The lithium battery for your VW Transporter.
The Transporter is Britain's favourite small-camper conversion base, and it is tight on space - which is where TITAN's compact 105Ah DIN battery, a size no other UK brand makes, earns its place. This page is for T5, T6 and T6.1 conversions. If you have a factory VW California, that is covered on the VW campervan page.
The Transporter story - and one important change in 2024
VW built the Transporter through three modern generations: the T5 (2003-2015), the T6 (2015-2019) and the T6.1 (2019-2024). All three came as a Transporter panel van, a Kombi with rear windows, and a Caravelle passenger version. These are the vans that fill Britain's conversion industry. Space is tight in all of them - especially under the seats, which is the natural home for an aftermarket leisure battery - and that tightness is why the compact 105Ah DIN case exists. It goes where a standard 100Ah leisure battery will not.
One thing to be aware of if you are buying used or advising someone who is: the Transporter sold in the UK from 2024/2025 onwards is not a VW van. It is a rebadged Ford Transit Custom, engineered by Ford and built in Turkey. If that is what you have, the smart-alternator setup and battery placement guidance on the Ford Transit page will serve you better than this one.
Starting from scratch with a Transporter shell? The van conversion guide walks through building an electrical system around the battery. Already running a campervan and looking to upgrade? The campervan battery guide covers the swap.
Sizing a Transporter conversion
A starting point by build. The Transporter is a compact van - size to how you actually use it rather than how long you spend in it.
| Build | How it gets used | Good fit |
|---|---|---|
| Pop-top weekender or day vanLights, fridge, phones, the odd night off hook-up | Light use | 105Ah to 150Ah |
| Full camper conversionHeating, fridge, water, devices, days off-grid | Typical vanlife | 150Ah to 230Ah |
| High-top or big-draw buildInverter cooking, longer off-grid, higher loads | Heavy, sustained | 230Ah to 330Ah or twin packs |
These are starting points, not fixed rules. The honest figure comes from your loads, not the size of the van, so total them in the battery size calculator. Twin packs in parallel are an option for larger builds where a single big case will not fit the under-seat space.
Where the battery fits on a Transporter
The natural home for an aftermarket leisure battery on a Transporter is under one of the front seats. The seat base acts as a ready-made battery box, and this is what makes the compact 105Ah case so useful here - it is designed for exactly this tight void. There are two positions:
- Under the driver seat. The most common location for an aftermarket lithium in a Transporter conversion. Access is straightforward and the cable run to the starter battery is short.
- Under the passenger seat. The factory optional second-battery location on a Transporter. Some builds prefer this to keep the driver side clear, and it is where the leisure battery sits in vans that left the factory with an auxiliary battery fitted.
In both cases, the seat-base height is the critical measurement - it is often tighter than the floor footprint suggests, particularly if the conversion includes a raised floor or extra insulation. Measure height, width and depth of your specific seat void before you order. Suitability varies by seat type and any modifications already made during the build.
Wherever it lives, keep it accessible enough to read the terminals and check the connections. The IP67-sealed case handles the under-seat environment well, though the RJ45 comms ports sit at IP32 while a cable is plugged in - so keep connected ports clear of standing water.
Charging a Transporter conversion
A Transporter camper charges from three sources: the engine alternator, roof solar through an MPPT, and mains hook-up when you are on site. Lithium takes all three happily and charges far faster than lead-acid, so a decent drive or a sunny afternoon puts real capacity back in.
The alternator is the part to get right. All T6 and T6.1 models (Euro 6, from 2015 onwards) have a variable-voltage smart alternator, which means the alternator will not reliably fill a lithium battery on its own. Some T5.1 models (2010-2015) with BlueMotion or start-stop technology also have one; earlier T5 (pre-2010) are more likely conventional. When in doubt, assume smart. The fix is a DC-DC charger, also called a battery-to-battery charger - we would fit a Victron Orion every time. It gives the lithium a clean, controlled charge and keeps the starter battery protected.
A split-charge relay is less reliable for charging lithium and some relays cause a backfeed that can quietly skim around 15% off your usable capacity. Feeding straight off the alternator with no relay and no DC-DC is not something we recommend. Plan the roof with the solar guide, check your charger against the compatibility list, and size the battery around the gap your charging cannot cover. Every TITAN carries a custom BMS, charges safely down to -30C, and comes with a lifetime, fully transferable warranty.
