Ok, so you've bought all your solar system gear and you are finally ready to install it. Congratulations!

Before you start, you need to make some measurements so you know exactly where each component will be fitted. This step will save you some monster headaches later on, so don't skip it.

First, decide whether or not you will add another solar panel at some point later on. If you think that's a possibility, then make sure to place this first panel in a position that leaves enough space for that second panel to be added. You should also account for a bit of space around each panel, so you can walk on the roof and sit beside either panel in order to wire it up. Some people lay the panels off-center for this reason. That choice is entirely yours.

You will have to figure out what works best for your panel size and available roof space. Once you know where your panel will go, make space to fit your junction box. That's the box that water-proofs the hole you make in the roof to thread the charging cable into the inside of the van. It may also take other cables, depending on your design, so allow enough space for that, and for cables to flex without damage between the junction box and the hardware it serves. If you will be adding any skylights, roof vents, internet dishes, or anything else to your roof, consider the space those units will take up, as well, and don't forget about space they may require around them for cables, hinges, and so on.

Checking the position of the panel to see if it fits as well as planned.

Now think about the other side of the metal. Anything that may be on the inside of the roof in the positions you may want to drill, such as wiring, lights, support beams and so on, must be considered. You want to avoid them, obviously, so you may need to get your tape measure and check everything more than once. It cannot be stressed enough that you need to take your time with this process and measure everything carefully, as cutting a power cable could be inconvenient at best and very dangerous at worst.

Ok. Back on top of the roof, you should mark the spots you intend to cut and drill very carefully, because you will be cutting holes in the roof of your van, which is not something you want to get wrong. Making the holes too big, or in the wrong places, can lead to leaks, rust and even roof weakness. See the last page for a remedy, in case you do make a mistake here.