Monday, April 15, 2013

Fourth Season with Electric Engine

This past weekend we launched Initram our 35 foot C&C for our fourth season with her. While fellow club members struggled to get old diesel and gasoline engines running after a cold winter in storage, we simply flipped a switch, and our boat was ready to go. The four sealed AGM batteries have made preparations for winter at haul out and launch very simple. All we do is charge up the batteries to 100% in the fall at haul out. On this our fourth year launching with the electric motor system, once again we turned the switch on and the monitor system showed that the batteries were 100% charged up and ready to go.


  1. i like the thought of replacing my small diesel that needs to be rebuilt or replaced. Have the costs to repower with electric come down to make it make more sense for a old blow boat that is only worth about $4000.00 ?

  2. Hey John,

    I'm a member over at National Yacht Club. I have an old boat with similar dimensions to yours and am thinking about going with an electric yacht system. How long can you run your system for at 3-4 knots and how many ah is the system? Also have you heard about anyone running a honda generator with a system equivalent to yours?


    Ryan Marr

  3. Cost-wise, re-powering with electric is about the same, once batteries and charging is included. you can scrounge parts and do it yourself and save lots of money, but you can also buy a used diesel and install that yourself for equivalent savings.

    One interesting development is the cost of lithium cells. Once discharge depth and cycle life are factored into the total cost of ownership, they are now the cheaper option by far. But with pleasure boats, it will be a long time before any of us reach 2000 charge/discharge cycles... The tipping point for me was the size and weight advantage. For the same amount of usable watt-hours, a lithium pack is half the size and 1/3rd the weight of an equivalent lead pack and about 2x the price. Also, the usable capacity of a lithium pack doesn't start to plummet as the amp draw increases. Read the spec sheets for your FLA and AGM batteries some time. The rated capacity is at a 5A draw or a 20hour discharge rate. Lithiums can deliver the same capacity at the 20hour rate as they do at a 1hour discharge rate. You should be able to put together a lithium pack for under $0.50/watt-hour, battery management system (BMS) included.

    As for serial-hybrid propulsion, there are two excellent use-cases below.

    Check out Mike'S Bianka is a Nonsuch 30 (16,000lbs) with a Thoosa 9000 system, in the same power range, and battery bank size. He regularly runs his system from a Honda 2000i generator through his 48V charger. The important thing is to make sure that your charger doesn't see the constant amp-draw as a problem in your battery bank and shut down charging.

    There is also a Bermuda 30 whose owner, Eric, is a contributor to the ElectricBoats YahooGroup. His Bermuda 30 weighs 10,200lbs and runs a 5.5kw system (the same one I am in the process of buying) with a 160Ah 48V lithium pack. He has posted some very pleasing "watts-to-knots" numbers. With his setup, he gets 4.4kts at about 1500 watts, which is as much as he can push things through his Yamaha 2000w generator indefinitely.

    To run in serial hybrid mode, you need to pick the right battery charger. It needs to be able to run as a power supply. Some chargers will think there is a problem with the battery pack if it doesn't see the voltage rise after a while. I believe the ProMariner Quad chargers have this issue. My vendor tells me the Elcon PFC2000+ charger has no issue being run as a power supply. Mike's Bianka runs a 48V Zivan charger through his Honda 2000i without issue as well.

    So yes, it's possible. Even practical, although...
    Keep in mind that a 2000w generator can put out about 1600w continuous. After conversion losses in the charger, you are looking at somewhere around 25A at 48V into the controller. So if you increase the throttle beyond that and the charger can push more than 25A, then you may overload the generator, causing it to disconnect the alternator and run at idle. The boat's power demand would be met by the batteries. Since these systems aren't integrated, it would be up to you to notice this fact and act accordingly. You'll need to keep your throttle at under 25A.

    Here is what my electrification will be:
    boat: 1978 Beneteau First 30
    displ: 7500lbs
    LOA: 30
    motor: PM-20 (
    power: 5.5kw
    batteries: 5kwh Lithium (48v - 100Ah)
    battery weight: 125lbs
    charger: Elcon PFC1500 or PFC2000+
    Prop: 12.5"dia x 14.5"pit 3-blade fixed



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