We doubled our solar capacity!
We are super excited to have completed this newest project, and show you how to install solar panels on a boat by yourself. It’s a project most yachties seem to take on eventually when they realize how quickly energy gets used up when you’re cruising or living on the hook.
When we purchased our vessel, she came equipped with 200 watts of solar installed on the radar arch, which was nearly enough to keep up with demand during the summer months. Nearly. Much of the time, however, it was a slow game of diminishing returns over a couple weeks of anchoring.
Batteries last longer if you can limit the depth of discharge and number of charge cycles. So, in order to keep our new house bank of batteries (see episode 23!) healthy and regularly charged, we decided to bone up our solar system.
We purchased two new 160-Watt poly-crystalline panels, measuring 1480mm/58.3″ by 670mm/26.4″. These particular panels are built for the “rugged Canadian outdoors”, so basically they’re meant to withstand tough environmental conditions. They have a tempered glass surface and aluminum frame.
I shored up the frame with additional aluminum supports. This was simply to give me more wiggle room and a sturdier surface on which to mount the Magma brackets that would secure the panels to our rails. We also use Magma brackets on our fish cutting table and barbeque – they have excellent holding power!
The Charge Controller
We also bought a SunSaver MPPT charge controller to match the existing unit that came with the boat. Incidentally, this unit sells as one of the top charge controllers in the market for our size of array, and ease of use/return on investment!
When choosing your solar panels and charge controller, just be sure to check the total ‘Open Circuit Voltage’ or Voc of your panels against the power-handling rating of your charge controller. You want to be confident that the maximum power delivery of your panels is an amount that your charge controller can safely handle!
The next step after mounting the panels to their new home on our railing was to connect and secure the cabling. These we ran from the panels, along the railing (secured with zip ties – nothing fancy), and down to where they would go through the hull into the boat.
In our case, I wanted our panels to be wired in parallel, so I connected them together this way on deck. This way, only one positive and one negative cable would need to run through our transom and into the boat.
Series vs Parallel for Solar… what’s the difference?
As a refresher (if you haven’t read/watched episode 23), a parallel connection will increase the wattage (amperage) output of the panels by adding their outputs together, while keeping their voltage output the same. The opposite is true for a series connection.
Many sailing channels appear to be carte blanche proponents of a series connection. While this may work better than a parallel connection in some scenarios (there are many variables to consider), in our case a parallel connection was the way to go for one important reason: output when shaded.
A parallel connection allows our two panels to work independently of each other. This means if one panel is shaded, it does not diminish the output of the unshaded panel.
If they were in series and one panel was shaded, the ‘system’ sees it as BOTH panels being shaded! They are inextricably linked together, so the system puts out whatever the least-producing panel is putting out.
Alright, so back to the install!
To bring the solar wires into the boat, I drilled a hole through our transom and installed a waterproof deck fitting to go over the hole and fished the wires through.
After then suffering through the nightmare that was running the cables from where they come in through the transom all the way to their new home under the cockpit, we installed the components that would link our new panels to our batteries. Namely, the MPPT Controller, the on/off switch, and the fuse box.
The last piece after this was wiring up of all these components and running some wires to the house battery bank. I also installed a remote meter to our new solar array so that we can monitor the amps and voltage output of our panels.
AAAANNNDDDD, voila! Brand-spanking-new solar panels delivering 320 Watts of delicious sun-ripened energy straight to our batteries!!
We hope you find this episode informative, and maybe even entertaining. It’s a little longer than a normal episode since it’s a how-to video, but we tried to keep things moving along. However, if we appeared to gloss over anything you wanted to know more about, please leave a note in the comments! I’m happy to answer any questions to help you with your solar project.
Be advised: there is some sailor-branded swearing video! 😄