A 2000W inverter in a campervan can draw very high current from the battery, especially on a 12V system. That means cable size is critical. If the battery cable is too small, voltage drop increases, inverter performance suffers and the cable may overheat under load.
This guide explains what cable size is typically used for a 2000W inverter in a campervan, how current draw affects cable choice, what fuse size is usually needed and when you should step up from 25mm² to 35mm², 50mm² or 70mm² battery cable.
To calculate your exact inverter cable size based on current, voltage drop and cable length, use the free MKGT tool here:
Open Cable Size Calculator →
How Much Current Does a 2000W Inverter Draw?
Current draw depends on system voltage and inverter efficiency. On a 12V system, a 2000W inverter can draw roughly 170–200A at full load. On a 24V system, current is much lower for the same power.
| System voltage | Approximate current draw | Comment |
|---|---|---|
| 12V | 170–200A | High-current battery cable required |
| 24V | 85–100A | Usually allows smaller cable |
This is why inverter cable sizing is much more demanding on 12V campervan systems than on 24V systems.
Recommended Cable Size for a 2000W Inverter
For a typical 12V campervan inverter installation, the correct cable size depends heavily on one-way cable length. The longer the run between battery and inverter, the larger the cable should be.
| One-way cable length | Typical recommended cable size | MKGT product |
|---|---|---|
| Up to 1m | 25mm² | 25mm² battery cable |
| 1–2m | 35mm² | 35mm² battery cable |
| 2–3m | 50mm² | 50mm² battery cable |
| 3m+ | 70mm² | 70mm² battery cable |
These are practical starting points only. Final cable size should always be checked using inverter load, cable length and acceptable voltage drop.
Why Voltage Drop Matters for Inverter Cables
A 2000W inverter draws heavy current, so even a small amount of cable resistance creates significant voltage drop. On a 12V system this can cause:
- reduced inverter performance
- inverter low-voltage shutdown
- alarm warnings under load
- hot battery cables and wasted energy
This is why inverter cable sizing should never be based on current alone. Cable length matters just as much.
Check voltage drop here:
Open Voltage Drop Calculator →
Example 2000W Inverter Cable Calculation
Example installation:
- System voltage: 12V
- Inverter size: 2000W
- Estimated current draw: approx. 180A
- One-way cable length: 2m
In a setup like this, 35mm² may work as a minimum practical size, but 50mm² is often the safer choice for lower voltage drop and stronger performance under heavy loads.
This becomes even more important if the inverter powers kettles, coffee machines, microwaves or other short-duration high-demand appliances.
Recommended Fuse Size for a 2000W Inverter
The inverter fuse should protect the battery cable. For a 2000W inverter on 12V, fuse sizes are usually much larger than for normal campervan circuits.
Typical examples:
| Estimated inverter current | Typical fuse size |
|---|---|
| 170A | 200A |
| 180A | 225A |
| 200A | 250A |
Common fuse families for inverter feeds include:
- MEGA fuse
- MIDI fuse
- ANL fuse
Check exact fuse sizing here:
Open Fuse Size Calculator →
Best Wiring Layout for a 2000W Inverter
A typical inverter feed should be wired like this:
Leisure battery → main fuse → isolator → inverter
Best practice:
- keep battery-to-inverter cables as short as possible
- use equal positive and negative cable sizes
- fit the fuse close to the battery
- use correctly sized lugs and terminations
- check inverter manufacturer guidance as well as cable calculations
25mm², 35mm², 50mm² or 70mm²?
For a 2000W inverter in a campervan, the right answer depends mainly on cable length.
- 25mm² = suitable only for very short runs
- 35mm² = common for compact installs
- 50mm² = strong all-round option for many real installs
- 70mm² = best for longer runs and lower voltage drop
Shop MKGT battery cable here:
Use a Calculator for the Exact Inverter Cable Size
Correct inverter cable size depends on:
- inverter power
- system voltage
- one-way cable length
- acceptable voltage drop
Use the MKGT calculators here:
FAQ
What cable size do I need for a 2000W inverter on 12V?
In many campervan installs, 35mm² to 50mm² is typical, but longer cable runs may require 70mm².
Is 25mm² enough for a 2000W inverter?
Only for very short cable runs. In many real campervan installations, it is too small once cable length and voltage drop are considered.
Should I use 50mm² for a 2000W inverter?
Yes, 50mm² is often a strong practical choice for 12V 2000W inverter installs, especially when the inverter is not mounted extremely close to the battery.
What fuse should I use for a 2000W inverter?
Typical fuse values are often around 200A to 250A, depending on actual inverter current draw and cable size.
Why does my inverter shut down under load?
A common cause is voltage drop in undersized battery cable. Longer cable runs and high load current increase the problem.