Electric motors for boats gain popularity every year. While simple trolling motors have been around for decades, today’s electric outboard engines compete with their gasoline counterparts on nearly every level.
What is an Electric Outboard Motor?
Outboards come in many size ranges and are typically used on everything from very small skiffs and inflatable tenders to sizeable offshore fishing vessels. Gasoline outboards come in sizes, but electric options are not only available for the lower end. Many boats can accept multiple motors, and this is an option with electric motors as well.
Electric outboards are designed based on the existing infrastructure of outboard boats. They share a similar footprint and require a similar mounting area on the transom of the boat. As with gasoline outboards, the transom’s height will dictate the length of the outboard shaft you need to buy.
One of the leading manufacturers of electric outboards, Torqeedo, sells models ranging from 1 to 80 horsepower compared to equivalent gasoline outboards. Such a range allows them to compete with all but the biggest gas outboards. For their high-power options, Torqeedo is using batteries manufactured for BMW automobiles and specially upgraded for marine use.
With such a wide variety of options, there aren’t many boaters who can’t use an electric motor on their vessel. For portable models under ten horsepower that can be carried and mounted by hand. Electric outboards provide a great alternative to gasoline motors. Bigger and more powerful models are available, and becoming more popular.
Things to Consider with Electric Motors for Boats
The benefits of electric outboard motors are many. There is no gasoline usage and no exhaust. There are no oil changes, and nothing to spill or pollute. Most are maintenance and trouble-free, while fuel issues and carburetors problems plague small gas motors. Instead of yanking at a starter cord endlessly, imagine just pushing a button and zooming off in stealthy silence.
Electric motors are torquey and very efficient so that you can get more energy out of a smaller package. Further, since most of the weight of an electric outboard is focused in the batteries, you can more easily balance the weight in a small boat. And obviously, electric motors are the greener option. They run quietly and can take you anywhere but the fuel dock.
Until now the most significant disadvantage, and the most limiting factor of electric outboards, has been batteries’ size and weight. Thanks to the rapid development and lower costs of production new lithium technologies have enabled smaller and lighter batteries. They’re able to be deeply discharged and they accept very high currents for discharge to run the motor at high RPM and recharge the battery. Depending on the size of the outboard you’re shopping for, the unit will have a small integrated battery or will connect to a larger onboard battery bank.
You can easily recharge your electric outboard motors battery bank at home, the dock, or onboard your boat via solar panels or wind power generator. Just plug the battery into its charging unit and that’s it. The only consideration that needs to be addresses is the voltage and amparage you have onboard your boat. Some chargers are specially designed to use high-voltage or high-amperage outlets for quicker charges. In this case the only option would be charging them on dock or at home. But if you’re using the electric outboard for your tender, you can charge the battery from your big boat’s system, using the engine alternator, solar, or AC generator.
Range and Speed with Electric Outboard Motors
The big question that most people have about electric motors for boats is, how far and how fast can they go? It’s a tough question to answer, not just because all boats have different weights and configurations, but also because users have different expectations.
By far, the most common application for small electric outboards is for small tenders and fishing skiffs. There are two types of users:
– those who want to replace rowing and move their vessels at hull speeds
-those who want to get on plane and travel long distances quickly
Moving a small tender or skiff at hull speed doesn’t take much power. It has been successfully done for decades with electric outboards. Indeed, trolling motors are an inexpensive way to make this happen. They usually are on the very low end of the power required to do it. Electric outboard engines will provide much more torque. Their prop designs and power consumption will result in a higher top-end speed and more efficient operation. Outboards in the one and a half to three horsepower equivalent range are perfect for this task.
Getting a boat on plane is a more challenging task. It requires a lot of excess power to break the water’s surface tension and get the boat’s hull on top of the bow wave. To make it happen, gasoline outboards need to be a minimum of eight horsepower for even the smallest and lightest boat. With electric outboard engines it can be done with the right combination of batteries and motor.