Electric Yacht

FAQ

Q: How does the weight of an electric system compare to a conventional gasoline or diesel system?

A: A: It depends on battery capacity.  A 36V 100AH system can weigh as little as 250 lbs.  A 36V 200AH system would be about 425 lb.  A 48V system would weigh in at around 550 lb.  By comparison, a typical engine, fuel, fuel tank, exhaust and other equipment might weigh in the 400 - 600 lb range.

Q: How does the hp rating of the electric drive system compare to a conventional gas or diesel motor?

A: Our electric drive systems are rated, 4.5 shp or 6 shp, depending on battery voltage.  On the surface, this seems low when compared to the published hp ratings for gas and diesel engines.   However, it is important to realize that most engines do not develop their rated hp in most applications.  Power is used to drive accessories and the match between engine and propeller is not good enough to achieve full rated power.  This puts the electric drive on a more even footing, in comparison.  Also, an electric motor can develop full torque right down to zero speed.  This means it can accelerate quickly when manuevering.  Add the fact that there is no warm up, no shifting and no motor stalls.  This makes for superior performance when docking and manuevering in close quarters.

Q: Are electric drive systems under powered?

A: It depends. A 36V or 48V system has enough power to drive most boats (up to about 32 feet) to hull speed.  Where the fossil fuel burning engine has an advantage is when driving into a chop and head wind.  In this case, the electric powered boat will lose some speed.

Q: How does the regen work?

A: Any elecric motor can be made to function as a generator.  When the motion of the boat causes the propeller to spin, the motor starts producing electricity.  The motor controller pumps this power back into the battery bank.

Q: What is the range of an electric conversion?

A: This is a function of battery capacity, boat performance and power setting. A typical system will have about 90 minutes of run time at full power.  At 6 knots, this translates into under 9Nm. Reduce speed to 4-5 knots and the power consumption drops off dramatically.  The range can increase to a 15-20Nm. Range can be extended further at lower speeds.

Q: Can I use my existing prop shaft and prop?

A: The Electric Yacht systems are designed to allow you to use your existing shaft and propeller. Though better performance can often be achieved with a larger propeller, we suggest you try the one you have. If it meets your need, there is no need to change.

Q: Can I swap out the electric motor while still in the water?

A: Yes. Our system is designed to make installation as simple and easy as possible. Since the existing shaft and propeller are used, there is no need to haul out to make the conversion.

Q: What are the advantages of the reduction unit?

A: Electric Yacht systems use a cogged timing belt reduction. This allows for maximum horsepower and efficiency from the motor. Provide the diameter and pitch of your propeller and the desired battery voltage (36V or 48V).  We will supply the belt reduction ratio that will give the best performance.

Q: What type of battery should I choose?

A: We recommend flooded lead acid 6V batteries commonly used for golf cars. These typically have a capacity of around 200 amp hours (AH). These are economical and are designed for deep discharge. The primary disadvantage to flooded batteries is they need to be mounted upright and need regular addition of distilled water. If your pockets are deeper, you may want to consider absorbed glass matt (AGM) or Gel batteries. These never need service and can be mounted in any position. They perform well in deep discharge applications, but cost significantly more.

Q: What size battery bank should I choose.

A: Again, this depends on your need and expectations.  A 36V system is recommended for boats under 30 feet.  Especially, weight conscience racers and those on smaller inland lakes and waterways.  A 48V system is recommended for larger boats and anyone wishing to maximize range and power.

Q: How do I recharge my battery bank?

A: Most boat owners will want to install three step "smart" chargers to charge when shore power is available. For extended trips away from home, a small gasoline generator can be used to charge the batteries through these chargers. In addition, the batteries can be recharged while under sail. Simply put the throttle in "neutral" and leave the key "ON". Any time there is enough boat speed to turn the propeller, the batteris will be charging.

Those who have a moored boat and those who wish to detach from the grid have other options. Solar panels and wind chargers can be set up to charge the batteries when used with an Electric Yacht charge converter.

Q: So what's the true cost of an electric conversion?

A: In addition to the Electric Yacht system, you will need batteries, battery boxes and chargers. The cost with flooded batteries can be expected to range from $300 - $1200. An AGM or gel system could run in the $2000 - $2500 range.