Solar setups for recreational off-grid use can consist of different components. Basic systems rely on one or two solar panels, a charge controller, a deep-cycle battery, and wiring to connect smaller devices and appliances that can run on 12VDC. This includes things like camping lights, fans, coffee makers, portable hair dryers and kettles, or the basics for shorter trips.
If, however, you rely on larger and power-hungry appliances like microwaves, air conditioners, and fridges, that work solely on 230V AC, then you’ll either use a mains connection dotting many camping grounds or an inverter to step up the 12/24-volt direct current supplied by multiple panels and batteries. The latter is your only option when off-grid. The higher your power needs with more demanding appliances (like you’d find in campervans and motorhomes) the more complex and costly the solar system becomes.
What are Solar Power Inverters? And Why You Need One in Your RV
Power inverters are electronic devices that convert the 12V direct current generated by solar panels and fed into one or more 12V batteries into usable 230V AC power. Larger RV necessities, such as ovens, washing machines, TVs and fridges require 230V to work. And the steadier power supply is what’s recommended when charging expensive electronics like laptops, phones and cameras. If you want the luxuries that RVs provide while on the road (and far from a mains connection), then an RV power inverter can make that happen. Simply connect it to your deep cycle battery, and use the power outlets and USB ports to power up all that you need.
Types of Power Inverters
Pure Sine Wave Inverters
These come closest to replicating the power supply from a mains connection. Alternating current travels in a sine waveform and the steady, continuous flow is what’s required to power most appliances without damaging wiring, motors, compressors, or sensitive circuitry. Any RV power inverter of the pure (or ‘true’) sine wave type ensures that things like air conditioners, fridges and computers work just as quietly and efficiently in your RV, caravan or camper as they would at home. Pure sine wave inverters are the costliest inverter type, but they provide ‘clean’ power without fluctuations.
Modified Sine and Square Wave Inverters
Modified sine wave inverters aren’t as complicated (or efficient), but still good enough to power simple electronics like heaters, kettles and lights without much issue. They’re just about right for basic solar setups, both in terms of price and the functionality they provide. Avoid square wave inverters as while these are the cheapest, they’re also more prone to power fluctuations (or ‘harmonic distortion’) and can easily damage some of your more expensive gear.
Which Inverter to Get?
When looking for a power inverter, you’ll need to consider size, power rating, battery compatibility, and efficiency among other things. Also, most inverters have built-in system monitoring as well as basic protection features so you won’t be fretting during power surges, outages, or overloads. A basic starting point in choosing what’s right is calculating your overall energy needs, and whether you absolutely need to be running just about everything in the RV at the same time.
Size and Power Rating
The size of the inverter roughly correlates to the power it can put out. Bigger inverters will be able to power more appliances and equipment but will need more space and consideration in placement. This should be in a dry place and as close as possible to the battery to ensure that there is minimal voltage drop.
Power output is given in Watts. To get the right RV power inverter, consider the power needs of the appliances and devices that you commonly use and the duration they’ll be running. Also consider that some appliances have typical running watts, but consume more during startup. For example, an RV air conditioner needs around 1500W on startup but settles to roughly 500W when reaching the desired set temperature. Smaller items, like lights or phone chargers, on the other hand, need much less, from 5 to 50W. An inverter rated for 2000W, then, can see you have a comfortable temperature with the A/C while charging your phone, and have additional leeway to put on the kettle for a soothing cup of coffee.
The cheapest sine wave inverters start out at around 300W of continuous power, with much bigger, heavier and more expensive variants topping out at around 5000W. Don’t oversize your inverter as they work their best when nearing full load. So spending enormous amounts on a huge inverter just to power a few lights and chargers doesn’t make sense.
The majority of deep-cycle batteries in solar systems are 12V varieties, so you’ll need an inverter that converts those 12 volts into 230V AC electricity. These two figures are known as the input and output voltage. There are also inverts that work with 24V batteries and smart inverters (with some complex electronics) that can handle varying input voltages, so offer more versatility.
This refers to how much DC power is converted to usable AC power. Some of this can be lost as heat, and some of it is consumed by the inverter itself when doing its thing. Generally, pure sine wave inverters are the most efficient, roughly 90 to 95 per cent, compared to 75 per cent in square wave inverters. Low power (or ‘eco’) modes when the inverter is on standby help in this respect.
Even basic inverters have audible alerts that inform about errors and possible hazards. Spend a little more to get crisp, legible screens displaying useful information such as daily power generation by panels, total power for a specified period, and more detailed data about the battery status. To protect expensive RV gear, look for inverters that have auto power shut off during an overload, short circuits, high battery temperatures, near-flat batteries, reverse polarity, and more.
So which inverter should you get? Simple. A pure sine inverter rated for the power output of your most-used appliances, one that is compatible with your battery type and voltage, and one that won’t cook your RV and everything in it when things go wrong.