Eric,
Thank you for taking the time to reply to my email. My sailing is 100% local bay and short trips around NJ/NY shores. I use motor only to get in and out of the marina which in my case can easily take 25-40 minutes waiting for two draw bridges while fighting the current.
Small generator is great and I also hear you can even power the motor with it rather than charging the batteries ( Did I get this right???)
My reasons to go electric are:
1) New system vs rebuilt parts of an old engine.
2) Silent drive
3) DYI, Looks to be less expensive than 5k rebuilt Atomic 4 or even more money with a diesel. I understand its not going to be perfect as it would be from one of the known vendors but on this 1976 boat it will do just fine. Again, I never intend to go on long ocean passages on this vessel.
4) Its possible the value of the boat will actually increase :)
5) Its a cool project :)
On Monday, October 28, 2013 12:46 AM, "ewdysar@yahoo.com" <ewdysar@yahoo.com> wrote:
Hi Val,
Here's some more info to think about.
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2. Range is a funny thing. I made sure that I could motor over 20nm at 4kts (that's 5hrs). But the boat is considered a sailing auxiliary, the motor is a backup. When my boat was still diesel, I never burned more than 2 gallons in a weekend of coastal cruising, most of my time was spent under sail. Of course, I couldn't blindly accept such a limited range under power, so I bought a portable generator (mine is a Yamaha ef2000is, very similar to a Honda.), a backup to my backup. It weighs 50 pounds with a full tank and fits in a cockpit locker for transport. I have tested it by plugging my shore-power battery charger directly into the generator running on deck and have found that the generator/charger/electric drive combination will drive the boat at 4.4kts without any power from the battery bank. I've motored like this for an hour to prove to myself that it would work (it did) and when I slowed down, the excess power charged my batteries. Here's the clincher, in three years, including weekend passages over 30nm one way to offshore islands, I've never needed the generator. I don't bring it on day sails. I've got no solar or wind generation and regen is insignificant at my boat's speeds. But with 8kWh (160Ah x 50V) range has not turned out to be an issue. I didn't expect that, but that's the way that things have turned out.
It really all comes down to how you actually use your sailboat. If you typically buy 10 gallons of fuel a month to motor around, then electric drive may be too much of a compromise. But if you spend most of your time sailing, then electric may be a good fit. Converting my ketch to electric drive has worked out well for me. I had the opportunity to convert my F-27 trimaran to electric when my outboard died. Electric would have been more expensive, slower, less powerful, more complicated, heavier and would not have met my offshore racing range requirements. I bought a new 9.8 four stroke outboard for that boat. Different answers for different problems. One size does not fit all.
3. A quality drive system will end costing very close to what an internal combustion DIY re-power would cost. I don't suggest that anyone convert to electric to save money. There are plenty of other good reasons to go electric.
The regular system vendors that have been recommended many times on this list sell engineered solutions with predictable performance. They take a good deal of risk out of your conversion. Some folks here have put together good efficient systems from loose components or very basic kits, others here have not been as lucky. Some of the homemade systems end up needing some rework, reducing or eliminating the perceived savings.
Personally, I converted a number of cars to electric in the mid 1990's. with that experience, I chose a complete drive system from Propulsion Marine in Santa Barbara. The combination of motor size, gear ratio and recommended propellor were spot on. The drive unit is surprisingly small and simple. I could have fumbled around on my own for twice as long and ended up with a system that worked, just not as good as the one that I bought. By the time you add in all the small components that come with the drive system, the kits don't save you as much as you think. I think that whatever premium I paid for a complete solution was money well spent, it may have even saved me money in the long run.
My personal recommendation is for you to seriously consider Lithium (LiFePO4) batteries. They seem expensive, but they are honestly better batteries for our purposes. I know a number of people personally that have installed lithium batteries, along with a few other people in this group, and every single one is glad that they took the plunge. Of course, I've heard plenty of arguments from people that have never used them, and heard of people on the Internet that have had problems, but I know none of them personally. It's your money and your choice. I know that they are worth it to me.
That should be enough to think about for now.
Fair winds,
Eric
Marina del Rey, CA
---In electricboats@yahoogroups.com, <vechnyak@...> wrote:
My boat is an old 1976 Catalina 30 (tall) and this past weekend we just pulled out the Atomic 4 engine. Over the winter I am planning to work on re-powering it with an electric motor. The boat is used for day sailing in the bay and short trips along the NY/NJ shore.
Information is available online about motors but battery info seems vague at least to me since I know next to nothing about battery types and their advantages. Does anyone know of any formula that would allow to calculate all the variables to achieve say 2 hours of propulsion and have a reserve?
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