Mercury unveils 350 and 400 hp Verado V10 motors, but the real story is the alternator!

This morning, Mercury unveiled their new 350 and 400 horsepower, Verado V10 engines. These engines follow the introduction of the highly successful, judging from transoms at the Fort Lauderdale Boat Show, Verado 600 horsepower, V12 engine. I’ve just spent the day at Mercury’s Lake X facility and I can tell you these are really impressive engines, but for many Panbo readers, that’s not the story. The story is the dual voltage, 12 and 48-volt, alternator!

Before we dive too deeply into the weeds of the alternator, let’s talk a minute about the V10 Verado. Coming on the heels of the 600 horesepower V12, the V10 delivers many of the same features in a smaller, lighter, and cheaper package. It lacks the two-speed gearcase, fixed powerhead, steerable lower unit, and mulit-plate clutch of the V12. But, at 697 pounds, it delivers more torque and refinement than any of the outgoing 350 and 400 horsepower options. In fact, it provides a level of refinement that’s hard to describe without firsthand experience. These are smooth, quiet, torquey, and high performing engines.

Now, back to the alternators. I’m not sure Mercury and Brunswick were ready for my barrage of technical alternator questions. Thus, I haven’t been able to get all my many questions answered. But here’s what I’ve learned so far. Also, a note, I’m planning much more in-depth conversations with the engineer responsible for this alternator in the near future. So, stay tuned for more details soon.

The standard alternator on these engines is a 150-amp, 12-volt unit. The engines are available with an optional 12 and 48-volt alternator. The 12-volt only alternator produces 150 amps or 1.8 kilowatts of power. I learned today that the dual voltage alternator produces less 12-volt power than the 12-volt only, but I’m not sure how much. When producing 48-volt power, it makes 6.5 kilowatts. At 48 volts and 150 amps, the alternator would output 7.2 kilowatts, so, it seems there’s some de-rating of the output, likely to manage heat.

The alternator can produce 12 or 48-volt power, but not both simultaneously. In my conversations with Mercury reps, I heard mention of activating additional coils to produce 48 volts. I think that means there are additional windings in the stator for 48-volt output that are only in play when the alternator is running in 48-volt mode. There are separate output terminals for 12 and 48 volts.

The engine will control revolutions to meet power demand, up to 2,000 RPMs. The ECU will track engine running hours separately for generator and propulsion loads. Mercury has done testing and says they’ve determined generator hours have a de minimis effect on engine longevity. I hadn’t thought about it, but tracking them separately seems like a very good idea.

The choice of 48-volt output from the alternator makes a great deal of sense. I’ve written about the case for 48-volts previously, as well as how one sailboat uses a 48-volt alternator and batteries to replace a generator. Brunswick is thinking along the same lines with their Fathom e-power system. This system uses Mastervolt’s MLi series lithium iron phosphate (LiFePO4) batteries, inverters, and other power conversion equipment to replace a generator.

Fathom has been available on several Sea Ray models for a few years. But, until now, these systems are really designed to use the engine’s alternators to slow the rate of discharge. There simply wasn’t enough alternator output to effectively charge the batteries from the engines. Instead, the plan would be to wait until the boat was back at a dock and recharge with shore power.

For perspective, let’s look at a Boston Whaler 380 Outrage, a 38-foot boat. I had the opportunity to take a ride on a quad-engined 380 today and experience what 40 cylinders can do moving 38 feet of boat around a lake. That was impressive, but even more impressive is output of the optional 7.5-kilowatt generator’s output to the V10’s.

If a buyer were to select four 48-volt capable motors, they would have 26 kilowatts of power available. Fortunately, it’s not an all or nothing proposition and you can mix and match 12 and 12/48 capable engines. Obviously, four engines, each capable of producing 6.5 kilowatts is overkill. So, it seems more logical to equip two engines with the 48-volt alternator and instead have 13 kilowatts of power available. That’s still a sublime amount of power available for a 38-foot boat.

Best of all, when 48-volt power is being produced, more of it can be harnessed than would be typical for a generator. Often, when a generator is running, it is very lightly loaded, which isn’t very efficient. But, becuase the power the engines produce is harnessed to recharge a large LiFePO4 bank, runtime in generator mode should be significantly reduced.

If you can’t tell, I’m quite excited, and very pleasantly surprised, about the alternator in these motors. 48-volt in boats has long seemed like a chicken and the egg problem. Many have been able to recognize the potential benefits of it, but also the difficulties. To date, there haven’t been enough 48-volt components available, and we haven’t seen mainstream builder adoption. Now, Mercury is advancing the cause of 48-volt in an engine that’s likely to see significant volume.

There is one thing potentially tempering my excitement. The 48-volt mode of these alternators is designed to be harnessed by Brunswick’s Fathom e-power system. It’s not clear if and how a non-Fathom system could leverage it. There’s nothing proprietary about 48-volt power, but controlling the output may require SmartCraft integration, and that might leave non-Fathom systems out.

I’m very hopeful that Mercury’s, and by extension Brunswick’s, inclusion of a 48-volt capable alternator will advance adoption. We need components including fuses, power distribution, bilge pumps, lighting, windlasses, and more. But, for these products to be developed, there needs to be demand.

I’m hopeful this entry into the world of 48-volt will create the demand needed to stimulate the development of 48-volt components. Only time will tell, but the support of a major player like Mercury certainly helps.