This is a big part of the build and my favorite. Teaching electronics for over 30 years, this is kinda my thing. The advances that have taken place in the past 20 years are amazing. LED light and LiFePO4 batteries are prime examples. Be sure to scroll down to see the videos for each section. If you can’t find what your looking for send an email or leave a comment on one of the YouTube video’s.
Main panel – Your main electrical panel will include your inverter, Solar Charge controller, DC Fuse Panel, AC Breakers, the Bus Bars, and main shut off.
Inverter and System Size – How big, and how much will this electrical system cost? To get an idea you need to find out the electricity you will consume each day. To do that gather together every item you expect to power. Yeah, that’s going to require some thinking!
You will need to calculate your usage in Amp Hours (Ah).
Amp Hours = Current in amperes x Time in hours
Current: the amount of electrons flowing in the wire. The unit is Ampere.
Time: Some items will not be on very long. For example, if you have a water heater it will be on for about 15 minutes to heat the water. It won’t be on all day long!
There are many calculators available online to do these calculations. The math is easy. The difficult part is getting all the appliances together to get the information!
You will only get an estimate with any of these calculators. Remember you energy production and usage will vary with the seasons. In the summer you will use more electricity to keep your refrigerator cold. In the winter you will not produce as much electricity from your solar panels since the sunlight days are shorter, and they may be covered with snow. The key is to calculate what is the maximum power that you will need at any given time. To find out, add the power of each device you plan on using simultaneously.
You need to select and inverter that will handle your simultaneous power usage. For example, I have a 4 gallon hot water heater that is 1500 watts. I do not expect to use that at the same time I use the insta-pot which is 1200 watts. But if I did use them at the same time, that would be 2700 watts. I would need a 3000 watt inverter.
I can go with a smaller inverter, but went with a 3000 watt. Why? To future proof my build. My needs may expand in the future. Spending a little more money now is the frugal thing to do. Otherwise if I find out later that I needed a larger inverting I would need to go to the expense again to buy a larger one. Spending money a second time is not Frugal! I Selected this Victron Multiplus Inverter for our build.
I did a great deal of research on inverters and solar charge controllers. The key reason I selected Victron products was Bluetooth. They all integrate with each other and I can monitor everything from my phone. This is the Solar Charge Controller we selected, more information on that below.
One of the best products Victron has the battery monitor. If I was to have only one Victron product it would be the battery monitor. Having this allows you to monitor your electrical system with your cell phone. This is the Battery Monitor I purchased, the BMV-712 has bluetooth connectivity!
Fuses and Circuit Breakers – A fuse is an intentional weak point in a circuit. Fuses are designed to fail! When too much current flows through a circuit, the filament in the fuse melts. This stops the flow of electricity and protects the wire and equipment.
Fuses and breakers are essential in any electrical system. It will protect the circuit, wires and the components against over current and possibly fire. There are two types of fuses used in the van build, spade fuses and ANL fuses.
Spade Fuses – Spade fuses are those colorful plastic fuses used in your car. Common Spade fuse sizes are: 2A 3A 5A 7.5A 10A 15A 20A 25A 30A 35A. I purchase this set, to ensure I always had spares!
ANL FUSES – These are higher current fuses used at your main electrical panel for the batteries and inverter. ANL are fuses used for circuits of more than 20 amps. Select fuses that are 50% above the maximum current of your circuit load, but below the amperage rating of your wiring. I used these Fuse Holders, and these ANL fuses for the main circuit panel.
Ancor Marine Grade Duplex Wire 
DC Circuit Breakers – Circuit breakers are like resettable fuses. When there is too much current the circuit breaker “throws” switching off. After fixing the problem that caused the overcurrent, the breaker can be turned back on. Breakers also allow you to easily disconnect a circuit from service. I use circuit breakers in the electrical system in places I need to disconnect a portion of the circuit for maintenance. A good example is the solar panels. Solar panels should be disconnected when servicing the main electrical panel or batteries. For solar disconnect I used these DC Circuit Breakers.
Fuses are more reliable than circuit breakers. I like fuses because they are simple and I have confidence they will work when needed.
What size fuses/Circuit Breakers? – The fuse must protect the wire, and electrical components. I will use a 12 gauge wire for all 12 volt connections in the van. 12 AWG wire will carry a 15 Amp load 15 feet with a 3% voltage drop. Use this calculator to determine your wire size – http://circuitwizard.bluesea.com/
So, the wire is safe for 15 Amperes or less. Next, I need to protect the individual components. Take a look at your ‘Electrical Load List”. This is the list you created when sizing the electrical system. On that list you should have the normal operating amperage of each device. Take that number and multiply by 1.5.
For example SEAFLO 42-Series Water Pump is 7.5 Amps. 7.5 x 1.5 = 11.25 Amps. There are no readily available fuses at 11.25 amps, so round up. In this case the closest fuse is 15 amps. If you only have a wattage rating for the device divide by the system voltage. For example a 12 volt fan that is 9 watts.
Current = Watts / Volts Current = 9/12 = .75 amps.
If this fan was on its own circuit a 2 Amp fuse would be used. A 12 volt fuse block is needed to supply the different amperage fuses for your DC loads. This is the 12 Volt Fuse Block, I also used another 12V fuse block above the sliding door.
Square D Load Center 
for AC Breakers.
SOLAR CHARGE CONTROLLER – I will use a MPPT charge controller. Based on my research this type of charge controller does a better job when it receives high voltage. So my solar panels will be connected in series. Connecting them in series adds up the voltage from each panel, and keeps the current the same. If I connect them in parallel the voltage would remain the same and the current would add.
The negative of connecting in series is that the solar panels rely on each other. If one panel has a bad cell, or low voltage from shading it may affect the entire system. If you have a break in a series circuit, the entire circuit will not work. The benefit is that you know something is not working properly!
This design has a total of 400 watts of solar panels, comprised of two – 200 watt panels. Each panel has a maximum output voltage of 20.4Volts, and current 9.8Amps. Remember this is the ideal maximum.
Connected in series this will provide a maximum of 20.4 x 2 = 40.8 volts at 9.8A
Charge controller sizes are based on the voltage and current. Victron charge controllers are named according to the voltage and current they can handle. For example a Victron SmartSolar MPPT 75/15 Charge Controller will handle 75 volts and 15 amperes. That size would be good enough for my solar panels.
I have decided on a Victron SmartSolar MPPT 100/30 Charge Controller. Why? Well. As of right now I do not expect to add solar panels. But, in the future I might. Plus, what if I want to experiment with connecting these in parallel, that would be 20.4 volts at 19.6 amps. That would be too many amps for the 75/15 controller. I don’t want to purchase another charge controller if I decide to double the number of solar panels. There is enough room on the van for five 200 watt panels. I design and purchase components with flexibility in mind. It may cost a few dollars more, but over time may save money!
DO NOT disconnect the battery while the solar panels are hooked up to the charge controller. Whenever I need to work on the solar panels I use the circuit breaker to disconnect them from the system. The circuit breaker amperage should be no larger than the current of the charge controller.
Solar Cable – Solar cable is different. It will not be as flexible as other wire. Solar panel wire must have UV resistant insulation. If standard type electrical wire is used on the roof of your van the suns UV radiation will destroy the insulation on the wire. This may cause an electrical short, and possible solar panel failure. We used this TEMCO Solar cable.
Ring Terminals and Ferrules –There are many ways to connect wires together or to a terminal. Soldering and crimping are the most common. Crimping is easy, fast and effective. Crimping crushes the wire around the connector and ensures a solid electrical connection. When purchasing ring terminals, be sure to purchase those with heat shrink tubing. The heat shrink tubing will seal the wire, and provide a professional looking waterproof connection. These are the ring terminals we used. I also used this Ferrule Crimping Tool kit for the wires that enter the solar charge controller. Ferrules ensure there are no loose strands in a connection that could cause a short.
Ring Terminals with heat shrink 
Wire size, AC and DC circuits – You need to have the correct size wire for the amperage and voltage that will run through the wire. Remember every wire should be protected by a fuse, limiting the amount of current through the wire. For full information on wire size please see my “Wire Size” video below.
To determine wire size I recommend using Blue Sea Systems calculator – http://circuitwizard.bluesea.com/
Wire size is based on the amount of current going through the wire and the length of the wire run. Remember you can always use a thicker gauge wire in place of a thinner gauge wire. This will save money when purchasing wire.
The most amount of wire that will be run throughout your Van will be for DC, and AC appliances. For 12 Volts DC a 12 AWG wire should handle everything. A 12 AWG wire will handle 10 Amperes over a 20 foot distance. I do not expect any runs over 20 feet, or current needs over 10 Amps. The highest current draw DC item is the water pumps at 7.5 amps.
Ancor produces excellent marine grade wire. It is double insulated and fully tinned. I used this Ancor 12AWG flat duplex wire for most of the 12 Volt applications.
Wire Type – Solid wire (Romex) is commonly used in houses. Solid wire cannot be used in a moving vehicle, van or boat! The constant vibration creates what is called work hardening making the wire brittle. This will break the conductor over time. All wires used in your van build should be stranded and double insulated, or routed through split loom tubing, and secured with cable ties. If placing a wire through the metal of the van, use a rubber grommet to protect it from the sharp metal edges. Also if you drill a hole in the van body be sure to paint the raw metal before applying a grommet.
For A/C outlets – I will use a 12 AWG extension cord for all AC outlets. US electrical codes max current for circuits utilizing 12 gauge wire is 20 Amps. A 12AWG Extension cord has much thicker wire then the standard 16AWG extension code. If you have never held 100 feet of 12AWG extension cord, well you don’t understand — Its HEAVY
The high current items in our van build are:
Bosch water heater 1440 watts, 12 Amps
Air conditioner 5000BTU, 7.5Amps
Microwave 700 watt, 6 Amps
Insta-pot 1000 Watts, 8.3 Amps
We may have a kitchen blender or other kitchen appliance, but they would not have a greater current draw than 15 amps. So, a 12 AWG wire size will be enough for all our AC needs. I purchased this 100Ft Extension cord, it was enough for all the AC outlets in the van.
AC Circuit Breakers – There are 4 AC circuit breakers in the system. One 30 amp, one 20 amp, and two 15 Amp. The 20 Amp breaker will be dedicated to the Bosch Water heater, and the outlet at the rear garage area The rear outlet may be used if I need to run any power equipment – drills, circular saws etc. I don’t expect to need this, but as I have mentioned before, always design with options. The 20 Amp breaker may be needed for that outlet due to the surge current of some of those devices. The other 15 Amp breaker will run the other outlets in the van.
The 30 Amp breaker will be the master shut off. It will take the power from the Inverter. This breaker will be connected to the other breakers. The inverter is capable of providing 50 Amps of current. This breaker will limit that to 30 Amps. Yes, it is possible that we could exceed 30 amps if we run multiple items all at the same time. This would throw the breaker and cause no harm. We would then know to turn something off!
CABLES and LUGs – Crimping terminals onto cables requires heavy duty crimping tools. The most basic, and cost effective crimper is the hammer crimper. This is what I used. You can also buy a hydraulic crimping tool. This tool may provide more consistent results, but it is more expensive. It’s also not as much fun. The hammer crimper lets you get vent your super hero frustrations. This is the Hammer Crimper I used.
In the video you will see that I not only crimped the connections, but also flowed solder into the connection. This may be more then needed. But, filling any gap reduced the chance of future oxidation of the copper.
2/0 Lugs – Many sizes available at this link. Also check this LINK for cable, lugs and heat shrink. Find the best deal for what you need.
Batteries – You need to decide how many cloudy days you want to go without moving. What I mean by this is – if it is cloudy, overcast, or winter you will not generate much solar power. If you are not moving the van you don’t generate power from the alternator. Batteries are rated in Amp Hours. So calculate the number of amp hours per day. Then multiply that by the number of days you want to go without generating power.
I have decided on a 3000W inverter and 400 AH of lithium batteries. Now, I will use lithium batteries which will provide the full 400 AH of power. If you use AGM of gel batteries you can only use half their capacity. Using more than 50% of their capacity could damage the batteries. Lithium (Lipo4) is also smaller and lighter.
There are many website that will tell you the difference between Lead-Acid, Gell-Cell, AGM, and Lithium batteries. I am not going to list the features of them all. I am using Lithium (LiFePO4) batteries, because they are more efficient and cost effective. They are very expensive. But their life span and capabilities are higher than any other type of battery, they are simply better. Sometimes spending more money is actually the frugal way! They are actually cheapest over time.
Compared to other batteries lithium LiFeP04 are: Lighter, smaller, need no venting, and can be fully discharged without harm. The negative of lithium batteries – High cost, and temperature. They cannot be charged below 32 degrees. So, if you travel in freezing temperatures you should have a heating pad for the batteries.
Lithium batteries have a BMS or battery management system. This BMS ensures safe use of the batteries. The BMS monitors and regulates battery voltage, current and temperature. If the battery gets to cold, the BMS will not allow it to be charged. All batteries are not the same. Some brands are better built, with better quality management systems.
Battery Connections – When connecting batteries use the same size and length battery cables. This ensures the same resistance, so that all batteries are handling the work load equally. Batteries can be connected in series or parallel. If connected in series the voltage will add up, and the current remain the same. If connected in parallel the current capacity adds up, and the voltage remains the same. I will connect my batteries in parallel, maintaining a 12 volt system.
Charging – A battery charger goes through several stages when charging a battery. These are called bulk, absorption, and float. Bulk charging sends high current to the battery. Absorption slowly reduces the current over time. Float maintains the full charge of the battery. Lithium batteries do not need the float stage. It is important to have the correct charging stages for the type and manufacturer of the battery you are using. Different batteries require different charging profiles to maintain there health.
I decided to purchase batteries from Big Battery. The reason was the case. The metal case would allow me to open it up and service the BMS or individual cells when needed. If one of the prismatic cells, or BMS goes bad it would be easy to replace. In a sealed plastic case like many manufacturers there would be no way to service without destroying the case! Also, the case used Anderson type connectors, making it easy to connect the batteries to the system.
Bus Bars – The video below shows you – Step by Step – how make a bus bar for your electrical system. By using a bus bar you will cut down on the number of short wires and lugs needed at your main electrical panel.
DC to DC Charger – You can charge your batteries from your vehicles alternator. The alternator delivers power to all the vehicles electrical components and keeps the starter battery charged. The vehicles alternator may deliver more than 180 amps. Let’s say that 80 amps are needed for the vehicle that leaves a surplus of 100 amps. Those 100 amps can be used to charge your lithium batteries.
To charge from the alternator you need an Isolator, Charging relay, or DC to DC charger. These devices charge the starter and lithium batteries together.
A BIM, or battery isolation manager monitors voltage and connects batteries when needed. It will connect for 15 minutes, disconnect for 20 minutes, and repeat this cycle until the coach battery is charged. If the coach battery resting voltage exceeds 13.4 V then the BIM will disconnect. A resting voltage greater than 13.4 V indicates a fully charged battery. The BIM will disconnect if the alternator voltage exceeds 14.4 V. This protects the coach battery from over charging. If the BIM did not disconnect it could continue to put a load on the vehicles alternator – reducing the life of the alternator, or causing it to fail.
A safer method is using a DC to DC Charger. A DC to DC charger isolates the starter battery from the house (lithium) batteries. It also controls the current and voltage taken from the starter battery. This insures that you do not harm (or discharge) the starter battery or alternator. Based on my research a DC to DC charger is safer for the vehicles alternator! So that’s what I chose for my van build.
I selected this 40 AMP DC-DC from Renogy. It was simple to setup and so far is simply working! See the video below for complete installation instructions. A common question I am asked is why didn’t I use a Victron ORION DC to DC Charger. The answer is simple, it wasn’t available at the time. The Renogy unit is 40Amps, and available in 60Amps. The Orion is 30 amps, but you can connect more of them for higher amperage charging. The Renogy unit has been working well for over 2 years – I will keep it. But I expect there is nothing wrong with the Victron, they make top quality products.
SOLAR PANELS – How many watts of solar do you need? The design of this van will have room for two, 200 watt solar panels. That’s 400 watts. Some vans have 200, 400 or even 1000 watts of solar. I also wanted a roof deck. So I didn’t want to cover the van with solar!
Generating solar will vary with the season ( in winter months the “Solar day” is shorter), location and where you park. To be safe and ensure that the solar panels meet your expectations multiply by 4. What I mean by this is if you expect to generate 100 Ah of power each day, you need to have 400 watts of solar. So, I have 400 Ah of batteries, and only expect to generate 100 Ah of electricity from solar each day. If my power usage is more than 100Ah per day I would not keep up with my needs using only solar.
Remember I can also charge from shore power, or the alternator! Actually, in over 2 years we have never plugged into shore power. We have it, just never used it (other than testing that it worked).
For our van the most important item to power is the refrigerator/freezer. It uses 65 watts, or 1560 Wh (65 x 24 hours). 1560 Wh/12 volts = 130 Amp hours. So, If I am using 130AH per day, and only gain 100 watts from solar, I am at a loss of 30AH per day. 300/30 = 10 days. The result is that the van can sit for 10 days on solar power. After that I would need to start the van to charge from the alternator.
We selected these solar panels due to their size. They fit perfectly across the rails on the top of the van. The provide 200 watts per panel in the smallest physical size. These are the Solar Panels we purchased.
LED Lighting – For LED lighting most van builders use puck lights. I decided to do something a little different. I wanted to be able to remove the ceiling panels in case we needed to run any additional wiring. I also did not want to use shiplap for the ceiling. I felt it was to heavy. I used 5mm plywood panels covered with marine vinyl for the ceiling. This allowed me to create indirect lighting, so you don’t see the lights – just a nice glow! So, all of the lighting in the van is made with LED strip lights . In the cabinets and above the sink we put the strip lights in this aluminum housing it included mounting clips making installation easy. I purchased additional LED electrical connectors to make up a separate LED light for each cabinet. Inside the cabinet I placed a switch to turn on and off the LED light. Check out the videos below for details.
Fuse Covers – For the main electrical panel we needed fuse holders. These fuse holders had a logo on the front of them. It blocked seeing the fuse below. In one of the videos below, I show how to easily remove this logo.
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