Electrical System
To live and work full-time in a 72 square foot tiny home, electricity is pretty necessary if you want to be self-reliant on the road. If your vision of VanLife means a life away from refrigerators, lights, and charging your electronics — by all means, don’t install an electrical system! For us, having those things was crucial to living #vanlife long-term, having fulfilling careers, and being comfortable on the road.
Learning how to design, install, and understand how your electrical system works takes time, but it’s fascinating. Plus, it’s going to be really handy down the road if a fuse breaks, a switch stops working, or a component malfunctions. You’ll save a lot of time, money, and frustration if you have a good understanding of how it all works.
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Be forewarned: it took us several weeks of researching to really understand what we needed to buy, how to install it, and how it all worked. We designed our system, called a tiny house electrical contractor to double-check our work (worth its weight in gold, I tell you!), and got to work putting it all in our van.
If this sounds like something you want to learn, this guide will serve as your big, firm foundation for your design and installation. If this is overwhelming and designing & installing a power system isn’t something you want to deal with, we’d recommend buying a Goal Zero Power Station with some Goal Zero Solar Panels or finding a professional to do the work for you. There’s zero shame in that – and you’ll be out on the open road even sooner!
But if you’re ready to learn the ins and outs of van electricity, get ready to be shocked (ha!). This guide covers all the what-have-you’s to get your system up and running.
Table of Contents
All the details on those fun terms like volts, amps, fuses, and a few other essentials. You’ve never known fun like this!
We’ll help you plan out what size of an electrical system you’ll need by tallying the loads you’ll power on the road. We’ll also cover the many components that make up your power system and what they do.
This is where we’ll detail how to size your wiring and connect all your components when you actually install your system.
Our recommendations for three electrical systems — the easiest, the most budget-friendly, and an all-encompassing power system that we opted for.
Part 1: Electricity 101 – Volts, Amps, Fuses, and Circuits
One of the first questions folks have about their solar system is the
difference between amperages (amps), volts, and watts. Let’s think about
it using an analogy: think of electricity as water flowing through a
pipe. Amps are the volume of water flowing through the pipe (how much
& how fast). The water pressure is the voltage. The power that the
water can provide is the watts. Still confused? Don’t worry, you won’t
have to deal with watts very much. We’ll primarily talk about amps and
volts.
Volts
Let’s get into volts. There are two different voltages that your electrical system will run off: 12V and 120V. The most familiar use of a 12V system is your car battery. That little car plug-in (that looks like a cigarette lighter) that you can use to charge your phone — that’s a 12V system. The batteries you’ll buy to power your van electricity system will also be in 12V. It’s really efficient to run things at 12V, so you’ll also run 12V loads like your lights and fan on 12V, too.
You can also opt for 120V in your van, which is what your standard house’s electricity socket is. You can run things like a tea kettle, an induction plate, and power your computer from a 120V socket, which is really convenient. But since your batteries are at 12V and your tea kettle is at 120V, you’ll need an inverter to “step-up” your battery’s voltage from 12V to 120. But we’ll get into that later.
In general, powering loads off of 120V is 15% less efficient than running them on 12V, so we’ll try to keep as many loads on our 12V system as we can.
You’ve maybe seen 12V systems labelled as DC power and 120V systems as AC Power. DC stands for direct current, and AC stands for alternating current. You don’t really need to know the difference between DC and AC for the purposes of this guide (but knowledge is power! The more you know, the more you know.). Just know that some people will refer to their 12V system as DC and 120V system as AC. For the lay person, a DC system is interchangeable with 12V, and AC is interchangeable with 120V. (Sorry for over-simplifying, electricians!)
Amps
Ok, now let’s talk about amps. Remember how amps are like the amount of water running through a pipe over time? You can think about amps as the amount of ‘power’ something needs to run. The more energy an appliance needs, the more electricity it will need — which means bigger wires to carry more electricity and bigger batteries to keep up. We use amp/hours (Ah) to measure how much electricity a device uses per hour hour. This is helpful for estimating the proper size of battery bank you’ll need for your system. Imagine the difference in amp/hours between running some 12V LED lights and a 12V A/C unit. Even though they’re both 12V, the A/C unit is going to use way more electricity (Ah) than the LED lights in an hour, right?
A quick note about amps and amp/hours: when planning how much energy we’ll need in our electrical system, we do most of our thinking in amp/hours — how much electricity a device uses per hour. But sometimes you’ll see products measured in amps — that’s its measured instantaneous consumption. You’ll use this to estimate the maximum amps a device will use at a given moment. This is helpful for figuring out the correct size of wire and fuses you’ll need – but more on that later.
To sum up volts and amps: most of your electrical system will run on 12V, and a few higher-power appliances will run on 120V. We’ll use an inverter to “step-up” part of your 12V system to 120V. Each appliance has an amperage associated with it — maybe 3A for lights, 5A for your fridge, etc. — that’s the amount of power it needs to run. We’ll estimate the amps for each and every appliance, outlet, and light so that you use the correct size of fuses and circuits. We’ll also estimate the amp-hours of your entire electrical system so you can get the right size of batteries and solar panels, but more on that later.
Circuits, Wires, and Fuses
Circuits
Next, let’s figure out how electrical circuits work so we know how to wire our van. Let’s keep it simple at first: imagine we’re going to use a 12V battery to power a 12V light. We’re going to need a battery, 2 wires, a fuse, and our light.
A simple circuit
12V circuits have two wires running from the battery to the light . The red, positive wire (called the ‘hot’ wire) connects from the positive terminal of the battery to the positive terminal of the light, and the black, negative wire (called the ‘ground’ wire) connects the negative terminal of the battery to the negative terminal of the light. Now stored electricity can travel from the battery, through the positive wire to power the light, then return through the negative wire to the battery. But that’s not super safe yet! We need a fuse.
The fuse acts like a “speed limit” on the positive, red wire between the battery and the light. If there’s an unexpected amount of electricity running through the circuit, the fuse will blow instead of your wire breaking and catching fire. Fuses are cheap and amazing.
That’s the basic structure you’ll use to power everything in your van: battery, 2 wires connecting your load to your battery, and a fuse to keep it safe. You’ll have one circuit to power your lights, a separate circuit to power your fridge, and another circuit for your fan.
Enough about circuits, let’s move on to wires.
Wires
The more electricity a wire carries, the bigger the wire diameter needs to be. To go back to our water analogy, a fire hydrant hose carries a lot more water than a garden hose, and it’s also a lot bigger. Knowing which size of wire to use for a given circuit is essential to making sure your system is efficient and safe. In order to size your wire properly, we’ll have to calculate how many amps the load uses (but we’ll get more into that below). Remember: in a 12V system, we use a red wire for the hot/positive and a black wire for the negative.
Fuses and Breakers
In case there’s ever too much electricity going through a wire, fuses and breakers will break the circuit to protect your system and keep it from lighting on fire. They’re non-negotiable, crucial parts of your system. Never use a fuse that’s too big for the load – that’s offering no protection and opting to burn your wire (fire!) instead of blowing your fuse.
When a fuse does blow, you’ll have to replace it with another fuse — they’re cheap and can be found pretty much everywhere. Breakers are more expensive, but when they blow, you can simply reset it like a switch. This is a great Fusing Guide that you’ll want to read to make sure you’re using the proper sizes.
Part 2: Introduction to VanLife Electricity
How much power do you need?
Before we can get into all the different components you’ll use in your van, we’ve got to start at the beginning. The first step to designing your van’s electrical system is to plan how much power (in amp/hours) you’ll use for your daily electrical needs. This is called your daily consumption. Knowing how much power you’ll need each day is an essential step to making sure you get the right size battery and solar panels for your build. A person who only needs a power system to run a fan and lights will have a very different-looking power system than someone who’s also running a tea kettle, induction plate, TV, and an air conditioner.
It will take some time to calculate your daily electrical consumption, but you’ll only need to do it once to make sure you have the right size of electrical system — that is to say, big enough batteries and solar panels to power what you’ll need. Once you’ve listed out each and every load you’ll use and the power they’ll need, you be able to estimate how large (or little) your electrical system will be so you can buy the correctly-sized batteries and solar panels.
Calculating your daily electrical consumption is easy. To start, make a list of every single load you plan to have in your van. That list might look something like this: lights, fridge, fan, phone chargers, computer chargers, and an induction plate. Make sure to include everything you’ll plan to use!
Next, you’ll need to look at the instruction manual for each of your loads to figure our how many amps each load uses. Stores like Amazon are great for this — you can usually find the specific electrical information for a load in the product’s fine print. Once you know how many amps a load uses, multiply the load’s amperage and by how many hours you plan to use it each day. For example, our induction plate uses 15 amps to run. We’ll plan to use it 1 hour a day at 80% of its maximum heat, so it will use 15 amps * 0.8 * 1 = 12 amp/hours (Ah) a day. One of our bigger loads for sure!
Once you’ve calculated the Ah for each load in your van, add them all up to get your daily power consumption. If we’re using a blender and an induction plate every day (not very likely), we’ll be using about 42 amp/hours of power a day. That’s quite a bit, but we can cut it by more than half taking those two appliances our of our daily routine. For most days on the road, we’ll plan to use about 30 amp/hours of power a day.
We created a free Daily Power Consumption Calculator that you can use to figure out how much power you’ll use each day. We even created a few examples in it to make it easier. Total up how many amp/hours you’ll use a day, and then we can move on to sizing your electrical system! Yay for figuring out what size of batteries and solar panels you’ll need!
What battery is best for Van Life?
In our example above, we learned that we’ll use 30 amp/hours of energy a day. The next step is to choose a battery size that fits your electricity needs. It’s important to note that you’ll want to be able to go a few days without having to charge your batteries (in case it’s not sunny or you’re not driving), so you’ll want your battery system to accommodate that. We advocate for getting a battery that is 2-4 times larger than your daily consumption. Going bigger is more expensive, but it buys you convenience and peace of mind.
There are a number of different battery types on the market, but when it comes down to it, we recommend either AGM or Lithium-Ion batteries. Flooded-lead acid and gel-cell batteries are sometimes used in RVs and other off-grid systems, but they’re not ideal for van life (with the necessary maintenance and venting). AGM and Lithium-Ion batteries also don’t have to be vented and don’t have an electrolyte that can spill and catch fire. That’s a nice, big plus.
AGM Batteries
AGM batteries are a great choice because they’re very hands-off: their maintenance level is almost non-existent (no need to vent or fill with water), they’re relatively cheap, and they do a good job of powering your loads even in colder weather. The two cons here are that they’re heavy (our 155Ah battery weighs 90 lbs), and you can only discharge them to 50%. That means that we can only use 77.5 Ah of our 155 Ah battery! You essentially have to buy two of them for their power rating.
In our example, we use 30 Ah of energy a day. We multiplied that by 3 so we could go 3 days without charging, so now we looking at a 90 Ah battery. But since you can only discharge 50% of an AGM battery, that means we need a 180 Ah battery.
Lithium-Ion Batteries
Lithium-Ion batteries are a good choice if you’ve got the money for them and don’t plan on driving in the cold. Technology-wise, it’s the same type of battery that’s used in most phones and computers. They’re as low maintenance as AGM, they can be discharged deeper than AGM, but they’re more expensive and can’t be charged when it’s below freezing. Technology and pricing for lithium-ion batteries has gotten better and better, and we’ve heard a lot of people raving about how great their lithium-ion batteries are.
Our Recommendation
In the end, we decided to go with two 155 Ah AGM batteries (we went with Vmaxtanks’ 155ah Deep Cycle). We balked at the price of Lithium-Ion, and since we’re planning to ski throughout the winter, we didn’t want to have to worry about the cold temperature affecting our batteries. (Note: we know winter VanLifers that use lithium ion batteries no problem, so this might be a non-issue). Because we can only discharge AGM batteries to 50%, that means we have 155Ah of stored power and plan to use 30 Ah a day, so theoretically our batteries will power our needs for five days (in an ideal world).
Here are a few battery brands we recommend and have heard good things about in the van life community:
– Vmaxtanks
– Renogy
– BattleBorn
– Rolls
– Lifeline
– Dragonfly
Battery technology is getting much more efficient and cheaper lately, so we don’t mind upgrading our system in 3-5 years when there are better products on the market. Keep in mind that batteries are typically the most expensive component in your electrical system if you’re building a larger system.
Our 155 Ah AGM batteries have served us well for 1.5 years, but we’re probably going to get an even larger system when we replace them. It’s so, so convenient not to need to worry about your power needs on the road, trust us, so get a bigger system than you think.
A few safety notes about batteries
For safety, use identical batteries in your power system – don’t try to combine AGM and Lithium, or different brands, or different capacities, or even different ages of batteries. When you connect your batteries, you can wire them in parallel (keeps the voltage the same and doubles the capacity [Ah]) or in series (doubles the voltage but keeps the same capacity). We wired our two 12V, 155Ah in parallel so that we double our capacity. You can read more about wiring in Series and Parallel over at Renogy.
Use Bus Bars
You’ll also want to buy a positive and a negative bus bar when you wire your electrical system together. It can be dangerous to try to connect a whole bunch of wires to two studs on your battery — it’s a lot of wires for two studs. A bus bar is essentially an extension of your battery’s stud — but it has six studs so that you can make plenty of connections. Essentially, it allows you to attach all of your wires to a bunch of studs instead of trying to fit them all on the battery stud. To install a bus bar, connect a negative bus bar to the negative end of your battery terminal (and the same for your positive terminal), then run connect your load wires off the bus bars instead of the battery terminals. Then, you can buy a rubber cover to place over your bus bar. Safe and clean. We opted for a Blue Sea Systems 250A 6 Stud Bus Bar.
Use an On/Off Switch
Finally, it’s also a good idea to wire a master on/off switch between your batteries and everything else. We placed ours on the wire between the positive terminal of our batteries and our positive bus bar. If you need to check your wiring or if there’s ever a fire, you’ll need a way to completely disconnect everything from power at the flip of a switch. We opted for the Blue Sea Systems 350 Amp E-Series Battery Switch.
Now that you’ve found the right sized battery bank for your van, we’ve got to decide on how we’re going to power it.
3 Ways to Charge Your VanLife Batteries: Solar, Shore Power, B2B Charger
Solar
For most van lifers, solar power is the way to go for powering your battery bank. Nothing looks quite as badass as solar panels mounted to the top of your adventure-mobile, and you get those warm-fuzzy feelings of powering your electronics with carbon-free electricity. Yew!
How many solar panels do I need?
How many panels do you need? Usually, a 100W solar panel can charge 25 Ah a day in ideal, perfect conditions (which you won’t have). We went with 320W of solar on our roof, but we were hoping to fit a 540W array (but it was a bit too big with our ceiling fan). In a perfect day, we should bring in 80 Ah of power a day and consume only 30 Ah; since conditions are never ideal, we decided to “over-build” our solar so we didn’t have to worry about it. So far, our panels keep up with our needs super well!
Flexible or Rigid Solar Panels?
Flexible solar panels have a lot going for them: they’re super thin because they don’t have a frame, they’re lightweight, and they can be attached to your van roof with adhesive instead of screws. However, they do have a shorter lifespan, and we worry about how secure they are on a van roof, exposed to the elements and exposed to highway speeds. Rigid panels are the more tried-and-true type of solar panel — they’re thicker, heavier, and need to be screwed to your van roof, but once they’re installed, they’re not going anywhere. Plus, their average lifespan is 25 years, so you shouldn’t need to touch them again.
We decided to get rigid solar panels because we were skeptical of adhesive keeping our panels on the roof while driving on highways over a long period of time. They’re more time-consuming to mount. Most rigid solar panels come with brackets that you can screw into your van’s roof. We didn’t want to put screws in our roof (more holes in the roof means more places for leaks), so we opted to attach our solar panels to custom-cut angle iron (that we bought from a local metal yard), which we then attached to our roof rack. It was a lot more work (and probably overkill), but now we have a super-secure solar panel array and didn’t put a single screw through the roof. This custom design also sits lower to the roof than the included brackets. Rad!
Monocrystalline or PV Solar Panels?
You’re ok going with either. Monocrystalline have a high efficiency rate, are space efficient, and have a great lifespan. Polycrystalline panels are less expensive. Just don’t get an amorphous panel — they’re big, inefficient, and expensive.
Series or Parallel?
Just like wiring batteries, you have the choice of wiring your solar panels in series (double the voltage) or in parallel (double the capacity). If you use an MPPT charge controller between your solar panels and your batteries (more on that below!), we recommend wiring in series. It lets you use a smaller wire to your solar panels and can make your array more efficient (it can charge your batteries on cloudier days). If you decide to get a PWM solar charge controller, then you’ve got to keep your solar voltage the same as your battery voltage – 12V – so parallel is the way to go for that. We recommend spending the extra money to get an MPPT charge controller and wiring your panels in series.
Other Solar Considerations
It’s very important to get a good brand of solar panels these days. Renogy is the popular options for vanlifers (we’re happy with ours!). They also have bypass diodes, which can help mitigate the effects of partial shading on your panels. That means they work better if a tree limb is blocking out part of your panel, which frankly is something you never want to worry about.
We’ve seen some folks build a way to manually tilt their solar panels to get better sunlight. That can make a big difference in the winter when the sunshine is low or when you’re out boondocking. You can even get fancy and use a motor to tilt the solar panels or create a manual way to tilt them yourself. We didn’t decide this was important to us, but this would be a really-cool project to do.
Finally, you might consider using a portable solar panel to supplement the array on your roof. They’re easy and cheap to add to your build, and it’s a great way to draw in more sunlight when you’re boondocking. A number of solar panel manufacturers create suitcase-like panels that you can store in your van when you’re not using them — but it won’t be a good option if you’re planning to stealth camp. We’ve considered getting one for winter boondocking, but we haven’t committed to it yet.
Our Solar Panel Choice
We decided to buy two Renogy 160W Solar Panels and wire them in series to be 24V. This increases their efficiency, and our MPPT charge controller changes the 24V to 12V for our batteries. Renogy is a reputable and popular brand that we felt comfortable using for a long time, and they also have a plethora of resources and guides that we found helpful during our research. Pair that with their customer service, and they seemed like a great match.
We originally wanted to purchase two of Renogy’s 270W panels to have a 540W solar system on the roof, but opted to have a smaller and more stealthy array instead. That’s what we tell ourselves, anyway, since the 540 watt panels wouldn’t fit on our roof after we installed our roof fan. So far, 320W has worked well for us, but going bigger always buys more peace of mind.
Shore Power and B2B Charger
Having another way to charge your batteries other than solar power can really come in handy when it’s wintertime or it’s cloudy out. The sun isn’t going to shine bright every day on your coveted solar panels, so we’ve got two other recommendations for charging your batteries.
Shore Power
You can use shore power by plugging an inverter-charger into a standard electricity socket from your friend’s garage or a campground. Our 2000W Inverter that powers our 120V devices actually has a charger built into it, so all we have to do is add a wire to our inverter so that we can plug into shore power to charge our batteries. Score! I love a device that has multiple uses. We’re glad we added this to our build because it was super simple, but we (luckily) haven’t needed to use it yet.
B2B Charger
You can also use a Battery-to-Battery (B2B) charger to power your house batteries while you drive (just like how your van battery gets charged). You can use an ACR relay instead of a B2B charger to save money, but it’ll shorten the lifespan of your batteries. That’s because an ACR relay doesn’t charge your batteries at an ideal voltage for your batteries; it’s not dangerous, but you’ll probably pay more for it in the long run.
We went with a Sterling BB1260 B2B Charger, and it’s great. It’s hands-off — it automatically charges our house batteries whenever we drive and delivers a healthy level of power specific to our AGM batteries. If you’re looking to save some cash in the short-term, the ACR Relay is a great alternative. We would definitely recommend getting one of these for your build.
Components Galore: Everything You’ll Need to Power Your Van
We’ve already talked about a handful of components for your van’s electrical system: a battery bank, solar panels, and an optional B2B charger to power your batteries while you drive. But there are a few other essential components to your electrical system you’ll need.
Charge Controller
A charge controller is an essential component if you use solar panels. It’s wired between your solar panels and your battery bank. Its job is to take the energy from the solar panels (which is changing instantaneously due to slight variations in available sunlight) and make the voltage ‘play nice’ to charge your batteries well. If you have solar panels, you need a charge controller.
There are different sizes of charge controllers (in both voltage and amps), so you’ll have to look at the specs of different models to see how much solar it can handle. Our Victron 100|50 charge controller can handle 50A and 700W of nominal solar panel power, which is great if we want to add an extra panel later on. Their 100|30 handles 30A and 440W of nominal solar panel power, and their 100|20 handles 20A and 290W. Always, always read the instructions to make sure you get a charge controller that’s big enough for your solar panels. When in doubt – call their customer service! I think Victron and Sterling almost knew me by name the month I designed our system.
Important side note: When you’re wiring your panels, charge controller, and your batteries, be sure to always connect the charge controller to the battery before you connect the solar panels. As soon as the solar panels are hooked up to the charge controller, the charge controller needs to send that energy somewhere. So when you’re connecting the three components, connect the solar panels last. When you’re disconnecting them, disconnect the solar panels first.
MPPT or PWM Charge Controller?
There are two types of charge controllers: MPPT and PWM. MPPT are more efficient when it’s colder and less sunny. MPPT even lets you wire your solar panels in series to suck more energy from the available sunlight and still charge your 12V batteries at a correct voltage. The con is that they’re more expensive than PWM charge controllers.
In the end, we went with a Victron MPPT 100/50 Solar Charge Controller, and we love it. We’re big advocates for ‘buy it nice or buy it twice’ for your electrical system if you can afford it — it’s cheaper financially in the long-term, and you won’t have to re-learn and re-wire later on if you decide to upgrade.
Battery Monitor
A battery monitor is optional, but it lets you know a lot of information about your power system – what percentage of battery is left, the voltage, how many amps are going in/out of your batteries, and so much more. Plus, a few of the models come with bluetooth so you can monitor your batteries from your phone. While a battery monitor isn’t essential, it is really helpful for making sure you’re keeping good care of your batteries and to eliminate unexpected power outages.
We went with the Victron BMV-712 battery monitor because Victron is amazing and we like the bluetooth capability. Since it’s the same brand as our charge controller (which also has bluetooth), we can keep an eye on our entire electrical system from one intuitive app. Super convenient! But honestly, we don’t use the bluetooth that much — we just check the wall where we mounted our battery monitor.
Inverter
If you want to have standard, 120V household electrical sockets in your van, you need an inverter to step-up the voltage from your 12V batteries to 120V for the outlet. You’ll also need to make sure to find the right size of inverter to power your needs. If you want to use an 1800 watt induction plate in your van, you’ll need an inverter that can deliver at least that much power. The trick is to look up the amount of watts your most demanding appliance will need, then purchase an inverter above that wattage.
We recommend buying a pure sine wave inverter instead of a modified inverter. Without getting into the weeds about it, pure sine wave inverters are more expensive, but they offer a very “clean” type of power that’ll keep your loads healthy. If you cheap out and get a cheap modified inverter, you might notice your electronics start to fritz. Not good if you’re using it to charge a computer!
If you buy an inverter charger, your inverter doubles as a way to charge your batteries via shore power. Inverter chargers have an AC In and an AC Out, which means a) it delivers power from your 12V batteries to a 120V socket, and b) can plug into shore power to deliver power from an external power source to charge your 12V batteries. They’re well worth it, in our opinion, because they let you charge your battery system at an RV campground or a friend’s electrical socket.
We decided to buy an AIMS Power 2000 Watt 12V Inverter Charger, and so far we’re very happy with it. We’ve also heard great things about the Samlex pure sine wave inverters a well as Victron.
Fuse Block
While it’s not technically a component, your fuse block is essentially the breaker box for your van’s 12V DC system – but it uses fuses instead of breakers. Each and every load you have — your lights, fridge, and fan — will have its own set of wires running to and from it, which will also have its own fuse. A fuse block keeps all your fuses in a safe, easy-to-organize box for easy tinkering. Blowing a fuse is inevitable, and you’ll be happy to have a fuse block readily available to replace the fuse when it happens. We’re happy with our Blue Sea Systems ST Blade ATO/ATC Fuse Block.
Part 3: Putting It All Together: Wiring
You’ll need a pair of wires running between each and every component and load in your system, and it can get overwhelming if you don’t know wire sizing yet. But no fear! It’s not very difficult to get the hang of it, it’s just putzy to keep it organized.
Wires: AWG, Wire Colors, and Duplex/Triplex
The unit we use to talk about wire sizes is called AWG, or American Wire Gauge. The most confusing thing about learning AWG wire sizes is this: the larger the AWG, the smaller the wire actually is. The 16 AWG size wire we use to power our lights is much smaller than the 8 AWG wire we use to power our inverter. Here are the common AWG wire sizes you might use in your van, from smallest to largest: AWG 18, 16, 14, 12, 10, 8, 6, 4, 2, 0, 00 (called two aught, written as 2/0), and 3/0 (called three aught, which means 000).
When you’re selecting wire, keep to the code! In a 12V system, use red for your positive/hot wire going to the load and black for your negative/ground coming back from the load to the batteries. It’s also important to keep in mind that your wires will be shaking *a lot* in the van while you drive and in all likelihood will be exposed to some moisture via condensation. We recommend buying Ancor marine-grade wire (you can purchase it by the foot). It’s certified for use on boats and yachts (bumpy, potentially wet places) and will stand up to the rigors of VanLife. Is it necessary? Maybe not. Do you want to rewire your van after you’ve put insulation, walls, and cabinetry over your wires? Definitely not. It’s worth the hassle to get marine-grade wire.
What’s this duplex and triplex wire all about? Well, if you go to the hardware store and ask for a 8 AWG duplex, they’ll direct you to a nice protective sheath of plastic that surrounds an 8 AWG red wire and an 8 AWG black wire. Duplex is a convenient way to wire your 12V loads — it has your positive and negative wire in one sheath. It’ll be classified as 8/2, which means a sheath with 2 wires of 8 AWG. Triplex is a three-wire sheath for your 120V circuits, which includes a colored hot wire, a white neutral wire, and a green or bare copper wire for grounding. If you buy 8 AWG triplex, it’ll be classified as 8/3 — 3 wires of 8 AWG. Make sense?
Sizing your wire
It’s ok to use too big of a wire, but it’s never ok to use too small a wire. Each wire has a maximum current capacity, which is simply the maximum (safe) amount of electricity that can move through it. Bigger wires have larger maximum current capacities, which means they can carry more electricity to power bigger loads. You don’t want to use a small wire to power something big, or the wire will go over its maximum current capacity and fry. Not good!
Luckily, sizing your wire isn’t too hard thanks to this handy-dandy tool: the BlueSea Circuit Wizard! (They even gave it a cool name. Of course they did. BlueSea is the best). This will help you find the delicate balance of wire-sizing that’s safe and efficient.
- When you’re sizing your wire, simply type in information about your circuit:
- – circuit voltage (is your load 12V or 120V — running off your batteries or running from your inverter?)
- – load current (how many amps is the load going to need? Usually, the manual of your load has a recommended fuse size — you can use that same amperage for the load current. The guide will size above it so the fuse blows before the wire.)
- – length of conductor (how much wire are you using from your battery to your load and back again? Sum up your positive red wire running to the load + negative black wire running back)
- – allowable voltage drop (3% for critical loads like inverters, 10% for non-critical loads like lights, fan, computer charger, fridge, etc.)
By following this guide, you can determine the proper wire size you’ll need between each and every one of your components. Pro tip: write down the fuse, wire size, and wire length for each of your circuits for ordering and installing – organization is your friend. This organization will help a lot when you actually start installing the wire!
An important safety note about circuits and wiring your system: never connect a positive wire to a negative terminal and vice versa. And never let the positive wire come into contact with the negative wire while you’re working. Always do all of your wiring when your circuit is not connected to the battery (remember the handy-dandy On/Off Battery Switch we said to install? Just turn that to “Off” anytime you wire).
The first step you should take when doing any electrical work is to disconnect everything from the power source so you don’t get shocked while you work. The final step should be to connect the circuit back to the battery. And remember: it’s always ok (just less efficient) to use a bigger wire, but it’s never ok to use too small of a wire. Always use a fuse that’s properly sized for the load — too big of a fuse doesn’t offer any protection, and too small of a fuse will blow even when the component is running as it should.
Connecting your wire
Wire to Wire
To connect one wire to another wire, you’ll need to crimp them together using a butt connector. Our favorite tool for this is to use a heat shrink butt connector – they’re a few more dimes than other connectors, but they’re waterproof and more permanent (which is great in a van that vibrates on the road!). We also noticed they’re higher-quality and easier to use. Be sure to get the right size butt connector for the wire you’re using. You’ll need a crimper hand tool and a small hand torch or heat gun to shrink the connector over your wire once you’ve crimped it.
Here’s how to use a butt connector: to successfully crimp the wires, you’ll strip back a bit of both wires, insert the wires into the butt connector, use the crimper to crimp the butt connector over the wire, and use the hand torch to lightly heat the heat shrink over the two wires’ insulating sheath. Be careful not to get too crazy with the hand torch. Here’s a helpful video about how to use a heat shrink connector and another guide (with photos!) of how to crimp.
If you want to join two wires non-permanently, Ancor also makes some [Heat Shrink Disconnects](https://amzn.to/2NT6dMS) that’ll do the job. The female end of the disconnect should be on the hot side of the wire that’s closer to the battery.
Wire to Component
If you want to connect your wire to a battery terminal or a fuse block, most of the time you’ll use a ring terminal. You’ll need to get the right size ring terminal for both the wire size you’re using and the size of the screw/stud on your component that the ring terminal will attach to. Many components don’t need a ring terminal, you’ll simply insert the wire into the component and screw down a metal clamp to connect it.
Crimping a wire to a ring terminal is really similar to using a butt connector. Just strip back the wire a bit, insert the wire into the ring terminal until the wire is just past the barrel, crimp the wire to the ring terminal, then use the hand torch for the heat shrink to shrivel and congeal.
Splicing Wire
We wired our lights in parallel, which means we had to splice a wire into a running wire — think of a T-intersection, but wire. We used a Pico Weather Proof Quick Splice for our wire splices, but there are a variety of other quick splice options out there. The Pico quick splices were easy to install and have gel inside them to ensure the splice stays clean and connected. We have one that failed after about a year, and it’s been really hard to fix since it’s not accessible after we put our ceiling up. If you add these, try to ensure you’ll be able to access them later if possible.
Laying Your Wire
You want to be strategic about where you decide to lay your wire in your van, because you never want to screw into it or otherwise damage it. We decided to run our wires alongside the pillars/supports that run along the van. We’ll screw our walls and cabinets to those supports, so our electric lines are safely to the side. To make sure the wires didn’t rattle and move while we drive, we used zip ties and an adhesive mount to attach the wire to the van itself.
You might also use split loom tubing to run your wires in to keep them more protected. A bonus of using tubing is that you can run wires through it later (without having to take apart your walls) if you need to re-wire for some reason. We decided not to do this, and hopefully we won’t regret it later.
Part 4: 3 VanLife Electricity Setups – the easiest, the cheapest, the all-encompassing
Maybe you just read our entire guide above and you’re feeling overwhelmed, or maybe you skipped down here to get a better idea of what size of a system works for you.
Here are three tiers of van life electricity setups you might consider for your van:
Electricity Setup #1: The Easiest
The easiest electricity set-up is to buy a Goal Zero Yeti 1250 Power Station and a few Goal Zero 100 watt solar panels. The beauty of this power system is that you don’t have to lay a lot of wires, it’s completely transportable, and you don’t have to spend time designing and installing your own system. The downside is that it’s relatively expensive for what it is, and it’s a smaller system overall. That won’t be a problem if you don’t plan on using a lot of power.
It has the capability to power both 12V and 120V loads, which is great if you want to add lights in your van. It’ll take 9-24 hours to charge the battery to full using 200 watts from their solar panel, and you can also charge it from the wall in 18 hours. Just be sure that it meets your daily consumption needs so you don’t have to worry about running out of power.
Electricity Setup #2: The Cheapest
If you don’t want to go all-out on a big power system and only need 12V, you can go a long ways by getting a battery and a way to charge it — either using solar panels and a charge controller or getting an ACR Relay to charge while you drive.
To use solar, simply get a battery, 2 100W Renogy Solar Panels, and a Victron 100|20 Charge Controller. The grand total for these components is $690, and after that you’ll just need wiring to put it all together. Your solar panels will be able to keep up with your battery, which has about 63 Ah of use in it. That’ll go quite a long ways on a 12V system to power your lights, fridge, fan, and phones.
To use a relay to charge your battery while you drive, simply get a battery and a KeyLine Relay for a grand total of $365. This is great if you plan on driving a lot and only need it to power some smaller loads. Additionally, you can upgrade this system and use an inverter-charger like the AIMS 2000 to power your 120V loads and be able to plug into shore power to charge your batteries at campsites and friends’ driveways.
Electricity Setup #3: The All-Encompassing
Maria and I consider ourselves #premiumdirtbaggers, and our version of VanLife means not worrying about electricity to power our computers, tea kettle, and an occasional induction plate. Our no-regrets setup has 155 Ah of electrical storage — enough to power a decent load for a couple days off the grid. We also opted for charging our batteries through 320 watts of solar, a B2B charger while we drive, and an inverter-charger for shore power. We sized our charge controller with room to grow so that we can add a collapsible solar panel later if we want to boondock off the grid for a week or two.
Here’s the full list of component we opted for in our van:
– Solar Panels: two 160 Watt Renogy Solar Panels (wired in series)
– Charge Controller: Victron SmartSolar 100|50 with Bluetooth
– Battery: two VMAX SLR155 AGM Deep Cycle Batteries (wired in parallel)
– B2B Charger: Sterling BB1230 (check if you need the BB1230 or BB1260)
– Inverter Charger: AIMS Power 2000 Watt 12V Inverter Charger
– Battery Monitor: Victron BMV-712 battery monitor
– Fuse Block: Blue Sea System ST Blade ATO/ATC
– Battery On/Off Switch: Blue Sea Systems 350 Amp Battery Switch
– Bus Bars: Blue Sea Systems 250A 6 Stud Bus Bar
Wiring:
– Ancor Wire (various sizes)
– Ancor Duplex wires (wiring lights & other small 12V loads)
– Ancor Ring Terminals
– Ancor Heat Shrink Butt Connectors
– Pico Weather Proof Quick Splice
– Hobart Lug Crimper (use this with a vice grip to connect large wires to a lug for batteries and inverter – highly recommend!)
– Zip ties & adhesive mounting
– Innova Multimeter
– Cable Connector (for ‘splicing’ larger wires for B2B charger)
– Blue Sea Fuse Block (between bus bars and components)
– Blue Sea Terminal Fuse Block (sits on positive terminal of battery)
– Blue Sea Circuit Breakers (placed between solar and charge controller, charge controller and battery)
And here’s the full list of our loads we use in our van:
12V Loads:
– Lights:
– Acegoo LED Recessed 3W Lights (2 circuits of 4 lights each, wired in parallel)
– 12V Dimmer Switch for LED Lights
– Fan: Maxxair 00-05100K MaxxFan
– Fridge: Dometic CFW 40W Electric Cooler (super low draw)
– USB Charger: TBD
120V Loads:
– Computer charger (87 W draw)
– Induction plate: TBD
– Tea Kettle: TBD
– NutriBullet (600 W draw)
