Essential insights into managing electrical systems on board — from winches to water makers, based on what we've actually measured aboard SV Intle Breeze.
Using something on 12V is more efficient usage of power than using a 220V electrical item. The inverter has to convert this 12V from the battery and change it into 220V which is not efficient. So for sure, do not plug in a 12V charger through a converter into the 220V plug as then you are double inefficient. But rather try and use 12V items, than 220V items like the water maker.
So to consume power, you should consume water as well, because every time you have to make water you have to use power, regardless if it is 12V or 220V water maker. This is besides the water pump that is working to supply you your water!
If your boat comes with a water heater, then these should be switched off. They usually take 20 minutes to heat up, but do not need to stay on all the time. When you are in warmer countries you probably will not even use hot water.
Anything that is in a plug we realised is drawing some kind of power, maybe not that much, but start adding all the chargers you have plugged in for things like your computer, iPad, iPhones etc etc then the total does add up.
If the printer is plugged in and on, but in "sleep mode" then it is drawing power! Unplug it.
If you have a TV on your boat, then again here if it is in "standby" mode so the remote can power it on, then it is drawing power.
As amazing as the Starlink is, it also draws a lot of power up to 150W. So switching this off when you not using it, will save power, just remember that booting it up does take a while.
We have gas stove and oven. However we also have an electric oven/microwave combo which consumes at least 1,000 Watts for the Microwave and an induction plate which consumes at least 2,000 Watts! So they are big consumers, but having this was something we wanted. We use it wisely and rather use the air fryer as it consumes a lot less power.
We have electric winches on our boat, but what we did not realise is how much power they take! When I push the button I see the power usage spike with an extra 1,250 Watts. Although not for long periods of time, it is just to be aware that these take a lot of power.
We have a Fusion system with 6 speakers, but play all the speakers loud and watch how your consumption spikes up. When they say it is a 50W speaker, it means it can use 50 Watts of power, per speaker! So with 4 speakers, that is 200 Watts — bigger ones of 75W and you can see where I am going with this.
We use this sparingly, usually only when we need to sleep and there is no breeze. The batteries, if 100% charged, cannot run the AC for more than 5 hours — they will then drop down to 40%, and we prefer not to go below that. If this is the case, the generator gets started to assist and charge the batteries. At start up the AC will use 3,500 watts for the compressor and one air handler. We do not air condition the entire boat, only our cabin, as each air handler of course consumes power. The power usage drops once the compressor is at temperature and then maintains at about 1,500 watts.