Is the intended system properly waterproof? An absolute minimum requirement to ensure! It's about fundamental safety at sea. Water always finds a way in when accidents happen. A drowned motor equals a new one.
Is the battery system covered by a warranty of at least 6 years, and is it approved for boat use, waterproof, and equipped with a Canbus/Torqlink system? Never purchase a battery system that isn't approved; it's about fire and operational safety. Insist on seeing certifications. All reputable manufacturers possess these.
There's no shortcut to a good and durable battery system. How energy-efficient is the intended system? The system battery is the most significant expenditure. A highly energy-efficient motor saves space, weight, and ultimately money.
Air-cooled motor? Generally, an air-cooled motor has very low efficiency and is typically not waterproof. Therefore, we never use these.
Does the manufacturer have a certified service center in Denmark?
A "use and discard" China system is generally a poor purchase. All reputable manufacturers have an extensive service network.
Is the motor system fully digital with Canbus/Torqlink, including the battery bank? A minimum requirement to ask! It's about operational reliability, safety features, and accurate consumption display.
Motor Controller? Is it digital and water-cooled, or old-fashioned air-cooled and not waterproof? Good cooling is essential for energy efficiency.