Planning Your Electrical Wiring in Your Van Build
Disclaimer: WE ARE NOT ELECTRICIANS. Electrical work is really serious stuff. After copious amounts of research we felt comfortable enough to wire our whole system. If you have any technical questions PLEASE ASK A PROFESSIONAL.
Planning the electrical wiring of your van build will be a little daunting at first. But it quickly begins to make sense. Our first step was to sit down and decide on the appliances that we used every single day of our lives. Once you decide on your daily power requirements times that number by two or three just to be safe. As you will never want your batteries to go below 50%. This will compromise the life span of your batteries.
Our System Includes:
(6) Acegoo RV Boat Recessed Ceiling Lights
LED 12v Strip Lights
(2) 12v DC Dimmer Switches
Blue Seas System ST Blade Fuse Box
(3) Renogy 300 Watt 12v Solar Panel Kit
Renogy 2000w 12v Off-Grid Battery Inverter
3 Alpha Cell 100 Ah Batteries
Bayite 12v DC Water Pump
Vitrifrigo Stainless Steel Refrigerator/Freezer
This list includes everything that runs off our solar panels. The solar panels are our only source of power.
How to Size Your System
Most devices will have a label somewhere with the amount of watts the item uses or in the owner’s manual.
Example: we planned on having our lights on for at least six hours a day. Our Acegoo RV LED lights use three watts each. At the maximum all six lights would be on at once.
6 (lights) x 3 (watts) = 18 watts
After you’ve calculate the number of watts of electricity you use, then multiply it by the number of hours you plan to use that electricity to figure out how many watt-hours (Wh) of electricity you use for each item that you use.
Watts x Hours = Wh
18 watts x 6 hours = 108 Wh
Once you figure out your Wh per each day, you’ll need to figure out how big your battery capacity needs to be. Battery capacity is measured in amp-hours (ah), convert your Wh of power consumption into ah by dividing by the system voltage (12V).
Once you have this number, times it by two. You never want to drain your batteries below 50%. This will seriously compromise the life span of your batteries.
Now its time to figure out how many solar panels you’ll need to fully charge your batteries each day.
Solar panels are in watts. A good rule is to match your solar panel wattage to your battery Ah capacity. We have 300 watts of solar panels for our 300Ah battery capacity.
After you’ve calculated your power requirements, its time to run your wire for your outlets and lights. We ran 14 AWG stranded wire to all of our 12V outlets and lights. 10 AWG stranded wire was used to wire our fridge. To protect our wiring from possible shortages due to vibrations while driving we used black plastic conduit.
Pro Tip: Use stranded sire instead of solid core wire. Stranded is more flexible and can handle the vibrations of a moving car.
You’ll need thicker wiring for your batteries, inverter and ground cables. There are a lot of great resources out there to figure out how much wire and what gauge you should use. Check out Gnomad Home’s Epic DIY Campervan Van Build or Blue Seas Systems Circuit Wizard Wire Sizing Calculator.
The main function of a fuse is to provide over current protection. This will protect from potential fires and failures. We blew a few fuses wiring our system and thats ok! This means the fuses did their job and protected us from some major electrical issues. We bought our Blue Seas System ST Blade Fuse Box from Amazon along with a set of blade fuses.
Always choose above your max current load and below the average amp rating of your wiring.
For larger items, always be sure to check your manuals for the inverter, batteries, charge controller and solar panels for the recommended size fuses to use.
The job of the solar charge controller is to regulate the power going from the solar panels to the batteries. Overcharging your batteries will significantly reduce battery life. Having a charge controller is absolutely essential to your electrical system. There are two types of charge controllers : MPPT and PWM.
MPPT Charge Controllers:
Our MPPT charge controller came with our Renogy Solar Panel Kit from Amazon. MPPT stands for Maximum Power Point Tracking – meaning they are able to convert excess voltage into amperage. Solar panels can at times deliver way more voltage than your batteries require, resulting in overcharging and damaging your batteries. An MPPT charge controller will essentially turn this excess voltage into amps.
PWM Charge Controllers:
PWM charge controllers are less expensive than MPPT charge controllers. If you’re balling on a budget, its better to have an PWM charge controller than no charge controller. PWM stands for Pulse Width Modulation meaning they are able to slowly lower the amount of power that is applied to the batteries.
Batteries store energy when you aren’t generating any and are also responsible for delivering the energy. The most commonly used batteries in van builds are deep-cycle batteries.These batteries are designed to be cycled (discharged and recharged many times). This means these batteries are ideal for long-term use. Deep-cycle batteries are rated in Ah (amp-hours). Amp Hours are a measure of how much electricity the battery can hold. More Ah equals more power storage. The most common deep-cycle batteries used for off-grid scenarios are Flooded-Lead Acid (FLA), Absorbed Glass Mat (AGM), and gel-cell.
Pro Tip: Lead acid batteries should never be discharged below 50%. This is called the Depth of Discharge (DOD). If the battery is consistently discharged below 50% it will compromise the life span of the battery.
Gell Cell Batteries:
Gel-cell batteries are more expensive than any of the other deep-cycle batteries. These batteries do not need to be in a well ventilated area and are spill free as they are filled with gel rather than liquid. Another advantage is they are resistant to extreme temperatures, shock and vibration making them ideal for vans. We ultimately chose three AlphaCell 3.4HP batteries because of having our battery bank placed in our “basement” (the area under our bed we use for storage).
Flooded-Lead Acid (FLA) Batteries:
These are the oldest type of recharagble batteries in use today. This option is also the cheapest of the recharagble batteries. So if you’re balling on a budget this is your best option! One major drawback of FLA batteries is they are very high maintenance. They need to be periodically checked and filled with water in order for them to operate properly and be stored in a well ventilated area. Since they are filled with liquid there is also a chance of leaking their acidic electrode solution.
Absorbed Glass Mat (AGM):
This is type of lead-acid battery in which the elctrolyte is absorbed into a fiberglass mat resulting in being able to handle higher temperatures and to self discharge slowly. They are maintenance free and do not require a well ventilated storing area unlike FLA batteries. These batteries hold their charge very well but are sensitive to overcharging. AGM batteries typically have a shorter lifespan and are more expensive than FLA.
Battery inverters convert the DC power your batteries store into AC power your normal household appliances use. This isn’t necessary for every van build. If you dont plan on charging a laptop or running a blender than you can get away with not investing in an inverter. In our case we knew we needed to charge our computers to work everyday and we truly enjoy a smoothie every morning. Therefore, we invested in Renogy 2000w 12v Off-Grid Battery Inverter. In our case we knew we needed to charge our computers to work everyday and we truly enjoy a smoothie every morning. Therefore, we invested in Renogy 2000w 12v Off-Grid Battery Inverter.
There are two type of inverters: Modified Sine Wave / Multi Step Wave (MSW) and Pure Sine Wave (PSW). If you plan on powering items like computers PSW is the only way to go.
For a quick reference, DC appliances commonly come with a usb plug and AC appliances use the two or three prongs you see household items use.
Modified Sine Wave / Multi Step Wave Inverter:
These inverters are less expensive than PSW inverters. MSW inverters create a choppy wave length making it hard for some appliances to run properly on them. Another drawback is these inverters create a buzzing noise which can be slightly irritating in a small space.
Pure Sine Wave Inverter:
Although these are more expensive they have no limits on what appliances you can use with them. They are slightly more efficient as long as you are not trying to pull more energy than the inverter can deliver.
Sizing Your Inverter:
Inverters are sized by how many watts they can output in two different ways:
-Continuous watts: this will be the number of watts the inverter is sized by. Basically meaning how many watts the inverter can produce at a steady continuous rate.
-Peak or Surge Watts: when turning on many appliances they will have a starting surge of watts that is much higher than their operating watts. be sure your inverter can handle the surge rates of your appliances as well.
You’ll first want to add up all of the watts you’ll be planning on using at the same time. Then pick an inverter thats about 130% over that load.
We chose to go with 2000w inverter because we wanted to be able to grow with our power needs. We work online and can at times be charging two computers while running other appliances. Jon also wanted to have enough power to run his power tools as we create jewelry and wood work while on the road. Having a significantly larger inverter can be inefficient but after doing the necessary calculations we feel we needed a larger inverter.
We recommend sitting down and calculating how much power you will need and what your budget allows. After many discussions and calculations we are comfortable with the money we spend and how we are using our power sources. This is your build. Do what you need for your life and van.