Today marks the end of the 3rd consecutive week since we took ownership of our boat here in Cape Town. We have been working hard to install all the systems we need, taking only one Sunday off out of three to relax and decompress. Practically, we spent these 3 weeks supervising the installation of the electrical systems we designed. Electricity is crucial when you live off the grid.
In a marina, the shore power cord acts as an umbilical cord. The AC power is the primary energy source and its availability is more or less unlimited. At sea, in the absence of a constant AC source, the DC system is the primary energy source. The availability of DC energy is strictly limited by the capacity of your batteries and by the charging power of your alternative source of energy, like solar for example. The DC system is rarely, if ever, adequately tested at the docks to see if it has the necessary capacity. All too often, once away from the docks the DC system crashes or you don’t have enough power for your systems and your devices. This is the #1 problem on cruising boats.
And that’s why the electrical system was item #1 on our To-Do-List. This is what we were able to carry out during our first three weeks on board:
As Battery Charger and Inverter, we have installed the Victron MultiPlus 12/3000/120. This is our big guy, and it has various functions. For example, when we are connected to shore power in a marina, it will charge our batteries. And at sea, it will convert the DC current coming from our house batteries into AC current so that we can run our power hungry devices, such as the washing machine. It’s a very important system on a boat, and Victron is cutting edge technology.
The “problem” that we are trying to solve with a secondary smaller inverter is that when we will be at sea, even if no loads are switched on, the big inverter is going to use at least 4 amps in stand by mode. And this is a waste. To solve this “problem” we have installed the Victron Phoenix 12/375 VE.Direct, a small inverter that will be on all the time connected to one dedicated plug for charging laptops or anything that can’t be charged through a USB port (we have many of them all over the boat).
To monitor everything that’s going on and be on top of our systems, we installed the Victron Venus GX. We can connect to this little unit with our smartphones via Wi-Fi and have everything at our fingertips. This unit also logs all our energy data in the cloud, to the Victron VRM portal, which is pretty useful.
The UI is pretty simple and intuitive and it allows you to change all the settings, and also to switch the inverter on and off. In this screenshot you can’t see our solar panels, since they are not ready yet. But when they will be installed, you will be able to see how much is coming in and how much is going out. Neat!
As a battery monitor we installed the Victron BMV 712 Smart. This little unit allows you to see all the important information of your systems at a glance. You can also connect to it via bluetooth using a very well designed app. It shows you the battery voltage, current, power, ampere-hours consumed and state of charge, remaining time at the current rate of discharge. You can set up alarms, or a relay to turn off non critical loads or even to run a generator when needed (we don’t have a generator on board). It stores a wide range of historical events, which can be used to evaluate usage patterns and battery health.
Thanks to the Sterling Pro Alt C E13 Alternator To Batter Charger, we will be able to charge our batteries 5 times faster using the engines. It’s a very useful back up system, in case our primary system (solar panels) fails. Or if we are in bad weather and there isn’t enough sun to recharge the batteries. This unit also has some useful temperature sensors for the battery and the alternator. Practically, it’s a sophisticated DC-to-DC converter that manipulates the voltage on both sides of the device. By dropping the voltage on the supply side it forces a conventional alternator to supply the current needed on the load side.
So this is all we have done so far for power management. We also installed a couple of power hungry systems on our boat:
As AC unit we installed a 12,000 BTU Dometic CruiseAir. It’s also a heater, with heating capacity of 3500W. It is a 230V system that consumes approx 1000W. We will probably never need to run it, unless we are in a windless marina. If we are at a marina, we’ll have shore power to run it. However, another use case would be if we were in the tropics and we couldn’t sleep at night with the hatches open because it may suddenly rain overnight. In that case, we might use a small portable Honda generator in the cockpit, and to help the AC motor to start up we also installed the EasyStart soft starter.
When you live off the grid is very important to have your own water. The reason why we chose the Spectra Newport 400 with Z-Ion is that it’s very energy efficient, automated, and easy-to-use. It only uses as little as 15 watts per gallon (4 watts per liter), making it possible to run it straight off the batteries. We were very excited to drink the very first glass of water we produced. We will never have to pull into a marina to fill our water tanks. We will be able to make our own!
On top of these systems, we also managed to install an important piece of electronics. Our radar was installed at the factory, but we added an important piece of the puzzle:
The AIS is a very important device for a sailboat. You can not only receive broadcasts from other vessels, but also transmit your own boat’s information. In this way you will be seen on other vessels’ systems. Paired with the radar, is a very important navigation and safety device. Since all our nav systems are RayMarine, we went for the new AIS 700.
This is 3 week’s worth of work, including Saturdays and sometimes also Sundays. There are some more other things that needs to be done. We are building a stainless steel structure to support 3 big 320 watts panels, and adding 5 flexible panels on the roof. We have already done the first dry fit for the stainless steel structure. We found a small shop that does wonders with stainless steel!
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Hopefully the structure will be completed by the end of the forth week. Then, we’ll take some time off the boat and we’ll explore the country.
So far we haven’t seen much of Cape Town unfortunately, but the little we saw is spectacular! Looking forward to discover more about this beautiful country!