It's great to see electrification taking off, as was definitely evident at a recent boat show. It's a little less great to see how much charlatanism and huckstership have tainted the nascent field of marine lithium batteries and the equipment that uses them.
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This 1100 W electric outboard is equivalent to a 3 hp gas engine!
1100 W is 1.475 hp, by the literal definition of horsepower which is 1 hp = 745.7 W. Stop lying.
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You can replace your 25 hp gas engine with our 12 kW electric motor and the boat will perform just as well!
No, it won't. See above. This "performance" comparison is based on one specific metric: the time to accelerate from hull speed to on-plane speed. The 25 hp gas engine makes its 25 hp at 6000 rpm. It can't reach that until the boat's already on plane, because the advance velocity of the propeller is too low during the climb "over the hump" and therefore the engine has to slog through that phase at perhaps 3500 rpm. The electric motor, meanwhile, can crank up its coil current and supply its full 12 kW (16 hp) at the lower speed. Once the boat's on plane, and the gas engine is free to rev up, that comparison is no longer valid, and the 12 kW (16 hp) electric will perform almost exactly like a.... you guessed it.... 12 kW (16 hp) four-stroke.
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Look how awesome this pontoon boat is with its 180 hp electric outboard and our proprietary lithium battery! It can cruise at 30 mph!
OK, how big is the battery?
It's 43 kWh but you can have two or even three batteries for $30,000 each. The boat's range is 55 miles per battery.
43 kWh into a 180 hp = 134 kW motor is 19 minutes from full charge to depletion assuming perfect efficiency. I doubt you're actually breaking the 80% efficiency mark in reality, and I don't see any air or water cooling on that battery pack, so I'm guessing more like eight minutes before it goes into thermal limp mode. Does the pontoon boat run 172 mph, or are your range claims and your cruise speed claims made under very different conditions?
Umm, the range estimate is at 5 mph.
All right, and it's a pontoon boat hull with a uniform cylindrical section and a very stern-down trim. You do realize that if you had spent an extra \$4,000 on a hull shape that's meant for efficient hydrodynamics at 5 mph, you could have cut your \$60,000 to \$120,000 propulsion expense in half while keeping the range the same, and had money to spare for some small hydrofoils to make the short 30 mph sprints possible?
(Dumbfounded stare)
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These lithium batteries are a drop-in replacement for your Group 31 AGMs.
Great. Nicely packaged, very stylish. What chemistry and cell type is inside them?
Lithium.
Yes, that's what you said. Is it lithium-iron-phosphate, or LMO, or one of the cobalt-rich types? Who made the cells?
It's lithium. We don't disclose our proprietary details.
All right, well, to an engineer like me there's a pretty big difference between soldering together a bunch of UltraFire 18650s you got off AliExpress, versus boxing up some LFP prismatic cells from CATL's reject dumpster, or using carefully-binned Winston LFPs that are top-balanced on every full charge. I can't buy the thing if you can't answer this. What're you using for a BMS?
Oh, it's a wonderful BMS. Fully integrated, protects the battery against everything that could go wrong.
Where's it's communication port?
What do you mean? It's all internal. Self-contained.
So, it responds to anything going wrong by.... suddenly shutting off the battery entirely? With no signal to the alternator regulator and solar controllers to ramp down smoothly, just a sudden open circuit and then the charging sources respond with an inductive spike that blows up half the electronics on the boat?
(Dumbfounded stare)
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These are the absolute best electric outboards I've ever used. Very efficient, reliable, easy to carry.
They look quite nicely made, although the industrial design is a little, well, odd. What's the price?
This one's 5 kW which replaces your 10 hp gas motor (Grr......) and it's $13,000 including a 100 Ah, 48 V battery.
(clutching chest in shock) OK, that sounds a little steep for (checks calculator) 57 minutes and 10 miles between three-hour recharges on something that competes against a $3000 7hp gasser. But it's a nice piece of engineering, and good luck to you all the same. I hope the manufacturer does well enough to invest in some factory automation and bring the price down from the stratosphere.
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I'm very much in favour of electrification wherever it makes sense.
I think lithium-ion batteries (and, coming soon, sodium-ion batteries) are an excellent choice for many applications, including both propulsion and house power on boats that are appropriately designed to make use of them.
And, as regular readers may recall, I'm working on an all-electric boat for my own use.
But this kind of ignorant, ill-informed salesmanship is not in the customer's best interests. It's not in the industry's best interests. It's sloppy, lazy, and those of us who actually have the real technical knowledge can see right through it.
If you're a buyer, then beware. Take the time to learn and understand the technology before you break out the credit card. In my experience, somewhere between 60% and 80% of salespeople pushing this stuff are full of hot air and don't have even the most basic technical understanding of their own products.
If you're an industry insider, then it's time to sit down with your staff and ask some hard questions. Take some training. Read up on the basics of electricity and propulsion systems. Be able to do the math. And, most importantly, be able and willing to tell the customer the truth about what you're selling — what it can and can't do, how it really compares to what they already have, and how you'll commit to supporting it in the long term.