How Much Solar Power do I Need for my RV?
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If you own an RV, you must have a plan in place to ensure that you have some electricity to use while away from the shore power. Unless RV is your primary residence and you have to stay at the site with power available most of the time, solar electricity can help you with keeping your batteries charged.
Solar power is not just one of the most popular ways to power homes these days, but it works really well for powering motorhomes. It’s a renewable source of energy that doesn’t cost anything after purchasing and installing needed equipment.
If you like to live comfortably while on the road and enjoy the benefits of a renewable and reliable energy source, then using solar power is right for you!
Powering an RV with solar panels may seem simple, but it does take some knowledge and skills to get the setup going. If you are planning to power all your RV with solar when shore power is not available, you will need to calculate your daily energy usage by adding up the wattages of your appliances and equipment.
A typical RV can consume roughly 20000 watts (20Kw) every day, with lower values during normal weather and greater amounts during hotter or cooler seasons. Also, some larger equipment like refrigerators or air conditioners vary quite a bit in size and therefore how much electricity they consume.
You may need 2 large roof’s A/Cs in your RV to keep you cool during the summer, but some people would be quite happy with a portable standing air conditioner (paid link) like this:
How much you really use generally comes down to your preferences and needs. This is why you need more precise calculations to make sure that you get all the power you need, but don’t overspend (by getting too large of the equipment).
You can get a reasonably accurate reading of equipment or appliance power usage by looking at its label. The wattage of most electronic products is printed on a sticker underneath it and this is what it usually looks like (example):
Use this formula to converter amps and volts to watts:
Watts = Volts x Amps
The most important number that your will need is the “running watts” or “continuous watts“. This is what your device constantly needs, while “surge watts” will be needed only for a few seconds. The surge watt rating is more useful in determining the size of the generator or inverter, to make sure that it can actually power your appliance.
If you don’t feel like “hunting” for stickers and turning everything upside down (literally), you may want to get a device called an “energy meter”. This useful device will give you a better understanding of how much energy your (very important) gadgets consume on a regular basis.
You can use this number for estimating the size of your future solar setup. Here is a very popular energy meter from Kill-a-Watt (paid link):
Your solar demands will be determined by how you use your RV, and if you are willing to make some adjustments. Some RV owners prefer to live a minimally electrical lifestyle on the road, while others want to have all of the modern conveniences with them.
If solar is your primary and only source of electricity, you’ll need to be cautious with how you use your appliances and other devices. If you get back to the grid once in a while, your batteries could be recharged there and a minimum solar setup will be required to keep your batteries topped off on the road.
Average RVers use about 14-22Kw per day. The biggest power-consuming device in RV is usually an air conditioner. If you properly manage your A/C power consumption, you may get away with needing a smaller size solar setup.
How to do it? Some people dedicate a generator to run their A/C during the night. Other people isolate their bedroom and get a separate smaller 5kw air conditioner just for a comfortable good night’s sleep.
This way, if you don’t use your bedroom during the day, your roof A/C will be cooling down the living room only and therefore use less power. Getting black, thermal curtains to keep the heat away from your RV is also a good idea.
Why is optimizing your A/C usage so important? A typical solar system with 600 watts of panels on the roof would require nearly a full day of optimum sunshine to power one hour of air conditioning!
So, you either have to find a way to reduce your consumption (and still be comfortable) or invest money into a larger solar setup.
To reduce your energy consumption, you must keep an eye on everything that uses electricity!
This means unplugging devices that aren’t in use and using smaller, more practical appliances. Appliances that are specifically made for RV units, are usually small enough to fit in tight spaces and are lighter in weight which is also very beneficial.
Use microwaves with a modest capacity or learn how to make toast on the skillet (not as complicated as you may think) to save some energy. Go with the minimum you can get away with and you will not be sorry.
In order to save some electricity, consider using smaller appliances with fewer features, but more suitable for RV travel. If you pay close attention, there are 12-volt refrigerators that are not bulky and more efficient in power usage.
If the main purpose of RV travelling is actually to TRAVEL, so you probably want to keep it light and energy efficient.
Here is an example to give you an idea of how your daily electricity usage is calculated. You can use this table format to find out how much power you need on the daily basis:
|Device||# of units||Watts||Daily Hours||Daily wH|
Just in this setup, your daily power consumption will be 8,426 watts per day. This also means that your monthly usage of electricity is:
In order to calculate your solar setup properly, you will need the following numbers:
- Your daily energy consumption in watt-hours. This is how many watts you use per hour (see the example above).
- How much sunshine will you actually be getting? You can look that up online and make sure that you size for the month with the least amount of sunlight.
Once you figure out how much power you need on a daily basis and have determined approximate gloomy days with no sunshine, now it’s time to figure out what kind of solar setups are actually available.
A complete solar power system setup includes panels, a charge controller, a lithium-ion battery, and an inverter (to power your 120-volt appliances):
Photovoltaic panels (which typically range in size from 100 to 300 watts) convert sunshine into direct current (DC), which after passing through the charge controller and the batteries, gets converted into Alternating Current (AC) by the device called – an inverter. Only after passing through this long string of devices, electrical current can be safely consumed by your 120-volt appliances.
Very often people ask if they can connect solar panels directly to the inverter and appliances. A good answer to that one will be from the video below the quote:
“Even though it is possible to connect your solar panels directly to the inverter and use your appliances with it, it is generally not recommended because 20-volt power that is coming from your panels will highly likely overheat the inverter and therefore shorten its lifespan.
Here is that video with the solar panels/inverter test:
As an RV owner, you know that a good, quality power backup system provides peace of mind. Some RVs come “solar-ready”, which means it already has the cables in place for you to install panels, others require professional installation of solar panels and appropriate wiring of all needed devices.
Here is a “solar-ready” sticker from Zamp Solar:
Solar is usually a good choice if you plan on boondocking or staying for prolonged periods of time without access to electricity. You should anticipate generating roughly 30 amps of power for every 100 watts of solar panels, with some offering more or less.
Solar panel placement
Keep in mind that you can only charge them efficiently when the sun is shining brightly, which is approximately six hours each day (in most places). You should have a good sense of how many panels you’ll need to meet your power requirements if you calculate how many panels you’ll need.
And don’t forget your “roof real estate”! You’ll need adequate room on the RV’s roof for solar panels and that is especially important if you want many of them!
You should also consider getting extra fold-up panels that you can set up at your destination right on the ground if your power needs are especially large:
Foldable solar panels
This particular solar panel from Jackery (paid link) has a five-star rating and is foldable for easy storage:
Foldable, portable solar panels can easily help you with collecting more sunshine when you run out of roof space while boondocking or just camping out in the wild ????…
** Very important! Without a backup power source, solar panels can’t power everything in an RV. A typical RV solar system will generate 4000 watts per day (enough to power lights, TVs, and small appliances but not a refrigerator, heater, or air conditioner).
Thoughts about generator
A modest travel trailer can benefit from one to three 100-watt panels, which can provide up to 1,500 watts of power each day. Larger RVs will almost certainly require up to 8 panels to provide 4000 watts of power per day.
An 800-watt system can power all of your small appliances and you may be able to use your microwave but only to a certain extent. If we go back to our original example of 8,426 watts per day, you will need a lot more than 8 panels to accommodate that!
Just to be reasonable, most RVers prefer investing money into a small generator to power big appliances and use solar only for basic necessities.
Going totally solar is a great idea, but you will need around 20Kw each day to keep your air conditioner and fridge running. Be prepared to pay at least $10,000 for such a setup and try not to run out of roof space!
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