In order to maintain our independence and lifestyle, we added a solar power system to Pearl Lee. While solar power can make you more independent you must consider power generation, storage and consumption as a complete system.
We started by cutting our power consumption. We found LED bulbs for our original interior light fixtures on Amazon. These cut power, and interior heat, a real win-win for us. We wanted to keep a warm glow similar to incandescent lights, so we stuck with “warm white” or 2700k color. One bulb is brighter than the other. That’s no accident, it allows us warm, soft light when one is lit, but nice, bright light when both are lit.
We were also be able to find LED bulbs for navigation lights. This was a bit more time consuming since we had to have bulbs as close to original as possible. That means 2700k color temperature because that matches the incandescent lights they were designed for. For equivalent brightness look for an LED bulb between one quarter and a fifth the original incandescent bulb. The toughest part was finding LED replacements with equivalent dimensions. If done correctly, there is no reason LED’s can’t be effective replacements in incandescent fixtures.
Solar power really starts with solar panels. Solar panel size/shape may be dictated by the mounting locations available on your boat. They must be as shade free as possible. Even a line of shade from a line can significantly reduce output. On our ketch the only reasonably sunny spot was to mount them on our dinghy davits. It was a rainy, cloudy day when I took this picture, so I hadn’t bothered to clean them. Normally keeping them clean will help output a lot. After all, dirt is shade. Normally, while they’re still wet with dew I just squeegee them off.
Our panels are Hyundai 280 watt, 32 volt panels measuring about 39″x64″. Because of the size, shipping is expensive, so it’s best to find a local dealer or do a group buy with some friends.We have two panels, totaling 560 watts, but keep in mind that’s under theoretically ideal conditions. Our mounts don’t even have a way to aim them at the sun, so we’ll never achieve that output. We simply mounted them flat on our davits using angle aluminum, which also stiffens them for the rough ride they get on a boat.
The next item in a solar power system is a Charge Controller, which is a battery charger powered by solar panels. We needed a controller with the capacity to handle both the volts and watts from our panels while delivering the right voltage to our batteries. There are two types, Pulse Width Modulation (PWM) Multiple Power Point Tracking (MPPT). PWM controllers are less expensive, but can’t regulate output voltage. Because of this, a PWM system requires solar panel voltage to be near battery voltage. MPPT controllers may be a little more efficient, but they big news is they step down higher voltages to what our batteries need.
For us, the higher cost of an MPPT controller was more than offset by the savings of having two large panels, which put out 32 volts, rather than many smaller panels. We chose the Midnite Solar Classic 150 due to features and reputation. Note in the installation above there are appropriately sized breakers between panels/controller and controller/batteries.
One thing we like about the Midnite Solar Classic is that the control panel can be remotely mounted. This allowed us to “hide” the controller, breakers and wiring while still keeping tabs on our solar production. I too this picture on a very overcast day, but we’re still making a little solar power. So far our best days have been a bit over 200 amp hours (2.5 kilowatt hours), not bad. You can see by the voltage that our panels are currently mounted in series, but we can change to parallel easily should we wish to experiment.
Finally, we need to store all this solar power. Our system charges eight Crown CR-225 batteries. These are heavy duty, deep cycle, 6 volt golf cart batteries. Our batteries are wired in series/parallel configuration. That means every pair is wired in series to give 12 volts, then the pairs are wired in parallel to give us a total of 900 amp hours. Since you should never go below 50% that gives 450 amp hours (or 5.4 kilowatt hours) of “useable” storage.
Our solar power works pretty well, but sometimes struggles to keep up during periods of high usage or low solar, such as the short days of December.