Home Technical Sailing Videos How We Generate Power Onboard

How We Generate Power Onboard

written by Terysa September 13, 2017

Meeting our onboard power requirements is a constant balancing act.

We spend much of our time considering how we are going to power all our electronics onboard our boat, and looking at ways to reduce our energy usage. Nick made this great video explaining exactly what power generating equipment we have installed and how we charge our batteries, monitor their charge levels, and reduce the power draw.


First, how do we store our energy? We use Trojan T105 6 volt batteries in our boat, which are wired in series and parallel to make a 12v battery bank. We have 450 amp hours, although lead acid batteries are considered to be effectively flat when the charge falls to less than 50%.

Engine Alternator

Although there is a school of thought that you shouldn’t run your engine purely to charge your batteries (ie, run your engine not under load) because it causes damage, we believe that this is outdated information and not relevant to modern diesel engines. We find that running our engine to charge our batteries is a reliable backup for when our renewables aren’t keeping up with our requirements. Which brings us on to…

Solar Panels

We have semi-flexible solar panels by a company called Solbian attached to the roof of our bimini. As with most solar panels they are very sensitive to being even partially in the shade. So the shadow from a backstay for instance reduces the output considerably. In full sunshine we can get 11amps from them.

Wind Generator

First on the list was a wind generator. The market seems to be split into those low cost units that are able to trickle charge the battery, and those more expensive units that can generate enough energy both at anchor and at sail to run equipment and charge the batteries. We ended up going with an Airbreeze unit which is very quiet- just as well since it’s situated right where we sleep and spend all our free time! At wind over 15 kts it is happy. It can generate anything upto 15amps which is more than enough. However, at lower wind speeds it generates very little.


When under sail and not running the engine regularly- such as when we’re doing offshore passages- we use our 300 watt Watt and Sea hydrogenerator. This is really only useful when sailing for long distances and is quite an expensive piece of equipment. We think it’s worth it because the alternative would either be running the engine regularly or buying a separate generator.


Hope that all helps! Please leave a comment with any questions or thoughts.



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