spinningmagnets
100 TW
Brushless motors can tolerate a wide voltage range, more volts than we can afford. The limits of concern for the motor is heat. You would do well to add a temp sensor to the stator (they are tiny). This way you can explore the limits. At the very least, you will learn the temperature where your type of motor dies.
If the motor is always cold, it's probably larger, heavier, and more expensive than your loads need. 190F is too hot, and temporary peaks of 140F is a useful goal. If you frequently hit 160F, you might consider selling the motor while it still runs, and getting a slightly larger one.
The Pikes Peak racer used a common 1,000W 9C direct drive bicycle hubmotor. He drilled large holes in the side plates to let the heat out, and ran it at 111V. I think he used 50A, but it was a long time ago. Its rated for 20A at 48V.
Lithium batteries are typically listed as being charged full at 4.2V per cell. They will last twice as long in months of daily use if they are only charged to 4.1V, and 4.0V is slightly better. There is no benefit to charging to 3.9V.
As soon as you use a cell for a minute, the voltage has a sharp drop-off to its fat middle, where it is reasonably steady at its "nominal" average for the whole cycle. Most cells list this voltage at 3.6V-3.7V
At roughly 3.3V the useful range is used up, and voltage will begin dropping off rapidly. There is no useful range below 3.0V. That is where many BMS's and controllers set the Low-Voltage-Cutoff LVC.
72V is usually considered to be 20S when selecting matching components. Nothing wrong with using 22S or 24S. Zero motorcycles uses 28S. Many years ago, 72V was often achieved by using two 36V / 10S packs in series.
If the motor is always cold, it's probably larger, heavier, and more expensive than your loads need. 190F is too hot, and temporary peaks of 140F is a useful goal. If you frequently hit 160F, you might consider selling the motor while it still runs, and getting a slightly larger one.
The Pikes Peak racer used a common 1,000W 9C direct drive bicycle hubmotor. He drilled large holes in the side plates to let the heat out, and ran it at 111V. I think he used 50A, but it was a long time ago. Its rated for 20A at 48V.
Lithium batteries are typically listed as being charged full at 4.2V per cell. They will last twice as long in months of daily use if they are only charged to 4.1V, and 4.0V is slightly better. There is no benefit to charging to 3.9V.
As soon as you use a cell for a minute, the voltage has a sharp drop-off to its fat middle, where it is reasonably steady at its "nominal" average for the whole cycle. Most cells list this voltage at 3.6V-3.7V
At roughly 3.3V the useful range is used up, and voltage will begin dropping off rapidly. There is no useful range below 3.0V. That is where many BMS's and controllers set the Low-Voltage-Cutoff LVC.
72V is usually considered to be 20S when selecting matching components. Nothing wrong with using 22S or 24S. Zero motorcycles uses 28S. Many years ago, 72V was often achieved by using two 36V / 10S packs in series.
