Ummm, there are two sides to this and it depends on the application.
If you are using a dc motor without a gearbox, ie direct drive with only one ratio to the wheels then at slow speed the motor will draw more current and work less efficiently. Driving slowly in traffic like this would reduce the range a little due to the lower efficiency.
However, if you drive at consistantly high speed most of the time then the motor will mostly be running at the upper end of it's speed range and will be more efficient and so range may be improved due to the higher efficency.
If you had a gearbox giving a range of ratios then in slow speed driving a lower ratio can be selected to keep the motor at the upper spped range adding to more efficient running.
However, a multi speed gear box has a lot of moving parts adding to mecanical drag that ls less efficient then without. also there is extra weight to carry around as well and that all reduces the efficiency.
Ultimately there are gains and losses either way and it would epend on what your application is, the sorts of journies you will take and the road conditons you will be driving on.
If you are using a dc motor without a gearbox, ie direct drive with only one ratio to the wheels then at slow speed the motor will draw more current and work less efficiently. Driving slowly in traffic like this would reduce the range a little due to the lower efficiency.
However, if you drive at consistantly high speed most of the time then the motor will mostly be running at the upper end of it's speed range and will be more efficient and so range may be improved due to the higher efficency.
If you had a gearbox giving a range of ratios then in slow speed driving a lower ratio can be selected to keep the motor at the upper spped range adding to more efficient running.
However, a multi speed gear box has a lot of moving parts adding to mecanical drag that ls less efficient then without. also there is extra weight to carry around as well and that all reduces the efficiency.
Ultimately there are gains and losses either way and it would epend on what your application is, the sorts of journies you will take and the road conditons you will be driving on.