Solar Part iii

We had a wonderfully unseasonal bit of weather at the weekend, so I took advantage and fitted the new solar panel.

250 Watts of Panasonic HIT

Its a Panasonic HIT 250w panel, which happens to be a perfect size to go on the central section of the roof. It replaces the 4 x 50w Lensun semi flex panels I had on before. The Lensuns lasted about 2.5 years after which two of them delaminated and lost their top cover. Underneath they were a sticky rubber, causing dirt and water to stick to them. I lost one out of each series string (two series strings in parallel) so the performance took a real hit.

Time took its toll on the 4x 50W Lensun panels. Having lost their top cover, water would pool on them and they lost a lot of power. Obviously the two knackered panels are in the centre.

I chose the Panasonic panel for their width and after the experience with Semi-flex panels, I wanted to try a rigid panel. It hit my power and size requirements (same or more than the lensun in terms of power and baiscally the same size). It has a useful 44v output (similar to the lensun parallel/series arrangemnent) helping to keep feed cable sizes small.

I used the Photonic universe mounting brackets/wind deflectors to mount them. I wanted a wide mounting surface and to stop wind going under the panels, both from a cabin noise and from a flight risk point of view. Using the brackets was not a simple task at all. They are designed only for 600mm panels, so I had to use two pairs cut to length (which took quite a while with a hacksaw).

I used some of the spare off cuts to make central brackets (both to hold panels but also to give them some central support). I also added some front support brackets, as side brackets get a solid

The roof is curved, and more at the front. The two bracket halves are at angles and I had to enongate the bolt holes in them to allow for some angling.

The main contacting parts of the brackets and the side brakcets are all bonded on with Plexus MA310 structural adhesive, which is recomended for use with the ASA roof . Where I still had some space to fill due to the angle of the roof , I used Sikaflex 512 to fill the remaining gaps. All the bonding areas were sanded and degreased first.

I was concerned with the extra weight (15kg panel) and compared to the lensuns, I did put the panel much lower on the roof so more of the weight moves around the pivot point. The struts seem to handle it ok. They can’t hold it at the part open state (but they couldn’t before either). It goes all the way up and stays but think there is a reduction in tension now and I can pull the roof down a lot more easliy (it needed a bit of a tug before).

Of course the rigid panels add a small amount of height compared toi the lensun panels before. I hope the neater roof will have less wind noise and be more robust though.