Searching for solar
With the cost of living currently soaring, could solar panels help reduce your fuel bills? Boater John Souter describes his experience.
DURING the time we’ve owned our 55ft narrowboat Dragonfly – a little over 15 years now –there have been many occasions when we have gazed longingly, admiringly, and even enviously, at the varied and often substantially impressive solar panel systems bedecking many of the boats we have passed on our various adventures around the cut.
It often went through my mind that with such a system it would no longer be necessary to have to worry about making sure that our three-bank leisure battery system was regularly charged, either by cruising or when stationary, by our 30-year-old-plus willing, reliable, but ageing 1.8 BMC engine.
I imagined the assurance that could be enjoyed by mooring peacefully and stationary for a few days and thinking that we didn’t need do not worry in the slightest about engine running for battery charging and our subsequent levels of power usage – as our solar panels would take care of all that for us.
As with other major decisions in life – new clothes, changing the car, an interior boat revamp – once the seed had been set it was all systems go with the thinking, research, and planning process.
Initial thoughts were:
*What are the actual pros and cons of having solar power?
*Is the expense worth the benefit? *Will it mean a change in the size/ capacity of the battery bank?
*How do you go about finding out what is available and who can supply?
What sort of system?
Being able to put my knowledge of how solar charging systems operate on the back of a postage stamp, it wasn’t rocket science to come to the conclusion that I would need to do some serious research to get a reasonable idea of what sort of systems are available, how it all works, a basic understanding of what sort of system would be best suited to meet the needs of the sort of boating we did, and, crucially, where did we go to get the advice, equipment and installation.
Researching the internet, magazines, online articles and more proved productive in terms of gathering information, but the net result was that I ended up with far more questions than answers. Rigid or flexible? Monocrystalline or polycrystalline? MPPT or PWM controllers? Calculating output against consumption?
And as for amps, volts, watts…
I’d be the first to admit to a severe shortage of understanding of electrics and trying to get my head round how it all worked just produced a fuzzy headache and a bulk supply of painkillers being considered as an addition to the shopping list!
To minimise future bouts of headache-inducing research, I decided to focus my attention on the areas that were more understandable and leave the power calculations and requirements to the experts. So, first off I looked at what sort of panels were available and discovered that the choice primarily lay between the monocrystalline or polycrystalline versions.
In summary, firstly the technical bit. Monocrystalline panels have solar cells made from a single crystal of silicon whereas polycrystalline panels have solar cells made from many fragments of silicon melted together.
Now here’s the important bit. Monocrystalline panels are usually a uniform black in colour whereas polycrystalline have a bluish hue and a less uniform, more speckled look. Crucially monocrystalline panels also have higher efficiency rates than polycrystalline ones (typically 15-20% compared with 13-16%) and this difference in efficiency level results in them producing more power per square foot. They also tend to perform better in low light conditions and better in higher temperatures, which, as a consequence, makes them projected to have a longer life span.
So, in the end, the decision as to which type of panel to use was an easy one. Although the production cost of polycrystalline panels is simpler and therefore can make them cheaper, the efficiency, longevity and looks of the monocrystalline panels generally make
them a much better option. So, first decision made – monocrystalline it was.
Next question. Should it be rigid or semi-flexible panels? And if semiflexible, then should it be screwed or glued fixing? Opinion appeared to be divided between the rigid off-roof raised and/or tilting version or the semi-flexible attached-directly-tothe-roof option.
I can completely understand the reasoning that says that on a bright and sunny day the heat from the sun on a hot steel roof can have an adverse effect on the performance and longevity of semi-flexible panels fixed directly on to the roof. But at the expense of aesthetics ruling over sensibleness, this decision was also an easy one. And, bearing in mind that raised panels could possibly hinder cruising viewing and as a slightly older ‘silver cruiser’, there is always the increasing risk of trip hazards, we decided to go for the semi-flexible option and rely on the fact that improvements in technology have considerably improved semiflexible panel longevity.
As for the actual roof fixing, my initial thoughts were to go with what my research had shown to be the popular option – i.e., having the panel(s) permanently fixed with an adhesive.
However, on the advice of Mike Smith, from Off Grid Happy (of whom more to come later), I reconsidered and agreed that having the panel(s) screwed down was a much more sensible option.
The thinking behind this is that the adhesive option is very permanent and can prove to be a very messy and damaging process to reverse in the event that at some time in the future we might want to remove the solar panels, change to a different configuration, or repaint the whole roof.
As the screw fixings to be used were going to be highly waterproof and Allen key-secure, it seemed to be a much more flexible and sensible choice.
So far so good. Now for the all- important choice of controller. There are essentially two choices: PWM or MPPT.
PWM means Pulse Width Modulation. Less expensive, but it’s more restricted in its versatility and less efficient in its delivery of power.
MPPT stands for Maximum Power Point Tracking. More expensive, but with cost levels coming down. These are more sophisticated controllers and better at maximising the power and efficiency of the system, especially when conditions are cloudy or shady. The technology also allows for remote control via smartphones apps. The more sophisticated software will allow for earlier charging in the day and charging over a longer period, and could prove to be more flexible if at some point in the future we might want extra panels to be added. The MPPT wins hands down.
Next steps
Having got this far and finding that, as my knowledge and familiarity with what is available increased, and with a consequential increase in my reassurance as to my overall understanding, this had a direct impact on: a) My continued enthusiasm for a solar system for Dragonfly, and b) A subsequent reduction in fuzzy-headedness and painkiller requirements!
So, having decided on the type of panel, choice of controller, and semiflexible fixing option, the next step was to find out exactly how we sourced the necessary equipment and got it installed.
More research resulted in another plethora of options. Fitting the system myself was a total no-go area, so that narrowed it down to: a) Having it supplied and installed by a specialist company. b) Having it supplied and fitted by a marina, ideally one local to our mooring. c) Buying the equipment independently, e.g. online, and having it fitted by an independent installer. Exploring the various options produced a surprisingly mixed bag of results. Contacting marinas resulted in generally positive responses but with a requirement that the boat be taken to them for the installation. Some specialist suppliers were able to give helpful advice and provide everything needed for an appropriate installation but didn’t do installations themselves and so it would be left up to us to find an installer. Exploring this latter option, it subsequently turned out that it was very hard to find an independent installer able to do the job in our area.
Then, just at the point where exasperation was about to set in, an article supplied by a friend allowed us to come across Mike from Off Grid Happy (OGH).
Our initial enquiry was met with an almost immediate positive and helpful response. The sketch we supplied of how we pictured the installation to look was subsequently turned into a colour- matched diagram showing how their proposed installation could look.
The panel sizes and power output were calculated by OGH and designed to fit perfectly with our non-residential boating needs, and a time was easily agreed for fitting to take place at our mooring location to fit in with when we were available to attend, watch, and have full input into the work taking place.
Installation
Thursday, April 15, 2021 and we awoke early to a chilly but dry and sunny start to the day. At this point the conditions looked great for the installation work to be done, with the only concern being a forecast saying that there was the possibility of rain later in the day.
Not long after waking we got the call from Matt, the OGH engineer/ installer to say that he was almost with us, and shortly after we were helping him down to the pontoon with an assortment of boxes of various sizes.
The location of the panels was crucial; if they were not in exactly the right place, every journey at the helm would probably involve thoughts like ‘I’m sure they’re not quite straight…’ But after having unpacked the solar panels, there was a detailed rooftop discussion involving various measurements and lots of ‘to me a bit, to you a bit…’ – with not a hole being drilled until the panels were exactly where we wanted them to sit.
The rest was down to Matt. Panels fixed in place, cables connected, access hole drilled and cables brought inside, MPPT controller fitted, connections made… and the system was up and running. The set-up inside was equally pleasing as the external access point for entry of the cables in to the rear cabin was chosen in such a way as to minimise the unnecessary running of cables within the cabin and produce a really neat and tidy finish.
As for the rain that was forecast, luckily that didn’t arrive. By the end of the installation the sun was shining, and it was so satisfying to see that the panels were already putting power into the system.
Outcome
And finally, what did it all cost? Answer: a very competitive figure at a cost more competitive than anyone else we made enquiries of. Happily it all came together headache-free and perfectly in the end, with Off Grid Happy being able to provide excellent options for the panel sizes to fit in the areas we wanted them to go, at a power output perfect to our needs, done very efficiently at our home mooring location, and even within the initial budget we’d set for the work.