2017-07-09: Fitting roof light and fan

We fitted the fan and the roof light this weekend. Each job took a whole afternoon.

I started with with the Maxxfan. I didn’t take many photos because the whole job was a bit stressy and I wasn’t sure it was going to work. I needed to concentrate.

The Maxxfan is great – we were pleased with it straight out of the box. The plastic is not flimsy, installation is well thought out and it looks good. It is designed so that you can fix a retaining ‘flange’ to the roof and then the machine itself screws onto the flange later. This means you can easily remove the machine for repair without having to phaff about with the bit that holds it onto the roof. Likewise, the decorative bit inside that hides wires etc gets screwed in place independently.

This is a bonus for us because we don’t yet know what we are going to clad the van with, and how thick the roof will be. So we can still drive about with the fan fixed in and worry about trim later.

Caravan bits are designed for flat roofs. The sprinter doesn’t have a flat roof in any direction – it has bobbly bits which can’t be avoided.

I started by trying to draw the 40cm square  for both the roof light and the fan on the ceiling of the van where we wanted the holes to be.

This was very difficult, (rulers too long/ short/ bendy, neck and arms hurting, right angles never matched up).

marking the roof light square inside the van

I got fed up in the end and using a punch, made some discrete mini dents (one at each corner) then got up on the roof and using the dents as a guide measured the 40cm square again (much easier on the roof).

Here’s the square for the fan:

The square marked out for the fan (close to the back of the van)


And here is square for the roof light

The 40cm square for the roof light, near the front of the van

Then I cut out some squares of some plastic stuff we had hanging about at home that we found on a skip. (Andrew know what it’s actually called – Andrew: it’s called expanded PVC). it’s bendy, about 6mm thick and can be carved easily with a Stanley knife. The squares matched the flange for the roof light  (variable widths) and the fan  (same width all the way around) and also had a 40cm square hole cut in the middle.

The plastic insert for the roof light

Next I carved bits out of the plastic insert to correspond to the bumps on the roof. Each cut is at about a 45 degree angle or more to accommodate the roof shape at best as possible.

Then I sanded the plastic and cleaned it with degreaser.

The following photos and account are mainly the roof light, but I’ve slipped in a couple of photos from the fan where I didn’t have the equivalent roof light photo.

We were pretty disappointed with the roof light when it arrived. It was advertised as white but is in fact more magnolia coloured. It feels flimsy, and the installation needs you to have determined the thickness of your roof.

The roof light. (No forced ventilation so it doesn’t whistle when we drive)

I sellotaped a bin liner inside the van to catch the worst of the metal filings, and a bit of cardboard on the roof to try and stop them getting under the solar panels.

The bin liner sellotaped inside the van to catch metal filings (fan)

Then the noisy bit!

Up on the roof again, I drilled a hole in each corner  (10mm bit) for the jigsaw bit to start in. Then I cut the four lines.

To minimise vibration I put duck tape across each cut I had made when I finished that side of the square. It also stopped the cut out falling into the van.

I didn’t bother with masking tape on the plate of the jigsaw because everything is going to be covered with sealant. We have a cheap  £40 jigsaw from Machine Mart and it did the job fine. Going over the bumps was noisy, wobbly and a bit tricky, but I found if I kept the front of the base plate pressed down where possible while keeping it level, it didn’t matter too much that the back end was in the air and the blade coped ok.

Hole cut for the roof light

The bit of cardboard didn’t work – the filings got everywhere. So after filing down the edges I hoovered the whole roof and everywhere else and removed the bin liner carefully.

I sanded the edges and a little way around the opening, cleaned with degreaser,  painted Hammerite primer on the bare metal edges and had a cup of tea.

Then I stuck butyl tape (see in the picture above) around the opening to seal the plastic insert to the roof.

Butyl tape stuck around the hole for the roof light

The tape was 20mm wide so in some places I used two strips. You can cut it with a Stanley knife. It’s like chewing gum.

Then I put the plastic insert on the top of the tape:

My plastic insert on top of the butyl tape.

I used Sikaflex Caravan Sealant 512 (also pictured in earlier photo) to seal all the way round and fill any gaps between the insert and the bumps on the roof.

This sealant sets (stops being sticky) but stays rubbery. I think the butyl tape doesn’t set (the bag it came in was not airtight at all). Ordinary bathroom silicone sealant which I intended to use originally dissolves the butyl tape and turns it into a slimy mess (lucky I tested it first).

Now the insert was in place I wanted to get everything tightened up together before the sealant set.

In the case of the fan, I put a continuous square of butyl tape on top of the plastic insert and the provided roof insert is then screwed (using about 20 screws) through the metal of the van roof. We also cut four bars of wood and clamped them inside the van so that the screws went into wood after they had gone through the roof (the sandwich of materials went like this from top to bottom: maxxfan plastic roof insert, butyl tape, my homemade plastic insert, butyl tape, roof metal, wood) Then I sealed all around the edges and over the screw heads in a big smeary mess.

The fan in place and fixed to the plastic flange insert that has been screwed to the roof  – you can just see the screws.

The bits of wood that we used inside the van were a last minute decision when we realised how the screws just poked randomly through the roof.  They aren’t totally necessary. In retrospect it would be better to make something neater and smaller in advance (like we did for the roof light).

In this picture the fan has already been lowered into the plastic fixing flange in the roof hole.

The roof light was slightly different. Since repairing or replacing the roof light involves removing the entire thing- the seal needs to be less permanent.

I applied a thick bead of Sika Lastomer 710 as per instructions to the underside of the roof light. and eased it into the hole. This stuff stays flexible and sticky, like the butyl tape.

This picture shows the underside:

Underside of roof light

It is supposed to have a clearance of 2-3mm all the way round. (my hole was a titchy bit tight but its almost impossible to re-jigsaw a cut and filing more than 1mm off a cut edge isn’t feasible either, so i’ll just have to hope its OK).

I used about half the tube of Sikaflex and it bulged out nicely from under the plastic so I know I got a good seal, but it was a bit messy clearing the excess away.

Roof light sealed into place

Off the roof and into the van now.

Here is the bit that fits inside the van:

Roof light plastic insert fits inside the van.

Andrew had earlier made a 40cm square out of 12mm plywood, 50mm deep and held together with small metal brackets at the corners: you can see it in the video at the end but I forgot to photograph it.

This filled the gap inside the van between the bit of the roof light that sticks through the hole you’ve cut and the bit of plastic inside the van (way more complicated and fiddly than the maxxfan). You are supposed to measure the gap between the inside of the roof and the cladding of your van to calculate how much to chop off the plastic bit inside the van.

We haven’t insulated or cladded the van yet so we had no idea about this. The maximum depth the plastic can extend to without leaving a gap is 60mm anyway and since our celotex insulation is 50mm, Andrew thought the wooden frame should be 50mm deep. Turns out that this was a perfect guess.

The plastic bit that fits inside the van and is supposed to slot inside the plastic square poking down through the hole. The screws marry up and their plastic surrounds butt up against each other. This is what braces the inside part and outside part and holds the roof light in place.

Yep- we thought it was all rather flimsy too. So the wooden frame is to prevent too much compression.

Roof light stuck onto roof and inner plastic flange screwed into place from inside the van to pull it down onto the roof and tighten the seal. Wooden frame sandwiched between the two parts.

Later you clip the rather hideous peachy plastic trim to the plastic bit I’ve just screwed into place. Won’t be doing that till we’ve cladded the van inside.

Decorative trim that goes inside. Nasty mottled beige blackout blind and a useful fly screen.

Next I went back onto the roof and attempted to clear up the bulgy bits of sealant. Not very successfully – it looked rather a mess.

This bit wasn’t too bad. You can just see the plastic insert I made.
This was the worst bit – where I tried to clear excess Sika Lastomer, I disturbed the not quite set Sikaflex sealant I had applied around my plastic insert

Here are the tools I needed for the job.

Ladder, Towel, Jigsaw with metal blade, Drill and 10mm drill bit for metal,  extension cable, hoover, ear muffs, googles, Hammerite paint and small brush, metal file, Sharpie, ruler, set square, tape measure, pencil, punch and hammer, duck tape, masking tape, large bin liner, paper towel, degreaser (strong detergent), sandpaper, butyl tape (20mm X  9 metres was plenty) SikaLastomer 710, Sika Caraven sealant 512, caulking gun, screw drivers, a few bits of wood and angle brackets and a couple of large clamps, a sheet of 6mm plastic, Stanley knife.

Tools for cutting the hole in the roof

Here is the Plastic insert I made, Sikaflex caravan sealant 512, Sika Lastomer 710,

The plastic insert I made, Sikaflex, SikaLastomer and butyl tape.

Here’s the video:





2017-07-02: Starting the electrical install

This weekend, we started running cables and mounting components so we can get the electrical systems hooked up. We already have the solar panels on the roof, and the battery fitted under the passenger seat. We also have a fair amount of conduit routed through the side panels of the van so we can run cable from front to back (e.g. from the fusebox to the ceiling lights or rearmost USB sockets).

Green lights are always a good sign. We are now successfully charging our battery from our solar panels. Very exciting.

Nothing at this stage is fixed, but we need to commit to some decisions so we can continue the build. So it’s a delicate balancing act of deciding where things should go, while leaving options for us to change our minds. In practical terms, that means:

  • Making prototype mounting boards and boxes for components roughly out of MDF to test out placement and design before rebuilding them properly in nicer plywood.
  • Making some educated guesses about where we want wires to emerge, and cutting cables to length.
  • Wherever possible running wires – cut to a generous length – through conduit so we have some flexibility in exactly how we place the end components (lights, sockets, appliances, etc.).

Our electrical system starts in the area immediately behind the cab. It’s something of a no-mans land that in many conversions would just be wasted space. We’re hoping this will be a space-efficient placement. The main elements are:

  • Leisure battery in the passenger bench seat base (with space for a second battery in the other half of this seat base if we need to expand)
  • Solar controller on a board mounted to back of passenger seat base (with space for some other components we might add later, such as a battery-to-battery changer, inverter, or mains power charger)
  • 12V fusebox and distribution mounted to back of driver’s seat base.

By separating the ‘power in’  (solar, alternator, shore/hookup power) and ‘power out’ (12V circuits) into 2 areas, we have more space to mount components without intruding into the main living space of the van.

Meanwhile, the insulation installation continues, as we desperately try to clear our house of bulky building materials.

We’re getting through cans of expanding foam at an alarming rate.

China Is About to Bury Elon Musk in Batteries

Interesting report from Bloomberg:  as demand for Li-Ion batteries increases, we should expect to see affordable Li-Ion become much more widespread and available for other uses – such as portable power in camper vans, etc. While this is on the 5–10 year horizon, it’s interesting to keep tabs on.

We’ve already seen a similar effect with GPS chips, cameras, and other components in the so-called ‘smartphone bounty’.

Lithium-ion batteries have long been used in smartphones, laptops, and other personal electronics, but demand is forecast to explode in the next five years as electric vehicles proliferate and power companies install giant storage systems to smooth the ebb and flow of wind and solar.

Telsa produced nearly 84,000 vehicles in 2016 and has said it plans to make 500,000 in 2018.

While Tesla may be building the biggest and splashiest factory, the Chinese government has launched a sweeping effort to increase the country’s dominant market share.

Roughly 55 percent of global lithium-ion battery production is already based in China, compared with 10 percent in the U.S. By 2021, China’s share is forecast to grow to 65 percent, according to Bloomberg New Energy Finance.

“This is about industrial policy. The Chinese government sees lithium-ion batteries as a hugely important industry in the 2020s and beyond,” Bloomberg New Energy Finance analyst Colin McKerracher said.

In all, global battery-making capacity is forecast to more than double by 2021 to 273 gigawatt-hours, up from about 103 gigawatt-hours today. That’s a huge opportunity, and China doesn’t want to miss it.

Source: China Is About to Bury Elon Musk in Batteries – Bloomberg