Battery for the electric conversion: types, costs and the right size (2026)
The battery devours 40–60% of the total cost of an electric conversion and determines range, weight and charging speed. According to emobility.energy (2025) it is thus the most important and most expensive single component of any conversion project. Choose wrongly here and you pay twice — with less range and a shorter lifespan.
This guide compares all relevant battery types for the conversion, explains how to calculate the right capacity and shows what batteries cost per kWh in 2026. You will also learn why VW MEB modules have become so popular and what the BMS has to do with the safety of your vehicle. If you are just starting out, we recommend our complete guide to electric car conversion.
TL;DR: The battery accounts for 40–60% of the conversion cost (emobility.energy, 2025). LiFePO4 cells offer the longest lifespan (3,000–5,000 cycles), NMC the best energy density. For most projects the sweet spot is 30–50 kWh. Battery prices have fallen by around 50% since 2020 — a good time for a conversion.
Why is the battery the most important component in an electric conversion?
No other component influences your conversion project as much as the battery. According to emobility.energy (2025) 40–60% of the total cost is attributable to the battery pack alone. On a typical project with a €20,000 budget, that is €12,000 to €15,000 — just for the cells, the housing and the management.
At the same time, the battery determines three critical properties of your vehicle: how far you can drive, how fast you can charge and how much your conversion ultimately weighs. A battery that is too small makes everyday use impractical. One that is too large increases the weight and puts unnecessary strain on suspension and brakes.
What the battery decides for the entire project
The choice of battery drags a whole chain of follow-up decisions with it. The cell chemistry determines which cooling system you need. The form factor decides where the modules fit in the vehicle. The voltage must match the inverter and the onboard charger. Whoever chooses the battery first and plans the rest around it saves themselves expensive detours.
You will find the complete cost breakdown of all components in our cost guide for the electric conversion.
Which battery types are suitable for the electric conversion?
Three lithium cell chemistries dominate the conversion market: LiFePO4, NMC and LTO. According to Battery University (2024) these types differ fundamentally in energy density, lifespan and safety behaviour. The right choice depends on your vehicle, your budget and your usage profile.
LiFePO4: Der Ausdauerspezialist
Lithium iron phosphate cells (LiFePO4) are considered the safest and most durable option. They reach 3,000 to 5,000 full charge cycles — with daily charging that corresponds to a lifespan of over ten years. They are also thermally stable: even when damaged, thermal runaway is extremely unlikely.
The downside? At the same capacity, LiFePO4 cells weigh around 30–40% more than NMC. Their gravimetric energy density is about 90–160 Wh/kg compared with 150–250 Wh/kg for NMC. For light vehicles with limited space — a Porsche 911, for example — that can become a problem.
LiFePO4 cells currently cost €80–120 per kWh at cell level. They are particularly suited to vans and everyday vehicles where weight is less critical than durability and safety.
NMC: Der Leichtgewicht-Champion
Nickel manganese cobalt cells (NMC) are found in most modern production electric cars — from the VW ID.3 to the Tesla Model 3. Their high energy density of 150–250 Wh/kg enables more range at less weight. That is precisely why NMC cells are the first choice for sports cars and compact classics.
The flip side: NMC cells are more sensitive to overcharging and thermal stress. They need more sophisticated battery management and active cooling. The lifespan is 1,500–2,000 cycles — solid, but well below LiFePO4. The price ranges between €120 and €180 per kWh.
LTO: the fast charger for special cases
Lithium titanate cells (LTO) are the exotics among conversion batteries. Their strength: extreme fast-charging capability and over 10,000 charge cycles. According to Battery University LTO cells tolerate charge rates of up to 10C — a 20 kWh battery would theoretically be full in six minutes.
In practice, LTO cells play hardly any role in conversions. The reason: their energy density of only 50–80 Wh/kg makes them extremely heavy and bulky. They also cost €200–400 per kWh. LTO is therefore used almost exclusively in buses and stationary storage — for passenger-car conversions it is rarely sensible.
Vergleichstabelle: LiFePO4 vs. NMC vs. LTO
| Property | LiFePO4 | NMC | LTO |
|---|---|---|---|
| Energy density (Wh/kg) | 90–160 | 150–250 | 50–80 |
| Lifespan (cycles) | 3.000–5.000 | 1.500–2.000 | 10.000+ |
| Cost per kWh (cell) | 80–120 € | 120–180 € | 200–400 € |
| Safety | Very high | Medium | Very high |
| Cooling required | Optional | Ja (aktiv) | Optional |
| Weight (30 kWh) | ~250 kg | ~170 kg | ~450 kg |
| Ideal für | Transporter, Alltagsautos | Sportwagen, Leichtbau | Busse, Spezialfahrzeuge |
How do I calculate the right battery size for my vehicle?
The required battery capacity results from the vehicle weight and the desired range. As a rule of thumb, according to ADAC (2025): an electric vehicle consumes 12 to 25 kWh per 100 km depending on weight and aerodynamics. Light classics are at the lower end, heavy vans at the upper end.
The rule of thumb for your project
Calculate like this: desired range in km divided by 100, multiplied by the estimated consumption in kWh/100 km. For a VW Beetle with 1,100 kg total weight and a 200 km target range it looks like this: 200 ÷ 100 × 15 kWh = 30 kWh of usable capacity.
Plan a buffer of 15–20%, because the usable capacity is always below the nominal capacity. The BMS keeps a range at the top and bottom as a reserve. So 30 kWh of demand becomes around 35 kWh of nominal capacity.
Consumption values by vehicle type
| Fahrzeugtyp | Weight after conversion | Consumption (approx.) | Recommended battery |
|---|---|---|---|
| VW Beetle | 1.050–1.200 kg | 13–16 kWh/100 km | 25–48 kWh |
| Porsche 911 (F/G/964) | 1.200–1.400 kg | 15–18 kWh/100 km | 40–48 kWh |
| VW T1/T2 Bulli | 1.400–1.700 kg | 18–22 kWh/100 km | 48–80 kWh |
| VW T5/T6 | 2.000–2.400 kg | 20–25 kWh/100 km | 65–82 kWh |
Have you already decided on a vehicle? Our guide to the VW Beetle electric conversion goes into detail for the most popular conversion candidate.
Why are VW MEB battery modules so popular for conversions?
VW MEB modules from the ID.3 and ID.4 have established themselves as the standard building block for professional conversions. According to Fraunhofer ISI (2025) the Modular Electric Drive Matrix (MEB) is based on NMC cells with an energy density of around 170 Wh/kg — and by 2025 VW had produced over 1.5 million MEB vehicles, which secures the availability of spare parts and modules.
Vorteile der MEB-Module
MEB modules come in a standardised format that makes integration easier. Each module delivers around 8.7 kWh at a weight of about 28 kg. The modules are designed for active liquid cooling — an advantage if you are planning CCS fast charging. The documentation is also comprehensive, which makes the TÜV approval easier.
Another plus: MEB modules are now also available as individual components on the used market. Accident vehicles and leasing returns provide supply. Whoever buys cleverly pays €60–80 per kWh for used modules in good condition.
Limitations and alternatives
MEB modules require a compatible BMS and a cooling system. Integration is not plug-and-play — you need adapters and control electronics matched to the VW cell chemistry. For simpler projects, prismatic LiFePO4 cells (such as CATL or EVE) can be the more straightforward choice.
If you want to get an overview of the various motor options, we recommend the Vergleich: Tesla-Motor im Oldtimer.
What makes the battery management system so important?
The BMS monitors every single cell in your battery — voltage, temperature, state of charge. Without a functioning BMS, the risk of thermal runaway increases many times over. According to a study by Journal of Power Sources (2023) over 80% of battery faults in EVs can be traced back to inadequate cell monitoring.
Aufgaben eines BMS
A BMS performs three core functions. First: cell balancing. It evens out minimal voltage differences between the cells so that no single cell is overcharged or deeply discharged. Second: protection. In the event of overtemperature, short circuit or overvoltage, the BMS disconnects the battery from the vehicle system. Third: condition monitoring. It calculates the current state of charge (SoC) and the state of health (SoH).
Sounds technical? Think of it like this: the BMS is the bodyguard of your battery. It intervenes before anything goes wrong — and tells you how fit your energy storage still is.
BMS for the conversion: off-the-shelf or self-build?
With professional kits the BMS is matched to the cells used and already calibrated. That saves an enormous amount of time and reduces sources of error. Whoever assembles individual components has to configure the BMS themselves — and that requires a deep understanding of cell chemistry.
With NMC cells in particular, a high-quality BMS is indispensable. These cells react more sensitively to overcharging than LiFePO4. A cheap China BMS for €200 can work — or, in the worst case, fail when it matters. Better to invest €500–1,200 here in a proven system with active balancing.
How must the battery be installed in the vehicle?
The placement of the battery determines crash safety and TÜV approval. The TÜV checks according to Leaflet 764 (based on ECE-R 100), whether the battery cannot penetrate the passenger compartment in an accident. Improper mounting is the most common reason for failing the individual approval.
TÜV requirements for battery mounting
The fixing must withstand at least 20 times the acceleration due to gravity (20g) in the direction of travel. Similarly strict values apply laterally and vertically. In practice that means: bolted connections to the vehicle frame or to reinforced body points, no adhesive tapes or makeshift brackets.
The battery must also not be located in the crumple zone. On the Beetle the front end (former luggage compartment) is a common position; on the T1/T2 Bulli the underbody is a good option. For the TÜV you need either a strength report or — with certified kits — the manufacturer documentation supplied.
Do not forget weight distribution
A 250 kg battery changes the axle-load distribution considerably. Ideally you position the modules so that the weight is distributed as evenly as possible over both axles. A 50:50 ratio is optimal but rarely achievable in practice. A distribution of no more than 60:40 is acceptable.
You will find all the details on the TÜV inspection and the required documents in our guide to the TÜV individual approval for the electric conversion.
What determines the battery when charging — AC vs. DC?
Whether your conversion works only at the wallbox or also at the fast charger depends directly on the battery and the installed charger. According to ADAC (2025) around 80% of all EV owners charge predominantly at home — but anyone who wants to drive long distances needs CCS fast charging.
AC-Laden: Die Basislösung
With AC charging, a built-in charger (onboard charger) converts the alternating current from the wallbox into direct current for the battery. Most conversions use 10 kW AC chargers. On an 11 kW wallbox a 40 kWh battery is thus full in around four hours — perfect for charging overnight.
AC charging is the simplest and cheapest charging solution. The charger costs €500–2,000 and fits into almost any vehicle. For commuters and weekend drivers, AC charging is entirely sufficient.
DC fast charging: freedom on long journeys
With DC charging (CCS) the direct current is fed straight into the battery — without the detour via the onboard charger. This makes charging speeds of 50 to 120 kW possible. A 40 kWh battery thus charges from 10 to 80 percent in 20 to 40 minutes.
DC fast charging, however, requires a CCS interface, a compatible BMS and a battery that tolerates high charge currents. NMC cells with active cooling are better suited to this than air-cooled LiFePO4 packs. Retrofitting costs an additional €2,000–5,000 depending on the system.
Anyone who wants to be on the safe side chooses a battery and charging configuration that supports both from the start. Retrofitting CCS later is technically possible, but more expensive and more involved than planning it in directly.
How long does a conversion battery last — and what are second-life batteries?
The lifespan of a lithium battery depends on cell chemistry, use and temperature management. According to BloombergNEF (2025) modern NMC cells still retain around 80% of their original capacity after 1,500 cycles. LiFePO4 only reaches this value after 3,000–5,000 cycles — a clear advantage with daily use.
What accelerates degradation?
Three factors age your battery faster than necessary. First: heat. Permanently high cell temperatures above 40 °C accelerate the chemical breakdown. Second: extreme charging. Constantly charging to 100% or discharging below 10% stresses the cells. Third: high charge currents. Whoever hangs on the DC fast charger every day ages their NMC battery faster than a pure AC charger.
The good news: with a good BMS and sensible use (charging between 20 and 80%), conversion batteries easily last 8–15 years. That is enough for the vast majority of projects.
Second-life batteries: cheap, but with reservations
Decommissioned modules from accident or leasing vehicles cost 40–70% less than new goods. A 30 kWh pack from a Nissan Leaf or VW ID.3 is available for €3,000–5,000. Sounds tempting — but the condition varies considerably.
Before buying, always check the State of Health (SoH) with a diagnostic device. Modules below 80% SoH are rarely worthwhile: the remaining capacity then drops disproportionately quickly. Reputable providers supply test protocols. Without a documented SoH value you should not buy.
What do batteries for the electric conversion cost per kWh?
Battery prices have fallen drastically in recent years. According to BloombergNEF (2025) the average pack price in 2025 was US$108 per kWh — a drop of around 50% compared with 2020. For individual buyers in the conversion market, however, prices are higher because economies of scale are missing.
Current prices by cell type (2026)
| Batterietyp | Cell level (€/kWh) | Pack level (€/kWh) | 30-kWh-Paket (ca.) |
|---|---|---|---|
| LiFePO4 (neu) | 80–120 € | 130–200 € | 3.900–6.000 € |
| NMC (neu) | 120–180 € | 180–280 € | 5.400–8.400 € |
| MEB-Module (gebraucht) | 60–80 € | 100–150 € | 3.000–4.500 € |
| LTO (neu) | 200–400 € | 300–500 € | 9.000–15.000 € |
Important: the cell level is the pure cell price. At pack level, housing, cooling, BMS and wiring are added — that often doubles the price. The statement "battery for X euros" without distinguishing between cell and pack price is a common trap in offers.
Where are prices heading?
BloombergNEF forecasts a further drop to under US$100 per kWh at pack level for 2026 — but only for large-series production. For the conversion market, prices are likely to fall more slowly because the volumes are smaller. Nevertheless: whoever still paid €250 per kWh in 2020 gets the same capacity for €130–180 in 2026.
Battery configurations at a glance: all options by vehicle
The right battery depends not only on the type but also on what kind of vehicle you want to convert. According to emobility.energy (2025) the spectrum ranges from 25 kWh for light city cars to over 80 kWh for heavy vans. The following table shows common configurations as professional providers put them together.
| Vehicle | Kit-Stufe | Battery | Range | Charging | Price |
|---|---|---|---|---|---|
| VW Beetle | PURE | 25 kWh | 150 km | 10 kW AC | 29.990 € |
| VW Beetle | PERFORMANCE | 40 kWh | 300 km | 50 kW CCS + 10 kW AC | 39.990 € |
| VW Beetle | ULTIMATE | 48 kWh | 350 km | 70 kW CCS + 10 kW AC | on request |
| VW T1 Bulli | PURE | 48 kWh | 200 km | 10 kW AC | 29.990 € |
| VW T1 Bulli | VOYAGER | 80 kWh | 400 km | — | 54.990 € |
| VW T2 Bus | PURE | 48 kWh | 200 km | 10 kW AC | 29.990 € |
| VW T2 Bus | VOYAGER | 65 kWh | 350 km | — | 54.990 € |
| VW T5/T6 | — | 82 kWh (MEB) | 450 km | 120 kW DC + 10 kW AC | 34.990 € |
| Porsche 911 | PURE | 40 kWh | 250 km | 10 kW AC | 44.990 € |
| Porsche 911 | PERFORMANCE | 45 kWh | 300 km | 70 kW CCS + 10 kW AC | 54.990 € |
| Porsche 911 | ULTIMATE | 48 kWh | 300 km | 90 kW CCS + 10 kW AC | on request |
| Porsche 964 | PERFORMANCE | 45 kWh | 300 km | 70 kW CCS | 59.990 € |
| Porsche 964 | ULTIMATE | 48 kWh | 350 km | 90 kW CCS | on request |
The table clearly shows: battery size alone says little about range. A VW Beetle reaches 300 km with 40 kWh, a heavy VW T2 bus needs 65 kWh for 350 km. The vehicle weight makes the difference.
It is also striking that lighter vehicles like the Beetle and the 911 get by with relatively small batteries. 48 kWh is enough for 350 km in the Beetle — a VW T1 already needs 80 kWh for 400 km. Anyone who wants to optimise range and weight should keep the base vehicle as light as possible.
Frequently asked questions about the battery in the electric conversion
Which battery type is best for the electric conversion?
It depends on the vehicle. LiFePO4 cells with a 3,000–5,000 cycle lifespan (Battery University) are suited to heavy everyday vehicles and vans. NMC cells offer the better energy density at 150–250 Wh/kg and are the first choice for sports cars and classics with little space. For most projects, NMC in the form of VW MEB modules is the most pragmatic route.
How many kWh do I need for my conversion?
Reckon on 12–25 kWh consumption per 100 km, depending on vehicle weight (ADAC, 2025). For 200 km of range you need around 30 kWh in a light Beetle, rather 50 kWh in a VW T5. Plan a 15–20% buffer over your calculated demand, because the BMS keeps part of the capacity as a reserve.
Can I use used batteries for the conversion?
Yes, but only with a documented State of Health (SoH). Used modules cost 40–70% less than new goods. Do not buy anything below 80% SoH — the remaining capacity drops disproportionately quickly after that. Reputable providers supply test protocols. VW MEB modules and Tesla modules are the most commonly available on the used market.
Do I need an active cooling system for the battery?
With NMC cells and CCS fast charging: yes. Active liquid cooling keeps the cell temperature constant and considerably extends the lifespan. LiFePO4 packs manage without active cooling in many cases, especially if you only charge via AC. At continuous power above 50 kW, however, cooling is also advisable for LiFePO4.
What does a complete battery for the electric conversion cost?
At pack level (including BMS, housing and cooling) you pay €130–280 per kWh, depending on cell chemistry (BloombergNEF, 2025). A 30 kWh LiFePO4 pack costs €3,900–6,000, a 30 kWh NMC pack €5,400–8,400. Used MEB modules in good condition are available from €3,000 for 30 kWh.
Conclusion: the battery decides the success of your conversion
At 40–60% of the total cost, the battery is the heart of every electric conversion. LiFePO4 offers durability and safety, NMC shines with lightweight construction and high energy density. VW MEB modules have established themselves as the pragmatic standard for professional conversions. And the prices? They have fallen by around 50% since 2020 — and the trend continues downwards.
Three things you should take away: First — calculate the required capacity based on your vehicle weight and your target range before you buy. Second — do not skimp on the BMS, because it protects your investment and your safety. Third — plan the battery placement and TÜV requirements from the start, not afterwards.
Ready for your project? Get started with our complete guide to electric car conversion und rechne die Gesamtkosten für 2026 . Everything about the TÜV approval of your battery installation is explained in our guide to the TÜV individual approval.
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