If you plan to operate where shore power isn’t always available, your generator becomes the heart of your trailer. Too small and you’ll be tripping breakers all day. Too big and you waste money and fuel. The right size comes from real numbers, not guesses.

Start With a Load List

Make a list of every electrical device you’ll run from the generator and write down its wattage. Common examples:

Refrigerator: ~800 watts running
Freezer: ~1,000 watts running
Water heater: 1,500–3,000 watts depending on size
Lights: 50–200 watts if LED
Vent fan: 100–300 watts
Small appliances: 300–1,500 watts each

Keep in mind that some appliances draw more at startup than during normal operation.

Adding It Up

Once you have the list, add the running wattages together. Then:

Add extra capacity (20–25%) for startup surges and future equipment.
Think about what truly runs at the same time. You may not need everything powered simultaneously.

Many smaller builds land in the 4,500–7,500 watt range. Heavier builds with electric water heaters and multiple hot appliances may need 10,000 watts or more.

Inverter vs Conventional Generators

Inverter generators are quieter and produce cleaner power, which is better for electronics and customer comfort.
Conventional generators are often cheaper per watt but louder and less fuel-efficient.

If you’re serving in neighborhoods or at events where noise matters, an inverter style is often worth the extra cost.

Fuel Type and Runtime

Consider how you’ll feed the generator:

Gasoline – Easy to find but can go stale in storage.
Propane – Cleaner and stores better, but you get fewer watts per gallon equivalent.
Dual-fuel – Offers flexibility and can be a smart middle ground.

Look at the generator’s runtime at 50% load. That will tell you how often you’ll be refueling during a normal day.

Placement and Ventilation

Where you place the generator matters for safety and customer experience. Keep exhaust away from customers and any trailer openings. Use heavy-duty cords rated for your load and protect them from trip hazards.

A properly sized, well-placed generator keeps your trailer powered without constant babysitting, letting you focus on serving customers instead of fighting your power source.