For a permanent van build, the answer is almost always: hardwire the inverter. Here's why, and the cases where a plug-in approach works.
Our free electrical calculator sizes the inverter from the 120V appliances you actually plan to run, then adds the battery, cables and fuses around it.
Hardwired inverter
How it works: Heavy gauge cable runs directly from battery positive (through a large fuse/breaker) and battery negative to the inverter's DC terminals. The inverter is mounted permanently in the van.
Advantages:
- Lower resistance = less voltage drop under load = more efficient operation
- Can support large inverters (1,000W, 2,000W, 3,000W+) — plug connections can't safely handle the current
- Cleaner installation, secured mounting
- Easier to integrate with a master switch or remote panel
Cable sizing for hardwired installation:
| Inverter size | Full load current | Minimum cable (3 ft run) | Minimum cable (6 ft run) |
|---|---|---|---|
| 1,000W | ~90A | 1/0 AWG | 2/0 AWG |
| 2,000W | ~175A | 2/0 AWG | 4/0 AWG |
| 3,000W | ~260A | 4/0 AWG | 4/0 AWG |
Always fuse within 18 inches of the battery positive terminal. Fuse rating should be 125% of the inverter's maximum DC input current.
Plug-in inverter
How it works: The inverter connects via a 12V socket (cigarette lighter), Anderson connector, or SAE connector rather than being wired directly to the battery.
12V socket (cigarette lighter): Most are fused at 10–20A, limiting you to 100–200W. Fine for a small inverter charging a laptop or phone while driving, but not for any serious van electrical work.
Anderson SB50 or SB175 connector: A heavy-duty connector rated for 50A or 175A. Some van builders use these for a portable inverter that can be moved between vehicles. Works well for up to 500W (SB50) or ~2,000W (SB175). Adds a small voltage drop at the connection.
Anderson PowerPole: Smaller connectors for lower current — not suitable for inverters above ~200W.
When plug-in makes sense
- Portable inverter for on-the-go use: A small (150–400W) inverter that you use occasionally while driving, then store when not needed. A 12V socket or SB50 is fine.
- Temporary setup or van conversion in progress: Plug-in while you build out the full system.
- Dual-vehicle use: Anderson connector allows the same inverter to move between a van and a tow vehicle without rewiring.
When you must hardwire
- Any inverter over 500W
- Any inverter that will be used regularly or full-time
- Any inverter integrated with shore power (inverter/charger with ATS)
- Any inverter powering a fixed induction cooktop, microwave, or AC outlet panel
Related
- Inverters & 120V power guide
- How to install an inverter in a van
- How to wire 120V outlets from an inverter
- What size inverter do I need?
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Jack Kennedy is a self-builder who has built two vans. He created Roam Wired to simplify conversion planning and share free tools, supported by affiliate links.
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