General Category > Electric Boat Conversions

What choice motor and controller for 55v nominal battery?

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Ziper1221:
Hello, I am looking at one of the 3kw BLDC motors for an electric boat conversion with a 55.5 v nominal (63v fully charged) battery. I'm looking for about 6000 RPM loaded. I realize I won't get this directly from the BLDC, so I will probably have a small belt or chain overdrive. This voltage puts me right between the 48 and 72 v motors. I assume that I am better off going with the 48v model and carefully watching my current draw and temperatures rather than undervolting the 72v motor and needing an even greater transmission ratio.

I don't really understand the differences between the ESC but I assume I will want the "EZkontrol 72 Volt Universal BLDC Motor Controller" since it is set up for liquid cooling. However, is it programmable enough so that I can set the low voltage cutoff to a lower value for my 55.5v pack?

Finally, if I want to control the ESC remotely, is it as simple as using a 5v digital to analog converter?

Thank you,
Robert

Bikemad:
Hi Robert andto the forum.


--- Quote from: Ziper1221 on January 19, 2025, 07:19:48 PM ---This voltage puts me right between the 48 and 72 v motors. I assume that I am better off going with the 48v model and carefully watching my current draw and temperatures rather than undervolting the 72v motor and needing an even greater transmission ratio.
--- End quote ---
I also think that the 48V motor would be preferable over the 72V motor, and I would suggest that a 48V controller should be used in preference to a 72V controller.


--- Quote from: Ziper1221 on January 19, 2025, 07:19:48 PM ---I assume I will want the "EZkontrol 72 Volt Universal BLDC Motor Controller" since it is set up for liquid cooling. However, is it programmable enough so that I can set the low voltage cutoff to a lower value for my 55.5v pack?
--- End quote ---
I suspect that the EZ-A48400 (or EZ-A48500) controller might be a more suitable choice than the VEC200 as the 48V EZkontrollers have a maximum voltage rating of 72V, which is well above your 63V maximum battery voltage.
Unfortunately, I have no direct experience with the EZ range of controllers, so I don't know what the stated "Hundreds of programmable control parameters" actually relate to.


--- Quote from: Ziper1221 on January 19, 2025, 07:19:48 PM ---Finally, if I want to control the ESC remotely, is it as simple as using a 5v digital to analog converter?
--- End quote ---
I've never tried using a digital to analog converter to provide a throttle signal feed for a controller so I don't know for sure if it would work correctly, or how the controller might react if the digital to analog converter malfunctioned while the controller was powered up.

Alan
 

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