It’s always 68 degrees and sunny here in Maine.
No matter what climate you’re coming from, the weather is always perfect inside our shops at Front Street Shipyard. Come enjoy the warmth when you need the upgrades, maintenance and refit work that keep you cruising around the globe. You’ll also get deep
unnecessary. When this second large alternator becomes very useful is when we parallel the house and start alternators onto the house battery bank. In that configuration, we can produce over 9kW of charging for the house battery bank. In our standard configuration, with only a single house battery bank alternator, we have 4.5kW of power available all the time. We can run air
ENERGY IN ACTION
Backup generator: The combination of the 6kW 240V inverter and the 9kW of main engine charging capability allows us to have a backup generator without giving up the space. Generators are reliable and we have never experienced a disabling fault,
power draws rather than peaks. It’s amazing what a relief it is to not have to manage loads, worry about what is running when, and not have to go out and reset the breaker multiple times each day. Suddenly shorepower “just works.” And there will be times when old shorepower breakers can’t deliver their rated output. I’ve often seen 16A breakers that will pop at anything over 12A. That’s fine too. We just set the charger draw to what is available onshore and forget about it, knowing we will take what we need but never more than the shorepower system can provide.
The 240V power systems in many U.S. and Canadian marinas is actually 208V. And, when overloaded, the “240” can sag down below 200V, which can damage electrical appliances. With the combination of a 240V inverter powering the house and only the battery chargers connected to shorepower, the boat always sees rock-solid 240V power through the inverter, while the battery chargers deal with voltage sags and other shorepower problems. The Mastervolt chargers will charge on just about any voltage and frequency in the world, so it all works without exposing the boat systems to sags, spikes and other shorepower related anomalies.
Our boat has both a 240V system and 110V system. The 110V system has a 4kW inverter and, if it fails, the only way to get 110V is to plug into 100V, 60Hz shorepower or start the generator. With the 240V inverter, we can still get 110V anytime without running the generator via the 240V inverter. It feeds singlephase 240V to the 240V system just as the generator would and the Nordhavn standard step down transformer will just keep producing nice, clean 110V output even if the 110V inverter fails.
You might ask why bother with the 110V inverter at all? It could be eliminated without giving up any advantage described here but a larger 240V inverter would be required if we gave up the 4kW of 110V inverter. If we were doing a new build today, we probably would opt for a larger 240V inverter and omit the 110V inverter entirely.
BATTERY PROTECTION
As mentioned before, our battery selector switch has three input options: shore, generator, and auto. Auto is an interesting configuration. In this mode, a large 120A continuously rated relay is used to select between shorepower and the generator. If shorepower is available, the battery chargers are run from the shorepower system. If the shorepower system fails, is unplugged, a breaker pops, or any other fault causes a loss of shorepower, then this relay switches the battery charger source to generator.
Since the generator is not running, you might wonder what value there is in switching to the generator. Dirona is equipped with generator auto-start, so, if the batteries are discharged to 50 percent capacity, the generator starts, the load is brought on after two-minute warm-up, it recharges the batteries, the load is removed for a one-minute cooldown, and then the generator shuts off again. The auto-start system is a simple extension of the Northern Lights Wavenet system.
The normal use of auto-start is to take care of the batteries and ensure they get charged when needed rather than when I remember. Jennifer and I are often late getting back to the boat after shore-side exploring. Rather than allow the batteries to discharge excessively, shortening their life, the generator just turns on and gets the job done without attention.
Auto-start is a personal decision where each owner needs to weigh the risk of running a generator without attention against the risk of allowing the batteries to discharge. Our take is well-maintained equipment works well and, just as most people wouldn’t think twice of having their furnace kick on to prevent frozen pipes when they are not at home, we think auto-start is good for the boat. Even if you don’t decide to install auto-start, the Northern Lights Wavenet system is strongly recommended. We love it.
The combination of the “auto” position on the charger selector switch with generator auto-start/stop means that if something goes wrong with the shorepower, the generator will start a day or so later, recharge the batteries, then shut down and wait until needed.
If the shorepower comes back, it switches back to shorepower and uses it again. We will also get email notification if the shorepower gets disconnected, and there are on-board alarms that signal this event, but it’s still good to have backup to protect the nearly $8,000 worth of batteries. Even if we weren’t cruising in 50Hz countries or remotely, where a generator failure would be a setback, we’d still install a 240V inverter. In fact, we’ve become so dependent on the system that we’re considering getting a spare.
In the past, we needed to run the generator under way or at anchor to make water, do laundry, or for baking. We now only run the generator at anchor, either to charge the batteries, or for extended 240V loads. The 240V inverter and either shorepower or the main engine can handle the rest.
A shorepower connection anywhere in the world is now effectively the same as if we were in the U.S., with the added advantage of isolation from low or sagging supplies. And having air conditioning while under way in hot weather is wonderful.