Go Back  Bike Forums > Bike Forums > Electric Bikes
Reload this Page >

Advice Needed For First Ebike Project

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

Advice Needed For First Ebike Project

Old 01-27-16, 01:03 AM
  #1  
mcicare
Newbie
Thread Starter
 
Join Date: Jan 2016
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Advice Needed For First Ebike Project

Greetings all,

My first post on Bike Forums so here goes ... Have been riding road bikes most of my life and now in my later years find my self in need of some assistance on those longer rides. Thought adding a small electric hub motor to my bike would be a great idea. Decided not to mess with my beloved CAAD9 alum/carbon fork road bike so I bought a good used vintage Specialized steel MTB for the project instead.

The bike will be used here in south Florida on level roads with some inclined inner-coastal bridges for rides of 30 to 40 miles. I would like components that would give me 15 to 20 mph with me supplying constant medium to hard (hard for the bridges) pedal assist. I'm 125 lbs. - bike is currently 28 lbs. Will be purchasing a rear geared hub motor and lacing it up myself into a 26" rim. Plan on using a V3 Cycle Analyst to manage everything.

Questions:

After reading this great post from chas58 (4/25/13, "Q100 Stealth Builds -") I've pretty much decided on this motor from BMS ... Q100H, 36 Volt, 350W, 260 rpm, 12.6 ratio. BMS describes this as a high torque version of the Q100 with the same dimensions. BMS recommends this controller for it. It's described as a "Torque Simulation Sine Wave Controller" which is different from a regular controller. Does anyone have any thoughts, opinions, or suggestions for a different controller or motor? I'm really set on a rear drive sub 6 lb. motor, with what ever controller that works and is reliable, again will be using Grin's V3 computer to manage everything.

As for a battery, I like the 38120S Headway LiFePO4 3.2V, 10Ah cylindrical cells. A 12s pack gives me 38.4V (nom.) 10Ah, 3C discharge rate. Fewer cells to make a pack and a much greater cycle life ... the 9lb wt. and pricing may not be as good as a lighter premium 18650 pack but it still seems like a good choice to me. I really like the concept of screw terminals on these cells as opposed to the spot welding on 18650 cells. I realize the 38.4V at 10Ah only gives me a 384whr pack but I will be drawing less than the 3C rate of 30 amps ... hopefully a lot less. So does that mean I can expect an increase in the watt hours of this pack?

The total price for the (12) 38120S cells, BMS, cell holders, buss bars, assembly kit (wires, terminals, anderson connectors, (2) 6" x 6" Lexan sheets and shipping ( $31.12 ) is $417.12 from this supplier . Not sure if their BMS will work with my small motor. Any thoughts on these batteries and BMS ?

I loaded all this data into Grin's motor simulator . Used the outrider std. (300rpm unloaded) hub motor rated at 250 to 500 watts (closest I could find to the Q100H motor) and using the 38.4V pack. At 75% throttle, 0% grade, and no pedaling, the graph showed 15mph with a range of 30 miles. Electrical data box showed motor pulling 7 amps, battery supplying 188 watts at 5 amps with .4V voltage sag. Putting in about 90 watts of pedaling effort I'm up to 18mph with range up to 355 miles. Motor now pulling 700ma (.7A) with battery supplying 19 watts at 500ma with no voltage sag. I wonder if Grin's simulator factors in wind resistance? Am I missing something here?... almost sounds to good to be true. Anyone used this simulator before?

Trying to nail down all the details before I make any purchases has been a daunting task for me, think I'm pretty close now thanks to this forum and other great websites.

Would greatly appreciate any suggestions or thoughts you folks might be willing to share. Especially as to trusted sources for these specific components. Thanks very much!
mcicare is offline  
Old 01-27-16, 07:28 AM
  #2  
2old
Senior Member
 
Join Date: Jul 2014
Location: socal
Posts: 2,318
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 393 Post(s)
Liked 165 Times in 120 Posts
Well thought out; as you've already discovered, C58 is the best resource for your project. Think your range might be optimistic for an MTB. Let us know about your progress.
2old is offline  
Old 01-27-16, 10:58 AM
  #3  
mcicare
Newbie
Thread Starter
 
Join Date: Jan 2016
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by 2old View Post
Well thought out; as you've already discovered, C58 is the best resource for your project. Think your range might be optimistic for an MTB. Let us know about your progress.
Thanks for that ... I'm trying not to make any costly mistakes.
Seems like I've been doing research on this project for ever.

Yes, C58's thread really helped me in nailing down the type of motor
I might need. Now that I think about it, should have placed my post
on his thread that I had referenced ... would really appreciate his
thoughts on the higher torque version of the the motor he used.
Being a new member I don't know if it would be appropriate to send
him a message asking for his input ... is that acceptable on this forum?

I've got the MTB set up for the road ... narrow tires, comfortable
saddle, fairly upright riding position. 40 miles shouldn't be a
problem for me with the motor assist and the right capacity
battery ... we shall see.
mcicare is offline  
Old 01-27-16, 12:33 PM
  #4  
2old
Senior Member
 
Join Date: Jul 2014
Location: socal
Posts: 2,318
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 393 Post(s)
Liked 165 Times in 120 Posts
Think you need 50 posts to send a PM.

When I referenced MTB's, my comment was related to aerodynamics; be fun to see how it transpires.
2old is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Deves
Electric Bikes
7
12-15-17 08:43 AM
steve mareno
Electric Bikes
7
08-09-13 10:30 AM
gogreenpower
Electric Bikes
10
12-20-12 12:18 PM
Volkswagner
Electric Bikes
3
07-30-10 10:02 PM
crimsonsnake0
Electric Bikes
2
06-26-10 09:38 AM

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.