Van Tour: Solar

As with all vans you see on Instagram you have no idea what’s really under all the wood and panelling and our van is exactly the same. Based on the questions we get from you guys we thought we would pull back the curtain a little and talk you through what went on during our self build conversion from panel van to camper van.

photo credit: The Indie Projects

What are the types of solar panel?

I have to admit I was totally confused when I was reading about solar panels, I had no idea there were so many options and some many different schools of thought on which were the best type of solar panel to use on your campervan. I’ve tried to simplify what I’ve read about the panels here just to make it easy.

Thin Film

Thin film panels are made by spraying a thin layer of a semi conductor onto a surface, it’s a similar process to how mirrors are made except they are a layer of reflective material. Because of this method the thin film panels are the cheapest sort of panel however they are also the least efficient and as such you will need more panels to generate the same amount of energy as the other panel types which negates some of the cheapness.

Mono Crystalline

Mono crystalline panels are made up of a number of modules which are what collects the solar energy. Each module is made up of a single silicon crystal and as such they are the most efficient as the entirety of the module is able to generate energy. This efficiency comes at a cost and as such the mono crystalline panels are the most expensive type we’re considering however will require less of them to produce the same amount of energy as the thin film panel due to the efficiency.

Poly Crystalline

Similar to the mono crystalline panel these are made of a number of modules however the modules on the poly crystalline panel is made up of small silicon crystals put together. It is the inevitable small gaps between crystals that means the poly crystalline panels are less efficient than the mono crystalline however with the size of battery we and most other converters are using this efficiency gain is minimal and comes at a much increased cost.

As well as these three types of solar panel we also wanted to consider where and how we were going to be attaching these to the van. The majority of solar panels come as rigid rectangles which need to be bolted to your van however the alternative is a flexible panel which can simply be glued down onto your roof.

What panel did we choose?

We decided for our set up we would use a 50W Flexible Thin Film Panel.

Solar Panel

Although a 50W panel may seem small compared to a lot of videos and articles we have seen about campervan solar panel set ups based on the way we have organised our electrics, the fact we have only a 110Ah battery and the fact we didn’t have to rely on solar as our sole means of generating power due to us having a split charge relay we decided that it would be sufficient for our needs. This has proven to be true, we are still able to regularly pull in 10-20Ah worth of power on a sunny day and that coupled with the split charge relay keeps our battery full the majority of the time.

We have since adding a further 100W panel to our set up specifically for the winter where there is less sun and it is at a worse angle for our panel.

The reason we decided on a flexible panel was that we wouldn’t have to screw the panel into our roof and any opportunity to avoid putting more holes in the van we look to take as they can become a weak point for leaking water which is the last thing we wanted. It being a flexible panel means that it is also extremely lightweight and significantly more aerodynamic than a traditional rigid panel.

There are however compromises we had to make with our choice of panel, while our panel is extremely efficient its efficiency level drops in the winter by nearly 30%. This is due to the fact that it is stuck to the van in one position with no ability for us to angle the panel to be able to collect more of the direct sunlight from the winter sun which is at a lower angle.

That being said it is important to note again that this set up would not be required to account for our complete power generation and as such it is a nice way of us keeping the battery topped up using solar without a huge outlay on some of the more expensive panels.

What is a Solar Charge Controller?

If you decide that you want to add a solar system to your campervan then you will need the solar panel but you will also need what is called a solar charge controller. The purpose of the charge controller is to manage the energy flowing through the solar system and is essential if you want to protect both the battery and the solar panel.

A solar panel will harvest solar energy any time that it is in direct sunlight however if your battery is full you don’t want to continue to attempt to put energy into it. The charge controller will prevent this by not allowing the energy harvested from the solar panel being passed to the battery to over charge it thus protecting the battery and increasing its lifespan.

Similarly there is a risk that when there is no direct sunlight power can flow back into the solar panel from the battery, the charge controller prevents the flow of energy in this direction also thus protecting the panel itself.

Not only does our charge controller act as protection for both battery and panel it is also the information centre where we can find out the state of charge of our battery, how much energy we are harvesting from our panel and how much energy we are using at any time.

How have we set up our system to work?

Because we are not using solar power as our sole source of power in the van we have our set up differently from how we may have it arranged if it was. The panel itself feeds directly into the charge controller as well as the battery being connected directly as well. This means that when we have enough sun the panel will top up the leisure battery.

Because we also have a split charge relay connecting our leisure battery with our starter battery the solar will also charge our starter battery. When the voltage in our system goes above 13.3V the split charge relay will connect the starter and leisure batteries and both will be charged.

Although the charge controller has an output where you can connect your fuse box and thus power your system through it we instead opted for a separate fuse box directly linked to the battery. Instead we have our outlet on the charge controller connected directly to two USB ports which only take their power directly from the solar panel not from the battery. This gives us the option of charging devices without drawing power from our leisure battery so if there is an abundance of sun or we already have a full battery we can still utilise the power through these ports. This also means we have a back up should we have any issues with our battery and as we have found out in the past having options and back ups are vital when living in a van.

For further Van Tour reading why not have a look at our van tour page where we will be adding more in depth information about the specifics of our van!