Cheap Chinese vs Cheapish Conversion?

[Deleted member 4366]

Well it seems today was my lucky day so the bike I wanted was on offer after a mislisting and so bad reviews.

www.amazon.co.uk/exec/obidos/ASIN/B006KAZ7LG/ref=ox_ya_os_product

Unless my partner decides she wants the bike I'm going to look at adding a front hub motor and stashing all the battery's and junk needed in the top bar/mid bar gap like an old style motorbike fuel tank. Also means less messy wires coming back.

Any ideas on what kit/kits to get?

I keep coming across dozens of controllers and with/without hall sensors(?) and torque sensors and other sensors, what ones are good bad? Prefer less wires but if the extra sensors will save unseeded ware on the motor or battery's then surely it is good.

Also respoke or new wheel, I'm not a pro wheel builder but have done a couple.

You're not far off with your calculation. You should think about a controller with a panel that gives several levels of pedal assist, and the other thing you should look at is hidden wire brake sensors instead of the ebrakes that they give with most kits. Also a torque arm is also useful in case your drop-outs aren't strong enough. Most motor kits offer a range of wheel sizes, so no point in building your own wheel unless you want it to match. The bike in your link has 36 spoke wheels, the same as the motor. Be careful with other bikes: 28 and 32 spoke wheels are fairly common.

 

[Clockwise]

Looks like the bike is single speed.

You don't need dozens on an electric bike, but a few, say three, would be good.

Yes, single speed with a rear hub coaster/brake so backpedel and the brake kicks in. I did a ride on the weekend of 30 miles on my regular mountain bike going across london and back via another route keeping in 2/3(front) and 5/7(rear) so mid geared and it was fine so if I swap the rear cog from a 22 to a 15-16 it should be perfect. If I needed to hill climb then I wouldn't be picking this bike ever lol

You're not far off with your calculation. You should think about a controller with a panel that gives several levels of pedal assist, and the other thing you should look at is hidden wire brake sensors instead of the ebrakes that they give with most kits. Also a torque arm is also useful in case your drop-outs aren't strong enough. Most motor kits offer a range of wheel sizes, so no point in building your own wheel unless you want it to match. The bike in your link has 36 spoke wheels, the same as the motor. Be careful with other bikes: 28 and 32 spoke wheels are fairly common.

As it has a coaster/hub brake on the back wheel do any sort of sensors for that exist?

My current to add list is this.

torque arms
http://www.bmsbattery.com/36v/450-a-pair-of-ebike-torque-arm.html
front hub motor/wheel - 250w 36v?
http://www.bmsbattery.com/ebike-kits/420-250w350w-q-85100sx-motor-e-bike-kit.html
controller(unsure what type assume the above is ok?)
display, mid mounted due to handlebar curves(above in kit again?)
right side(front) brake grip(again from above?)
thumb throttle, what does the button add?
http://www.bmsbattery.com/accessory/231-thumb-level-throttle.html
http://www.bmsbattery.com/ebike-parts/54-thumb-level-throttle-with-battery-meter-and-a-switch.html
battery, 10AH 36v?
Little confused here, are the black shrink wrapped box looking things the same as the nice aluminum cased ones? Should I be ignoring them all and buying the cell things and a pcb? I had it all kinda figured out when I was looking at buying a kit that came with a pannier thing but now it's all kinda gone up in the air
http://www.bmsbattery.com/36v/522-bottle-ebike-battery.html
http://www.bmsbattery.com/36v/495-36v-10ah-lithium-ion-electric-bicycle-battery-pack.html

 

[Clockwise]

Ok, some more searches and looking up just building a battery and not an ebike battery I found plenty about wiring up smaller AA looking battery cells into bigger packs. A little more info on the pcbs that balance them when charging and I should be good to go.

Headway 38120S LiFePO4 Battery Cell - 10x these?
+
Headway 38120 38140 Holder - however many to mount them 20 or so to have spares
+
Headway 38120 38140 Connector 20 or so again, plenty of spares
+
pcb?
Smart BMS 5~13 Cells in Series - BMSBATTERY

 

[Deleted member 4366]

Now you're getting to the most difficult bit - deciding what to buy.
You should buy the kit with the LED panel:
Q100 36V250W-350W Front E-Bike Kit with LED Meter - BMSBATTERY
Remember that this motor runs out of steam at 15mph, unless you increase the voltage.
You have to have a vision of how and where you want to fit the battery before you decide which one to buy, The 38120 cells are relatively heavy for the size of battery. The aluminium cased ones normally fit on a rack.

I don't think you can fit sensors to coaster brakes, but it should be ok as long as you have one on the front, although that bike doesn't appear to have a front brake, which would be a big problem. The PAS sensor causes the motor to run on a bit, so you need at least one brake switch. The half-throttles are easiest to fit because they fit any bike that doesn't have twistgrip gears.

 

[Clockwise]

Now you're getting to the most difficult bit - deciding what to buy.
You should buy the kit with the LED panel:
Q100 36V250W-350W Front E-Bike Kit with LED Meter - BMSBATTERY
Remember that this motor runs out of steam at 15mph, unless you increase the voltage.
You have to have a vision of how and where you want to fit the battery before you decide which one to buy, The 38120 cells are relatively heavy for the size of battery. The aluminium cased ones normally fit on a rack.

I don't think you can fit sensors to coaster brakes, but it should be ok as long as you have one on the front, although that bike doesn't appear to have a front brake, which would be a big problem. The PAS sensor causes the motor to run on a bit, so you need at least one brake switch. The half-throttles are easiest to fit because they fit any bike that doesn't have twistgrip gears.

According to the description it should have a front brake. The multiple 1* reviews as it is badly listed on amazon is what I guess pushed the price down.

Hopefully this plan makes sense. The red bit will be some sort of plastic, thin metal or maybe even fibreglass "fuel tank" that I can put the controller and battery in. The yellow wires go upto the brake and the led/lcd thing and the throttle. Purple wire to the motor and the green bit is the motor. Orange to any sensor I need there?

PS - Before someone says... I will be sticking with a blue and black theme so no crazy colour motors and cables.

 

[RobF]

The bike has a front cantilever brake - if I read the spec right.

It will be actuated by a standard lever, so no worries about fitting a cut-out.

 

[Biker44]

Battery inna backpack with a longish cable - quite popular over the pond I believe: BUT you must remember to unplug yerself before walking away!

My dad warned me of someone who'd put a can of coke in the pocket of his Belfast, fallen on it and broken his hip.

Since then I've been very careful - no chain over my shoulder and certainly nothing hard in a back-pack!

 

[Clockwise]

The bike has a front cantilever brake - if I read the spec right.

It will be actuated by a standard lever, so no worries about fitting a cut-out.

Yes but the back hub contains a coaster brake so pedel backwards and it brakes. Would a PAS know that?

 

[KirstinS]

Yes but the back hub contains a coaster brake so pedel backwards and it brakes. Would a PAS know that?

The PAS sensor will detect no pulses when you pedal backwards. So pedalling backwards will not engage the motor

I can be sure of this as I accidentally fitted mine backwards. So the motor only engages when I pedal backwards. Nothing at all happens when pedalling forward

 

[KirstinS]

Sorry should add that if you have independent throttle then you will be able to engage motor and brake at the same time - bad

The pas won't act as a power cutoff in reverse

 

[KirstinS]

I just checked the kit - looks like independent throttle to me

So I think you are a bit stuck with the coaster brake issue

But as long as you get into the habit of touching the canti brake at same time as back peddling then you will never get a brake on/motor on combo

 

[Clockwise]

The PAS sensor will detect no pulses when you pedal backwards. So pedalling backwards will not engage the motor

I can be sure of this as I accidentally fitted mine backwards. So the motor only engages when I pedal backwards. Nothing at all happens when pedalling forward

Ok so fitting a PAS with a throttle and the front brake sensor means unless I pedal backwards and hold the throttle on it won't want to keep the motor going.

So now I just wait till Friday when hopefully my bike arrives from amazon so I can get a tape measure on the space to fit stuff and draw up a plan of the box/tank/thing. I'm looking at fibreglass now as I think I should be able to craft a foam thing in a suitable shape and then it's similar to highly toxic papermache followed by cutting the foam to insert battery packs and softer foam.

 

[Clockwise]

I just checked the kit - looks like independent throttle to me

So I think you are a bit stuck with the coaster brake issue

But as long as you get into the habit of touching the canti brake at same time as back peddling then you will never get a brake on/motor on combo

I haven't ordered anything apart from the bike yet so if a different kit is better I can order that instead. Or if people know better places to buy batteries or anything I'm all ears.

 

[KirstinS]

Ok so fitting a PAS with a throttle and the front brake sensor means unless I pedal backwards and hold the throttle on it won't want to keep the motor going.

So now I just wait till Friday when hopefully my bike arrives from amazon so I can get a tape measure on the space to fit stuff and draw up a plan of the box/tank/thing. I'm looking at fibreglass now as I think I should be able to craft a foam thing in a suitable shape and then it's similar to highly toxic papermache followed by cutting the foam to insert battery packs and softer foam.

No - not what I meant

Either the PAS or the throttle will engage motor. However the front brake cutoff will override those in the interest of safety when the lever is pulled

So you will not be able to have the motor engaged AND the front brake on. This is good

However, you will be able to apply the rear brake (by back pedalling) and engage the motor via the throttle at the same time. This is bad

Your two workarounds are

1) only use PAS

2) get in the habit of always applying both brakes


None of this is actually essential - just safer

I have no cutoffs on my bike. However one sleeting day the throttle stuck on and it was a bit scary

Hope this makes sense !

Btw I'm not away of any PAS sensor that will act as a brake cutout when reversed. Others may know better

 

[Clockwise]

No - not what I meant

Either the PAS or the throttle will engage motor. However the front brake cutoff will override those in the interest of safety when the lever is pulled

So you will not be able to have the motor engaged AND the front brake on. This is good

However, you will be able to apply the rear brake (by back pedalling) and engage the motor via the throttle at the same time. This is bad

Your two workarounds are

1) only use PAS

2) get in the habit of always applying both brakes


None of this is actually essential - just safer

I have no cutoffs on my bike. However one sleeting day the throttle stuck on and it was a bit scary

Hope this makes sense !

Btw I'm not away of any PAS sensor that will act as a brake cutout when reversed. Others may know better

I think I just worded it badly but that all sounds fine. I'm going for a thumb throttle over a twist throttle to make it harder to engage.

So unless someone throws out another option PAS sensor, throttle thumb thing, brake lever, led/lcd display with mode buttons.

 

[jackhandy]

I'm looking forward to following this build:

It has the potential to be a little cracker of a bike

 

[Deleted member 4366]

Before deciding on a kit, you need to decide on the battery, I like your idea to put it in the top part of the frame, but finding one that fits there could be a problem. If you're brave, you could get a bottle battery, chuck the case and reconfigure the cells inside, but then you'd have to make a new case for it somehow.
This battery might just fit in front of the seat tube. You'd need to check the measurements:
36V9AH panasonic lithium ion battery for e-bikes-GreenBikeKit online store for electric bicycle components-GreenBikeKit.com
More details here:
36V/11.6Ah e bike battery, High discharge, Panasonic NCR18650 cell,Multi Fit,10S4P-in Electric Bicycle Battery from Sports & Entertainment on Aliexpress.com
Greenbikekit, BMSBattery and Elifebike all do similar kits. This one from GBK has the whole kit with battery for nearly the same price as a battery. You might be able to take the battery out of its case and mount it how you want:
36v250w electric bike conversion kit, front driving with 36v10ah frog lithiun ion battery and charger-Greenbikekit.com online store for electric bicycle components-GreenBikeKit.com
If you order from GBK, don't forget to select the LED meter as an option.

 

[Clockwise]

Before deciding on a kit, you need to decide on the battery, I like your idea to put it in the top part of the frame, but finding one that fits there could be a problem. If you're brave, you could get a bottle battery, chuck the case and reconfigure the cells inside, but then you'd have to make a new case for it somehow.
This battery might just fit in front of the seat tube. You'd need to check the measurements:
36V9AH panasonic lithium ion battery for e-bikes-GreenBikeKit online store for electric bicycle components-GreenBikeKit.com
More details here:
36V/11.6Ah e bike battery, High discharge, Panasonic NCR18650 cell,Multi Fit,10S4P-in Electric Bicycle Battery from Sports & Entertainment on Aliexpress.com
Greenbikekit, BMSBattery and Elifebike all do similar kits. This one from GBK has the whole kit with battery for nearly the same price as a battery. You might be able to take the battery out of its case and mount it how you want:
36v250w electric bike conversion kit, front driving with 36v10ah frog lithiun ion battery and charger-Greenbikekit.com online store for electric bicycle components-GreenBikeKit.com
If you order from GBK, don't forget to select the LED meter as an option.

I have a plan for the new case.

Step 1 - spray some foam onto a motorbike tank or similar nice shape
Step 2 - cut/trim/sand to make a mould
Step 3 - fibreglass the mould then cut off extra bits at edges
Step 4 - take out the fibreglass and fill with a more suitable foam
Step 5 - cruising

Have helped a friend do fibreglass for a car subwoofer and the idea is the same just thicker mat and more layers so it is more solid.

 

[Clockwise]

So another nights reading up on parts and comparing them and it seems I am looking at the following is all I need help on.

Motor - m85 m100 - now I don't know the differences as the specs are near the same? Kits from elfiebike so just 1 order.
Battery/Cells - kit from elfiebike, guessing I need a soldering iron and meter but apart from that it's mostly in the kit?
36V 10AH HEADWAY  LiFePO4 Battery Pack DIY kit for ebike - Elifebike Online Store

LCD display from/for controller, they don't seem to stock them, am I at a disadvantage by getting a simple one with LEDs?

Also any idea about customs/tax/hidden charges? Not exactly wanting to import something to have a nasty surprise bill.

 

[Deleted member 4366]

Check the sizes of the cells in that battery very carefully, They're bigger than they look. You need room for the BMS too, but you can mount it in a separate box under the lower cross-bar with the controller.

The bottle batteries have three sections inside, which could be separated and put one behind the other instead of on end to end to fit in your box.

The 85 motor is smaller and less powerful than the 100 version. It's narrower to fit in narrower forks. You need to check the width between the front drop-outs of your bike when it arrives. Hopefully 100mm for the 100 motor. You also need to check that they don't narrow down too quickly to catck on the motor side-plate.

I was going to suggest using GRP,. I think it's a good solution. I'll be using it on my next project.