Posted directly below is “Electric Outboard Drive for Small Boats” , a 43 page on-line handbook created by Todd Wells. This is a very thoughtful and practical guide providing real detail, useful suggestions, and important issues to consider for anyone planning to build or modify a boat with electric outboard propulsion. Todd has recently completed a very nicely done installation on a 17ft ‘freighter’ canoe up in the Pacific Northwest and wanted to share his experience with others interested in similar projects. I helped Todd source some of the components he used for his project and he is graciously allowing me to distribute this document via epowermarine.com (thanks Todd!)
Please take the time to read it; you’ll be glad that you did! Capt. Todd Sims
Frequently Asked Questions that you may find
helpful in exploring electric boating in general, and electic boats in particular. If you still have questions
after reading these, please feel free to contact us for
additional assistance.
1. What do you mean an “electric boat”? Is this some new, untested technology?
Not at all! Electric boats have been around for well
over a hundred years. At the 1893 Worlds Fair in Chicago,
a fleet of 55 electric launches carried people to and
from the water-based venues. These boats ran all day
everyday and were considered a great success. Once the
internal combustion engine was invented, the practicality
of electric propulsion was all but forgotten - not necessarily
for the right reasons.
Even now, electric launches remain very popular in Europe, and also enjoy a large following in Southern California. Although the basic concepts are similar to the boats of yesteryear, huge advances in motor, propeller and battery technologies now allow us to enjoy an ecologically sound alternative to 'combustion engine boating'.
It’s also worth mentioning that most huge cruise ships, many military ships and submarines, and most freight/passenger trains operate on electric drive systems powered by diesel generators. The electric drive is nothing new - but until now has not been a readily-available choice for recreational boating.
While most of us love to go fast in our boats, many have never experienced the unique pleasure of cruising slowly and silently in an electric boat. Waterways we thought we knew come alive in new ways, and without the environmental impact of sooty exhaust, irritating noise, or large wakes to spoil the moment and disturb the peace.
There are now many choices for the savvy consumer to consider. Everything from small runabouts with tiller steering all the way up to a 24 foot diesel-electric hybrid on which you and 11 of your closest friends can stay out on the water all day.
These boats are safe, stable, and simple to operate - with almost no maintenance, and operational costs of less than $2 a day! Electric boats are a perfect choice for lakes, ponds and many of the waterways in South Florida and no matter where you live, EPower Marine can show you the way.
3.
How fast does it go and how long can I stay out?
Generally, all of these boats are “displacement hulls”, and are designed to be operated within a pre-determined range of speed – from 'making way' up to about 8 MPH, depending on the model. The top speed is limited not only by the hull shape, but by the motor controller. Anywhere within this range, all of the components will work efficiently together.
You can expect to motor for 8 hours at 75% throttle, yielding a distance of approximately 40 miles. The slower you go, the longer the batteries will last, and the more miles you can cover.
Most people are very surprised just how ‘fast’ 6-8 MPH really is! Considering that this boat is designed for inland cruising, like the Intracoastal Waterway and residential canals, this is a perfect speed for the intended usage. Plus, you never have to worry about a ‘no-wake zone’, because there is hardly a wake!
Another important measure of ‘performance’ is not speed at all, but “throttle response”. These boats are inherently responsive to throttle changes, and provide the operator precision control, unlike most 'powerboats'.
4.
What can you tell me about the batteries used onboard?
Lead Acid/Wet Cells/Dry Cells
There are 2 general types of batteries used on our electric boats. The ‘lead-acid’ group includes deep cycle ‘wet cells’ similar to most golf cart batteries, in either 6 or 12 volt. Also in the lead-acid group are the AGM drycells, more correctly called ‘Absorbed Glass Matt Valve Regulated Starved Electrolyte’ batteries.
These are used in the higher end boats and have some real world benefits for marine applications. ‘Gel’ cells are also in this group but we do not use them because they are easily destroyed if not charged correctly. Many people confuse AGM and Gel, although they are not the same.
Lithium Manganese The other general type is “Lithium Manganese”, produced by Torqeedo in Germany. These are available for the small portable outboards and will soon be available for the larger boats. They are much lighter weight in comparison to Lead Acid for the same capacity. Cost and availability continue to be a challenge but this is where battery technology is headed..
Weights & Measures
In the Lead Acid world, battery capacity can be loosely compared to the weight of the battery bank. One 500 lb battery bank has essentially the same storage capacity as the next 500 lb bank. Yes, different brands, construction methods, sizes/cases, and operating characteristics will produce small differnces, but lead is lead. It will produce a constant ‘amp hour’ rating.
Electric boat owners care less about ‘cranking’ or ‘starting' amps, but are concerned with the ‘amp/hour’ rating, as it directly effects the time on the water. So, if an 8 hour cruise is your goal, you want to know how many amp/hours your batteries will give up during that time period. The rule of thumb is that the more amps you use over a short time frame, the more your total capacity is reduced.
For example, take a 100 amp hour 12 volt battery at a 20 hour rate. That means that the load (motor) can draw 5 amps over a 20 hour period before the battery is depleted. Even with a highly efficient hull and motor combination, 5 amps is going to be a slow trip.
More realistically is that same 100 amp hour battery, but with a load (motor draw) of 50 amps at ‘cruising speed’. You might think that you’d get 2 hours out of this battery (50 amps x 2 hours = 100 amp hours) but sadly, this is not the case. Since 50 amps is a large load to a 100 amp hour battery it is likely you will see only 80 amp hours of capacity, and will therefore deplete the battery in as little as 1.5 hours.
While the math can get bothersome, most electric boats can provide you with easy to read battery gauges. EPower Marine can help you size your battery bank according to your nautical needs.
The short answer is ‘you don’t! And that is because the boats have instrumentation that tell you how much power you have so you can make decisions about how fast and how far you can safely go. Seriously, this is not a big problem with these boats.
We can install a “LINK 10” power meter on your boat. You can consider this is your ‘fuel gauge’, although it displays more information than that. By monitoring this gauge you can accurately see how much power you have used, how much you are using at the moment, and how much power remains.
As any sane boater would plan fuel usage for their trip, the same holds true for electric boats. Plan on 1/3rd to get to your destination, 1/3rd for the return trip, and 1/3rd reserve emergency capacity. We recommend never discharging your batteries lower than 20%, and your batteries will certainly last longer if you don’t discharge them down to zero.
A good practice is to always have your boat plugged in whenever possible, as the automatic charger will not charge beyond capacity, and will therefore keep your batteries ‘topped off'.
All of our boats have built-in chargers that plug into regular 120 volt dockside outlets, sometimes called ‘shore power’. This is the same kind of outlet you'd see in your home.
Usually a 'full charge' takes overnight and costs about $1 or $2 dollars depending on your local power rate. These chargers are 3-stage smart chargers - they will not under charge nor over charge your batteries. Most of these chargers can and should be left plugged in all the time to maintain a ‘float level’ on the batteries.
Depending on the boat, we sometimes use a ‘bank’ charger that charges the entire bank as one, while sometimes we use individual chargers that charge each battery individually. It really depends on the boat, wiring, and some other factors.
7. What can I expect for required maintenance and total costs?
Compared to a powerboat, you can expect very little maintenance. Basically you will need to keep the batteries charged. The battery indicator will make this a simple task, and the automatic charger will always prevent damage from overcharging.
Compare this to the annual maintenance on a gas or diesel boat: oil changes, spark plugs & wires, fuel filters, fuel system cleanings, winterization, summerization, transmission service... none of which are required with EPower Marine boats. The operational savings (time & money) really start adding up to more time on the water and pennies a day!
Then there's fueling - either with cans or at the fuel dock, refueling with diesel or gasoline
is not only unpleasant, it's a fairly dangerous and nerve-racking activity that jepoardizes the waterways in which you operate, and is now completely unnecessary.
8. What warranties are offered with these boats, and who can service them?
All of the boats we sell have manufacturer's warranties. Terms vary, but typically everything is covered for the first year, and then a schedule of items are covered for longer terms. Some of the boats carry a lifetime warranty on the drive train components (motor, controller, and propeller). Batteries are usually full replacement for an initial period, and then pro rated after that.
These boats are not complicated to service, and all of the parts were chosen for long life and reliability. Many of the parts are standard ‘marine’ components and can be serviced by any capable boat yard. However, should you need service and are not located near a dealership, EPower Marine can arrange for a competent contractor to handle your repairs locally, and we can manage the warranty process for you!
