Help me build my 48V e-bike

[Speedfreke]

Hi, After 3 yrs riding a 408 c'lyte at 72V (SLA) and not very happy with that set-up I decided it's time for a new build. I thought that I could get better speeds and more endurance and less weight with a new motor and a new 48V/20ah lifepo4 pack. However I need help from the experts here. Here's my question: What motor/controller combination is fast, reliable and efficient? I need speeds in the mid 30's mph. I'm thinking probably C'lyte or 9C or BMC plus the appropriate controller. What's your opinion?

 

[spinningmagnets]

From the archives, speed with full-sized adult riding on flat ground:

-5303 in 26" wheel at 48V, 61-kph/ 38 mph
-5304 in 26" wheel at 48V, 48-kph/ 30-mph

 

[torker]

Not sure if a 406 would have enough speed. maybe a 405 Crystalyte. Man I bet that 408 on 72 v has some serious torque.

 

[MattDog]

Your issue might JUST be the batteries. The 408 might not be the greatest motor in the world, but at 72v you SHOULD be hauling ass. Are you sure you want to take a bicycle much above 30MPH for an extended period? Perhaps an electric motorcycle project is in your future...

 

[Speedfreke]

Mattdog, I used to race bicycle at downhill speeds over 50 mph with other rider just inches away. motorcycle is out of the question. I got one for sale.
Nobody vouching for Bmc or 9c?
Which of 5303 or 406 uses less juice?
what about 5302?

 

[Russell]

Just out of curiosity how fast is the 408 on the SLA's, what is the Ah rating of the batteries and the current limit of the controller you use?

-R

edit: Nevermind I read your other post;

http://endless-sphere.com/forums/viewtopic.php?f=2&t=13652&start=0

 

[Speedfreke]

top speed of 408 with 72V is 32 mph with 20amp controller and 12ah batteries. maybe not the best set-up

 

[Speedfreke]

with a big motor like the 5303 is dual suspension advisable?

 

[Russell]

You can try out different combinations on the ebike.ca simulator but keep in mind you'll need over 1,000W to hit 35 mph and double that to hold it up a 5% grade or with a 15 mph headwind.

http://www.ebikes.ca/simulator/

-R

 

[Drunkskunk]

SLA Suck. There's your problem.

My 408 with 74V of Lipo hits 36mph at the 20Amp limit I have programmed in. I can run the bike at 40 Amps, but have never hit full speed at 40 amps. Thats running on big 2.5" balloon tires. A narrow wheel would be faster

But thats not what I would recomend. A 9C would melt down at the power levels needed to go that fast, So I wouldn't recomend that either.

You need a 530X. and not much point running it at 48 volts either, if you want it to preform better than your 408. A 5303 at 48 volts is putting out about 850 watts. About the same as a 408 at 72 volts.
If you want better preformance, go with a 5304 at 72 volts or more. Just make sure the rest of your bike can handle it.

 

[spinningmagnets]

More from the archives (copied from user posts, accuracy not verified)

At 72V...
-5306 in 26" wheel, 56 kph/ 34 mph flat and 49 kph/30-mph on 10% hill
-5305 in 26" wheel, 63 kph/ 39 mph and alone can climb on 8% hill

 

[Anonymous]

......... get an Etek motor, get 4 12v 9ah SLA mount it in the V-frame, hide it with 3 or four triangle bags cut in half, attach it to a freewheel pedalling system, hey presto! 70mph! for 20 miles!

 

[Speedfreke]

thanks for the responses. I know I can get great speeds with 72V but my new lipo4 pack is going to be limited to 48V20h.I think this is a good balance between weight and power. I'm 58 years young and don't like hauling a heavy bike up and down the stairs of my home and believe that a fast 48v set-up is possible.
But I've been searching ES and learning a lot. Mostly - 'don't even think of a new build'- especially after reading oatnet's experience with the V3) but some positive things as well.
I'm waiting for replies concerning the V2s and possibly bafang but I'm not going to rush into an 'experimental' set-up.
If I'm gonna spend a couple of thou it better work right. Still searchin'

 

[Russell]

I'm waiting for replies concerning the V2s and possibly bafang but I'm not going to rush into an 'experimental' set-up.
If I'm gonna spend a couple of thou it better work right. Still searchin'

Oh my gosh I love the dickens out of my Bafang but mine tops out at 23.5 mph at 48V and if you were to try to push it much higher on a continuous basis it's likely to turn into mush. I would suggest first getting the 48V/20Ah LiFePO4 battery and using it with your present set-up and then see how you feel about it.

-R

 

[MattDog]

I think you could actually do it with 9c, I've heard of people running 72v at pretty high amps on the AmpedBikes forums (and some other places)....of course it could just be a lot of smoke. Ultimately--I don't think the wires to the motor would survive...pretty sure you would wind up pulling the covers off and replacing the +/- and the hall sensor wiring.

 

[TPA]

The 20A limit is holding you back.

I have a 406 in a 26" wheel and can get 26-27mph at about 40v (freshly charged) and about 20A (800W), but it takes some time to get there since the acceleration is not so great with a 406.

If I had a limit of 20A, my max speed would top out with each increase in voltage. If I went to 72V(1440W), I would probably max out at around 35 mph. But, since my controller is capable of 35A my max power is 72V*35A=2520W, I could go a good deal faster, but I don't know how fast exactly.