Selecting the Right Inverter for Your Campervan or Motorhome: A Technical Guide

In campervans and motorhomes, an inverter is essential for converting the 12V DC power from your battery into 240V AC power for running household appliances. This guide covers the critical factors in selecting the right inverter, and includes a list of common 240V appliances and the inverter sizes required to power them efficiently.

1. Understanding the Basics: Inverter Types

There are three main types of inverters for campervans:

• Pure Sine Wave Inverters: Ideal for sensitive electronics, the following appliances require a pure Sine Wave Inverter:
• Laptops and Computers: Modern computers and laptops with sensitive circuitry need a stable power source. Using modified sine wave inverters can cause overheating or damage to the internal components.
• Smartphones and Tablets: Charging these devices with a pure sine wave inverter ensures optimal charging efficiency and protects the battery from potential harm.
• Televisions: Modern flat-screen TVs, especially LCD, LED, and OLED models, require clean AC power to function properly without flickering or noise interference.
• CPAP Machines: Continuous Positive Airway Pressure (CPAP) machines and other medical devices need a reliable power source to function safely, which is best provided by a pure sine wave inverter.
• Refrigerators and Freezers: Compressor-based appliances like refrigerators work more efficiently and with less wear and tear when powered by pure sine wave inverters.
• Microwaves: For even cooking and to avoid damage, microwaves need clean power.
• Blenders and Coffee Grinders: High-powered appliances with motors will run smoother and more efficiently with a pure sine wave inverter.
• Modified Sine Wave Inverters: Suitable for non-sensitive appliances but may not work with all electronics.
• Square Wave Inverters: Least suitable due to poor compatibility.

2. Power Requirements: Wattage Considerations

To determine the inverter size, you need to calculate the wattage of the appliances you plan to use. Inverters are rated by continuous power (for steady appliance operation) and surge power (for starting up appliances).

The inverter size you need depends on the total wattage of appliances you want to run simultaneously. For example, if you plan to run a laptop (100W) and a microwave (900W) at the same time, you’ll need an inverter with at least a 1000W continuous power rating to ensure smooth operation.

For appliances with high surge power demands (like microwaves or refrigerators), make sure the inverter’s surge rating can accommodate those initial spikes, which are usually 1.5 to 2 times the continuous wattage.

List of 240V Appliances and Required Inverter Sizes

		Continuous power rating
Home and kitchen appliances		300W	600W	1000W	1500W	2000W	3000W
Table fan*	50W
Sewing machine*	100W
Halogen light**	100W	-
Pedestal fan*	100W
Blender*	350W	-	-
Small fridge*	200W	-
Large fridge*	500W	-	-	-
Washing machine (no heating)*	700W	-	-	-	-
Microwave oven**	900W	-	-	-
Coffee maker*	1200W	-	-	-	-
Iron	1500W	-	-	-	-
Hair dryer*	1200W	-	-	-	-
Toaster	1200W	-	-	-
Vacuum cleaner*	2000W	-	-	-	-	-
Single Ring Induction Hob	1500W	-	-	-	-
Air conditioner*	3000W	-	-	-	-	-	-
Electric oven	5000W	-	-	-	-	-	-
		Continuous power rating
Audio and video appliances		300W	600W	1000W	1500W	2000W	3000W
Satellite TV receiver	30W
DVD / Blu-ray player	50W
20'' colour LCD TV	100W
Xbox Series X	220w	-
Playstation 5	200w
42'' colour LCD TV	200W
		Continuous power rating
Computers and home office		300W	600W	1000W	1500W	2000W	3000W
Mobile phone charger	5W
Small inkjet printer	40W
Laptop	50W
Desk lamp	50W
Desktop computer with 17'' monitor	400W
Large laser printer*	800W	-	-	-
		Continuous power rating
Power tools and other equipment		300W	600W	1000W	1500W	2000W	3000W
Drill*	800W	-	-	-	-
Electric chainsaw*	1000W	-	-	-	-
Electric lawn mover*	1000W	-	-	-	-	-
Pressure washer*	1000W	-	-	-	-	-
Grinder*	2000W	-	-	-	-	-
Air compressor*	2000W	-	-	-	-	-

  *Appliances marked with a star are likely to have a starting power consumption several times greater than their normal working power (typically this is caused by electric motors). This should be taken into account when choosing the correct size of inverter.

3. Recommended Victron Phoenix Inverters

To help you choose the correct inverter for your needs, here are some reliable Victron Phoenix inverters available from Van Junkies:

1. Victron Phoenix Inverter 12/250 230V With VE.Direct Port – 250VA, ideal for powering small devices such as mobile phones, fans, and LED lights.
   

2. Victron Phoenix Inverter 12V 375VA VE.Direct UK – 375VA, suitable for light kitchen appliances or small electronics.
   

3. Victron Phoenix Inverter 12/500 VE.Direct UK – 500VA, great for moderate loads like laptops, TVs, or lighting.

4. Victron Phoenix Inverter 12V 800VA VE.Direct UK – 800VA, sufficient for microwaves or small power tools.

5. Victron Phoenix Inverter 12/1200 230V VE.Direct UK – 1200VA, suitable for larger appliances such as coffee makers and electric kettles.

6. Victron Phoenix Inverter 12V 1600VA VE.Bus – 1600VA, great for multiple medium-load appliances such as kitchen equipment or heating elements.

7.  Victron Phoenix Inverter 12V 2000VA VE.Bus – 2000VA, powerful enough for running appliances such as heaters, power tools, and refrigerators.

8. Victron Phoenix Inverter 12V 3000VA Smart – 3000VA, ideal for heavy-duty devices like air conditioners and large power tools

4. Battery Compatibility and Considerations

Ensure that the inverter matches your battery's voltage (typically 12V or 24V). Larger appliances or higher power consumption needs may require higher-capacity inverters and battery systems, such as 24V or even 48V setups.

Battery Recommendations for Various Inverter Sizes

300W Inverter

• Power Consumption: Low (suitable for small devices like phone chargers and LED lights).
• Battery Recommendation: 12V 50Ah Lead-Acid or Lithium Battery.
  • Explanation: A small 300W inverter draws about 25 amps at 12V (300W ÷ 12V = 25A). A 50Ah battery could theoretically run a 300W load for about 2 hours (depending on battery type and depth of discharge).

600W Inverter

• Power Consumption: Moderate (suitable for running laptops, small TVs, or fans).
• Battery Recommendation: 12V 100Ah Lead-Acid or 12V 60Ah Lithium Battery.
  • Explanation: A 600W inverter draws around 50 amps at 12V (600W ÷ 12V = 50A). A 100Ah lead-acid battery or a 60Ah lithium battery would run a 600W load for about 1.5 to 2 hours.

1000W Inverter

• Power Consumption: Higher (suitable for appliances like microwaves or larger TVs).
• Battery Recommendation: 12V 150Ah Lead-Acid or 12V 100Ah Lithium Battery.
  • Explanation: A 1000W inverter draws approximately 83 amps at 12V. A 150Ah lead-acid or a 100Ah lithium battery would support a 1000W load for around 1 to 1.5 hours.

1500W Inverter

• Power Consumption: Significant (suitable for small kitchen appliances like blenders or coffee makers).
• Battery Recommendation: 12V 200Ah Lead-Acid or 12V 150Ah Lithium Battery.
  • Explanation: A 1500W inverter draws about 125 amps at 12V. A 200Ah lead-acid or 150Ah lithium battery would power this load for about 1 hour, depending on usage.

2000W Inverter

• Power Consumption: High (suitable for power tools, fridges, and electric kettles).
• Battery Recommendation: 12V 250Ah Lead-Acid or 12V 200Ah Lithium Battery.
  • Explanation: A 2000W inverter draws roughly 166 amps at 12V. A 250Ah lead-acid or 200Ah lithium battery would support a 2000W load for around 1 hour.

3000W Inverter

• Power Consumption: Very high (suitable for air conditioners, large fridges, or multiple appliances).
• Battery Recommendation: 12V 400Ah Lead-Acid or 12V 300Ah Lithium Battery.
  • Explanation: A 3000W inverter draws about 250 amps at 12V. A 400Ah lead-acid or 300Ah lithium battery would provide around 1 hour of run time.

5. Efficiency and Standby Consumption

Choose an inverter with a high efficiency rating (85-95%) to minimize energy loss during power conversion. Additionally, low standby consumption is essential to prevent unnecessary battery drain when the inverter is turned on but not actively powering any devices.

6. Size, Safety Features, and Installation

Pick an inverter that fits your campervan’s available space and has built-in safety features like overload protection, short circuit protection, and over-temperature shutdown. It’s important to install the inverter with proper ventilation to avoid overheating and extend its lifespan.

Summary

Selecting the right inverter for your campervan or motorhome involves matching your 240V appliance usage with the appropriate inverter wattage. By calculating your power needs and understanding the demands of your appliances, you can choose a reliable inverter that provides a comfortable and functional off-grid experience. The recommended Victron Phoenix inverters offer robust performance across a wide range of power requirements, from basic electronics to heavy-duty appliances. Always opt for an inverter with a slightly higher power rating than you anticipate needing, to account for any unforeseen power surges or extra appliances.