Solar Hot Water Systems
Minimum 400w of solar and 300Ah domestic batteries
Sailing yachts generally heat the water in their boilers either from an engine heat exchanger or from shore power. At anchor for a couple of relaxed days in a secluded bay or moored somewhere without shore power, this tends to mean cold water!
Green Yachting offers three solutions to that problem for ALL yachts with at least 400w of solar and 300Ah of domestic battery capacity. Which is right for you will depend on your solar and battery installation:
>400w but <600w solar panels connected to at least 300Ah lead/acid (AGM) 12v batteries:
12v/300w replacement water heating element controlled by our patent intelligent controller. Optional remote panel. The controller turns on the heating element automatically if the battery level permits (>12.8v) and the water temperature is under 40°C. It turns off if the battery voltage drops below 12.0v or if the water temperature rises over 52°C. With a low voltage cutoff, it does not turn on again until the system returns to >12.8v. The shore power connection works as before but water heating is slower.
>600w but <1000w solar panels connected to at least 400Ah lead/acid 12v batteries:
Uses either a 900 or 1200w replacement water heating element controlled by our patent intelligent controller that switches on or off our inverter. Optional remote panel. The controller turns on the heating element automatically if the battery level permits (>12.8v) and the water temperature is under 40°C. It turns off if the battery voltage drops below 12.5v or if the water temperature rises over 52°C. With a low voltage cutoff, it does not turn on again until the system returns to >12.8v. The shore power connection works as before and overall heating time is identical to that of the old unit.
>600w solar panels connected to at least 400Ah lithium 48v batteries:
This solution is a benefit from part of a wider upgrade from lead/acid domestic batteries to lithium. A lithium system, using our 3 or 6Kw packs will, if correctly configured will provide constant hot water using the existing water heating system untouched. Please note that this does need a different solar controller and an additional device to charge lithium batteries from your alternator.
SOLAR OUTPUT SENSOR
It is obviously important to make sure that our device does not over deplete your domestic batteries. This little device sits between your solar panels and our controllers and turns them off if the solar output is less than 12v. There is a manual over-ride in case you really want a shower at night and are happy to draw on the domestic batteries.
With the first two lead/acid based solutions, you are using solar energy that in summer would otherwise be discarded from around noon onwards. With lead/acid, It will always be unwise to take a shower after sundown since all the current will come from your batteries and they are intolerant of deep discharge. Sensitivity to energy use will be a requirement even with one of our lithium installations but storage capacity is so great compared to probable consumption that you can behave with the freedom that you enjoy at home.
Replacement calorifiers with 12 & 220v heating elements
If for whatever reason you are thinking of replacing your existing water heating system, then consider ours that has both 12 and 220v heating elements in addition to the usual engine heat exchanger coil. The 12v element is connected to our intelligent solar hot water controller so that it ensures proper battery management without the risk of excess discharge. Cost is a bit higher than say Quick or Isotherm, but insulation and water temperature control are much superior, and we are unique in offering both 12 and 220v heating elements in a single calorifier.