If you’re traveling in an RV, you are traveling with some of the comforts of home – air conditioning, fridge, microwave, television, and other appliances. To enjoy those amenities, you will need a power source. Portable generators provide an effective and economical solution to your power needs.
But what size generator to buy? First you need to understand that generator models are classified by watts – starting watts and running watts.
The more watts your generator has, the more items you can power at the same time. To know how much you will need, calculate all the wattage requirements of all the accessories you plan to operate on generator power. Typically, wattage is listed on the device, on the back or on the bottom. If not, a simple formula for determining watts is multiplying volts x amps. The total will tell you the model of generator you need.
One thing to remember is some devices have starting wattage requirements that are larger than running watts, like the air-conditioner, which is the biggest power user. To calculate the minimum number of watts you need, use the starting watts of the air conditioner plus the running watts for all other devices. This is the minimum wattage you will need from a generator.
Let’s make this a bit clearer with this example:
A 13,500 btu air conditioner will take about 2,800 starting watts. After it has powered up, it will run at about 1,800 watts. With a 4,000 watt generator, you have 1,200 watts to power other items. So, if you plan to run more items that will exceed 1,200 watts, you will need a larger generator.
The chart below will give you a better idea of approximate running wattage of some common items used in an RV.
Please note: This is just a guide. Individual appliances may have varying wattages.
| Appliance | Running Watts (Approx.) | Starting Watts (Approx.) |
| Air Conditioner 15,000 btu | 2,000 | 3,300-3,500 |
| Air Conditioner 13,500 btu | 1,800 | 2,800 |
| Coffee Maker | 1,750 | 0 |
| Keurig Coffee Maker | 300 | 1,500 |
| Electric Grill | 1,650 | 0 |
| Electric Fry Pan | 1,300 | 0 |
| Microwave (650 Watts) | 1,000 | 1,000 |
| Blender | 400 | 850 |
| Fridge | 180 | 600 |
| Laptop | 200-250 | 0 |
| Outdoor Light String | 250 | 0 |
| Slow Cooker | 170-270 | 170-270 |
| Radio | 50-200 | 0 |
| Cell Phone Battery Charger | 25 | 0 |
| Inflator Pump | 50 | 0 |
Another important factor to consider is how long you will be running your generator. The generator run time is found on the generator spec sheet and owner’s manual. Run time is determined at 50% load levels and the power used directly impacts the run time. The more power used, the shorter the run time and the sooner you will have to refuel.
When using a generator, always be aware of safety and the danger of carbon monoxide. Keep the generator in an outside space, far from occupied areas, with its exhaust pointing away from RVs and campsites. Never transport your generator in the back of your RV or your SUV if you are towing a camper. The best way to transport your generator is to have a platform built on the back of your RV.