Introduction and questions

[nocarrier]

Hello to everyone. Nice to meet all of you.
I've been looking into electrifying a couple of my bicycles, which has lead me here.
I've done the 2 stroke motorized bike thing, transitioned into classic mopeds for the last few years and am now and wanting to take the next step.
Having done the 2 stroke bike/moped thing has be prepped with most of the basics on the bike side of the business. Smoking ecigs already have me familiar with 18650 battery tech. So I somewhat have some of the fundamentals to get me started.
I just picked up a imax b6 mini last week and have been learning how to use it and testing and charging cells and familiarizing myself with a somewhat of a "smart" charger compared to the chargers ive been using for my ecig batteries the last few years.
Now, I have indeed used the search function, and yes, i know these are crappy quality, beginner level abc/123 parts but I value the input of a community who's been there and done that. Regarding front hub, yes i know front hub is not preferred but im putting them on a couple single speed steel beach cruisers we have.
I've been talking with this guy in hong kong about purchasing two of these:

http://www.ebay.com/itm/Electric-Bi...%3Af0b67d5115c0abc0119384e0ffff5131%7Ciid%3A1

I notice the controller on this kit is not like the other china kits that use the long shiney controller box. Is this kit and more crappier than the chinese kits? The reason I was looking at this "crappy" kit was 1. it has a disc brake that i can rig up a caliper to. 2. it has the lcd compuer which the cheap chinese kits on ebay do not. it the chinese kit the better route to go and add a lcd computer, it would probably be a couple hundred bucks less, but i would lose the disc brake. i got the seller talked down to about 600 shipped for two of the above. thats 30 or 40 bucks off.

As a starter battery im going to buy 10 of these packs and split them up between the bikes. To start I was just going to charge each pack independently, and when i put them in the bike, hook them up in parallel.

http://www.ebay.com/itm/10-LG-36V-4...id=100005&rk=1&rkt=6&mehot=pp&sd=172657519593

So if you can tell me whats a bad idea, and whats a slightly better idea even though its not an ideal setup, i would certainly appreciate it.

 

[d8veh]

At 36v and a controller rated at 500w, that motor will lack torque, so only buy it if you don't weigh much and your rides don't involve hills. A 500w geared hub motor would most likely be more suitable for a beach cruiser typr bike.

You should never buy a motor unless you know its speed. that will affect every other performance characteristic. Also, you need to know how many amps the controller allows, because that also has a big effect on performance.

A beach cruiser with a 260 rpm geared hub-motor, a controller around 20 amps and a 48v battery would be a nice bike. If you could find a 260RPM DD motor, that would be a close second, but most DD motors are closer to 400rpm, which means that they're gutless and very inefficient at lower speeds and when hill-climbing. You need to feed them 30 amps or more to bring them to life.

 

[nocarrier]

We're probably in the 170lbs range.

When you say never buy a motor unless you know its speed. Isnt that almost based mostly on the controller? I thought you could basically over power most hub motors and that I read in the wiki that a 36v 500w would get you to about 23-25mph. I must have that incorrect. is that something I should be asking the seller?

I somewhat wanted to stick with 36v and use the hoverboard packs as is. Should I wake up from that dream and just accept that I will tear down the hoverboard battery packs and make my own battery packs from the individual cells?

 

[LewTwo]

I think I might start with ONE(1) of those packs before I had enough trust in an unknown ebay vendor to send him $2,500 for 18650 batteries.

 

[nocarrier]

It's $250.00, not $2500.00.

I do are where you're coming from though. For 200 cells at 1.25 a pop, that's not too bad.

You think it's worth spending extra for the single pack strictly for testing. It's a bit more pricy when you buy a single pack. On the other hand it would save me 250 of junk cells if not. From what I've read they were manufactured in 2015 I believe.

 

[LewTwo]

It's $250.00, not $2500.00.

I do are where you're coming from though. For 200 cells at 1.25 a pop, that's not too bad.

You think it's worth spending extra for the single pack strictly for testing. It's a bit more pricy when you buy a single pack. On the other hand it would save me 250 of junk cells if not. From what I've read they were manufactured in 2015 I believe.

I saw my error. A single pack is $35. He does have a good feedback score but most of his NEGATIVE feedback is for batteries. Buyer Beware
http://www.ebay.com/itm/172648854096

 

[d8veh]

When you say never buy a motor unless you know its speed. Isnt that almost based mostly on the controller? I thought you could basically over power most hub motors and that I read in the wiki that a 36v 500w would get you to about 23-25mph. I must have that incorrect. is that something I should be asking the seller?

I somewhat wanted to stick with 36v and use the hoverboard packs as is. Should I wake up from that dream and just accept that I will tear down the hoverboard battery packs and make my own battery packs from the individual cells?

I think you're misunderstanding. It's quite complicated how a motor behaves in response to the power that the controller and battery allow. As a basic rule, you should choose a motor with a winding speed that's about 30% higher than the speed that you expect your modal speed to be.

Whatever the motor's winding speed is at its nominal voltage, you can change it by using a different voltage. It's maximum speed changes in direct proportion to voltage.

If you use any motor at full power at a speed less than half of its maximum, it becomes very inefficient, so it'll heat up and lose power.

The motor you linked to probably has a high winding speed. You need to find out what it is. At only 36v and low amps, it won't have the power to pull you out of the inefficient zone, so it'll be sluggish and your range will be much lower than it could be with a more efficient motor. Normally, at only 36v, you'd need to give it a high current, say 35 amps or more to give it the torque to get it out of the inefficient zone.

Increasing to a higher voltage doesn't necessarily help because it makes the maximum speed increase, so the inefficient zone spreads out to a higher speed too. You need the power and torque to get through that zone into the efficient cruising zone, but then you'd probably be going too fast for your beach cruiser.

Geared motors not only give much higher torques, but they also generally have lower maximum speeds, so would most likely be more suitable for a beach cruiser.

 

[nocarrier]

Thank you for taking the time to explain that. It now somewhat is starting to make sense.

I've asked the seller if he has any additional information/details on the motor. If he doesnt, I guess its time to look for a different kit.

"Normally, at only 36v, you'd need to give it a high current, say 35 amps"

using the lg cell lgeamf11865 as an example, it has a max discharge rate or 4.05a per cell and a capcity of 2200mah. is this a cell that is considered not ideal as its discharge rate is too low?

if i recall correctly some of my ecig batteries can dishcharge at 30amps.

sorry for all the newbie questions, i know how much that is frowned upon in the forums, but i do appreciate the help.

 

[d8veh]

It's 4 amps per cell, so you put as many in parallel as you need to get the required current.

 

[d8veh]

It's 4 amps per cell, so you put as many in parallel as you need to get the required current.