Another Solar question

[Mobile Solar]

The alternative to fixed mounted solar panels is the rollable/foldable option. The advantage is you park in the shade and position the panels in the sun. Not a bad idea when its 40C. Thin film flexible lend them selves for this purpose. -

 

[Petrolburner]

I like the idea of parking in the shade and tossing the panels out in the sun. No issues with drilling holes and sealing the roof of the camper as a bonus. The downside I suppose is that they would not be recharging your batteries while underway but the vehicle's alternator could do that just the same.

 

[ianc]

And they're also easy to nick!

 

[Herbie]

I like the idea of parking in the shade and tossing the panels out in the sun. No issues with drilling holes and sealing the roof of the camper as a bonus. The downside I suppose is that they would not be recharging your batteries while underway but the vehicle's alternator could do that just the same.

I like the best of both worlds. I mounted my panels in a rack on the roof, so I can have charging all the time, but the panels can be easily slid out and re-located wherever the sun is shining.

 

[Petrolburner]

Good idea Herbie

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[Joe917]

Don't forget whatever panel type you choose or mounting system you adopt panel shading will destroy your panel output. Even just a corner of one cell. You have to keep in mind the position of the sun relative to the panels and roof vents, roof racks etc when you park. Think about that when you locate your panels on the roof.

 

[Iain_U1250]

I have 4x85W rigid panels on the roof at an angle, and another 85W and a big 300W panel mounted on the roof flat, but it can be taken off and put in the sun so we can park in the shade.

I took a lot of time sorting out the protection bars for the fixed panels, so that they don't form any shadows. I tested the85W panels and just a shadow on the corner means the output drops a huge amount.

I used the overhead light to look for shadows.

I would be wary rigid panels on the roof without some means of protecting them, one tree could really do a lot of damage.

The removable panels are not on yet, but the are bolted to the tropical roof but with brackets that are easily removed.

There is a 12mm gap under the edges of the panel for airflow, and the top edge has a 25mm gap due to the angle. I was planning on drilling holes in the top side to increase air flow, but will wait and see if the heat really is a problem

 

[Joe917]

Looks good Iain, I would have to be really desperate for power or shade before I carried one of my 315watt panels off the roof though. I guess its nice to have the option in a longer term camp site.
BTW drilling the roof is not necessary if you bed the brackets in a high quality adhesive sealant like 3M 5200. Avoid silicone.
Cheers, Joe.

 

[Iain_U1250]

My brackets are all glued on with Sika252. The protection bars are also stuck on, based on the area of each support, the aluminium would tear before the glue came unstuck. The only holes I was planning was in the frame of the solar panels, to help with ventilation under the panels.

Taking the big panel off the roof is a two person job, but not that difficult. I agree, not something you would do every stop, but if we are camped up in the shade for a few days, it would stop us having to move into the sun. Our roof if very well insulated, so we don't expect much heat transfer, having 80mm insulation, thermal paint and a tropical roof/solar panel over most of it. We have been to quite a few spot where it is good to park next to a tree for shade when not inside the truck and being able to move a large panel out into the sun would be a definite advantage.

 

[gwgreece]

Aluminium semi flexible solar panels

Hi Ian,
Yes I have a 100w thin panel that is attached to the top of a hard shell roof top tent. My panel is semi flexible aluminium backing and 2.5mm thick, I have it attached to the fiberglass top with silicone sealer and small stainless screws. From the website you posted, it looks to be the same brand as you are looking at (but I do see that ebay sellers often "borrow" photographs ).

I spend a lot of time off road and travelling in quite harsh terrain, it has proven to be very robust, except that you can scratch the plastic film with tree branches in the bush. Real light weight at only about 2.5 kg compared to the 14kg pannels that I previously had on my roof rack for the same wattage.

I will post a few photos when I am home again.

I have just put a deposit on a new James Baroud hard shell roof top camper so I am now looking to get some new thinner panels with EVA plastic backing for my new rooftop tent project. The main difference that I want is to not have a junction box on top of the panel, I want the cable out the back so it is completely flat. Unfortunately it seems hard to find pannels that have no junction box on top and some of them are extremely expensive for top end offshore yachating applications.

Hi. I have same panels as Ian. I note you screwed through your aluminium panels. Is that ok? I asked my ebay seller if I could and he informed me not to do that. I really need to drill some small holes along the edges to screw down and am worried about doing that, so if you have done it without any problems please let me know. Cheers George

 

[dwh]

Hi. I have same panels as Ian. I note you screwed through your aluminium panels. Is that ok? I asked my ebay seller if I could and he informed me not to do that. I really need to drill some small holes along the edges to screw down and am worried about doing that, so if you have done it without any problems please let me know. Cheers George

The main purpose of the frame is to keep the glass sandwich from flexing, and to protect the edges against chipping.

Drilling mounting holes in the frame is normal practice. Just don't make the holes big enough to weaken the frame, and stay well below the glass sandwich.

 

[toyotech]

I have 4x85W rigid panels on the roof at an angle, and another 85W and a big 300W panel mounted on the roof flat, but it can be taken off and put in the sun so we can park in the shade.

I took a lot of time sorting out the protection bars for the fixed panels, so that they don't form any shadows. I tested the85W panels and just a shadow on the corner means the output drops a huge amount.

I used the overhead light to look for shadows.

I would be wary rigid panels on the roof without some means of protecting them, one tree could really do a lot of damage.

The removable panels are not on yet, but the are bolted to the tropical roof but with brackets that are easily removed.

There is a 12mm gap under the edges of the panel for airflow, and the top edge has a 25mm gap due to the angle. I was planning on drilling holes in the top side to increase air flow, but will wait and see if the heat really is a problem

The glass on solar panels are rated for hail impact so I wouldn't worry about protecting them. Protecting the aluminum frame doesn't do much. The glass is also tempered




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[Iain_U1250]

I suppose it depends where you take your truck, we had our leaning against a tree on one side slope, I doubt the panels would have survived without the protection bars.


In our travels we have only hit one tree branch hard, it snapped of a 100mm thick branch that I didn't see, but sure fell it, the protections bars did their job and apart from taking the paint off the leading edge, we had no damage. I doubt a thin aluminium frame and sheet of tempered glass would have taken the hot and survived. Out protection bars are 25mm high tensile steel and the whole lot cost lest than one of the panels.

Regarding the portable solar panel, we ended up with three 100W flexible panels mounted onto a aluminium frame, they work great and it allows us to park the truck in the shade and still have some panels in the sun.