Installing Solar Panels on our RV

The main purpose for converting the bus is so that we can free camp (boondock), while we travel around Australia, thus we needed to seriously look at alternative power sources amongst other considerations. We really don't want generators as they are smelly,  noisy and bothersome for neighbours as well as ourselves. Thank God for the invention of solar power which has possibly been the single greatest impact on the RV community in the last 20 years if not more. The benefits of solar power are many. Maybe in a later post, I will go into more details of why you should go solar, but for now I am just going to show you a bit of how we set up the solar panels on our bus.

Do it yourself

As with just about most aspects of our bus to motorhome conversion, Rob is handling the installation himself. With careful research and internet crawling, we saved hundreds of dollars. Solar packages, esp for the RV markets can be rather expensive, yet they are no better than standard units and with a little be of knowledge and practical application, it can be handled by the handyman or woman.

How many units?

After installing the vents, antenna and skylights and then painting the roof, we wanted to cover as much of the roof as is possible with solar panels. Why waste any area? Rob also decided to lay the water pipes down first. They are not going to heat up very efficiently, but the residual heat from the solar panels will take the edge off the water temperature and thus reduce the amount of  'proper' heating the hot water will need.

See the water panels underneath the panels

After working out our roof area and the best size panels that would fit, we went ahead with the purchase of 32 monocrystalline panels of 40watts each. We'll have 1280 watts  with max 80 amps. This will allow us stay out without mains power for as long as we like, even with a week of wet weather.
A question of price? The 32 panels (1280watts) at $45 per unit (July 2013) were cheaper than the 3 larger panels we bought about 4 or 5 years ago which only supplied 240 watts.  
Why so many? It may seem like overkill but look at it this way, we have the room up on the roof and this way we will still have more power on a week of overcast days with so many panels.
Where do I get them? We bought ours ebay via OzPlaza.  They did not accept a lower price offer since we were buying so many, however once we decided to purchase anyway, they were fast and efficient. Even when one of the panels sent were faulty, they quickly replaced it free of charge including shipping. We would deal with them again and thus can recommend them (and before you think of it, we are NOT getting any benefits from them for stating such!)

Small solar panels v larger units

We decided to purchase small panels  and join them together for 2 main reasons:

1. We can can a better roof coverage with smaller panels (roof area is valuable real estate so we want to use as much as possible) 
2. We will not lose as much solar input if some shade were to fall on even part of a panel. Research taught us that smaller panels are more efficient in partial shady conditions. For example, if the shade of an antenna falls across a panel, then that panel's maximum input is reduced by half. So if we have one 120 watts panel and some shade falls across a corner of it, then it's input is reduced by half to 60 watts. Whereas if we have three 40watt panels affected by the same shade but the shade only falls on one panel then only that panel is reduced to half, producing 20 watts and the other two panels' input is not affected thus producing 40 watts each. This way we will still be getting 100 watts in partial shade compared to the 60 if it were just the one larger panel.

Rope used to secure panels whilst silastic adhesive drys

Assembling the sets of solar panels

Rob assembled the panels: wired them in parallel into sets of 3 (to go across roof) on the work bench for ease rather than do it all up on the roof. (3 x 40watts = 120watts) to the shape of the roof. He joined the panels with aluminum T sections. These sections are then fitted together and then will be wired into the control box separately.

The 30 panels equals ten sections - equals ten cables. Once again it might seem like an overkill, but this way, because of our 24volts, every second section is joined together which equals 5 panels at 12 volt each joined together to make 24 volts.

wiring of the solar panels

Coupling the wires

See the air gap under the solar panels for air flow

Sides finished off to look neat - holes for ventilation

We chose to use lithium batteries as our power storage units. They are lighter weight and much more efficient.