Since Coronado is our floating home, we do not have access to unlimited electricity and water like our friends on land. The following is a summery of how we make and use electricity on Coronado.
Solar
For electricity, we primarily generate our power from the sun via our 2,400-watt solar array. All our solar panels are mounted on an arch off the back of the boat. This puts the panels in an area of the boat where they are least likely to be shaded by the mast or sails. When at anchor, we typically pull the boom to one side to help ensure there are few shadows on the panels. On the solar arch, we have mounted six 400-watt panels. Our panels are bifacial, which means they have solar cells on both sides of the panel. Since the panels reside above the water, they can capture the reflection of the sun off of the water. We see the best benefit of this in the morning and evening when the sun is low and the glare off of the water is high. This allows us to generate solar power for a longer period during the day.
The solar panels are wired to three solar controls (two panels per controller), which regulate the power produced versus consumed. If the batteries are fully charged and we are not using any power, the controllers will turn the power off. However, if the batteries are fully charged and we continue to need power, the controllers will divert the power where it’s needed. This is one reason we save high power-consuming activities, like running the washing machine, dishwasher, or watermaker, for the day. We are basically washing our clothes with power directly from the sun!
Generator
We have a 13,000 Watt diesel generator when there isn’t enough sun to keep pace with our power demands, like when it’s been raining for several days and we are stuck on the boat. We also use the generator to power our dive compressor and air conditioning. Our battery bank could power both of these, but they use a lot of power over a long period of time. We primarily use our air conditioning only when we’re in marinas – at anchor, the boat points into the wind, so we usually have a nice breeze with the hatches open. When we purchased Coronado, we had the option of two generators, one that was too big for our needs or one that was too small. We opted to go “too big”. The upside to the larger generator is that we can literally turn on everything electrical in the boat, and the generator could handle it. The downside is the additional weight of the larger generator.
Engine Alternators
When Coronado is motoring, we also get power from our two 125 amp alternators on our diesel engines. This gives us a third option for generating power. The more redundancy you have, the more self-reliant you can be.
Shore Power
Occasionally, we are in marinas and can plug directly into shore power. Since we travel the world, and electricity standards vary from country to country, I have configured Coronado to accept 120 and 230-volt power sources. Rather than use adapters for each region, I installed an EU-style plug for 230 V and kept our US-style plug for 120 V shore power. This makes it very clear which type of power is being used.
Since Coronado is a 120 V (US spec) boat, plugging into shore power in the US means all the electricity on the boat is coming from the local power grid. I plan to enable an option allowing our solar to provide power and only augment power from shore when needed, but I haven’t implemented it yet. Coronado consumes shore power a little differently when we’re in parts of the world with a 230 V power grid. On 230 V, power is used only for charging our batteries and running the air conditioning. Since we’re a 120 V boat, we don’t want power going straight to the outlets in the boat.
There is also a frequency difference between the 120 V US power, which runs at 60 Hz, and most of the 230 V world, which runs at 50 Hz. We can easily step down the voltage from 230 V to 120 V, but changing the frequency is more complex. We have many items on Coronado that will not run at 50 Hz, our oven and cooktop being the most critical. So, to get around the frequency mess, we just run everything off the batteries, like we would at anchor, and use a battery charger that supports 230V/50Hz power to replenish the power we drain from the batteries. As mentioned, the air conditioning only runs off the generator or shore power. When plugged into 230 V shore power, we have a transformer that steps down the voltage to the air conditioner. But what about that frequency problem I mentioned? Luckily, the air conditioners are one the items on Coronado that will run at either 50 Hz or 60 Hz.
Batteries
So far, I’ve written about how we generate power. Now, I’ll talk about how we store power. At home, you don’t need to store power. You take what you need from the power grid. On Coronado, we need to store the power we generate during the day so we can turn on our lights at night. We store the power we generate in a 1,600 Ah lithium battery bank (Lithium-Iron-Phosphate (LiFePO4) to be exact). The reasons we use lithium batteries are many, but one of the biggest reasons is that lithium batteries can absorb a lot of energy in a short period of time compared to the lead acid-type batteries you use in something like your car. This makes lithium batteries a great companion with solar power. Our solar array puts out a lot of power during the peak of the day. If we used lead-acid batteries, we would not be able to capture nearly as much of the sun’s energy. Even with our generator, it can run for a significantly shorter period of time before the batteries are fully charged.
Another big advantage of lithium batteries is their usable capacity. In practice, you should only discharge a lead acid battery to about 50% of the capacity; going lower regularly will damage the batteries. (Have you ever run down a car battery and noticed a month later it needed to be replaced?) Lithium batteries do not have this limitation. You can drain a lithium battery to near zero and it’s fine. I’m sure many of you have done this with your phone! All said, that means a 1,600 Ah lead acid battery bank is only 800 Ah of usable capacity. It’s not uncommon on Coronado for our lithium battery bank to get down to 30% after a couple of days of clouds and rain, only to have the sun come out again and fully recharge our battery bank by 2:00 PM.
Inverter
Finally, I’ll touch a bit on using power. On Coronado, we have a 5,000 W inverter/charger. The inverter/charger’s role on board is to turn AC electricity into DC electricity and vice versa. If you don’t know the difference between the two, AC typically comes out of the socket in the wall and DC typically comes from a battery. On Coronado, we have power stored in batteries (DC) but need AC power for the outlets and to run appliances. On the other hand, we get power from the generator and shore power, which comes into the boat as AC power, but we need to store it in our batteries as DC power. With a 5,000 W inverter, we can produce a lot of AC power. This is how we can run large household appliances like our electric oven, induction cooktop, washing machine, dishwasher, and water heater from our batteries.
If you want to see how this all comes together, check out our Victron Remote Monitoring portal. Here, you will get a real-time view of the power produced and consumed on Coronado.
https://vrm.victronenergy.com/installation/294319/share/4c5df64b
Sailing Coronado 