Calorifier....?

What is that? As a Norwegian I had never heard the word before starting to look for a 12 Volt water heater.

Luckily, nowadays boat equipment steadily improves with time. Comfort levels rise, and possibilities increase. On the Lucky Strike we now have a fairly comfortable amount of solar panels. Enough to keep the batteries charged most of the time when not using shore power (which is almost all the time). In addition there is a wind generator and of course the engine generators. Even though the batteries are old fashioned AGM that requires much energy to enter top charged condition, on sunny and/or windy days we actually have an energy surplus. But this surplus ends up blocked by the solar regulator or being led into the wind generator dump load. That means it is useless.

We would like our boat to be well equipped for cruising, and this means being independant of shore power and also use the engines as little as possible for battery charging and hot water production.
Our concept has a weakness from a comfort point of view regarding hot water. Without shore power, the only hot tap water source is the port engine coolant fluid. The hot water tank is 40 liters, so the engine use when entering a harbour or when anchoring is by no means enough to heat it. In addition, we usually motor on one engine ony, which means that no hot water is produced when it is the starboard engine's turn to contribute. It would be nice to have a more available source of hot water, be it only for dishwashing, personal hygiene or a short shower.

It will have to work on 12V. And thus be quite limited in volume. And the immersion heater in it must not load the batteries too heavily, better to use a bit more time with less power.


Is this the solution?

It draws around 25A. I do not know how long it takes to heat up to acceptable temperature. But I presume that it will vary a lot with the starting temperature.  Big advantage is that it will be usable with the starboard engine producing electricity.

A possible setup will be to use a selector valve between the 2 tanks hot water feed line to the galley and owners suite.

So I have ordered one. Hope to be able to install it this summer. It would be very exciting to see how it turns out.