Campervan Conversion - Part 5 - The Solar Panels & Major Electrical Items

This is number five in the series of posts about our campervan conversion, following on from Part 4.   

The solar panels arrived last weekend so it was time to fit them on the van roof.

I've bought 3-off identical 100W panels from Renogy.  Using monocrystalline cells, these are quite compact panels measuring just 1,074 x 498 mm.  This particular panel design is narrow enough to fit between our rooflights, and it also has a low open-circuit voltage which can be important when choosing controllers.  I'd considered 2-off at 150W or even a single 300W panel, but these layouts didn't fit properly on the roof space available and they also tend to operate at a higher voltage. 

the panels ...

panel nameplate data ...

So we've nominally 300 W of solar power available under bright sunlight conditions, although during standard rating test conditions the light source is positioned perpendicular to the panel surface, whereas on the van roof the panels will always be horizontal and therefore the actual available power is likely reduced by around a quarter, so let's say it's a maximum 225 W installation.

Separately, I'd bought three sets of aluminium Z-brackets for mounting the panels, a pair of 3-to-1 MC4 connector adaptors to hook them up in parallel on the roof, and a 10 m length of MC4 cable to bring the power inside the van.  

installation materials ...

I pre-assembled the brackets to the panels whilst on the ground, and also stuck a length of mastic tape under the foot of each Z-bracket, leaving the protective film on at this stage.  The stainless steel fixings provided with the brackets only included standard hexagon nuts, but I fitted my own A2 stainless nylocs for added security.

The previous day I'd been up on the van roof to clean it thoroughly, and also to remove the LED floodlight from above the rear doors.  This had been poorly fitted originally and water was seeping through the bolt holes and cable penetrations - this had caused local damage to the steel roof sheet on both sides, which needed repairing.   However, I saved the actual LED unit because it's an expensive floodlight and can probably be refitted after modifications to the mounting design.

Anyway, back to the solar panels, it was time to get up on the roof again and lay out the panels.  Luckily it turned out be a fine and calm day for this !

After setting out all three panels where I wanted them, I lifted each corner and removed the protective film from the mastic under the Z-bracket.  I then pressed the panel corner down so it was temporarily held by the mastic only.

The lateral centre panel was the last to be fixed.  Before setting this down, I lifted the RH edge and connected all three panel cables to the 3-to-1 adaptors, and also connected two lengths of cable to be passed through the roof inside the van.

I then fixed the panels to the roof using self-drilling screws through the bases of the Z brackets.   The screws made their own holes in the mastic and hopefully this is enough for a good seal at the penetration, although we also covered the screw heads themselves with sealant afterwards.

panels fixed on the roof ....

In the foreground of the photo above you can also see the ongoing roof repair above the rear doors where that LED floodlight was mounted.

To bring the power through the roof, I used a proprietary cable penetration box with a pair of glands.  I drilled two holes in the roof, treated the hole edges with Zinga, and then pushed the cables through using rubber grommets to stop them chafing on the hole edges.

Inside the van, I routed the cables over to the side where I wanted them.  Their first connection is to the double-pole isolator / changeover switch in the cabin control panel.  If you're wondering why a changeover is necessary at all then that will be revealed in a future post ...

I went back outside and stuck the edges of the cable penetration box onto the roof using mastic.    The bent cables were quite springy and so I needed to use duct tape and a couple of bricks to hold the box in position until the mastik had partially cured.   

cables through the roof ...

Internally, further cables were run from the isolator switch down to the floor level where the solar charge controller is mounted.  This area will be under the sofa / bed when it's eventually all framed out.

The solar controller is a Spark 25A MPPT dual battery charger.  Initially at least, there'll be no separate dual-charging of the leisure batteries via the vehicle alternator - all power for the camper side of the van will be provided by the solar panels.   

The chosen controller has a useful feature in that when the leisure batteries are fully charged then a current of up to 1A will be directed to the vehicle start battery to help keep it topped up if the vehicle is not being moved for a few days, e.g. if we're camped up somewhere for a while.

I bought the remote monitoring kit option so an LCD display can be fitted in the cabin control panel, and also a temperature sensor & cable which the charge controller can use to more accurately adjust the charging parameters depending on the battery temperature.

charge controller, inverter and the battery tray ...

Also in this underbed area, I've re-mounted the 1,000W pure sine-wave inverter that was originally fitted to the vehicle.  I tested this unit last week and it seems to be working fine, and I've bought a RJ11 extension cable so the inverter start switch & monitoring display can be relocated to the cabin control panel - it's not very convenient to start moving bedding around and lifting hinged doors etc every time we'll want to switch on the inverter.   Having said that, it's likely only to be used regularly for running our laptops, perhaps a microwave oven, and charging powertool batteries - all other electrical consumers including USB charging ports will be fed directly from the 12V system.

The delivery of two new 105Ah batteries has basically completed the installation, and the charging system is now operational and keeping both the leisure and vehicle start batteries fully charged.  

finished for now ...

So that's the major electrical equipment installed although I want to tidy the cables up a little, the inverter's not yet connected to the batteries and there's still the 12V electrical distribution system to start.

However, that's all for a future post ...