I'm working on converting my catamaran sailboat to hybrid electric and want to use a Kubota z482 12hp diesel engine. I'd like to build a 5kW 48V generator to charge a 48V 27kW battery bank that powers two 48V motors for propulsion and an air conditioner. The plan is to keep the weight down by using lightweight 15kg axial flux 7kW BLDC motors. Since I'm removing two old Volvo 18hp diesels, can I use another 7kW BLDC motor as a genset with the same motor controller I'm using for propulsion, but just set to regenerative braking? It would be great to have all identical motors and controllers for spares, but I'm unsure if this setup will actually work efficiently. The controller is liquid-cooled and rated for 200 amps continuous, with my genset outputting around 100 amps at 48V. Any thoughts on this?
3 Answers
It sounds like you're mixing up some principles of regen charging. While it can help conserve energy when slowing down, it doesn’t necessarily work well as a primary charging method when under load. You might be better off directly coupling the diesel to a reliable DC alternator instead. I'd also suggest diving into the efficiency specs of the motors you're considering—it's important to ensure they can handle the load effectively.
Using regen for charging with a motor controller might not be the best idea. It's usually more efficient to have a direct alternator setup for powering batteries. You might not achieve that 5kW output you’re hoping for with this method. Plus, the electronics you’re considering could be too complex and heavy for this use. A straight-up 48V alternator paired with a good charge controller seems like a simpler, more reliable way to go. Just my two cents!
That makes sense! I want to keep things light, so I'm avoiding heavy equipment. What kind of alternator setup would you recommend for this application?
I design electric motors and controllers, so I can definitely help! If you share the details about the motors and controllers you're looking into, I can offer insights based on what I know from related marine applications. I have a few recommendations that could fit your needs.
Thanks! I'm looking at the Golden Motor 7kW and the Netgain products for this purpose. I'll share more specs to see if you can help further!
You're right about the efficiency. I want to make sure everything works seamlessly together without unnecessary complications. I'll have to look deeper into those motor specs.