My first ever Ebike and to save money I have decided to convert my Mountain bike. Your post has answered some of my questions, thanks for that.the way marketing people say that their TSDZ2 is 250Wor 350W or 500W or even 750W is very confusing. Tongsheng makes the same motor for two voltages: 36V and 48V. The controller is programmable, It is factory set at 16A but can be changed.
36V at 16A = 576W maximum
48V at 16A = 768W maximum
The motor is labelled 250W for road legal kits.
I would suggest you get a road legal 48V TSDZ2.
48V 16A is a good trade off between hill climbing ability, stress on the motor and stress on your battery.
How to find range?
You can use the motor simulator here:
https://www.ebikes.ca/tools/simulator.html
You want to look at the load curve versus speed. You can set your weight and gradient, the math is done for you.
For example, this is a 5% gradient:
https://www.ebikes.ca/tools/simulator.html?bopen=false&motor=MBPM&axis=mph&grade=5
The load chart gives (approximately) maximum speed at 18mh with the 48V TSDZ2 (768W battery power) and 15mph with the 36V TSDZ2 (576W battery power).
The battery consumption per mile is battery power / speed.
Climbing a hill at 18mph, battery consumption is 40WH-42WH per mile,
this is a chart for flat road:
https://www.ebikes.ca/tools/simulator.html?bopen=false&motor=MBPM&axis=mph&grade=0
the 48V TSDZ2 maximum speed is 28 miles, battery consumption is 27WH per mile.
The 36V TSDZ2 maximum speed is 23mph, battery consumption is 25WH per mile.
The above examples assume the motor is derestricteed.
If the motor is restricted to road legal, the battery consumption at 15mph is the same for both 36V and 48V, 12WH per mile.
Now the range.
The maximum range is battery capacity in WH / battery consumption per mile.
If you have a 48V TSDZ2 kit with 12AH battery, maximum range is about 576WH/12WH/m = 48 miles.
However, it is unpleasant to ride assisted when the remaining battery capacity is below 20%, the practical range is 20% less than the maximum range, about 40 miles.
Someone has put a link of a uk seller and I am planning to buy a TSDZ2 of them. I am going to build my own battery pack with Samsung 25R. 14S 7P 57v 17.5ah. Is that combination any good?