hub motors/hill climbing

forgive me if this is a silly question. I am curious to know how some hub motors are better at hill climbing than others, although they are the same at 250w. Obviously the weight of bike and rider will have some bearing on this but are some motors better at climbing than others just by design, or is it to do with the other components ie controllers, gearing etc. If I wanted to improve the climbing on my Freego Eagle, would it be possible and if so how?

many thanks gray

Good question. There's several factors.

Some motors like the Ezee and BPM in the Emotion Neo are physically bigger and designed for more power.

Next factor is the current that the controller allows. The more amps, the better they climb, but small motors can get too hot if you push too much current through them. Most bikes with small motors are set to about 14 amps, but the motors can be run at 20 amps if you don't laboour them at low revs, which gives a significant improvement to climbing ability. Many controllers can be modified to give higher current.

A controller set at higher current can be a problem if your battery can't provide it. Often the controller is set to what the battery can give, so higher amps is only an option if you have a big or strong battery. Conversely, if your battery is too weak for what the controller is set to, the voltage sags and you get less power.

Next factor is speed of the motor. A low speed winding on the motor will allow higher efficiency when climbing slowly, but a higher speed version of the same motor will produce more power than the low speed version when in a small wheel.

thanks D8veh That explains it well. How would I know if the motor on my Eagle was able to accept more current or if in any way it could be improved. The battery is 17.5ah

regards gray

although they are the same at 250w.

Are they?

Get a watt meter on them and I think you'll be surprised

You have to open up the controller to find the shunt. I've never seen an Eagle controller, but if you're very lucky, it'll be behind the end-plate like this one below.. The Cyclamatiic oone runs along the way inside, so is a bit more difficult. If you need to remove the whole PCB, yoy have to remove the screws in the side as well. Start with about 1/3 of it. Don't go more than that without being able to measure the current with a watt-mere like this one. 18 amps is safe. Steve (Saneagle) runs his at 22 amps, but it's noisy and I don't know how llong it'll last.

New 60V 100A Battery Checker Balancer current Analyzer Watt Meter Servo Test | eBay

Maybe this one. I've just asked him what's max volts and current,

Red Convenient Simple Design Easy Use Watt Meter Power Meter | eBay

before

http://i451.photobucket.com/albums/qq236/d8veh/Beastamatic/KU63shunt.jpg

after

http://i451.photobucket.com/albums/qq236/d8veh/Beastamatic/KU63solderedshunt.jpg