Honda S90 Conversion

[wheelbender6]

I have been a member of the forum for a few years but mostly read posts about bicycles.
I have a Honda S90 that I would like to convert (like the one in the link)

http://www.davidregan.com/s90_ad4.jpg

The bike weighs 176 lbs. I'd like to reach 50 mph with a range of 20 miles.
Does anybody make a hub motor for an 18in wheel?
My ICE made 8hp, so would a 6Kw motor be adequate?
Would the Turnigy TR80-100-A (7kw and 48V) be adequate for my situation?
Can I achive my desired range with SLA batteries? (I know they need replacing after one year).
How many Volts and amp hours will my battery pack need? Thanks

[SamTexas]

Here's a rough power and energy estimate: You need around 3,500 watts to cruise at 50mph. Most hubs run at 80% efficiency so actual power is 4,375 watts (3,500/0.80). For a 20 mile range you need a battery that can supply 1,750 whrs (4,375*20/50) and a minimum continuous discharge rate of 2.5C (4,375/1,750).

[renago]

hi Sam
just a general question :
how did you get the power consumption figures of 3500 W to run at 50mph ?
is this from experience or is there a calculator ?

I am building something between a bike and a moped , so I will be interested to know .

thanks Renago

[SamTexas]

hi Sam
just a general question :
how did you get the power consumption figures of 3500 W to run at 50mph ?
is this from experience or is there a calculator ?

I am building something between a bike and a moped , so I will be interested to know .

thanks Renago

From a calculator: http://bikecalculator.com/
It quite accurately reflects the actual consumption in real life. But I have never run an ebike beyond 40mph.

[gwhy!]

hi Sam
just a general question :
how did you get the power consumption figures of 3500 W to run at 50mph ?
is this from experience or is there a calculator ?

I am building something between a bike and a moped , so I will be interested to know .

thanks Renago

From a calculator: http://bikecalculator.com/
It quite accurately reflects the actual consumption in real life. But I have never run an ebike beyond 40mph.

If this is correct ( Im not doubting it ) then a cvt setup is actually more efficent than a geared or direct drive, a gas auto scooter that has a peak power output at the crank of a tad under 3kw will do around 50-55mph it takes a long time to reach this speed but it is doable

[SamTexas]

hi Sam
just a general question :
how did you get the power consumption figures of 3500 W to run at 50mph ?
is this from experience or is there a calculator ?

I am building something between a bike and a moped , so I will be interested to know .

thanks Renago

From a calculator: http://bikecalculator.com/
It quite accurately reflects the actual consumption in real life. But I have never run an ebike beyond 40mph.

If this is correct ( Im not doubting it ) then a cvt setup is actually more efficent than a geared or direct drive, a gas auto scooter that has a peak power output at the crank of a tad under 3kw will do around 50-55mph it takes a long time to reach this speed but it is doable

That's too good to be true. The power rate provided by bikecalculator is based on physics. Gravity, rolling resistance and aerodynamics. It does not care about the power source or how it's delivered. So the only way for a gas scooter with cvt to beat the required power is to change one of the above characteristics. A CVT (or any other kind of power transmission) always requires additional power, never less.

[gwhy!]

True, and I cant explain it, I just have put to many 50cc auto scooters on dyno's, some scoots will put out just over 3kw and some just under ( dependent of a few things ) but they nearly all reach 52mph give or take a couple of mph's as long as the speed limiter is removed

Edit: Just thinking about it a little more I may be getting mixed up, a scoot without a after market exhuast will still only put out about 2.8kw and from memory the top speeds are lower around 45-48 , when a aftermarket exhaust is fitted this puts the power output upto around 3kw+ ( dependent of exhaust ) this puts the top speed up into the 50's , I have never really payed attention to it before, so It's prob me having a brain fart

[pchen92]

@50mph you need 4-4.2kW of electric power.
With a 20 miles range, you're going to a 2-2,5kwh battery or so. Lipo batteries from HK are quite good and cheap
I suggest you a more powerful motor (like 10kW).

[Gordo]

How is the conversion coming along?
The scooter in my signature does 50 mph on the flat and will maintain 40 on a 4% grade. Range is @ 35 miles at 30 mph, up and down hills. 20 TS 40Ah cells.

I have been a member of the forum for a few years but mostly read posts about bicycles.
I have a Honda S90 that I would like to convert (like the one in the link)

http://www.davidregan.com/s90_ad4.jpg

The bike weighs 176 lbs. I'd like to reach 50 mph with a range of 20 miles.
Does anybody make a hub motor for an 18in wheel?
My ICE made 8hp, so would a 6Kw motor be adequate?
Would the Turnigy TR80-100-A (7kw and 48V) be adequate for my situation?
Can I achive my desired range with SLA batteries? (I know they need replacing after one year).
How many Volts and amp hours will my battery pack need? Thanks