Inverter for campers: how to choose type and power

One of the devices that cannot be missing in the camper is undoubtedly the solar power inverter. Powering the notebook, the TV, the charger of an electric bike, an audio speaker system, or a small kitchen appliance: these are just some of the uses for which it is essential to have one of these devices capable of transforming the current to 12V, supplied by the service battery of the camper, in a 220V current very similar to that supplied by the electricity network in our homes. But what are the different types of inverters? Let’s see them below.

A first consideration to make concerns the power of the inverter: it is always good to buy an inverter commensurate with our energy needs without neglecting the fact that we may want to use the inverter to power a device that requires a lot of energy in the ignition phase, in the which we must pay attention to the peak current that the inverter can generate: by peak current we mean precisely the energy that the inverter can supply for a short period.

power inverter Types:

It is also important to distinguish between two large families of inverters: modified sine wave (or square) and pure sine wave (pure sin wave).

The former has a much lower cost, to the detriment of the quality of the output current. Without going into technical issues, let’s see what happens in practice.

First of all, it should be emphasized that any motor device is not suitable to work with a square wave inverter; so if we have to power refrigerators, drills, etc., we will have to use a pure wave inverter.

Other devices may also malfunction if powered with a modified wave inverter, especially audio systems; which often emit a hum due to the harmonics of the input square wave.

As for TV, notebooks, cell phones, chargers, etc., the matter becomes complicated. In theory, these devices can also work with a modified wave inverter; but it must remembered that these devices were tested with a pure wave current at the time of manufacture. As a result, they could, in the long run, damaged by a modified wave. I preferred to buy a pure sine wave inverter to power my electric bike’s charger.

In the vast majority of cases, purchasing a pure wave inverter is advisable because the price difference compared to a modified wave inverter is not so significant. The price of a decent pure wave inverter, capable of powering most electronic devices with continuous power draws below 150W; rarely exceeds € 100.

power inverter Capacity:

An important clarification must also be made: most inverters do not supply the energy we find declared. It happened to me several times to notice how pure wave inverters with a declared continuous capacity of 300W (and therefore, in theory, at least double the peak) could not even power appliances with 100W continuous absorption!

Conscious of this, I bought a 500W pure wave inverter to power the charger of my electric bike; which draws 100W continuous (2Ah 48V). In this way, I have not even encountered the typical problem of the device overheating, which determines the blocking of the same.

What do these problems depend on? There are two possible explanations:

• Some inverter manufacturers probably declare “inflated” powers.
• Current losses due both to the passage of current in the inverter (which transforms the 12V of the service battery into the 220V that we need) and to the subsequent passage in the eventual transformer of the device we intend to use (for example, the battery charger of a bike which will receive the 220V output current from the inverter to transform it into the voltage of our battery, typically 36V or 48V battery).

The combined effect of these elements could mean that a poor quality inverter, with a declared power of 300W; is NOT able to power even a normal charger that needs 100W continuous.

Considering what written above, I recommend the purchase of a pure wave inverter; with declared power far greater than the consumption of the devices with which we intend to use it. It is clear that if we intend to power appliances that require very high power (typical example: hairdryer); we will have to buy a good brand and very high-performance pure wave inverter, whose price could be quite considerable.

How to choose an inverter

A wall socket is used to power an electrical appliance in the house; which supplies an alternating voltage of 220/230 volts. On a boat, the current supplied by the battery is 12 or 24 Volt direct current.

The job of an inverter is to make the current generated by the battery compatible with household electrical appliances. A direct/alternating current inverter allows you to recharge or power a mobile phone, a microwave, a television; a washing machine, a camera, a DVD player, etc …

During mobile activities away from a 220 / 230V electricity network or in the open air (boating, camping, camping-car, 4 × 4 raids, trekking, etc.), whether connected to the cigar lighter socket of a car or directly to the battery terminals of the boat, the inverter transforms the direct current contained in the batteries with a voltage of 12V, 24V or 48V into alternating current with a voltage of 220 / 230V with which to power the electrical appliances. Whether the energy comes from a solar panel, a wind turbine; or another, the inverter always connected to the energy storage battery produced.

The electrical signal emitted by a pseudo sinusoidal wave device is less regular than that of a pure sine wave device.

This implies that using a pseudo sinusoidal wave appliance is only possible with electrical appliances that are not induction or electronic; such as incandescent lighting, simple irons, coffee makers, plates, ovens, radios, cathodic TVs, etc.

For other induction appliances that are sensitive or require a strong current to start (refrigerators/freezers, pumps, washing machines; plasma or LCD screens, computers, measuring instruments, etc.), a wave inverter strongly recommended.

Pure sine wave.

• Modified sine wave signals to pseudo sinusoidal wave: They are suitable for most electrical appliances, except for electric motors and microwave ovens, for which the performance is too weak. These inverters are perfect for devices that are not induction or electronic such as battery chargers for phones, razors, and digital cameras, and inverter battery chargers for electric tools.
• Pure sine wave inverter: This type of inverter is generally used for high powers (starting from 800W) for alternative night use to generating sets, which are too noisy, or to run the motor of more voracious appliances such as washing machines, microwaves, dishwashers, etc. It is also used for devices that need a stable signal without voltage peaks: plasma or LCD screens, computers, measuring instruments, etc.

The temperature of an inverter has a direct impact on the performance of the appliance. Its necessary to cautious about the values announced by some manufacturers; who use mean values of 10% higher than those measured after an hour.

Two power values characterize an inverter:

• Nominal power corresponds to the usable power with normal use.
• Instantaneous power corresponds to the power that the inverter accepts when energized.

Choosing an inverter capable of handling overloads, short circuits, and polarity reversals are recommended. Remember that you need to ensure that the output power allows you to use all the electrical appliances you need simultaneously.