# Can someone enlighten me on power requirements?

I’m a non-engineering background newb trying to understand power demands for motors. Any aid would be much appreciated. (I’m not shopping providers right now, only trying to understand the way specs are presented.) So …

These specs for a DC motor are from the electroauto.com Web site. How much power does this motor need to operate?

– 134 to 139 volts?
– 170 to 320 amps?
– 21.5 to 36.8 kilowatts?
– something else?

Here’s a link to the specs – they’re the bottom chart: http://www.electroauto.com/catalog/dcmotors.shtml

What are you trying to do? The page you show has the 8" and 9.1" motors from Advanced DC - good motors

The ratings show what you will get from each motor for a given amp / volt and the max it can take for a given time. This does not mean how much the motor requires, but how much they can absorb for a given power… for example, if you put about 139v at about 85 amps through the 9.1" motor, you’ll get about 14 hp out of it at about 11kw - about what a small car would need to go 25 - 30 mph on flat roads. You want to go up a hill ? More amps = more power. Faster ? If you double the speed of the car, the wind resistance quadruples. Aerodynamics start to matter above 45 mph or so.

A similar view could be made for your car today with an ICE - it may have a 300 hp motor, but it probably only “needs” 10% of that for most tasks, and will only produce the 300 ph if you have your foot to the floor and it is wound up to max rpms.

I’m trying to get a sense of how much power a motor is going to need, particularly for highway driving at 55-65 mph in a mid-size vehicle (4-door Honda sedan, for example).

I may be shifting jobs to a commute that would be 180 miles round trip, with all but about 5 miles being interstate-style roads on flat terrain.

[QUOTE=bdeck;4092]I’m trying to get a sense of how much power a motor is going to need, particularly for highway driving at 55-65 mph in a mid-size vehicle (4-door Honda sedan, for example).

I may be shifting jobs to a commute that would be 180 miles round trip, with all but about 5 miles being interstate-style roads on flat terrain.[/QUOTE]

That’s a very large range requirement. If you can charge at work it’s possible. However, even a 90 mile range is going to cost a large amount of money for the lithium batteries. Most lead acid conversions I’ve seen are doing good if they get half of that range (45 miles).

Brian