling approaches from one side. Two M8 bolts and spring washers are included with the battery for direct ring-terminal cabling. Need round (SAE/automotive) terminals instead? No problem - we ship high-quality, hot-stamped brass automotive adapters free of charge. Just leave a note at checkout and we'll include them.

One fitting note worth reading twice: the terminals sit on raised, insulated pillars with a fixing screw either side. Fit your ring terminals with the crimp barrel and cable pointing away from the case, so no part of the eyelet can reach across to those screws. Fitted flat and facing outward there is nothing to worry about.

Mounting

188mm tall, 315mm long and 280mm wide, so it goes where a standard tall pack will not. Upright on its base is optimal for longevity and performance, but the cells are stable in any orientation the install calls for. The case is metal, and a heavy-duty tie-down strap kit is included free with the battery - use it. Anything mounted under a seat should be secured so it cannot move under braking.

Bluetooth monitoring and the TITAN app

Bluetooth is built in. The free TITAN app (iOS and Android, 10 languages) shows live voltage, current in both amps and watts, SOC as a percentage and in Ah, individual cell voltages, internal temperature, estimated time to full or empty, protection trip history and live balancing activity.

It handles multiple batteries in series or parallel and re-calculates totals automatically, so whether you've got one 230Ah Underseat or three in parallel, the figures on screen match the actual pack.

Warranty, longevity and repair

Actual lifetime warranty

We're confident enough in the build to back every grade-A cell battery with a warranty that lasts the lifetime of the battery - fully transferable. Our parent company has been trading continuously since 1948, so we intend to be around to honour it in 20 years' time.

What the warranty doesn't cover is wear. All batteries lose capacity with use - the harder you work them, the faster that happens. LiFePO4 is remarkably resistant: expect a 5-10% capacity drop every decade of normal use. A brand-new 230Ah shows around 245Ah fully charged, a 10-year-old 230Ah around 215Ah, a 20-year-old 230Ah around 195Ah. Natural degradation isn't a valid warranty claim - if a battery stops holding enough capacity for your use, it's time to replace.

The warranty covers components against premature failure caused by manufacturing faults. Full terms are on our warranty page.

Cost over a decade

The TITAN 230Ah Underseat sits at £700 new. Over its 10-year design life that's £70 a year. The closest lead-acid equivalent - two Exide AGM EP2100 in parallel - is around £1040 with a 4-year design life, which means replacing it roughly 2.5 times over the same period. Call it £260 a year, with cascading labour each replacement. Around £1900 saved over 10 years, before you factor in the weight, volume and efficiency benefits. In practice most of our customers see 15-20 years out of a TITAN.

Module-based repair

If something fails we repair the failed module - BMS, balance board, a single cell - rather than replace the whole battery. Lower cost to you, lower carbon footprint, faster turnaround. As a family of battery specialists since the 1950s, there isn't much we haven't already rebuilt.