New E-Bike build attempt

Hello everybody,


As I recently somehow attained quite some money, I decided to approach my first E-Bike build.
I attached my basket screenshots at EM3ev and Luna Cycle and hope for a little bit of help before pressing order.
Furthermore I'll probably going to buy this bike:

https://www.thefixedgearshop.de/fixed-gear-fahrrader/pure-fix-india-8265

and these items:

https://eu.nkon.nl/rechargeable/18650-size/samsung-inr18650-35e.html
(I plan on building the Battery myself, probably 14s6p , 84 Cells)

http://vruzend.com/product/vruzend_basic_kit/
(because I don't own a spot welder and lack serious soldering skills)

https://de.aliexpress.com/item/14S-Smart-Li-ion-Battery-PCB-board-Bluetooth-Mobile-BMS-for-48V-58-8VLi-Ion/32794186005.html?spm=a2g0x.search0104.3.121.8tAVgO&ws_ab_test=searchweb0_0,searchweb201602_3_10152_10065_10151_10068_10193_10194_5400011_5430020_10304_10307_10137_10060_10302_10155_10154_5370011_10056_10055_10054_10059_100031_10099_10103_10102_5410017_10052_10053_10107_10050_10142_10051_10320_10321_10322_10326_10084_10083_10080_10082_10081_10177_10110_10111_10112_10113_5390011_10114_10180_10312_10313_10314_10184_10315_10316_10319_10078_10079_5420017_10073_10186-10152,searchweb201603_1,ppcSwitch_7&btsid=a201317f-03d0-4366-ab6a-26610c3e8be9&algo_expid=968fe88b-a8f2-4159-a6a8-a7c6844187da-16&algo_pvid=968fe88b-a8f2-4159-a6a8-a7c6844187da
(I thought about a bluetooth BMS)


I'm still not sure about some things:

1. First of all, do the Components work well together (especially the Cells and the BMS) ?
2. Will the Cells and the controller fit into the frame bag ?
3. Do I need the Wattmeter (if the bluetooth BMS sends me informations about the status of my Battery to my
phone) ?
4. If you go to Luna Cycle, there are two customer reviews on the Charger (international Version). One user
complains about the build quality and notes that there are potential dangers.
Does somebody have experiences with the international model ?
5. As You can see I'll use a bike with 700C wheels, on EM3ev is says that the MAC 12T will make about 32 Kph on
48V and 26 inch wheels. I imagine the bigger wheels and the higher Voltage will make it a bit faster.
Can somebody estimate how fast it will go, also how far (I'm about 174 lbs) ?
6. Do I need more Cables ?
7. Is it really true that shipping on EM3ev time takes 4 days to Europe on express delivery (while the normal
shipping is 3 weeks and cost just 16$ less) ?
8. Finally, do I lack something (I'm aware that I'll need better brakes)?


Many thanks in advance

LiFePO4 chemistry from Headway has bolt on cans, could be an option.
The 35E is a good solid choice.

Never seen that company before, I'd be more inclined to buy a BMS from Greentime on Aliexpress (or is it Alibaba).

Dont forget Torque Arms!!!!

I cant see the images you attached, I cant zoom in. I see its a MAC motor though.

Been reading this thread
https://endless-sphere.com/forums/viewtopic.php?f=3&t=65743&start=25
Their motors are low efficiency ~80%
You are better off buying a Leaf Motor like this one
http://www.leafbike.com/products/diy-bike-conversion-kit/26-inch-electric-hub-motor-kit/newest-26-inch-48v-1500w-rear-hub-motor-bike-conversion-kit-987.html

Some really good ready to ride name brand E bikes out there now for those with money. I'd say before you decide, rent or demo a full suspension bike with either a bosch, or shimano steps mid drive. A speed pedelec, I mean. A faster one.

The 35E is a good solid choice.

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Thanks, that's good to know
If possible I woud like to have bluetooth BMS, haven't seen those anywhere else.
Torque Arms are on my list (first picture).
I woud rather have a geared hub than a dd.

Some really good ready to ride name brand E bikes out there now for those with money.

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I'd like to DIY because of customizability and the building experiance itself.

I don't get it. Why would you take a light-weight fixie and stick a heavy motor and battery in it? If you want the battery and motor, surely, an MTB would make a better donor. If you want light-weight, fit a Q100 motor and a 30 cell battery. Here's my light-weight bike with 20 cell battery. Total weight 13kg:

Why would you take a light-weight fixie and stick a heavy motor and battery in it?

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I'm not going for light weight but I like the minimalistic approach, I don't need lots of gears (since I'm riding an E-Bike), nor do I need the suspension, also I'm not a fan of how bulky MTB's are.

CrawlingWhisper said:

Why would you take a light-weight fixie and stick a heavy motor and battery in it?

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I'm not going for light weight but I like the minimalistic approach, I don't need lots of gears (since I'm riding an E-Bike), nor do I need the suspension, also I'm not a fan of how bulky MTB's are.

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Minimalist is OK until you realise that there's no way to stop your heavy 50km/h projectile. That single tiny rim brake is fine for a 10kg bike with a light rider averaging 20 km/h. I'd love to see you try and stop it when going down a hill at 50 km/h by pack-pedalling after the pads have melted.

If you look at my bike above, you'll see hydraulic disc brakes. I put them on for a reason.

If, on the other hand, you only want 25km/h to be legal in Germany, a MAC with a 14S battery would be total over-kill.

Also, you need to think about the torque that a MAC can produce with a 14S battery. It can be absolutely brutal. Do you think that a 25mm tyre will keep traction with the road? I can see that bike high-siding when you throttle out of a corner and I can imagine it being completely unrideable in the wet.

Finally, I guess you know about the law in Germany, but in case you don't, 48v is the maximum allowed, 25km/h is the maximum speed and power must stop when you stop pedalling. I'm not sure how the last rule would be interpreted. A torque sensor would be allowed and a cadence sensor wouldn't work. On a fixie, the pedals will always turn when your motor is going, so that one is down to interpretation of the rule. I suspect that because the throttle will still work with your feet off the pedals, a throttle on a bike like that is not allowed.

I'd love to see you try and stop it when going down a hill at 50 km/h by pack-pedalling after the pads have melted

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I know the one small brake is not sufficient, that's why I wrote it (I also don't plan to use it fixed but single speed):

Finally, do I lack something (I'm aware that I'll need better brakes)

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Also, you need to think about the torque that a MAC can produce with a 14S battery. It can be absolutely brutal. Do you think that a 25mm tyre will keep traction with the road? I can see that bike high-siding when you throttle out of a corner and I can imagine it being completely unrideable in the wet.

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I'm still not sure if I go for the high torque model but regardless, if you don't turn the throttle the whole way, you should not wheely as with motorcycles, even if it's to sensible, there is the 3 steps limiter also I don't plan on using it in the wet.

I don't mean to sound rude but maybe somebody will actually answer my questions...

I'm trying to help you, but you don't seem to be getting it. I've built many bikes for myself and other people - everything from the lightest road-bikes to a 5.5kw one with three motors, and everything in between. I've been doing it more or less continuously for 7 years. I don't know everything, but I think I have a good handle on most of the problems.

You need to experience the torque of a 12T MAC at 52v and 25A to understand what I'm talking about. It's more suited to hauling a cargo bike up steep hills and it's the last motor you want to put on a light-weight fixie. If you're not going to run 25A, then there's no point in having a MAC. A Q128 is much better up to 20A, and a Q100 for up to 15 amps.

Regarding the throttle, most throttles are speed controllers, not power controllers, so you can't easily regulate the power without planning for it. Also, the frequent bumping on a bicycle makes it difficult to regulate the throttle.

If you're not going to run 25A, then there's no point in having a MAC

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Well, I did not know that, thanks. Since I wanted a geared hub, mac being such a popular motor and EM3ev declaring it as in the power range I wanted, I thaught it to be suiteble. I'm happy to see that the Q128 You mentioned is so mutch cheaper than the mac. Does the rest of the Components work together with that model ? What about the other things ?

I think the preferred controller for the Q128 is either the 17 or 20 amp KT sine-wave controller from PSWpower.com. You need the LCD with it. It's not an option.

You can choose any down-tube battery, but think about the weight. I wouldn't go higher than 13S4P. If you don't need to go too far, a 13S3P might be better, but they're not easy to find. Whatever battery you get, make sure that it has branded cells.

You need to choose the right speed version of the motor because it'll have an affect on efficiency and acceleration. Tell us what you want your modal speed to be and what sort of hills you encounter so that we can give suitable advice.

Sorry if I was a bit hard on you earlier. The problem with internet research is finding what's relevant. Most of the guys on this forum have a different frame of reference to the sort of bike you're building. You should have a look at the UK Pedelecs forum or, better still if you speak German, the German one.

http://www.pedelecs.co.uk/forum/
www.pedelecforum.de

d8veh said:

I guess you know about the law in Germany, but in case you don't, 48v is the maximum allowed, 25km/h is the maximum speed and power must stop when you stop pedalling.

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FWIW, I am not aware of any upper limit to voltage, only 250 Watt of _sustained_ power _output_ (just don't ask how "sustained" can be measured at all), not aware of any peak output limits, and 25 km/h is the speed at which the motor must stop supporting. The mere act of pedalling is required for the motor to "support" (there are no rules which say how hard that pedalling needs to be, just turning the pedals will be sufficient to "turn on the motor")

Then there is walking assistance - no pedalling required up to the eye-watering speed of 6 km/h.

Turn south, into Austria and Switzerland, and the rules are different (more power allowed, more "walking assistance" allowed).

Anyway, the OP needs to define the goals better. Based on that, a reasonable solution (components) can be designed. That solution will be different for the Baltic Sea when compared to the Bavarian Alps, always considering road use only.

Possibly cheapest way to proceed is to simply get some used donor bike with decent enough components and slap some ebike kit from ebay.de onto it. People on pedelecforum.de seem to quite like those kits.

On the note of pswpower - I ordered one of their KT controllers off aliexpress and am now entertaining a wonderful conversation about the "rated power" of the delivered controller not quite matching what is being advertised ...

I think the preferred controller for the Q128 is either the 17 or 20 amp KT sine-wave controller from PSWpower.com. You need the LCD with it. It's not an option.

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Won't the Contoller fron EM3ev work ? I like the option to have 3 programmable speed settings.
If not, will this throttle work with the contoller ?:

https://em3ev.com/shop/half-twist-throttle-3-speed-cruise/

You need to choose the right speed version of the motor because it'll have an affect on efficiency and acceleration.

Click to expand...

Won't I choose the 201 version anyway if I have 700C Wheels ? Speedwise I'd like to reach around 30 mph, if it's a bit less it's not that bad. The hills around here are not that steep but some are quite long.
Btw, what's the difference between the "normal" Q128 ratet for 400-500 W, the Q128C advertised for 500 W and the Q128H, which is advertised as 800W but strangely not available in a 48V "Version", like the other two ?

CrawlingWhisper said:

I think the preferred controller for the Q128 is either the 17 or 20 amp KT sine-wave controller from PSWpower.com. You need the LCD with it. It's not an option.

Click to expand...

Won't the Contoller fron EM3ev work ? I like the option to have 3 programmable speed settings.
If not, will this throttle work with the contoller ?:

https://em3ev.com/shop/half-twist-throttle-3-speed-cruise/

You need to choose the right speed version of the motor because it'll have an affect on efficiency and acceleration.

Click to expand...

Won't I choose the 201 version anyway if I have 700C Wheels ? Speedwise I'd like to reach around 30 mph, if it's a bit less it's not that bad. The hills around here are not that steep but some are quite long.
Btw, what's the difference between the "normal" Q128 ratet for 400-500 W, the Q128C advertised for 500 W and the Q128H, which is advertised as 800W but strangely not available in a 48V "Version", like the other two ?

Click to expand...

The PSWpower controller has a tick-list for appropriate throttle, PAS and LCD. There's no need to get one anywere else, but all throttles are compatible.
For 30 mph with 700c wheels, you need the 36v 201 rpm motor and run it at 48v. Real speed will be about 25 mph, but it will give power all the way to 30 mph. You won't get that up hills. If you want that sort of speed, you need to rethink the whole project.

The Q128C has the spline for free-hub gears. The others have the thread for freewheel gears. The Q128H spins faster internally and has a bigger reduction ratio, so it can handle more power.

daffy99 said:

d8veh said:

I guess you know about the law in Germany, but in case you don't, 48v is the maximum allowed, 25km/h is the maximum speed and power must stop when you stop pedalling.

Click to expand...

FWIW, I am not aware of any upper limit to voltage, only 250 Watt of _sustained_ power _output_ (just don't ask how "sustained" can be measured at all), not aware of any peak output limits, and 25 km/h is the speed at which the motor must stop supporting. The mere act of pedalling is required for the motor to "support" (there are no rules which say how hard that pedalling needs to be, just turning the pedals will be sufficient to "turn on the motor")

Click to expand...

The power limit is on the rating of the motor, not how much power it produces. The wording is something like " a maximum continuous rated power of 250w", where "rated" is a key word. The law in Germany is that electric bikes (pedelecs) must comply with EN15194, which only applies to electric bikes up to 48v. Some test houses interpret that as an absolute 48v, in which case a 48v system that actually charges to over 54v is not allowed. Others interpret it as a 48v system, so 13S batteries are allowed.

The PSWpower controller has a tick-list for appropriate throttle

Click to expand...

Can you post a link to that list ?

For 30 mph with 700c wheels, you need the 36v 201 rpm motor and run it at 48v

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Why do I take the 36V model over the 48V one ?

CrawlingWhisper said:

For 30 mph with 700c wheels, you need the 36v 201 rpm motor and run it at 48v

Click to expand...

Why do I take the 36V model over the 48V one ?

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A motor's maximum speed depends on the voltage applied to it, so it will go 33% faster at 48v compared with 36v. You could use the 36v 328 rpm one, but that might be too fast, and you'd need to increase the current by 33% to get the same power, which means a much bigger controller. Those PSWPower controllers are tiny, but the nearest equivalent for the same power at 36v is the BMSBattery S12S, which is massive and doesn't quite fit your idea of minimalistic.

Hi
D8veh has given you some good advice- none that I would disagree with. I'd like to second the point about the bike suitability. Even if you get a better brake on the front, that fork is totally inappropriate for an ebike, as is the rest of the frame. Weight saving is not an issue when you have power- handling strength and reliability are. Some points I'm concerned about.
-The crown of that fork will be to weak to be safe at increased speed and weight, a failure would be catastrophic at speed. And they do fail, not always straight away, but when some fatigue sets in.
It's also likely to be too narrow to accept a tyre more than 30mm which is not enough. Thick 50mm as a starting point.
- the frame will flex a lot with extra weight strapped to it, which will feel awful.
- you are too prone on it for safe hard braking
- there are no mounts ( that I could see) for rear brakes which you will need ( you'll need all the help you can get)

I'd think about that bike if I was doing an ultra light very low powered low speed conversion, but then what's the point- just ride it normally.
Get a brand name mtb frame with a decent front shock, decent brakes and be 10x safer at the speeds you'll want to be doing.
I've snapped a few frames, and a couple of forks in my time...( inappropriate use of lightweight xc frames ) It always hurt- a lot, but at least when they failed I was going at low speed.

A motor's maximum speed depends on the voltage applied to it, so it will go 33% faster at 48v compared with 36v.

Click to expand...

Shoud't it make no difference, if I use the 36V or 48V version, when maximum speed is only dependent on the Voltage I apply to the motor ?

Get a brand name mtb frame with a decent front shock[...]

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Isn't there a way around a MTB ? Wouldn't a solid steel bike be enough ? Maybe if I'll change the fork? Because I woud like to change the handlebar (and maybe seat) anyway, to something that allows a more vertical seating position. If I woud do that to a MTB, it woud look ridiculous. Also there are mounts for rear brakes (I called the shop for this very reason), they just are hard to see because the frame is black.

[/quote]
Isn't there a way around a MTB ? Wouldn't a solid steel bike be enough ? Maybe if I'll change the fork? Because I woud like to change the handlebar (and maybe seat) anyway, to something that allows a more vertical seating position. If I woud do that to a MTB, it woud look ridiculous. Also there are mounts for rear brakes (I called the shop for this very reason), they just are hard to see because the frame is black.[/quote]

Might look ridiculous... but drives nice and less of a theft target.

Might look ridiculous... but drives nice and less of a theft target.

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I do not doubt that it drives nice, with that handlebar it even looks quite decent but not really what I had in mind. I'm just asking if there is an option. Also, theft is not much of a problem to me.

Got the motor in the wrong end.

A motor's maximum speed depends on the voltage applied to it, so it will go 33% faster at 48v compared with 36v.

Click to expand...

Shoud't it make no difference, if I use the 36V or 48V version, when maximum speed is only dependent on the Voltage I apply to the motor ?

Click to expand...

I still wonder, could you pls answer ?

CrawlingWhisper said:

A motor's maximum speed depends on the voltage applied to it, so it will go 33% faster at 48v compared with 36v.

Click to expand...

Shoud't it make no difference, if I use the 36V or 48V version, when maximum speed is only dependent on the Voltage I apply to the motor ?

Click to expand...

I still wonder, could you pls answer ?

Click to expand...

A 48v 201 rpm motor will spin up to 201 rpm at 48v
A 36v 201 rpm motor will spin up to 268 rpm at 48v

CrawlingWhisper,

I ride a bike with a Mac 6T motor , and a bike with a Q100c Motor.

Here is some very important information for you ...

1) Do , Not , get that Fixie bike for a e-bike conversion !

2 ) For the speeds you want to go, Do , get a bike with good Disc Brakes ( Avid BB7 at the least, or Shimano Hydraulic Brakes are better )

3 ) For any speed over 20 mph ( 34 Kph ) you are better off with a front fork or at least a bike with some kind of front frame or stem suspension .
examples are Older Cannondale bikes with the Headshok , or the newer bikes with a little suspension at the stem/steerer tube like the new Specialized Rubaix or better yet the New 2018 Specialized Diverge .
( although with the newer Specialized bikes, or most new bikes for that matter you will have to go with a mid drive motor since most good bikes being sold now have Through axle Wheels/Frames )

4 ) For the speed you want to go the Q128 is the minimum size motor to get, even then I would not expect over 25 mph though in real world riding, the Mac will have more power,
But it is best to lower your desire of speed down to around 34 kph - 40 kph , if you do not want to get a strong Mountain bike ,and you do want to get a fixie looking type bike, like lighter weight 700c wheel , minimalistic type of bikes, then lower the speed to 30 kph and under.

5) Only a mountain bike with front suspension if you are getting a Mac motor
and
A Q100 or Q128 for use on a light weight 700c wheel bike.