Solar Panel Mounting

Prices of solar panels have finally come down to reasonable prices. Also the "flexible" panels make fitting much easier as well as significantly lighter. Photonic Universe on eBay had an offer for 1/3 off 100W panel at £140 - which in retrospect seems genuine since they are £215 today.

I decided that, since I was unlikely to use the panel over the winter, that I should make it removable.
I also plan to fit a roofbox this year, and long term it may make more sense to mount the panel on the roofbox.
So rather than glue the panel directly to the roof I sourced some plastic "j" section so that the panel could slide in on out.
After much searching around I found this from www.claddingwarehouse.co.uk

2.5mm kpanel edge strip

You can get it in 2 or 3 metre lengths for £3 or £4, and shipping is only £3.50

Initially I tried using Tiger Seal to stick the rail down - which worked really well with the Aluminum awning rail. But after 3 attempts I came to the conclusion that this material wasn't in the "works with most plastics" category. Some Evo "sticks like s**t" did the job.
 

To stop any would be thieves I used a couple of  domed coach bolt screwed into the rear roofrack fixings.

To feed the wires through the roof, people typically use these

These ugly bits of plastic cost about £10.
The underside is open, so if you have a problem with the sealant you will get water ingress - and no way of knowing you have problem.
The other problem I found was that the cable glands were too big for solar panel cables - probably because they are usually used to TV/Satellite cables






A much neater solution was to use a solar panel junction box

These don't seem to be available in the UK, though they are easy enough to get on eBay from Hong Kong - or maybe Germany.
It very easy to open the box to check if water is getting in.
So I removed the internal connectors, and just fed the wires though holes (with grommets) in the roof, and stuck the box down with Tiger Seal





Here's the finished article.

The cables are terminated with MC4 connectors which plug into the solar panel connectors.

There are loads of solar controllers on eBay, many claiming to support MPPT, which is basically a method of supplying the battery with maximum available current at the optimum voltage, regardless of  whatever voltage is coming from the panel. Unfortunately many of eBay models are fake, using the standard PWM type charging, which is less efficient, or even worse, just a bunch of bits that look like its a controller. I eventually went for a  German designed Votronic MPP165 from an eBay seller from New Zealand for about £55. It arrived within a week and seems to be genuine, though I haven't got the time (or inclination) to do proper testing - unlike the dozens of people posting on YouTube. I sent a few questions to the manufacturers in Germany, and they were very helpful and quick to respond.