Sizing DIY Batteries and Components for 10kW motor

[wpduhe]

I've never built anything electronic ever. But I have been doing some research and have a list of components I'd like someone to peer review to make sure I'm not going to waste what budget I have on components that won't do the job.

My goal is to repower my 12,000lbs sailboat with a 10kW motor (it should seldom experience that kind of output). The battery and BMS (planning on 48V) will be powering that motor, a 3000W inverter, and small 12VDC house loads using a 35A DC-DC converter; but never all of them simultaneously (typically 2 out of 3). My concerns are mostly around sizing a battery and BMS that can power the motor since it will be the largest load. According to the specifications on the website, the motor at 48VDC is rated at 21kW peak, and 8.6kW continuous. I don't expect to exceed 10kW, but I'm not an expert in this area. So based on the 8.6kW cont. rating, I guess I'm looking at ~179A potential continuous to the motor controller (I still don't think I'll be using that much power, maybe more like 60A - 100A, hopefully even less 50A?).

This is what I need to power (hopefully only to 50%):
The motor: ME1507 from electricmotorsport.com
Motor Link: https://www.electricmotorsport.com/...-sevcon-gen4-48v-450a-motor-drive-system.html

This is what I think will power it:
I'm planning on using these LiFePO4 cells as they seem to offer 280A discharge?: 16 x EVE LF280K all in series
Battery Cell Link: https://www.docanpower.com/index.ph...product_id=456&search=lf280k&description=true

I'm undecided on the BMS. I want it to be exceptionally reliable which is why I prefer to use Overkill 16s BMS, but they only offer a 100A model. Therefore, I'm considering, and expecting, to have to use a Daly (or some other) 200A BMS. (this is my biggest concern).

Hopefully, I'm not missing anything.

I appreciate the incoming education and advice. Thanks everyone!

 

[krfish]

The biggest problem I see is that the motor appears to pull about 437 amps at full load startup. In fact, if you look at the link, it appears to state 450a (assuming 450 amps). That motors running amps looks to be around 179.

So the key things I would think to consider is making sure your have enough batteries in parallel to accommodate the startup amps and then calculate how long you think you will run the motor. You're going to use 179 amps an hour. 280 amp hour batteries are only going to give you an hour and a half of run time if you run them dead.

 

[wpduhe]

The power draw is regulated by the motor controller which, in turn, provides variable amounts of power to the motor based on input from the throttle to control the speed of the motor. So is the load ever actually 450A peak / 179A cont.? I would think only if you maxed out the throttle would it pull that kind of power. I hope to be operating this motor around 50A, which, at +-33% of its continuous draw, should give me +-1500 RPM. And closer to 5 hours of operation. I'm not really sure about all of this though. I'm a complete amateur.

Seeing as the motor controller is programmable, I plan to limit the power draw to 10kW, if possible. Unless, of course, I find that I require more power.

 

[Ampster]

It looks like a three phase motor so there might not be much starting surge. Some of those Curtis's controllers also have precharge circuits for the motor controller which is presumably a variable frequency three phase inverter.
Do you know anything about the torque and RPMs of the existing or former engine? My experience years ago was that there was a sweet spot in terms of RPMs, speed and consumption.

 

[wpduhe]

It looks like a three phase motor so there might not be much starting surge. Some of those Curtis's controllers also have precharge circuits for the motor controller which is presumably a variable frequency three phase inverter.
Do you know anything about the torque and RPMs of the existing or former engine? My experience years ago was that there was a sweet spot in terms of RPMs, speed and consumption.

The current motor is a Yanmar 3GM30F, 24HP continuous output diesel motor. When I use it, I run it between 1500 and 2000 RPM and usually for less than 1 hour. I have run it for longer when going upriver. But getting to open water is all it is used for under normal circumstances. I haven't been able to find any power curve charts for the motor (not in the document from which the attached image was copied). The electric motor purportedly has 34Nm of torque at any RPM.

 

[Symbioquine]

I think the EVE LF280K is rated to 0.5C discharge rate - so 140A per cell or battery. You're not losing much with the 100A BMS since you probably don't want to push each battery to that 140A rating all the time and probably want several batteries anyway from a capacity standpoint...