A Mad Scientist’s Take on the Ultimate Electrical System (Part 2)

Designing the Ultimate Electrical System For Truck Camper Rigs

In the previous article, we got the fluff.  Now it’s time to get into the weeds.  First though, I need to make a disclaimer. I am not a Licensed Master Electrician, nor am I a Licensed/Certified Professional Electrical Engineer. The information in this article, while detailed, is to be used only as an aid to understanding the concepts discussed herein. It is imperative, should you choose to apply any of this information to an operational system, that a Licensed Master Electrician or a Professional Electrical Engineer review and approve your design.

I don’t know how to start without first giving you the full picture. Below is the schematic for the entire project. It’s very detailed so I have asked Mike to provide a link to a high-resolution version you can download for printing/viewing. You can download the schematic by clicking here.

Electrical System Schematic

General

First, I need to recognize three Vendors that I used for the project.  (I am not being compensated for this, I mention them because of their excellent service).

PKYS (Peter Kennedy Yacht Services) – They are a Victron, Blue Sea Systems, and Ancor stocking dealer. I purchased most of the components for this project from them. Peter is a certified ABYC electrician and was most helpful with the procurement process as well as design suggestions. You can get to their website here.

DigiKey – I’ve been dealing with them since the 1980’s when all they had was a paper catalog.  Now they are huge, and their primary business is supplying OEM’s and Retailers with electronics and electrical components. However, they still maintain a retail presence, so anyone can buy from them. I will warn you though, you must know “exactly” what you are looking for since their website is designed for OEM’s and Retailers, and the number of selections is overwhelming. You can get to their website here.

Bolt Depot – This is a multi-generational hardware company that has evolved into an online fastener supplier. They have maintained a “local store” philosophy in that you can order “one” of anything. Most online fastener retailers require you to buy a box.  All fasteners used in the project came from them. You can get to their website by clicking on this link.

Part 1 of this series presented the design philosophy and component list for this project.  It can be found here. Please review to help your understanding of what follows.

A solar array with a nominal output of 1,400 Watts was the most I could fit on the roof of an 8.5 foot, cab-over camper.  The battery bank was sized based on the charging capability of the solar array.  The battery bank will have 7,680 usable watt hours of power available when fully charged.

According to the NREL (National Renewable Energy Laboratory), which is a national laboratory of the U.S. Department of Energy, the average, daily kilowatt production of a 1.4 kilowatt array over a calendar year for my location is 6.33 kilowatts. The Maximum Month averages 8.39 kilowatts per day, the Minimum is 4.11 kilowatts.  My AC/DC load calculations suggest a heavy usage, power requirement of 6.5 kilowatts per day (without Air Conditioning). So, for my location, the Spring and Summer months are great, the Fall and Winter months, not so much.  This will of course vary with location. These were the calculations I performed to size the batteries with the solar array.

After this, it was just a matter of sizing the rest of the equipment/components to fit the battery/solar capacities and the 120 volt 50 Amp AC Shore Power/Generator feeds.  When the basic schematic was complete I sized the electrical equipment cabinet and the battery/BMS cabinet, shown below.

Exterior Electrical Cabinet Layout
Battery/BMS Cabinet Layout

Components

The Victron components are specified in my original article so I am not going to re-hash them here.  This section is for the other equipment or equipment that has been changed/deleted/added since my original article.

1. Marine Panels – The use of these panels was predicated by three major factors. One, they are high quality; two, they are very compact; and three, they use Carling Tech hydraulic/magnetic circuit breakers. Rather than just being circuit protection devices, these breakers are also designed to be used as switches and are rated for 10,000, under power, actuations; another benefit is that they maintain their specified trip current rating throughout their operating temperature range which is -40C to 85C (185F).

Blue Sea Systems has an online app called “Panel Wizard” that allows one to design their own panels.  They also wire the panels, based on your requirements. Shop Drawings, if requested, are produced for your approval. Below are images of the AC and DC panels and their associated Shop Drawings:

AC Main Load Distribution Panel
AC Main Load Distribution Panel Shop Drawing
DC Distribution Panel
DC Distribution Panel Shop Drawing

2. Power Supplies and Converters – In this area I have made changes from the original article. Mainly to provide power to the 12 Volt cooling fans.  Refer to the schematic for wiring details. The current parts list is:

  • Mean Well HRP-600-12 – 120 Volt AC to 12 Volt DC 50 Amp Power Supply for DC Loads
  • CUI PYB20-Q48-S12 – 20-Watt 48 Volt to 12 Volt Converter to power Electrical Cabinet Cooling Fan
  • CUI PYB10-Q48-S12 – 10-Watt 48 Volt to 12 Volt Converter to power Battery Cabinet Cooling Fan
  • CUI VSK-S5-12UA-T – 5-Watt 120 Volt AC to 12 Volt DC Converter to power AC Panel Back Lights

I prefer to use industrial equipment since it is high quality and manufacturers must provide MTBF (Mean Time Between Failure) data computed with the MIL-HDBK-217F which is the “Military Reliability Prediction of Electronic Equipment” specification. The ability to work in harsh environments is part of the equation.

For example:

  • The Mean Well device has a MTBF of 140,000 hrs. or 15.9 Years
  • The CUI PYB devices have a MTBF of 1,000,000 hrs. or 114 Years
  • The CUI VSK device has a MTBF of 300,000 hrs. or 34 Years

My goal has always been to specify components that will outlive me, or in some cases, my grandchildren.  If there are any Navy guys/gals out there think “Zero Defects”.

Photograph showing the CUI components with a size reference.

3. Miscellaneous Switches, Connectors, and Fans – They are listed below:

  • Bulgin MPI002/TE/GN/12 – Integrated switch and LED for Lynx Ion BMS remote ON/OFF functionality and status light.
  • Amphenol C016-20G003-100-2 and C016-20H003-100-2 – Receptacles and Plugs to connect 4 wire, BMS control cable between the Electrical Cabinet and the Battery Cabinet.
  • TE Connectivity 5-2120871-1 and 2120864-1 – Jacks and Plugs for Cat5e/RJ45 data cable for VE.CAN communication between Electrical Cabinet and Battery Cabinet; and external Ethernet connection to the CCGX.
  • Sunon PMD1212PTB1-A.(2).GN – 12 Volt 160CFM cooling fan for electrical cabinet.
  • Sunon GF80321B1-000U-AE9 – 12 Volt 59CFM cooling fan for battery cabinet.

4. DC Load Center – MidNite Solar MNDC 175. This is a small enclosure (9 inches wide x 17 inches high x 3.5 inches deep) and is made from powder coated aluminum. I ripped out everything, except the main breaker and instead used marine grade hardware. The 175 amp main breaker is a Carling Tech hydraulic/magnetic F series rated at 125 volts DC. The two 50 Amp PV/Charge Controller breakers are panel mount Carling Tech C Series rated at 150 volts DC. A detailed drawing is below:

DC Load Center

5. Solar Panels – My plan for mounting the solar panels is to use Yakima Rails with four cross members, two for each set of panels. The panels are LG LG350Q1C-A5 350 watt. They will be wired two in series and then the two series sets, paralleled. This will give me a Voltage at Maximum Power Point (Vmpp) of 72 volts and a Impp of 19.4 amps. Perfect for a 48 volt battery system with a MPPT charge controller. Victron has a Charger Controller compatibility spreadsheet you can download from here. Haven’t decided on a combiner/circuit breaker design yet. I may also need to add some fairings to protect the panels from the wind at highway speeds. The layout is below:

Solar Panel Layout on Roof.

6. Wire, Tools, and Hardware – All wire, except for data and control cables, is Marine Grade (Class K/Type 3) stranded/tinned copper with an insulation Rating of 105C. Lugs are closed end, tinned copper and ring connectors are tinned copper with heat shrink insulation. Per ABYC, Wire Nuts are prohibited, as is solid wire. All mechanical fasteners (screws, nuts, etc.) as well as cabinet hardware are Stainless Steel. All Buses, Pass Through Connectors, and Terminal Blocks are Blue Seas Marine Grade. As for the tools, I’m not going to get into miscellaneous tools wrenches, screwdrivers, sockets, etc.; other than to say you’re going to need a bunch, both US and Metric.  Below are pictured the five required tools for a project like this.

Tools for the project.
  • Torque Wrench – Mine is a Snap-on, Electronic ATECH1FR240B 1/4-inch drive, which will torque from 12-240 inches-pounds. Being electronic, you can switch Units on the fly, between (inches-pounds, Newton Meters, foot-pounds., and three I never heard of).  It can handle all the torque values needed for this project. Torqueing is the most overlooked and, in my opinion, one of the more important steps in making quality electrical connections.  All connection points on all components have a manufacturer’s recommended torque value.  And yes, too tight can be just as bad as too loose.  Remember, you must torque each connection twice; wait at least an hour between the first and second.
  • Small Crimper – It’s a ratcheting crimper designed for heat shrink insulated connectors on 22-8 AWG wire.  This one is made by Ancor.
  • Cable Cutter – Made by Klein Tools, Model 63060. It’s a ratcheting cutter that will handle up to 400 MCM Copper cable.
  • Lug Crimper – This is a hexagonal crimper that is adjustable for 8-4/0 AWG lugs. The brand is Ancor.
  • Multimeter – Fluke 376 FC AC/DC Clamp Multimeter. It has the standard voltage, ohms, capacitance, continuity, and Hz (AC Frequency) measurements.  The thing that’s nice about this one is that you can measure amperage, through the clamp, for both AC and DC circuits.  If anyone is interested, it uses a “Hall Effect” sensor element for this.  Since we are dealing with both AC and DC circuits, it made sense to get one tool that does it all.

Two tools not shown in the photograph are a DYMO XTL 500 Label Maker/Printer and it’s included software, all labels (wire, panel, etc.) were created with this device; and a Ancor Heat Gun to set the shrink wrap.

Intermission

Time to get a cold one and some beer nuts. On second thought, better have three or four, thing’s get a little tedious from here on out. Play the Jeopardy music.

Putting it All Together

I’m a firm believer in the Six P’s (Prior Planning Prevents Piss Poor Performance) and the saying “The Devil’s in the Details.” Sitting in a room with boxes full of components and parts, I think “Crap, I’ve got to put all this together”. So, I begin, not with a screwdriver and wrench, but with a computer. Before I start work on assembling a major component, I first create a detailed wiring diagram and an associated “Wire Legend.” The Wire Legend is a complete list of all wires in the system, and includes:

  1. Code Number – Used for wire labels
  2. Wire Group – Describes the purpose of the wire in the system
  3. AWG – Wire Size
  4. Wire Color – ABYC Color Standard for Wire Group
  5. Length – How long
  6. Source Lug/Connector – Termination type at the source
  7. Destination Lug/Connector – Termination type at the destination
  8. Source – Description of Wire Source
  9. Destination – Description of Wire Destination

This looks complicated, but it’s the only way I know to build a Bill of Materials for your wires and connectors. Since I live in the Boondocks, everything had to be shipped in. I needed an accurate BOM.  Like the Schematic, the Wire Legend is very detailed, a viewable/printable PDF can be found here.  An example is below:

So, let’s get started.

1. Electrical Enclosure – Simply put, all electrical components, except for external sources and users, are contained in/on the enclosure. They are:

  • DC Load Center
  • AC Load Center/Distribution Panel
  • DC Distribution Panel
  • AC/DC Power Supply to power DC Loads
  • Victron BlueSolar MPPT 150/45-tr (12/24/36/48V) Charger Controller
  • Victron Quattro 48/5000/70-100/100 120V Inverter/Charger
  • Victron Color Control GX (CCGX) PLC (Programmable Logic Controller)
  • All Buses, Terminal Blocks, Misc. Devices, and Pass Through Connectors

The prototype enclosure is made from 3/4-inch plywood and externally measures 25.5 inches wide x 36.75 inches high x 21.5 inched deep. If I decide to build this for an actual camper, the enclosure will be powder coated aluminum which should be smaller and lighter weight. Below is the component placement drawing:

2. DC Load Center – Circuit Protection and Distribution for the primary DC power wiring. Using the schematic, I built a diagram of all wires entering and exiting the Load Center. Using the Wire Legend, I then labeled each wire. The little black donuts are grommets to protect the wires. Diagram is below:

3. AC Load Center/Distribution Panel – The heart of the AC System. All circuit protection, external source selections, inverter/charger AC input/output, and load circuit switching are controlled by this panel.  It is complex, but since the panel was built and wired by Blue Sea Systems, all I had to do was attach the input/output wires to the correct terminal. Because I am using a Pass-Through Inverter/Charger all the complex transfer switching and neutral/ground bond control is automatically handled by the Victron Quattro.

AC Panel Wiring Diagram
AC Panel Current Flow Diagram

4. DC Distribution Panel – This is the simplest panel. It provides a Main 50 amp Breaker for the DC input from the AC/DC Power Supply and circuit protection/switching for the DC load circuits. Just had to install the provided shunt and wire to the connection points.

DC Distribution Panel Wiring Diagram

5. Battery/BMS Cabinet – This Cabinet’s exterior dimensions are 29.5 inches wide x 18.75 inches high x 21.5 inches deep. As with the Electrical Cabinet, it will be powder coated aluminum if used in a camper. The main power wiring is simple, wire the batteries to the BMS input and wire the BMS output to the pass-through connectors. The complexity comes with the control, data, and fan wiring. The diagram is below:

Battery/BMS Cabinet Wiring Diagram with Data and Control Wiring.

6. Networking and Setup – Now that we have completed the “dumb” wiring, it’s time to network everything together and program it; this will give us a “smart” system. We have six devices in our network:

  • Control Computer – CCGX
  • Inverter/Charger – Victron Quattro
  • Solar Charge Controller – Blue Solar MPPT 150/45
  • Battery BMS – Lynx Ion BMS 1000
  • Two Victron HE Batteries

Networking

The wiring complexity is that we a dealing with four different communications protocols, (TCP/IP (Ethernet), VE.Can, VE.bus, and VE.direct). Luckily all but one uses the same, readily available, cable with factory termination plugs.

  • Cat5e UTP (Unshielded Twisted Pair) cable with RJ45 plugs. This is used for the Ethernet, VE.Can, and VE.Bus connections. For those of you who make your own cables, I ran into the greatest gadget since sliced bread, to insert the wires into an RJ-45 plug correctly. You use pass-through RJ-45 connectors and you must use a special crimping tool. Insert the wires into the connector and they go all the way through and come out the other end. If you have any out of sequence, just pull those wires out and put them in the correct place; then do your crimp. Klein Tools makes the crimper (Model VDV226-110) and the connectors.
  • VE.Direct – This is a proprietary Victron cable and can be purchased from their dealers. It comes in many lengths.
  • The CCGX and Lynx Ion BMS should have each come with two VE.Can terminators. Be sure they are installed in the correct locations.

Ensure there is no power on the system before you connect the cables. Below is the wiring diagram:

Data Wiring Diagram

Programming

This is where many people get into trouble. If you are not “Computer Savvy”, I strongly recommend getting help from a family member, friend, or neighbor, who is. If one is not available, then hire a professional to do this part. If done incorrectly, the best case is you end up with a system that does not work properly; or, worst case you fry a component or corrupt its internal programming to the point you must send it back to the dealer to be re-programmed. This section is going to be “high level”, since the only way you can perform this task, is to dig into the Victron Manuals and Documentation.

Before you start, download and install the VE Config and VictronConnect applications from the Victron web site, onto your internet connected computer. You will also need the following interfaces from Victron:

  • VE.Direct to USB interface cable – Connect to Charge Controller
  • Interface MK3-USB – Connect to Inverter/Charger VE.Bus

1. Firmware Update – The first step is to update the firmware. “I’ve never updated the firmware on my home computer, and it works fine”, I hear this a lot. Your home computer is a standalone device; we are now talking about multiple “dependent devices” that must communicate with each other. So, check the firmware version of each device and make sure it is the most recent version.

An important reason for using Victron equipment was a new functionality called DVCC (Distributed Voltage and Current Control); which allows the Battery BMS to control the charging voltage and amperage from the charging devices. Instead of setting up charging parameters in the Inverter/Charger and Solar Charge Controller the BMS directly controls these device’s charging output.  To use DVCC you must have the latest firmware on all Devices.

Victron has incorporated automatic firmware updates in some of them, so the order you power up the devices is important.  Some of the Victron Devices also offer wireless (Bluetooth or WiFi) internet connectivity.  I am hesitant to use these for firmware updates, I prefer hard wired connections.  If the connection is noisy the firmware update may fail and require a trip to the dealer to correct.

  • CCGX – This is the control computer, so it must be powered up first. Connect it, from its Ethernet Port, to your internet router. Then turn on the power, the firmware update is automatic.
  • Blue Solar MPPT 150/45 – Connect to your internet connected computer with the VE. Direct to USB interface cable. Apply power to the device and start the VictronConnect application.  The firmware update should be automatic, or you can manually perform it.
  • Victron Quattro Inverter/Charger – Connect it to your computer with the MK3-USB interface. After you apply power, use the VEFlash application (part of the VEConfigure distribution) to update the firmware. You will first need to download the latest firmware file from the Victron Professional website. Read the documentation, the procedures are not that straight forward.
  • Lynx Ion BMS and HE Batteries – These are fairly new, at least in the US, and doing the upgrade, while easy, requires an expensive MG CANBus to USB interface and the “Lynx Ion BMS Tool” software. The software can be downloaded from the Victron Professional website. Victron was nice enough to loan me an interface to setup up my system. I have recommended to Victron USA that they upgrade the firmware on all Lynx Ion BMS orders just before shipment. I also understand that Victron is actively looking at ways to streamline the upgrade process.

Again, read the manual, the connections must be made correctly, and the startup sequence is important.

2. System Setup – I thought I would have the system tested and setup prior to this article being published. However, I have just completed the installation of all components. Rather than delay the publication date I decided to include the setup procedures in the next part of this series.

Conclusion

You’re probably as happy as I am that we’re at the end. It was intense writing this, I can only imagine what reading it must be like. As I said earlier about prior planning, I would estimate that 85-90 percent of my time was spent on design, wiring diagrams, and wire legends; only 10-15 percent was spent physically putting it together. But, like I always told my associates, the hard part is the planning; if that is done correctly, building it is the easy part.

I have been reading posts on multiple RV forums about the dislike of automated, computer-controlled systems. I must admit, given the way the RV industry has implemented them, that I agree. People expect, and in my opinion, deserve, a reliable, functioning system. The three bedrock principles to achieve that are:

  • Good Planning and Design
  • The use of high quality components
  • An installation performed in strict accordance with the plans and specifications

Unfortunately, all this costs time and money. And, the ability to force external suppliers to conform to communications standards between diverse components. Since 2005 the RV industry has had a Can-Bus standard, through RVIA, for communications between RV components. It is called RV-C and information can be found here. Will it happen any time soon? I don’t know.

The system is now operational. Time to start the setup validation and operational analysis, I am renting Bench DC and AC Load devices to stress test the system to make sure all the breakers blow when they are supposed to and that there aren’t any surprises. At the same time, I will test the thermal management to make sure the cooling fans are sized correctly and nothing over heats. Should be fun.

In the meantime, here are some photos of the completed prototype.

Electrical Cabinet (left), electrical cabinet, leftside (right)
Electrical cabinet angle view (left), battery cabinet connections (right)
Battery cabinet interior (left), DC load center wiring (right)
Panel wiring and power supply (left), inverter-charger wiring (right)
Electrical cabinet interior (left), IT’S ALIVE! (right)

Until next time, The Mad Scientist.

Subscribe to Our Newsletter

About Pat Davitt 2 Articles
Pat Davitt is a former Naval Aviator who served on active duty for eight years and retired from the Naval reserves after 20. He worked as a senior project manager for a general contractor and later researched, installed, and setup computer systems for construction companies. Today, Pat lives on a small ranch in the Davis Mountains of West Texas with his favorite horse “Rocky” and dog “Zorro”. Even though he already lives in the “boondocks,” he wants to visit other remote areas in the United States, which led to his search for a truck camper.

Be the first to comment

Leave a Reply

Your email address will not be published.