Our 12v system that uses surplus solar energy to heat the water in your boiler has always found a ready market all over the world. We have customers all over North America, in the Caribbean, Thailand, and Down Under. It only needs 200w of solar and 200A of domestic batteries. The system has proved robust and effective.
However we have to accept that it does have two disadvantages:
You need to replace the existing 220v heating element with our 12v alternative. That is a tedious task that involves spilling a lot of water into the bilges
Because the 12v element is 300w whereas your existing element is probably 1200w, the water does take longer to heat up.
Our new product is ONLY SUITABLE for those having at least 600w of solar and 300A of domestic batteries, but the controller is coupled to a small dedicated inverter.
The price is similar to that for the 12v system, but of course installation is even easier and the water heats at the same speed as it does now when you are connected to shore power.
We are accepting orders at the site now.