Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Electric Bikes Here's a place to discuss ebikes, from home grown to high-tech.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 11-30-10, 10:35 PM   #1
15rms
Senior Member
Thread Starter
 
15rms's Avatar
 
Join Date: Oct 2007
Bikes:
Posts: 285
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Bionx 48 volt system

I see Bionx is going to be selling a 48 volt 350 watt kit starting in Feb. For those that understand this better than I, I have a question. Would the 48 volt battery hold 33% more energy than a 36 volt battery? And assuming so would you expect the bike to go 33% further on a charge or would the extra power and acceleration eat up the benifit?

http://www.greenspeed.us/bionx_PL350...l_edition.html
15rms is offline   Reply With Quote
Old 12-01-10, 10:15 AM   #2
Sangesf
Senior Member
 
Join Date: Oct 2010
Bikes:
Posts: 607
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
It doesn't say the AH of the battery.

Here is the calculations you need...

Volts times Amp Hours = Watt/Hours
More volts = more speed.
More AHs = more distance.
Wattage of motor = Pulling Power (torque)

So everything hinges on those calc...

Example....
36v 10ah = 360 w/h
36v 20ah = 720 w/h = more distance
48v 10ah = 480 w/h (compared to 36v 10ah) = more speed and distance
48v 20ah = 960 w/h (compared to 48v 10ah) = more distance.

Given equal batteries(lets say 36v 20ah), a 250w motor will use up all the battery in ~3 hrs. (720wh / 250w)
A 500 watt motor will give much better torque, but can use up twice as much power as the 250w one will. (720wh / 500w)

Given different voltages, it gets a little trickier...
A 36v 20ah running a 250w motor = a little less than 3 hours. (see above calc)
A 48v 20ah running a 250w motor = more speed and a little less than FOUR hours. (960wh \ 250w)
You'll notice the batteries have the same "AH" but you'll see that the 48v will give you more speed and distance.
A 48v 20ah running a 500w motor = even more speed, more torque, and less time (960wh / 500w = a little less than TWO hours.

Hope this helps.
Sangesf is offline   Reply With Quote
Old 12-01-10, 10:26 AM   #3
15rms
Senior Member
Thread Starter
 
15rms's Avatar
 
Join Date: Oct 2007
Bikes:
Posts: 285
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks Sangesf.

Last edited by 15rms; 12-01-10 at 11:24 AM.
15rms is offline   Reply With Quote
Old 12-01-10, 11:29 PM   #4
edcastrovalley
Senior Member
 
Join Date: Oct 2010
Location: SF east bay
Bikes: "e" marin, gary fisher, giant
Posts: 107
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Given different voltages, it gets a little trickier...
A 36v 20ah running a 250w motor = a little less than 3 hours. (see above calc)
My 500w hub motor kit came with a 36v10ah battery and was advertised to go 20 miles on a charge with a top speed of 20mph. But 360 watt-hours (batt) / 500 watts (hub motor) = 0.72 hours and 0.72 hours x 20mph = 14.4 miles! (My maximum range on a charge) Did I calculate right or did I get taken for a ride?
edcastrovalley is offline   Reply With Quote
Old 12-02-10, 11:03 AM   #5
Mabman
Senior Member
 
Join Date: Oct 2008
Location: The F/V Misty Moon/Clatsop Co. OR homebase
Bikes: Some
Posts: 206
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The fly in the ointment is the fact that batteries should not be drawn down fully before recharging so count on less ah than advertised.

If you want to get the best mileage, pedal along with the power.
Mabman is offline   Reply With Quote
Old 12-02-10, 11:30 PM   #6
Sangesf
Senior Member
 
Join Date: Oct 2010
Bikes:
Posts: 607
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by edcastrovalley View Post
My 500w hub motor kit came with a 36v10ah battery and was advertised to go 20 miles on a charge with a top speed of 20mph. But 360 watt-hours (batt) / 500 watts (hub motor) = 0.72 hours and 0.72 hours x 20mph = 14.4 miles! (My maximum range on a charge) Did I calculate right or did I get taken for a ride?
Well 20 miles on 10ah is a bit optimistic.

On 36v I average 7 miles for every 5ah. (at 22mph)
(LiFePo4)
Sangesf is offline   Reply With Quote
Old 12-07-10, 08:53 PM   #7
edcastrovalley
Senior Member
 
Join Date: Oct 2010
Location: SF east bay
Bikes: "e" marin, gary fisher, giant
Posts: 107
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Sangesf View Post
Well 20 miles on 10ah is a bit optimistic.

On 36v I average 7 miles for every 5ah. (at 22mph)
(LiFePo4)
7 miles for 5 ah sounds good! (especially at 22mph) On my longest ride I went 16 miles total without any signs of slowing down. I'm good with that.
edcastrovalley is offline   Reply With Quote
Old 12-23-10, 06:15 AM   #8
GTALuigi
Senior Member
 
GTALuigi's Avatar
 
Join Date: Sep 2008
Location: GTA
Bikes: Dahon Mu SL 08 / Matrix 08
Posts: 764
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
hmm... very informative.

I just learned something new today

Thanks!

Quote:
Originally Posted by Sangesf View Post
It doesn't say the AH of the battery.

Here is the calculations you need...

Volts times Amp Hours = Watt/Hours
More volts = more speed.
More AHs = more distance.
Wattage of motor = Pulling Power (torque)

So everything hinges on those calc...

Example....
36v 10ah = 360 w/h
36v 20ah = 720 w/h = more distance
48v 10ah = 480 w/h (compared to 36v 10ah) = more speed and distance
48v 20ah = 960 w/h (compared to 48v 10ah) = more distance.

Given equal batteries(lets say 36v 20ah), a 250w motor will use up all the battery in ~3 hrs. (720wh / 250w)
A 500 watt motor will give much better torque, but can use up twice as much power as the 250w one will. (720wh / 500w)

Given different voltages, it gets a little trickier...
A 36v 20ah running a 250w motor = a little less than 3 hours. (see above calc)
A 48v 20ah running a 250w motor = more speed and a little less than FOUR hours. (960wh \ 250w)
You'll notice the batteries have the same "AH" but you'll see that the 48v will give you more speed and distance.
A 48v 20ah running a 500w motor = even more speed, more torque, and less time (960wh / 500w = a little less than TWO hours.

Hope this helps.
GTALuigi is offline   Reply With Quote
Old 12-23-10, 08:19 AM   #9
Sangesf
Senior Member
 
Join Date: Oct 2010
Bikes:
Posts: 607
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Always glad to help... Any more questions?
Sangesf is offline   Reply With Quote
Old 12-25-10, 09:21 AM   #10
madfolder
On Training Wheels
 
Join Date: Mar 2008
Location: central new york
Bikes: Reach folding, Merlin Road, Devinci performance hybrid
Posts: 17
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Who builds the best controller and motors? What makes one motor better than another? What do you see as the ideal combination of power Motor(W) and Battery V/A? Seems people forget that as you increase both, you also increase weight and balance on the bike. That much I know, but I am a newbie here.
madfolder is offline   Reply With Quote
Old 12-25-10, 07:03 PM   #11
Sangesf
Senior Member
 
Join Date: Oct 2010
Bikes:
Posts: 607
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I always like to use 250w-350w motors because I don't need speed or power..
I always like as much distance..
I'm in south florida so it's all flat around here. If you live in a slightly hilly area, go with 500-750w motors.
If you live in very hilly areas, then an 800w+ motor is for you.

Just about any motor will do for me because I only run 250w-350w continuous and most motors handle that easily.
36v IMO is the best for price per weight.
Smaller wheels provide more torque and more speed compared to larger wheels...

I use Goldenmotor controllers, they run voltages 24-60v and when used with 24/36v they only pull 25a max. They have regen, cruise control, reverse, programable, alarm, horn, etc, etc all in one controller
Sangesf is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 01:54 PM.