Our autonomy and comfort depend a lot on the electrical system of our DIY camper van conversion. No power means no fridge, no lights, no heat, no fan, no Instagram = no #vanlife as we know it! Therefore, we want our electrics and wiring to be robust and reliable.

Designing the electrical system was an intimidating and a sensitive topic, especially since we did not know much about it and we had to start from scratch. The more we read about it, the more complicated it seemed. It quickly became obvious that we had to educate ourselves and that we had to make a bulletproof plan before doing any physical work.


This page was created to capture and organise our toughs, our notes and to pave the way that would lead us to our final electrical system design (and hopefully help others going the same route as us!)


This post is about the design process. For the actual installation of our electrical system, we recommend you to read the following post:

Electrical System Installation


DISCLOSURE: This post contains affiliate links, which means that if you click and commit to buy one of the product links, we will receive a commission fee. The price you pay remains the same, affiliate link or not. Buying through our affiliate links is a great way to say thanks if we were of any help in your van conversion! We only link to products that we personally bought or researched throughout.





1- What Do We Expect From Our Electrical System?

  • Power all of our “fixed” loads (fan, lights, fridge) and power our “external” loads as well (phones, laptop, etc)
  • Charge from solar, van & from shore power
  • Have an inverter for occasional & modest use of 120V
  • Be completely autonomous in full-sun condition and have a few days autonomy in absence of solar power and driving (no charge source)


2- Power Consumption

Our power consumption will dictate the “size” of our components (solar panel, battery, inverter, etc). Let’s make a list of our loads and calculate how much Ah (ampere hour) we will draw in total each day.


Summer Analysis
 Load Description Measured Instantaneous Consumption


Calculation Assumptions  Calculation  Daily Consumption (Ah)
 Fridge Novakool R5810 4.0A 24h per day @ 35% duty cycle  4.0A * 35%*24h=  34Ah
 Lights  3W LED Recessed Pucks (10) controlled by dimmer (2 zones) 1.3A (total 10 lights @ 100% intensity) 4h per day @ 80% intensity  1.3A*80%*4h=  4Ah
 Fan  Maxxfan 6200K

(10 power settings)

0.2A@1, 0.4A@2, 0.5A@3, 0.8A@4, 1.1A@5, 1.5A@6, 2.0A@7, 2.6A@8, 3.3A@9, 4.4A@10  24h per day @ 3 average  0.5A*24h=  12Ah
 Hot Water  Mr Heater BOSS XCW20  Guesstimate…  1Ah
 Water Pump  Guesstimate…  1Ah
 Sound System  Guesstimate…  1Ah
 Phones  Guesstimate…  1Ah
 Laptop  Guesstimate…  2Ah


Winter Analysis
Load Description Measured Instantaneous Consumption (A) Calculation Assumptions  Calculation  Daily Consumption (Ah)
 Fridge Novakool R5810 4.0A 24h per day @ 20% duty cycle  4.0A * 20%*24h=  20Ah
 Lights 3W LED Recessed Pucks (10) controlled by dimmer (2 zones) 1.3A (total 10 lights @ 100% intensity) 8h per day @ 70% intensity  1.3A*70%*8h=  7Ah
 Fan Maxxfan 6200K

(10 power settings)

0.2A@1, 0.4A@2, 0.5A@3, 0.8A@4, 1.1A@5, 1.5A@6, 2.0A@7, 2.6A@8, 3.3A@9, 4.4A@10  0.4A*12h=  4Ah
 Hot Water Mr Heater BOSS XCW20  Guesstimate…  1Ah
 Air Heater Webasto Air Top 2000 STC  Guesstimate…  20Ah
 Sound System  Guesstimate…  1Ah
 Phones  Guesstimate…  1Ah
 Laptop  Guesstimate…  2Ah


Our daily consumption is similar for summer & winter because in winter the fridge draws less power, but it is balanced by the Webasto air heater that needs some electrical power.



120V loads consumption can be measured using a “Kill A Watt”. The Kill A Watt is plugged into the 120V outlet, the appliance plugged into the Kill A Watt and then the consumption will be displayed.

Kill A Watt. Buy on Amazon


3- Battery Bank

We just determined that we will draw about 55Ah daily. Does it mean that, to have 4 days autonomy, we need a 55Ah*4days = 220Ah battery bank? No! There are more variables to take account of… keep reading the whole page and we will size the battery bank afterward…


3.1- Temperature de-rate of the battery bank

If you know someone that owns an electric car and uses it during winter time (let’s say a Canadian friend), you probably know that his/her car will do about half the kilometers than in summer (Canadian winters are cold AF & we still use the metric system. wait what?). Batteries are much less efficient in cold weather. The exact loss will, of course, depend on the battery temperature, but we will assume 30% less efficient as a general rule. For example, a 210Ah battery bank will actually deliver 210Ah*70% = 147Ah. Or, we could say that our daily consumption of 55Ah is in fact 55Ah*1.3 = 72Ah. We have to keep that in mind.


3.2- Charging a frozen battery

First of all, unlike water, a battery will not freeze at 32F (0°C). The freezing temperature of the battery depends on the depth of discharge. As the state of charge in a battery decreases, the electrolyte becomes more like water and the freezing temperature increases.  It is very important to make sure your battery stays fully charged in extreme cold weather. If a battery freezes, it can damage the plates and container leading to a potential explosion. A frozen battery must NOT be charged! Consult your battery manual.

As a guideline, this is extracted from our Rolls Battery Manual:

Specific Gravity


Depth of Discharge 

approx (%)

Freezing Temperature

C (F)

1.280 100 -69C (-92F)
1.265 92 -57.4C (-72.3F)
1.250 85 -52.2C (-62F)
1.200 60 -26.7C (-16F)
1.150 40 -15C (5F)
1.100 20 -7C (19F)




3.3- Depth of Discharge

The cycle life of a battery is directly affected by the depth of discharge. What is the depth of discharge? It is how deeply the battery was discharge during one cycle. Let’s say that a fully charge battery is 100% and a fully discharged battery is 0%. If we draw 30% of available capacity (from a fully charged battery), the depth of discharge is 70% (there is 70% of Ah remaining before the battery is 0%).

For AGM batteries, it is recommended not to go below 50% depth of discharge to maximize the battery life (it might be different for different type of batteries).

Cycle life vs Depth of discharge

Cycle life vs Depth of discharge


So, if one’s consumption is 55Ah daily and has a 100Ah battery bank, it means that at the end of the day the depth of discharge is 45Ah/100Ah = 45%? Well, not exactly… because the battery bank will get charged throughout the day by solar or by driving the van or by getting power from shore power. In fact, we observe our minimal depth of discharge in the morning just before the sunrise. Indeed, we dont have any charge source during the night. What we experienced so far is a depth of discharge of about 75-95% in the morning cause by the loads that run overnight (fan, fridge, air heater and some lights).


3.4- About battery types

There are many types of battery available. Let’s play PROS and CONS :


Flooded lead-acid


  • Cheapest battery type available


  • High maintenance (needs to be filled periodically with water and kept in a vented compartment)




  • Similar to Flooded lead-acid but the gel wont spill as easily


  • Similar to Flooded lead-acid
  • Must be charged at low rate




  • Low maintenance, good low-temperature performance


  • Expensive to buy (but good value in the long run)




  • Light, low maintenance, low self discharged


  • Unstable, Expensive


4- Charge Sources

If we had no charge sources at all, we would require a 220Ah battery bank to hold 4 days @ 55Ah daily consumption (in summer). In fact, we would require 440Ah if we dont want to go below 50% depth of discharge! Fortunately, there are multiple ways of recharging the battery to minimize the battery bank.


4.1- Solar Power

Harvesting power from the sun feels a bit like cheating to us; this is the exciting part of the electrical system! It is free to use, but it is not exactly cheap to setup at first.


4.1.1- The Panels

How many watts?

As a general rule of thumb, a 100W solar panel can generate about 5A/hr at peak power, that’s about 25Ah per day (sunny, summer day, best-case scenario).

We calculated previously that we will draw about 55Ah per day; it would be nice if the solar panel could provide at least that amount of power… We need 55Ah\25Ah*100W = 220W solar panel(s) to compensate exactly for our loads draw. Well, a bit more actually if we account for cold temperature de-rate & cloudy weather. However, solar power is not our only power source! When driving the van we will get some power from that as well; we have to keep that in mind…


Monocrystalline or Polycrystalline?

We read quite a bit about that and came to the conclusion that, these days, the quality of the solar panel (manufacturer) is more important than the type of the panel. If you want to learn more about that, Google is your friend! To start, here is a good article.


Should we use 1 large panel, or 2 smaller panels?

At the time of our research, we could buy one 300W or two, let’s say, 160W panels for 320W total. The cost of the 300W is generally higher than two smaller one, but is it really if you account that you need additional hardware to connect the two panels together (cables, connectors, junction box, etc…)?

One larger panel instead of two smaller ones:


  • Simple to install (no junction box and connectors)
  • Higher working voltage = lower amperage = minimise lost


  • Large physical size
  • Higher working voltage = use of MPPT charge controller recommended ($$)


Partial Shading is Evil!

When locating your panel(s) on the roof, ensure that no partial shading will be induced by any others component (fan, A/C, etc). Shading of just one cell could completely “block” the output of the panel! Many panels now come with bypass diodes that will allow the current to flow “around” the shaded cell(s) and therefore minimize the effect of partial shading.


Panel Orientation

A panel will deliver more current if oriented directly towards the sun. On large commercial solar plant, the panels are mounted on a motor-driven device that will optimized the orientation of the panel automatically throughout the day. Obviously, there is no such device for a van roof (until when?) BUT it is possible to add a tilt kit similar to this one:

Solar Panel Tilt Kit

Solar Panel Tilt Kit. Buy from Amazon


Adding a tilt kit will obviously add weight and slightly raise the panel(s). The worst part, for us, is that you have to climb on the roof to adjust the panels… knowing that we will be mostly on-the-go, we don’t feel that tilting the panels are worth it. But that’s us. The Wynns are doing a GREAT job at showing the effect of tilting the panels:



Panel Temperature

Wait for it!


Our Pick

We chose to install two panels of 160W* each, for a total of 320W. This is quite a lot of power, but we’re not messing around here! We had the roof space and we don’t feel like expanding later. Since we are using a PWM charge controller, we connected the 2 panels in parallel; this will keep the nominal voltage of the panels near the voltage of the house battery (12V).

*Update 2017: Grape Solar do not make the 160W panels anymore. It’s been upgraded for 180W panels with very similar physical dimensions!


Grape Solar GS-Star-180-US Monocrystalline PV Panel, 180-watt on Amazon


Our Solar Panels Installation:

Solar Panels Installation


From now on, we will use 320W solar power in our calculationThis should provide 320W\100W*25A= 80Ah of charge per day during summer, 30 Ah of charge per day during winter (guesstimate, time will tell for winter).


4.1.2- The Charge Controller

How many amps?

Charge controllers are rated based on the amount of amperage they can process from the solar panels.

Solar Panel Max. Watts / Solar Panel Max. Voltage = 320W / 18.5V = 17.30A

AMPS x Surge factor = 17.30A x 25% = 21.62A

Therefore a charge controller of at least 22A is required.



MPPT are the latest thing in solar charge controllers. They will be more efficient than PWM in cold temperature, partially sunny day and if the voltage of your solar panels are superior to the voltage of your battery bank. However they consume a small amount of power for themselves and are more expensive than PWM. The debate rage about the MPPT efficiency over PWM, but it is believed to be around 10%-20% more efficient depending on the conditions.

See Bogart Engineering take on MPPT vs PWM charge controller debate here (see FAQ “C1″)

MorningStar MPPT vs PWM comparison.

Side-to-side, real world testing of MPPT vs PWM charge controller here.


Our Pick:
Bogart Engineering SC-2030

Bogart Engineering SC-2030 Charge Controller. Buy from eBay.

We also considered:

Morningstar TS-MPPT-30 TriStar 30 amp MPPT Solar Charge Controller on Amazon

Victron MPPT 30A

Victron BlueSolar 100/30 MPPT. Buy from Amazon




4.2- Charging while driving
4.2.1- Inverter + Battery Charger

This is the setup we selected. The idea is to connect an inverter to the van battery (when driving, the van 230A alternator easily overcome the inverter draw). Then, this inverter will power a battery charger/converter to charge the house battery.

Our Pick (inverter):



Samlex PST 1000 Pure Sine Inverter on Amazon



We also considered:

Go-Power 1000W Pure Sine Inverter. Buy from Amazon

Xantrex Freedom 1000W True Sine

Xantrex Freedom 1000W True Sine. Buy from Amazon


Why the inverter + battery charger setup? Because we use a Smart Battery Charger/Converter that will provide a nice 3 stages charge profile to the house battery. When we are not driving, we can use this same Battery Charger/Converter to charge the house battery from shore power. Neat! In addition to power the Battery Charger, the inverter can also be used to power occasionally some 120V loads.

Samlex SEC-1230A 12V Smart Battery Charger / Converter on Amazon

The disadvantage we experienced with this setup is that we often forget to turn on the inverter before driving. To overcome this, we bought a small remote for the inverter. No big deal! Also, this setup might not be ideal for someone who use their inverter a lot when parked, since there is a risk of draining the van battery…



Samlex RC-15A Inverter Remote on Amazon


About using an inverter

An inverter will convert DC power to AC power. There will be a loss in the conversion from 12V to 120V of around 15%. So it is better to minimize the use of an inverter. If possible, get a universal 12V power adapter; they are quite common for laptop and such. 

We bought this one from Amazon and are really stoked about it! It works as it should, it has quality feel and the design is quite nice 🙂


90W 12V adapter on Amazon.com


How to check the actual wattage of an appliance (or how to avoid overloading your inverter!)

Most often, the wattage of an appliance will be much higher than the manufacturer claims… to check the actual wattage of an appliance, use a Kill A Watt:


Kill A Watt. Buy on Amazon


Modified vs Pure Sine-Wave Inverter

Good explanation here. This is a must-read if you need to choose between the two.


4.2.2- Battery-to-Battery charger

This option is quite popular these days as it is fairly simple and plug-and-forget. The battery-to-battery charger is plugged between the van battery and the house battery. It will provide a nice 3 stages charge profile. No need to turn on the device, it will turn on by itself when the van battery is fully charged and the van is running!

We did not go this route (but hesitated a LOT) as the battery-to-battery charger is not cheap and we still had to buy an inverter + a battery charger/converter (for shore power).

Sterling Power BB1250 Battery to Battery Charger 12V 50A

Sterling Power BB1250 Battery to Battery Charger 12V 50A. Get it on Amazon


4.2.3- Direct connection to alternator (via an Automatic Charging Relay)

It is possible to charge the house battery from the van alternator via an Automatic Charging Relay (ACR). The ACR will automatically combines the van/house batteries during charging and isolates the van/house batteries when discharging and when Starting engines.

Blue Sea ACR

Blue Sea 120A Automatic Charging Relay. Buy from Amazon


4.3- Shore Power
4.3.1- Battery Charger / Converter

If you did not skip the previous parts of this page, you understand that this is what we are using. If not, go through section 4.2 above (charging while driving, inverter + battery charger/converter)!

Our Pick:

Samlex SEC-1230A 12V Smart Battery Charger / Converter on Amazon

4.3.2- Inverter / Charger

An inverter / Charger is actually one device (plugged to your house battery) that will, first, act as an inverter and, second, charge the house battery from a 120V source (shore power). It is quite convenient, but we passed because of the price.

Magnum-MMS-1012 Inverter Charger 1000W

Magnum-MMS-1012 Inverter Charger 1000W on Amazon


5- System Monitor

A system monitor is not mandatory, but we strongly recommend it. Depending on your model, it will display the house & van battery voltage, amperage coming in/out of the house battery,  % battery left, amperage used since last charge, etc, etc. You will learn a lot from the monitor on: 1- the impact of shade on solar (and help you choose the right parking spot) 2- the impact of your load(s). This will help you better manage your energy. One of the most popular option out-there is the Bogart Engineering Trimetric TM-2030. This is the one we’re using in our system, because it will “pair” with our charge controller and this will increased the smart features. It might be fugly, but the electrical geeks out there know that this is a very well engineered product.

Our Pick:
Bogart Engineering Trimetric TM-2030-RV

Bogart Engineering Trimetric TM-2030-RV Monitor. Buy from eBay.


6- Battery Bank Sizing

Back on the battery topic. We now understand that if the charge sources were properly chosen and sized, the battery should (normally) get a full charge everyday (by solar and/or driving and/or shore power). So what dictate the size of the battery then? I would say overnight discharge + cloudy days + rough buffer + the price you are willing to pay…

We finally went for a 210Ah AGM battery. In summer, at sunrise, the battery will be 75%-90% capacity depending on what happened the night before (driving late generally means a full charge when we go to bed). At noon, the battery is generally fully charged from solar depending on the weather. For winter, time will tell…

The concept here is that there is a lot of variables to take account. We went on the safe side by choosing a medium-large battery bank (some people go up to 300-400Ah).


Our Pick:
Rolls S12-230 AGM Battery

Rolls S12-230 AGM Battery SPEC SHEET

 We also considered:

Lifeline 12v 210ah AGM GPL-4DL on Amazon


7- Logical Diagram

Before going any further, we drawn a logical diagram of our electrical system. We still refer to it very often.

(Different requirements would generate different system designs… this one works for our needs!)

Electrical Diagram, Logical, Ford Transit Camper Van V2

While parked, the 12V loads can be powered from either (shown in order of preference)

  1. shore power (if available)
  2. the house battery (should be the case most of the time)
  3. the van AGM batteries (if the house battery is running low)

While driving, the 12V loads can be powered from either

  1. the van (full house battery, enough solar power)
  2. the van, via the house battery for extra charging power (low house battery, weak solar power). We’re thinking this will be especially useful during winter when the solar power is limited.


8- Detailed Diagram

We did not want to waste time on that at first, but we are so glad we did it. When doing the actual physical installation of our system in the van, we realized how important it was to prevent messing up. Things will not clarify during the installation… the physical installation is quite overwhelming and referring to the diagram gave us a lot of confidence. When we first turned the switches on, we were not afraid to blow everything up 🙂 To this day, we printed a copy and leave it in the van at all time.

(click on products for more info!)

The image above is best seen on desktop… Click here for full-size high-resolution image (best for mobile!)


9- Electrical Wire

9.1- Wire Diameter (AWG)

Selecting the correct electrical wire diameter is crucial for the system performance and safety. The maximum current and the voltage drop need to be taken into account to select to appropriate diameter.

9.1.1- Maximum Current (capacity)

For a certain wire diameter, there is a maximum current carrying capacity of a wire. Going over that capacity would create a safety issue (i.e. bigger current requires bigger wire diameter).

9.1.2- Voltage Drop

There is a loss of energy (voltage drop) as current moves through passive elements (wires, terminals, etc) of an electrical system. The wires are a big contributor to the voltage drop and this should be taken into account when designing the electrical system. How? By selecting the appropriate diameter; the bigger the diameter, the smaller the voltage drop. Generally, wire diameter should be selected to provide a maximum of 3% voltage drop for critical loads (panel main feeder, inverter, electronic) and 10% maximum voltage drop for non-critical loads (lightning, fan, etc).

9.1.3- Selecting the correct wire diameter

Now, really, how do you selected the correct wire diameter? Let’s keep it simple and use the BlueSea Calculator (circuitwizard.bluesea.com)

The inputs are:

  1. Nominal Circuit Voltage (hint: it’s 12V)
  2. Load Current (it normally written in the owner manual of the load)
  3. Length of Wire (hint: you need to add the positive AND negative wires! For example, a load located 10 feet away from the battery would require 20 feet length of wire)
  4. Allowable Voltage Drop % (critical VS non-critical loads, see section 9.1.2 just above)

The outputs are:

  1. Recommended wire diameter
  2. Maximum current capacity of the wire (for reference)


9.2- Wire Crimping (connecting wire)

There are many ways to connect wires together. We will go straight to the point here, the best way to do it is crimping. Crimping will deform the connector into the wire and ensure a solid permanent mechanical connection with low resistance. To crimp, you need good tool and good connectors (heat shrink recommended):

Ancor Crimp Tool

Ancor Crimp Tool. Buy from Amazon


Hydraulic Crimp Tool

Hydraulic Crimp Tool for large wires (­>AWG 8). Buy from Amazon, or have them crimped by a professional at your local shop.


Heat Gun

Heat Gun for heat shrink. Buy from Amazon


Ancor Terminal Rings

Ancor Heat Shrink Terminal Rings. Buy from Amazon


Electrical System Installation Van Conversion (4)

You shall crimp with grace


Do not use pliers for crimping! Do not use cheap connectors! You will get poor connections that will not last in time and could create safety issues.


9.3- Wire Installation

For safety sake, the wires should not be installed loose and unprotected; as opposed to a house, there is a lot of vibration and movements that will damage the wires in the long run.

The wires should be routed through Split Loom Tubing (make sure to buy several diameters) attached with zip ties:

Split Loom Tubing

Split Loom Tubing. Buy from Amazon.

Zip Ties

Zip Ties. Buy from Amazon


The Split Cable Loom should be secured with Nylon Cable Clamps on wood:

Nylon Cable Clamps Kit

Nylon Cable Clamp. Buy from Amazon


The Split Cable Loom can be secured with Zip Ties Mount Adhesive on metal. Make sure the surface is cleaned (isopropyl alcohol works great) and warm enough.

Zip Tie Adhesive Mount

Zip Tie Mount Adhesive. Buy from Amazon


10- Fuses and Breakers

Fuses and breakers are essential in any electrical system! It will protect the circuit wires and the components against over current and ultimately fire. If you blow a fuse during your system installation (we did a few times), it means that you just avoided a potential failure or fire! Nice!

Each load should be fused according to it’s current maximum normal draw. Consult the owner manual of the load. This is achieve through a fuse box such as:

Blue Sea Fuse Box

Blue Sea fuse box. Buy from Amazon


The fuse will drive the wire diameter selection. For example, if wiring a load that draw 5A and a fuse of 15A is used, you should choose a wire capable of (more than) 15A! This is safety matters.


Breakers are similar to fuses, except that if it blows it is possible to reset it without replacing it. Fuses generally blow faster than breakers and therefore fuses are preferred for sensible electronics. We added a few 40 amp breakers in our system. Why? First, to avoid having to use big electrical wires. Indeed, our fuse block is capable of 100A; even if we know that we will never draw 100A, we need to size our wires for 100A ($$$). By adding 40A breakers, we can size our wires for 40A. We can also turn off portion of the system by switching a breaker off (for example, turn off solar panels to display on our system monitor the draw that the loads are pulling. Or the opposite to display the charge that the solar panels are providing).


Here is a more complete article about this topic: http://www.12voltplanet.co.uk/fuses-guide-uses.html


11- Conclusion

The design of the electrical system is not an easy task. Make sure to clearly define your own requirements and design your system accordingly!

There is a lot more to what we covered here, be we hope this will get you started!

Did we missed anything??



We did it! Yay!



(Very) Related Article:

Electrical System Installation





Join 2,500+ followers via Facebook, Instagram or e-mail:




Hello! We’re Isabelle and Antoine, a couple dreaming of being on the move and we’re seeking for the ride of our life. We bought a Ford Transit van, we’re converting it to a campervan and we are now selling our house to make our dream a reality. We are sharing this in hope of inspiring and helping others to follow their dreams too!



  1. Comment by david

    david Reply June 14, 2016 at 4:32 pm

    Thanks for the great info, question, is the “house” battery the second battery that came with your van as an option? Was just wondering why it is needed if you have 2 AGM batteries?


    • Comment by admin

      admin Reply June 14, 2016 at 6:04 pm

      Hey David,

      The “house” battery is an additional battery that is used to power all the loads that are not related to the van (refrigerator, ventilation, lights, etc). This battery is most of the time, depending on your design, independent to avoid draining the van battery; having a refrigerator is nice, but not able to start the van engine is not nice…

      The “van” battery is the battery that came with the van and is used to power all the van loads just like a car (engine start, van radio, etc). When ordering our Transit, we chose the “Dual AGM battery” option: these 2 AGM batteries are, in fact, the “van” battery (you can see it as one battery with MORE CAPACITY). The “Dual AGM battery” then allowed us to choose the following options:
      1- “Heavy-duty” 230 amp alternator: more charging power from the van alternator.
      2- “Auxiliary switch”: 4 switch on the dash with terminal port to connect up to 4 loads (20 amp max each load) of your choice under the driver seat. These loads are powered when the engine is running only.
      3- “Customer Connection Point, or CPP”: 3 x 60 amp terminals accessible beside the driver seat. These terminals are powered at ALL TIME.

      At the time of ordering the van, we were not sure exactly what to do with all these options but we were convinced it might be useful in the future. This is our little home, after all; we bought the peace of mind. We think the extra electrical power justified the extra cost (which was not that much).

      Thanks for stopping by!

  2. Comment by Patrick

    Patrick Reply August 17, 2016 at 3:12 pm

    Hi David:
    Your electrical system and components is similar to my 2015 Van. I am in the process of wiring and have alot of the components purchased, but not all (i.e. solar panels). How do you ground your system components?
    I’ve read that some have concerns about grounding to the vehicle body since the van is so electronically sensitive (like a running computer). The Ford manuals advise disconnecting the batteries when doing any drilling or cutting of sheet metal for example. Do you ground to the body, the chassis or something other than that?
    I have Sirius satellite antenna on the sheet metal roof (flush mount). Would grounding to the body somehow screw this up or other systems in your opinion? The Ford manual shows all grounding locations but what if I can’t access these locations due to cabinets or other modifications> Did you create your own grounding points and did you grind the paint off to assure a good conduction?

    • Comment by admin

      admin Reply August 18, 2016 at 8:03 am

      I am by no mean an expert on electrical matter, by my understanding is that the frame of the van is basically a giant negative bus bar. There is no “earth ground” in a car, since the tires will isolate the car from the earth. In our setup, we wired the negative pole of the van battery & the house battery together and that should a act as “grounding”. Individual components are not “grounded” (except the inverter and the battery charger), our readings on that matter suggested us it is not necessary on this type of 12V setup. We did not disconnect the battery when drilling the frame of the van and have not heard of anyone doing that.
      We will install our system by next week or so, we’ll let you know if everything blows!! Good luck with your build 🙂

  3. Comment by Patrick

    Patrick Reply August 18, 2016 at 1:00 pm

    Interesting analysis. Thanks for your response.
    So most of my components (water heater, water pump, space heater, fans, etc.) have a black ground wire and these are all designed for RV’s. From what you describe in your system you did’nt connect these to any vehicle ground but just left them unattached?

    In regards to disconnecting battery. It is written in the Ford manual for outfitting or converting your Transit, so I followed their recommendation. Sounds like you didn’t have any issues which is good to hear!


  4. Comment by Daryl

    Daryl Reply September 11, 2016 at 3:37 pm

    Thank you. This has been very helpful and explained in terms that I can understand. I have been researching ways to put a similar system in my van this coming year. Now this makes more sense and I can adjust my system to my needs, with your help with this article.

    Thank you again,

    • Comment by admin

      admin Reply September 15, 2016 at 8:01 pm

      Nice, so glad we could help! We’re about to end a week vacation in our van; the electrical is working great 🙂 As planned, except the refrigerator is drawing a bit more than expected. We will report on that subject soon…

  5. Comment by Mike

    Mike Reply November 21, 2016 at 3:04 pm

    Your blog and site are the best! Thanks so much for posting everything in detail. I have a T250 with HD alternator/ Dual batts I use for mobile office (photo/video) and skiing/mtb bike basecamp. I’ve been planning my solar for a long time and came across your electrical page last week. We have almost the same set up -same 160 watt panels and roughly the same electric demands with Webasto and other items..

    Are you happy with the system you designed so far? Any modifications since you first installed it?

    Do you use the Shore power charger system much?
    Thanks much!

    • Comment by Antoine

      Antoine Reply November 21, 2016 at 4:23 pm

      Our system works great so far! 320W is plenty of power for our needs; during summer, it will top up the battery by noon (we don’t know for winter yet)
      We are about to add a Samlex remote (Amazon link) to be able to turn the inverter on/off while driving (to charge the house battery from the van). We often forget to turn it on before leaving… I guess a Battery-to-battery charger (Amazon link) would solve that issue since it turns on automatically, but we like the fact that we can plug the Samlex battery charger (Amazon link) either to the inverter (charging from the van) OR the shore power. We don’t use shore power very often, but it’s nice to have the possibility to use it. It’s up to each individual to define her/his needs!


  6. Comment by Mike

    Mike Reply November 22, 2016 at 11:09 am

    Thanks for the response! Just a couple questions, because I am not an electrical person. What are the amp ratings for your shunt off the house battery, and the fuse between the 3-way switch on your Vehicle batteries? I do not have that but maybe I should? I have 3 x100ah Agm’s in parallel for my house bank and my inverter is a 2000watt.

    I’m wondering because I like your Samlex charger /converter idea..
    Thanks again!

    • Comment by Antoine

      Antoine Reply November 22, 2016 at 11:47 am

      The shunt is 500A (Amazon link) with a 0.1mV per amp precision (a 100A shunt will read 1mV per amp). In other words, the 500A is more precise.

      About the fuse, you MUST install one if you install an inverter. For safety reasons. The Samlex manual recommends to install a Class-T fuse located within 7″ of the battery positive (+) terminal. For a 1000W inverter (12V), the manual recommends a minimum 160amp class-T fuse. For a 1500W (12V) or 2000W (12V) inverter, the manual recommends a minimum 200amp (Amazon link) or 300amp (Amazon link) class-T fuse respectively.
      Your electrical cables should have a higher amp rating than the fuse you selected. Just follow the manual and you’re fine 🙂

      This is like a big puzzle; have fun!!

  7. Comment by Mike

    Mike Reply November 23, 2016 at 10:09 am

    Thanks so much for the information. It really is like a big puzzle!
    Best regards,

  8. Comment by Dave Orton

    Dave Orton Reply December 4, 2016 at 6:14 pm

    Have you had any problem using the 1000 watt vehicle powered inverter with the Transit? Do you have the dual batteries? Are you careful not to use the Transit electric air heater at the same time? The air heater is on if temperature dial is fully clockwise and engine water is cold.
    My plan is to use the remote 12 volt terminal to get power from one of the User Defined Switches. That way inverter automatically turns on with ignition in the on position or engine running. Do not use the ignition on position so that should not be an issue.
    My 1000 watt vehicle powered inverter is installed but not yet wired.

    • Comment by Antoine

      Antoine Reply December 4, 2016 at 6:32 pm

      No issue with the 1000W inverter whatsoever. We have the dual batteries: the inverter positive is connected directly to the positive pole of the van batteries; the negative is connected to the ground point located in between the driver & passenger seat.
      About the “electric air heater”: are you sure the Transit is equipped with the said feature? I could not find anything about that in the manual nor the BEMM. Winter has come here in Quebec, i wish it had the feature but i really doubt as my windows wont defrost until the engine is warm… (i have turned the heat all the way up)
      We had a few occasions where we started the engine while the inverter was running at the same time, no explosion so far!

      Thanks for stopping by Dave, you are a big inspiration for our electrical system!

  9. Comment by The Interstate Blog

    The Interstate Blog Reply December 7, 2016 at 8:12 am

    Your thinglink depiction is awesome! Thanks so much for this!

    • Comment by Antoine

      Antoine Reply December 7, 2016 at 8:20 am


  10. Comment by Terri

    Terri Reply December 8, 2016 at 12:03 pm

    I have a question about the 90 degree cable glands you used to bring the solar panel wires through the roof. Did you use existing holes in the roof? Does the locknut secure it in place pretty well? Another question: The description of the gland says it accepts a range of cable diameters. Are they adjustable? I think our panel comes with 10awg mc4 leads. We’ll probably mount it on our Transit next week.

    • Comment by Antoine

      Antoine Reply December 8, 2016 at 12:14 pm

      Hey Terri,
      I don’t think there is holes on the Transit roof, so we had to drill them our-self. Here is the install post: http://faroutride.com/solar-panels-installation/.
      The locknut secure the gland in place pretty well, yes. But we still recommend to seal them with Dicor self-leveling sealant, if not water will ingress for sure.
      Once you pull the cable in, you have to screw the nut and this will tight the gland on your cable; so yes, it is “adjustable”. Make sure to follow the spec and choose the appropriate one though (spec example: Cable diameter approx – 0.19″ to 0.39″).
      Good luck with the installation! 🙂

  11. Comment by Gerald Marsh

    Gerald Marsh Reply January 23, 2017 at 1:44 am

    Yours is the best electrical description I have seen in this forum. Great detail with the drawings. Batteries provided by Ford even with the dual setup are still quite small by RV standards. Looking at large motor homes you will find at least 2 8D size batteries for the house and 1 8D for the vehicle in addition to a large generator. Your choice of the Ford 230A alternator is a good requirement for anyone wanting to modify a Transit for RV use, of course this option does include the dual van batteries and the switch panel. Choosing the large house battery is a must when connecting large inverters and wanting to have AC powered equipment. You should always use sine wave inverters to prevent damage to some electronic equipment and power supplies. Watch out for heat build up in your electrical cabinets when operating chargers and inverters. I have my T150 wired with a a house battery, inverters, and the ability to jumper to the van battery for charging or starting. The Ford battery provided with the single battery installation has a small capacity and easily discharges to the point the vehicle will not start if an accessory is left on with out the engine running. Anytime the vehicle voltage goes below 11 volts, you may not have sufficent power in the battery to start- I know from experience. (single battery installation). Thanks again for such an informative discription of your conversion.

    • Comment by Antoine

      Antoine Reply January 23, 2017 at 7:55 am

      We are monitoring the van battery voltage, but still, we should probably add a low-voltage cutout switch to prevent draining the battery… we plan on using the van battery only for “backup”, when the house battery is running low.
      We left a channel for heat evacuation in our cabinet, but we could add a computer fan as required. Time will tell.

      Thanks for the tips and for the compliment!
      Have a great day!!

  12. Comment by Serge

    Serge Reply February 10, 2017 at 8:20 pm

    Hello Antoine,
    I would like to know about your ceiling lights are enough bright for your installation?

    • Comment by Antoine

      Antoine Reply February 10, 2017 at 8:29 pm

      They are perfect, we would not change anything about that! I highly recommend a dimmer as well for ambiance but also to save power.

  13. Comment by Richmond

    Richmond Reply March 29, 2017 at 12:51 pm

    Awesome job guys! This is a ton of great information. I worked as a solar and battery engineer and am impressed!

    There are a couple of things that I wanted to comment on:

    – For silicon solar panels, bypass diodes are at the panel level, so if one cell is shaded, the whole panel is still not outputting anything. The purpose of the bypass diode at the panel level is for connecting panels in series (to get a higher voltage for commercially installed systems). Since you connected two panels in parallel, if one cell is shaded on one panel, the other would still output normally even without a bypass diode.

    – All batteries are also affected by warm weather. These batteries are designed to operate at 25C. Increasing every 10C will cut the battery life in half. This means, if you use your battery on a hot day and use a full cycle, it really counts as two cycles. Even if you don’t use your battery at all, the warmer temperature will degrade the pack!

    – You should do some accounting for the aging of your battery as well, or at least make plans to supplement or replace your battery if needed when it ages. I think assuming 5-10% degradation per year for a lead acid pack is reasonable. Of course this depends on the weather you’re in, how much you use the batteries, etc.

    Seriously awesome job on the details.

    • Comment by Antoine

      Antoine Reply March 29, 2017 at 1:11 pm

      Hey Richmond,
      thanks for your input! We will add your comments to the page soon 🙂
      I’m surprised about the partial shading; I was under the impression that only a third (or something) of the output was lost. Too bad 🙁

      Don’t hesitate if you have more comments (good or bad!).

      have a great day!

  14. Comment by Gary

    Gary Reply April 8, 2017 at 8:17 pm

    What dimmer switches did you use?? Also do you find 10 lights is too many, I was looking at picking up 6 or 8, but I can’t find the lumen output described anywhere.

  15. Comment by wes greenwood

    wes greenwood Reply April 16, 2017 at 8:21 pm

    Hey Antoine!
    I am going to be installing a solar system in my Ford Transit this summer and plan to copy you setup to a T. Only difference is slightly larger solar panels since the cost is right.
    Anything that you would modify in hindsight? Is everything running as planned?

    • Comment by Antoine

      Antoine Reply April 17, 2017 at 1:08 pm

      It’s working great! Maybe install an MPPT charge controller in lieu of the Bogart (not that we don’t like the Bogart); I would install a Sterling B2B charger for install-and-forget charging from alternator and plug the inverter to the house battery. I think that’s it!
      I’m following your build with interest! Good luck!

  16. Comment by Wes Greenwood

    Wes Greenwood Reply April 20, 2017 at 4:37 pm

    I’m going to go with your two suggestions on the mppt charge controller and the battery- to – battery charger. I like the idea of not having to turn the inverter on to charge the battery, only when needed for 120v loads. It seems like a neat little device!

    I’m going to owe you quite a few beers if we ever meet up on our travels!

    • Comment by Antoine

      Antoine Reply April 20, 2017 at 4:43 pm

      We’re beer geeks, we’ll do anything for good craft beer! 😉

  17. Comment by Wes Greenwood

    Wes Greenwood Reply April 22, 2017 at 1:13 pm


    Another question… I swear if I had a penny every time I change my mind on things, I could pay someone to do this conversion for me lol.

    Just thinking out loud here… if I leave a conduit open from my vehicle battery to my house battery to fish wires through later, theoretically I could add the sterling battery to battery charger at a later time if I felt it was needed, right?

    Just thinking that if I set my system up the same as yours, but with an mppt controller and more solar power, 520w worth, the sterling charger might not be necessary but could be added later if needed.


    • Comment by Antoine

      Antoine Reply April 22, 2017 at 1:31 pm

      Haha I can soooo relate to this. Dude this is probably the most exhausting part of the conversion. Constantly questioning your decisions and arguing with the other half! Get used to it 😛

      You can definitely add the charger later. You will have a bus bar for your battery positive and negative right? Just keep a terminal available for later (on the + and -).

      We barely use the alternator charge in summer, but the alternator is very important during the winter months (short daylights and snow on the panels).


Leave a reply

Your email address will not be published. Required fields are marked *

Go top