It is September and a few months since the electrical upgrades are finished. We have made valuable experiences along the way during the past two months and we have found out what worked well and what did not.
Our starting point was a standard Victron battery bank of 640 amp and a MasterVolt Mass Combi 2500W inverter/charger. To charge off the grid we had a 10kw Fisher Panda generator.
To be able to stay longer off the grid, to be able to run everything on the boat from the batteries and to remove the dependency on gas were reasoning for upgrading the batteries and inverters. We also experienced that the standard battery bank ran empty after about 4 to 5 hours of sailing and we had to run the engine too often on longer passages.
To meet our objectives we decided to add 12kW of inverters in 4 MassCombi Ultras and 20kW of Lithium batteries divided over 4 MasterVolt batteries. We also added a Watt&Sea Pod600 and 1320W of solar panels to charge the batteries off the grid. We skipped a wind turbine simply because it does not give enough power relative to what we have to charge. We decided to keep the system 12v due to the cost of changing the 12v to 24v for the existing installations we did not change.
After the upgrades we are running everything except the water boiler of the batteries. The water boiler simply drains too much power from the bank to make sense. In stead we turn on the boiler for half an hour before we take a shower in the evening while we are running the generator. We have a 4 fridge drawers and 1 freezer drawer that is on all the time, lights and 220v plugs which constantly is charing an iPad or the vacuum cleaner. We have 36000BTU of air conditioners which drains the batteries in about 4 hours if left on. What we do is we cool down the boat, turn off one unit and set the other to a temperatur that does not result in the aircons running all the time. Typically we can keep the boat at around 24 degrees and run the generator to charge the batteries for about 8 hours a day.
We run the generator when we also run the water maker and heat the boiler in the evening. When the boiler, water maker and aircons are all on, the generator cannot keep up the power consumption. We have also had to limit the output from the generator to 80amp to ensure the generator does not run at a too high load. This is divided at 20amp charge to each of the 4 batteries, plus sending power to the boiler.
The solar panels are Panasonic HIT330 rigid panels and we had to custom make a bimini structure to hold the weight of the solar panels (19kg each). We have one Victron regulator for each panel to ensure maximum redundancy. Midday the output from the solar panels are at about 800 to 1000 amps and provides more power than what is consumed if we do not run the aircons, cooktop/oven or water maker. The cooktop/oven was change to a Force10 3 element ceramic cooktop and electric oven. The Watt&Sea Pod600 only gives us 10amps at around 6 to 6.5 knots sailing speed which is kind of disappointing. Promised performance was 30amps at 7 knots so we are a bit off target so far.
The largest problem so far is that the generator is not starting due to overheating after it has been off for hours and is about to start. We have set the generator to autostart to charge the batteries at 40% of capacity and turn off at 60%. We will change this to 80% to allow for longer duration between each run. It usually starts two times each night as we run aircons at night to sleep well. The bluetooth connection to one of the Victron regulators does not work and we have to change that unit.
We can run amazing loads off the bank with the 4 inverters. With all on, we have tested it at close to 1000amp without any issues. The boat has a fairly substantial battery consumption running a full size laundry machine, dishwasher, electrical stove, microwave, 4 aircon units, water maker, boiler, electrical BBQ, fridges and freezer, full size coffee machine, Vitamix mixer, 3 electrical furlers, hydraulic pumps for the outhaul, vang and backstay ++. We run all these appliances and we do not have any issues with the new battery bank and inverters. At sea, we have a net positive input to the batteries, the Pod600 and solar panels provide more power than what we use.