Q: What type of battery should I choose?

A: Most economical are 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 Mat (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 (LiFePO4) batteries. They provide twice the energy density/unit volume and three 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: The following table will serve as a guide for estimating your battery bank size, as well as the recommended system for your boat:

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 a 48V “smart” charger 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.  The battery monitor display will automatically switch to displaying the level of input.

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 flooded batteries is roughly 1/2 of AGM and chargers are listed here on the Web site. Numerous choices in batteries are available. If you want to estimate the cost of a system including batteries please go to our Design Page.  You will find a form to fill in that asks for your boat specs.  Send that in and in a few days you will receive a Performance Projection specific to your boat and your sailing style.

Q: Where do I start if I know nothing about batteries and electric power for propulsion?

A: If you are curious about the origins of batteries in propulsion and the development of all types of batteries, including Lithium-ion, there is a Web site called Battery University.  Tons of info on marine batteries.  Unfortunately, it’s author is not a sailor, but there is current, specific content about batteries for plug-in automobiles.