As some of you already know, I am currently traveling around the country while living in a converted camper van. This diary is part of a series on why and how to live fulltime in a van.
Part One: Why I Live in a Van:
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Part Two: Selecting a Van
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Part Three: Bureaucracy
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Part Four: The Logistics of Living in a Walmart Parking Lot
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Part Five: Internet, Cellphone, and Staying in Touch
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Back in my younger days as a backpacker, we used almost no electricity at all. I sometimes carried a small flashlight with me (good for reading paperback books at night), and some of the people I knew would carry small battery-operated transistor radios (to get the news and weather).
But today, the electronic revolution has changed all that. Once dismissed as “flashpackers”, today’s hikers are normally armed with a variety of electronic devices, from GPS navigators to cellphones to small “netbook” laptops.
Van campers of course have the advantage of not having to carry everything on our backs, so we can have even more gizmos and gadgets. In a well-equipped Class A motorhome or Class B camper van, you can find virtually every electronic device that any apartment would have, from a microwave to a TV set to a Playstation. There will also be electric lights, and perhaps an electric fridge, plus normal 110-volt outlets for anything else you want to plug in.
Your van, of course, will have its own battery, which is constantly recharged by the alternator. It also has a “cigarette lighter” outlet in the dash, into which you can plug cords for a variety of devices, including cellphones, GPS, and laptops.
For most people, however, this will not be a workable system to meet their needs. Car batteries are not designed to give repeated long periods of power; they are only designed to give short intense bursts of electricity sufficient for starting the car engine. External devices plugged into the cigarette lighter will drain the battery quickly and, unless you are constantly driving the entire time (and constantly recharging the battery with the alternator), you will quickly end up with a dead battery.
Instead, you will want to have your own independent source of electricity that is not configured to the car battery. There are two options for this: a generator, or a solar panel system.
Generators are, essentially, small gasoline engines that turn a magnet inside a wire coil to produce electricity. These come in a variety of sizes and produce different amounts of electricity. The greater the amount of electricity you use every day, the more powerful generator you will need. Most generators have built-in electrical outlets—these provide the same 110-volt electricity that your home outlets do, and you can plug anything into them which you can plug into the wall at home.
Generators are for more useful, however, if they are set up to charge a “battery bank” instead. For this, you will need a number of “deep cycle” batteries, which, unlike car batteries, are designed to give a steady electric current over a long period of time, and to last through many hundreds of cycles of draining and recharging. Deep cycle batteries are used to power electric motorboat engines, and can be found in virtually any marine supply store.
These batteries come in a selection of sizes and power outputs, measured in “amp-hours”. They also come in different types. Some deep-cycle batteries are “wet”; they use liquid sulfuric acid and lead plates to store their current. Like all batteries, they are very heavy, and they need to be periodically opened and filled with water. Since wet-cell type batteries can release sulfuric fumes which can be harmful in an enclosed space, and since they can sometimes leak acid, they are not really suitable for use in a camper. A much better option are the “sealed” batteries: the “AGMs” use glass-fiber mats soaked with acid, and the “Gel” batteries use a thickened jelly to contain the acid. These don’t leak, don’t release fumes, and don’t need to be topped off with water.
Without getting all mathy, every electric device you plug in consumes a particular number of “amps” per hour. So you must have sufficient battery power to provide all the amps you will need for the number of hours that you plan to run your devices in between charges. Some devices, such as small fans or LED lightbulbs, use less than one amp per hour. Most laptops use about five amps per hour. Other devices, like microwave ovens, can use over a thousand amps per hour (but of course you will only be running it for ten minutes a day).
So you will have to figure out the total amps that each of your devices will use, add them all up, and that will determine how much battery capacity you will need. Let’s say that your total amp usage will be 10 amp-hours, and you plan on running these four hours a day for three days before recharging the batteries again. That gives a total of 120 amp-hours. However, since deep-cycle batteries can be damaged if they are discharged below 50% of their capacity, you will want to save your battery life by providing a capacity that is twice what you expect to actually use—so in this example you will actually need 240 amp-hours of battery storage. You can obtain this by wiring together three 80 amp-hour batteries or two 120-amp-hour batteries together.
The idea is to run the generator to charge up the battery bank (your generator must be large enough to quickly recharge the batteries), then run all your devices from the batteries. If you use less electricity than planned, you can go longer between charges. If you use more electricity than planned, you will need to recharge more often—or you will have to add more battery capacity to your bank.
But you are not finished yet….Deep-cycle batteries produce a DC current at 12 volts of power. But nearly all standard electrical devices are built to run off ordinary household AC current at 110 volts. You will therefore need to connect your battery bank to an “inverter”, which will transform the current from the batteries into ordinary household 110-volt AC. The inverter will provide you with a number of standard electrical outlets, into which you can plug your devices, just as you would at home.
The generator/battery bank system is a workable one, and is used by many people, especially in large RVs. I, however, don’t like it and don’t use it. The disadvantages of the generator are that it is very loud when it runs, and you will annoy everyone within earshot whenever you charge your batteries. Another disadvantage is that the generator requires gasoline fuel to operate, which is just another thing that you have to periodically run out and get, and takes up storage room (and I don’t like the idea of having a gasoline can inside the van). And generators are big, and take up a lot of room inside the van. For most people, they will simply not be a usable option.
Fortunately, there is a better (and greener) alternative for the smaller van camper—the photovoltaic solar panel. In years past, solar panels were horribly expensive. But in just the last few years, the price has plummeted dramatically as more and more people have bought them to use in their homes. For the van camper, a solar panel system can provide all the electricity you need, quietly, steadily, and, once installed, for free. The solar electric system consists of four basic components. First is the inverter—this is where you will be provided with the 110-volt outlets that you can plug your devices into. Next is the battery bank—this is where the electric current produced by the system is stored until you use it. Then there is a device known as the “charge controller”, which regulates the amount of current flowing from the solar panel to the battery. And finally the solar panel(s), which produce all the electricity you will use.
The size of the battery bank is, again, determined by how many amp-hours you will actually be using each day. The size of the solar panel capacity is determined by the size of the battery pack you need to charge. Most solar panels come in standard 100-watt and 200-watt sizes. As a rough rule of thumb, 100 watts of solar panel power is enough to charge 100 amp-hours of battery capacity in a typical day. So if, as in our example above, you have 240 amp-hours of battery capacity, you will need to put either three 100-watt panels on your van’s roof, or one 200-watt and one 100-watt.
But there’s a catch (and here comes the disadvantage of a solar system over a generator)…… The bane of any solar panel array is rain and cloudy weather. While most solar panels today are efficient enough in their capture of light that they can still produce electricity in the rain (mine even produces a small charge if I park under a bright streetlamp at night), this will be much less than the charge produced on a sunny day (and keep in mind that the shorter days and less direct sunshine in winter produces noticeably less charge on the panel than in summer). So you will want some extra capacity, at least double, in both the battery bank and the solar panels, to get you through cloudy days. In our example above, where you are using 240 amp-hours of battery with a generator, you would need a total of 500 amp-hours of battery capacity with solar, and then either three 200-watt panels, or two 200 and one 100, to charge it.
In my case, my need for electricity is pretty small: I have my laptop which I use for working online, reading ebooks, watching movies and network TV, and which I charge every night; a small electric fan which I use on hot nights; my camera batteries, which I charge every few days; a couple of small LED “hockey puck” lights for the van interior which run on AAA batteries that get recharged once a week or so; and my electric razor, which gets used each morning. In total, these add up to about 6 amps per hour. So, running these for a total of four hours per 24 hours means I draw 24 amp-hours a day, meaning I require a minimum of 48 watt-hours of battery capacity for each day. My actual battery is a single 105 amp-hour marine battery.
So my electrical system consists of a single 100 watt solar panel on the roof, which runs inside to a charge controller that regulates the current to the battery. When the battery is low, the charge controller sends current from the solar panel to charge it; when the battery is full, the controller shuts off the solar panel. The battery in turn sends current to the inverter, which is where I can plug in my laptop, camera battery, etc, the same way as an electrical outlet at home. A full charge will give me a little over two days’ worth of typical electricity usage. During periods of cloudy weather I can temporarily run the battery down to its absolute minimum and go for about four days on a full charge.
I also have a smaller foldable solar panel that powers my laptop and charges my camera battery when I’m away from the van for the day. The foldable panel connects to a Tekkeon external laptop battery. This lets me work outside at a park or something whenever I feel like it. And of course I can always plug in the laptop or camera battery at a mall food court or library.