Radically different motor wattage but same top speed?!?

[minime]

Hello all

There are these two off-road bikes with a 1500w motor (linkA) and a 500w motor (linkB) respectively. Both specify a top speed of around 30mph. So what's the catch? What's the benefit of a more powerful motor?

 

[Woosh]

the direct motor (A) is of simpler construction, will last longer but has a shorter range because A is less efficient than the crank drive motor (B).
B gives slightly more acceleration.
You will need a large battery, at least 48V 13AH to run these motors.

 

[minime]

Thanks for the quick reply Woosh.

How much longer will the first motor last over the second motor? Could you give an example?
Could also give an example of the difference in range?
When you say "large battery", do you mean more voltage? More AH? They sell this battery called "big whale", 48v 17AH.

 

[Woosh]

How much longer will the first motor last over the second motor? Could you give an example?

a lot, I should think. Motor A is supended by two ball bearings, dirt cheap to replace, available on ebay, and they last easily 10 years.
Motor B has an all metal gearbox that needs greased roughly every 2,000 miles.
I think Woosh are the only source for spares in the UK for B.

 

[Deleted member 4366]

Firstly, it's not the motor that gives the power. It's the controller. Don't take any notice of what power is written on the motor or mentioned in any listings.

Secondly, the speed means nothing. You need three things to get a MTB type bike to cruise at 30 mph:
- a 500 rpm motor (assuming 26" wheel). In the case of a crank drive, it needs to be rated at the same as the controller below, plus you need the right gearing.
- a controller rated at 20A for 48v or 25 amps for 36v
- a battery that can give 20A continuously for 48v and 25 amps for 36v.

There is no guarantee that any one motor will last longer than another. The big DD motors get their own problems. I've seen more of them fail than geared motors, so I don't believe that they're any more reliable. They run hotter, so get hall problems. they're generally not made to the same quality, so problems of wiring and water ingress are more common along with magnets coming loose, and bearing failures too. Crank-drives too get their own problems and cause problems with the transmission.

I think that geared hub-motors win on reliability out of all the Chinese motors, but you need to choose one appropriate for you needs.

 

[Woosh]

When you say "large battery", do you mean more voltage? More AH?

more AH.
These two motors pull a lot of power.
Furthermore, I do not recommend running B at 48V, too much for it.

 

[minime]

@d8veh can you deduce the controller rating and motor rpm from the listings?

 

[minime]

@Woosh

Do you do custom bikes?

 

[Woosh]

@Woosh

Do you do custom bikes?

We fit our kits to customers bikes but no more than that.

 

[minime]

We fit our kits to customers bikes but no more than that.

So I have to bring in my bike so you can install your kits? Can I ship the bike to you?

 

[Woosh]

You can, but all the kits I sell are plug and play and with detailed manual, very easy to install.

 

[Deleted member 4366]

They sell two controllers as spare parts for the 1000w kit. One is 22 amps and the other 23 amps. My guess would be 25A or 30A for the 1500w bike.

You'd have to ask them about the Bewo one, but my guess would be 15 amps.

 

[anotherkiwi]

The Bewo, from memory, has an external controller so you should be able to use a 17-18 Amp one.