Electric Yacht

Q:  What type of battery should I choose?
A:  We recommend good quality flooded lead acid 6V deep cycle batteries.  These are commonly used in electric golf cars. They typically have a capacity of 200 – 250AH (amp hours). They 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.
Absorbed glass matt (AGM) batteries never need watering and can be mounted in any position. They perform well in deep discharge applications, but cost more.
Those who wish to be on the cutting edge may want to consider Lithium Iron Phosphate (LFP) batteries.  They provide twice the energy density/unit volume and four times the density/unit weight.  They are maintenance free.  With proper care, they can be expected to last many times longer.  They are expensive, but prices are coming down.

Q:  What size battery bank should I choose?
A:  Again, this depends on your needs and expectations.  Boats under 30’ on smaller inland waterways may be fine with a 100AH battery bank.  For most, a 48V or 72V bank of 200-250AH is recommended.

Q:  How do I recharge my battery bank?
A:  Solar panels, wind generators and regeneration can provide all, or most, of total energy needs.  Most boat owners will also want to install "smart" chargers for use 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 batteries will be charging.

Q:  So what's the true cost of an electric conversion?
A:  In addition to the Electric Yacht system, you will need batteries and chargers. The cost of 8 flooded batteries and a charger is about $1500. An AGM system with charger would be in the $2500 range.