Lindisfarne built 1995 (our home 1998-2012)
Old electrical system
The original system was designed with three battery banks, separated by voltage sensitive relays. Our main problem has been the charging capacity and the charging regulator, making our batteries deteriorate because of sulfation, almost whatever we have tried.
One of the nice things with the relays between the banks is that it is possible to save the other two (starter and bow thruster batteries which consume nothing under way using the engine) when charging the house bank during engine running for “days”. The simple method for doing that is just to put a breaker on the ground wire to the relay so that charging through the relay is cut. Of course the charging current has to reach the house bank first and then via the relays to the other two. This have saved our two other battery banks from cooking during “endless” engine hours i.e. in the Med.
The solar panel (60W) is almost enough to feed the fridge (equipped with a water cooled heat exchanger in a through hull fitting).
We use the wind generator (AIR 403) only when sailing using the autopilot, radar or other electricity consuming equipment.
As indicated above, our standard alternator (60Amp) with a standard charging regulator is our weak point.
In NZ we will exchange the alternator and use a temperature sensitive (both the battery and alternator temperature) external charging regulator, able to work with different charging regimes. New batteries of course. We will go for AGM for two main reasons. No sulphating (and of course no equalization then needed (we later learned that that isn’t really true)) and can be charged with the same voltage as open acid batteries.
Using Gel batteries there has to be a charging regime that regulates the voltage down to a maximum of 13,6 – 13,8 depending on the temperature. This means that even the solar panel and the wind generator has to be regulated to this voltage.
We have now read Nigel Calder’s excellent book “Boat owner’s Mechanical and Electrical Manual”. Had we done that before leaving Sweden, we would probably already have had our AGM batteries and a separate charging regulator!
Now (2008-9) we have rebuild the system!
In Opua NZ, November 2008 we finally did the long planned upgrading of our DC charging and battery systems.
First the new batteries. We had as you read above decided to go for AGM, but after talking to people and reading the manufactures fine print we understood that AGM’s need equalisation, almost in the same manners as a acid lead battery. Meaning that the main reason for us to have chosen AGM was gone!
We now decided to go for open deep cycle lead acid batteries. 1. Cheaper than AGM, 2 Overcharging, only top up water, whereas AGM are dead in that case. Another reason was our existing alternator, but more on that later.
4×6 volts 232 Amph Endurant R200 batteries in two new compartments. The old battery boxes was to shallow for the new deep cycle batteries. They are put together in series and parallel and gives us 12 volt and 464 Amph. The starter battery is charged as earlier via a voltage sensitive relay.
– We kept the old 60 amp alternator, with it’s inbuilt regulator as a spare and rebuild the old spare alternator to be regulated by an external regulator. We didn’t choose a bigger alternator for two reasons. The water maker is belt driven from the engine and uses the pulley we need for a bigger alternator, and by choosing deep cycle acid batteries, we could in fact not use a much bigger alternator (AGM and Gel batteries can be charged faster and more effective with a much bigger alternator compared with deep cycle acid batteries).
We could have bought a one belt driven 85 Amph alternator, but why another $1000 for 15 Amp!!!
A good rule of thumb is that the alternator has to take care of your 24 hours consumption. No problem for us, especially as we are running the water maker every three days for two to three hours, giving us more than enough Amph back in the batteries.
– The new external regulator, Balmar 612, for the alternator is a modern three stepped charger and can run different types of batteries. It can even equalize !! Temp sensors on batteries and alternators limit the output when temperature is too high. Our old alternator is much more efficient today. Charging the batteries much closer to 90% with full power.
– We have now got three solar cells, in total 240W. A new three stepped regulator take care of all those watts, ensuring no overcharging of the batteries. Even this regulator can equalize, and does it automatically every 30 day.
– Finally we got a new wind generator. The old one, AIR Marine 403, was completely worn out. Bearings and regulation was working very badly and finally we lost one blade in a squall south of Tonga.
The new one is still an AIR but a later much improved model called AIR Breeze. Almost silent and much more efficient, especially in light winds. Same bracket and cabling as the old one was on the + side, and it’s the lightest generator in it’s effect class.
To gain full safety we have an isolation transformer (3,5kVA to avoid overheating using a 10 Amp fuse (220v)) adjustable for different voltage ashore. No problem with leaking earth from the boat system out into the water creating corrosion by the stray current. Personal safety is also gained (actually the isolation transformer is in Sweden sometime called a safety transformer because of it’s use for protection of people).
All through hulls, propeller shaft and rudder shaft are protected with hull zinc anodes. The system is divided into three groups where all protected items are within “sight” of their respectively protecting zinc anode giving the zinc ions a shorter distance to travel through the water. There are some advantages and some disadvantages with this system. On the plus side, it is easier to monitor the system. With no complete bonding system that, eventually causes other problems, and has to take care of lightening current (making the system quite heavy). Minus is that we can get a small difference in potential between the groups effecting the rate of zinc consumption.
It’s important to clean the anodes from isolating zinc oxide, and change anodes when 50% is consumed.
We have gained our experiences cruising over 50 thousand miles from 70N to 65S with many of those miles in cold waters. But the Med, Brazil and the South Pacific gave us experiences in sunny and warm conditions.
Many of our Hints and Experiences are for that reason a little “to much” regarding the heating system for the normal circum navigator. But still there are more and more sailors who take advantage of the cold remote and lovely, not so crowded areas in the world.
In cold areas we have met several cruisers with almost no heating at all, and they have survived even if it was very cold, wet and uncomfortable.
It is all a question about priorities!
During the 2003-04 Winter season we changed the existing 40 L tap water heater for a combined tap water and radiator water heater. This “accumulator tank” is heated either by the running engine via a heat exchanger in the tank, by the oil stove (Refleks) in the bow cabin (hoses and pipes under the floor) or by shore power.
The “leaking” heat from the hot water transported from the stove in the bow cabin to the accumulator in the aft cabin gives us a nice and warm floor in the whole boat.
The radiator system is fed by the warm accumulator water and distributed to different radiators placed in different areas in the boat. Two of the radiators are fan driven, one in the head and one in the saloon gangway. Fans because it’s not always enough room for necessary radiator surface to be able to use a passive radiator.
During the winter of 2004-05, before we left Sweden, we lived in the boat to test all systems. The outside temperature in Gothenburg was below -10 degrees C for more than three weeks, but we still had +20 indoors.
The system was tested and found approved! As if this wasn’t enough, we have our Webasto 3,2 kW Air heater to be used on top of the water distributed heating. Very nice to run for half an hour cold mornings when we don’t run the water heater. And as we said earlier, the tap water for shower and galley is heated via an heat exchanger in the accumulator tank, almost like in a house.
Thanks to all our insulation work, especially at the hull and deck connection, there is very little condensation.