andyrebele

With that outboard at wide-open-throttle, you were emitting ~ 4 gallons of unburned gasoline per hour out the exhaust, not to mention the oil you cited.

There are all sorts of surveys, but the best source I've found for real data on how much these boats are used is this official report on fuel usage (2013):

https://www.fhwa.dot.gov/policyinformation/pubs/pl17012.pdf

Basically, it indicates that recreational boats use 1% of the fuel of all passenger cars.

While it's not a small market, it's in the Bay Area's blind spot. Fishing is the 2nd most popular outdoor activity in the US, behind running. In the US, there are 20 million people who fish for freshwater bass alone (1 in 16 Americans). Bass Pro Shops is the Missouri unicorn that grew from nothing to be big enough to buy Cabela's for $5 billion, based largely on their boat sales.

True, and they're so bad that CARB published a report saying one long day in a 2-stroke jetski pollutes as much as 10 years in a typical car.

Most 25-40 HP outboards sold today are 4-stroke. The only significant brand that's still 2-stroke in the US is Evinrude, and it has < 10% market share.

Besides the oil, the carbureted 2-strokes emit 25%+ of their fuel unburned.

The E-Tecs have done exactly what you said - a lot of engineering to meet emissions requirements. Unfortunately, the requirements for outboards include CO, NOx, and HC, but not P2.5 or P10 (particulate) emissions, because they are much simpler and less scrutinized than the regulations on cars (which DO have particulate limits). The E-Tecs put out 30X as much particulate emissions as the 4-strokes.

There are 3 answers to the "higher power" topic: 1) higher power motors are easy, bigger batteries are expensive and heavy. 2) frequency and regularity of usage are the best determinants of whether electric makes economic sense, not size/power, but the bigger power boats tend to go infrequently and highly variable distances. 3) longer-term the low utilization rate high capex problem is solved by shared usage models (as it has been in every other field).

We took a coaching launch like the one in this article, fitted with the Pure Outboard, from Pier 52 in SF to Alameda Island and back. (Granted, it was not the wisest move.)

This outboard motor is 100% compatible with existing hulls, and complies with ABYC standards. That's the beauty of the boat market - a built-in API for the interface between the powertrain and the hull. The rowing club in the article is using the same hulls they've had for years, and mounting the new Pure Outboards on them.

Ha! Thanks. The video (if you're referring to the one on the web site) is an attempt to give the viewer a modicum of the feeling you get with a ride in the boat. The FAQ on the web site, and the specifications listed there, address the questions you're posing.

There are 15.7 million recreational power boats in the US alone (1 for every 10 households), 70% of those in the installed base are powered by outboard motors. This is not the car market, but it is not tiny.

Most of the electric outboards have bad reputations for reliability, as you said. And the warranties are even shorter than those of gas outboards. But this one is the first to be designed from the ground up for electric, and while the warranty hasn't been announced, it will be far longer than those of gas outboards. The reason the other electric outboards break down so much is that there are weak links, borrowed from other products (like gas outboards).

The water. So they put the noise underwater, and it sounds quieter to the operator, so they think they're approaching the fish in a stealthier manner.

Before we did this outboard, I watched the Jamie Hyneman video you referenced. Because he doesn't use active thermal management of the cells, I would expect the cycle life to be ~ 300 rather than the 1500 we expect with this one. Since battery depreciation totals about 4-5X as much as electricity usage over the life of the system, not doing thermal management multiplies the cost of an outing by about 5X. The Hyneman system would effectively pollute more than gas outboards, because of how quickly the batteries would be consumed.

This is not 2-stroke. This is 4-stroke engines. There are no catalytic converters on marine outboard motors, so the 4-strokes are allowed to be > 100X as polluting as cars.

See an analysis of whether this makes sense for home, business, and utilities: http://www.purewatercraft.com/thinking-about-energy-storage-...

This post was not about boats; it's about li-ion batteries in general. We learned the lessons when developing our outboard motor battery pack, but the batteries we're using are the same cells used in laptops, and the same chemistry as used in cellphones, tablets, etc.

There is no specific charge level at which battery use becomes costly. It's just more costly to charge the higher the voltage to which you charge. Of course, overcharging (over the rated voltage) is extremely costly (and dangerous). Under that level, the device maker has to make an arbitrary choice about how to balance cycle life with calendar life, and that choice is usually near (but not at) top voltage.

Our tests have found that charging a cell to 80% instead of 90% can extend its life by more than 50% under the same conditions of use, sometimes much more (lots of factors: charge/discharge rates, temperature, time between cycles, etc.). I'm sure no cellphone/tablet maker is limiting charge to 80%.

I put a link to Battery University at the end. Some of the numbers came from there. Others come from cell data sheets (best ones from Panasonic). A lot of this is synthesis over many data sheets and white papers, none of which would by themselves be illuminating to the average battery user, because so much of the data would be cell-specific.

You're right that device manufacturers choose what to name "100%". Generally, cellphone makers are most attuned to people running out of power, so their 100% is pretty close to the real top charge level (not overcharge). They are rated and tested and reviewed based on tests like Walt Mossberg's run standard processes and see how long it runs until empty. The incentive provided by such make-or-break tests is to allow users to fully charge and fully discharge.

Better control and information would be provided if you gave the actual voltages and chemistries, but both are beyond what a normal user would be comfortable using on a daily basis. Internally, we almost always refer to state of charge in cell voltage terms.

Tesla and BMW provide the ability for the user to know and adjust the top of the charge. Tesla's approach is fairly user-friendly, and BMW's is a little more powerful, albeit less user-friendly.