Newbie first ebike built

[chrisbr]

Hi all ! First of all, great forum !! I've been reading here for the past few days and learned a lot (but still have a lot to learn, that's for sure). I'll try to be brief because i think you guys have to answer a lot of basic question all the time... I tried to find them here and there but still have some questions that surely your experience would answer. And also sorry for grammar, Canadian French here, so not my first language..

My ebike plans:
700c, steel frame, battery place: front frame over chainrings, battery case by me, front hubmotor 350W

What I want from it:
fast (35-45km/h and above if possible), I don't care about fast accelerating or going fast uphills, and I do a lot of bike so I'll be pushing 95% of the time, (90 rpm 53-11 biggest ratio)
"light": battery (LiFePO4) should not be more than 4kg.
if it could do a 30k no peddaling it would be fine, but like i say, i ll be pushing all the time

Components choosen so far:

36V 10AH V2.5 LiFePO4 Battery Pack, Ping
because of good reviews of ping and LiFEPO4 seem the way to go for safety and durability, i know weight is a bit high but i prefer durability...open to discussion here. Also the size does matter, with 10cm x15cm x15cm, it's really nice choice for me !
http://www.pingbattery.com/servlet/the-8/lifepo4-lithium-phosphate-iron/Detail

Bafang 36V350W BPM Front Driving Hub Motor RPM : 328
http://www.bmsbattery.com/front-driving/349-bafang-350watts500watts-bpm-motor-e-bike-kit.html
350W over the 250W because it seem that only the 350W can go above 201 rpm (328). Like i said, on a 700c...I read that it's not really the way to go but what else can i do if i want speed on a 36v LiFEPO4 with a small format ? also open to comments here

KU93 450W 9Mosfets High Speed Controller
http://www.bmsbattery.com/controller/363-universal-brushless-hub-motor-controller.html
Mainly because i need the connection for HWBS (Hidden Wire Brake Sensor). There no info on the Amp that this controller can put on http://www.BMSBattery, but i think it's a 22A max...kind of afraid of the mesurement since I'm making my first steps in the ebike world...

Accessories:
Half Twist Throttle (with the cruise control, i still have to read more on this...i read about an "6sec hold giving you a cruise mode" that would be nice)
2x HWBS (Hidden Wire Brake Sensor), anyone knows if these work pretty well on road bike brakes ?

There ! i think everything is there !
Like i said in the beginning, i am new with all of this, so there's probably some concepts that i have overlooked... I have no problem with the bike mecanics and i ll built the wheel myself, as for the connectors - soldering etc, i'll have the help of someone who know better... and i'll read a lot...that's for sure

It would be great to have your inputs on this project ! Can't wait to order all of this and start my first experiment !

Thanks !

Chris

 

[USAEBIKECO]

I would advise to invest in Kevlar tires and puncture resistant tire tubes. I know first hand they make a huge difference.

Nothing more annoying than getting a flat tire on the way to work.

Best of luck!

 

[The fingers]

How far one way and can you charge at work?

 

[chrisbr]

With that kind of set up, what should I except out of it ? (in tearm of autonomy), ebikes.ca is telling me some thing like 28k (if i go at full speed and no help(?))

(normal condition, roads, not to much stop and go, no hills really actually, and pushing "normally"... i how all these factors are subjectives..)

if the system could do a 25-30k by itself, i think i would be happy (and then i'll find out what needs to be push on the pedals by me to get the distances i want. My distances can vary from 5k to 100k, so really, i'm more testing my first ebike before going bigger..

No problem of recharging at work, i'll buy 2 chargers and leave one there

But my worries are more about the compatibility of all my components, could someone give me a heads up here (is the controller too high for my 350w motor ? 22amp(max output?) x 36v, so max output at 792w on a 350w motor...is that allright ? even for long period, let's say, a 5 min climb ?)

Thanks ! Much appreciated !
ps: lester12483, of course the tires wont be cheap, but i never tried puncture resistant tire tubes, will try it

 

[d8veh]

The 10aH Ping battery is a bit low on power for the BPM. The KU93 controller pulls 22 amps. 15aH would be better, but that makes it quite heavy.

The PAS on the KU93 isn't very friendly. The power algorithms are not very good, so you can't get the right power how you need it. There's always not enough power or too much. One of the modern controllers with LCD would be better (S09P 22amps or S12S 23 amps). You need to order a wheel-speed sensor and LCD separately because they're not included with the controller.

These batteries are quite good. Again, they're relatively heavy. They have headway cells inside which makes them very serviceable. They can give very high current, so much better suited to the BPM motor. I've had two of them for nearly two years with now problems.
http://www.bmsbattery.com/packs/154-36v-12ah-38140-lifepo4-battery-12-cells-ebike-battery-pack.html

 

[dogman dan]

I tend to agree about the size of the ping. Mostly so it will be discharged at a lower c rate, increasing it's potential lifespan. It will be bigger and heavier, but you should be able to still fit a 36v 15 ah in the frame. This will solve your range issue, you'll have 25 k for sure, at 35 kph speeds with little pedaling. And actually you will have more than that. 25 k will leave you some reserve so you don't pound your battery every ride, or have it when the weather is giving you a headwind.

The fast motor will get you what you want, assist at faster speeds. It will be less efficient up the steepest hills, but it will still climb 5% for sure with no big problems. It will also waste power into heat on all starts, so another good reason to upsize the battery just a bit. If you just pedal the first 20 feet before adding assist, you can avoid a lot of that wasted energy and motor heating. Since you are a real pedaler, it's not likely that the faster motor in the big wheel will punish you much.

But if you said all your riding would be in a large city, then I'd be recommending a slower motor and 48v. But maybe not as slow as 201 rpm.

 

[chrisbr]

The 10aH Ping battery is a bit low on power for the BPM.

let's see if i'm understand right: to run it at 328rpm easy conditions without helping the motor, i ll need 36v and 9.72amp continiously (350W=36v*A) (so 350W / 36v = 9.72A), and the ping batterie could do this, no (deliver 10amp or even more)? So what do you mean by "is a bit low on power for BPM" ?

The KU93 controller pulls 22 amps.

22amps OverCurrent mean Max current that could be deliver right ? is that to much for a 350 W mottor...would it be to much for a 250 W...is there a rule of thumb here ?

15aH would be better, but that makes it quite heavy.

Better for distance ? yes, but kg added..

The PAS on the KU93 isn't very friendly. The power algorithms are not very good, so you can't get the right power how you need it. There's always not enough power or too much. One of the modern controllers with LCD would be better (S09P 22amps or S12S 23 amps). You need to order a wheel-speed sensor and LCD separately because they're not included with the controller.

I dont really care about PAS, probably will put a 3 button speed with the throttle...or even just the throttle+cruise control. I'll probably end up putting a CA...it that's possible on this controller ? (didn't read about that, and not a priority)

These batteries are quite good. Again, they're relatively heavy. They have headway cells inside which makes them very serviceable. They can give very high current, so much better suited to the BPM motor. I've had two of them for nearly two years with now problems.
http://www.bmsbattery.com/packs/154-36v-12ah-38140-lifepo4-battery-12-cells-ebike-battery-pack.html

yes, this is an option...the 12Amps should do the trick for running 328 rpm ? (i guess my first question at the top will answer this one...)

Also, since i got you to answer my questions: I saw on other threads that you liked the HWBS (Hidden Wire Brake Sensor)...is it possible to install those on whatever controller or just the ku93-123 ?

 

[chrisbr]

I tend to agree about the size of the ping.

You mean, you agree with d8veh ? to small ? not enough power ?

The fast motor will get you what you want, assist at faster speeds. It will be less efficient up the steepest hills, but it will still climb 5% for sure with no big problems. It will also waste power into heat on all starts, so another good reason to upsize the battery just a bit. If you just pedal the first 20 feet before adding assist, you can avoid a lot of that wasted energy and motor heating. Since you are a real pedaler, it's not likely that the faster motor in the big wheel will punish you much.

Yes, this is what i have the intention to do.

But if you said all your riding would be in a large city, then I'd be recommending a slower motor and 48v. But maybe not as slow as 201 rpm.

48v ? would that not be running my motor faster rpm ? Do you have a motor in mind for a front setup ?


Thanks ! you guys are very helpful !

 

[dogman dan]

Sorry I wasn't so clear. I recommend a 15 ah size for 20-25 amps controllers.

For a motor using a 22 amps controller, it's typical to pull 25 amps spikes when starting up. And you chose a motor that will, unless you pedal first always, pull an extra long amp spike till you get rolling faster. So even when the controllers amp limiting kicks on and limits to 22 amps, it will still pull that full 22 amps for 30 seconds or so.

So a 22 amps controller combined with a fast motor in a large wheel will tend to punish the shit out of a 10 ah battery. The cells ping uses can handle 1.5c continuous fine. But they just hate pulling a big amp spike at 2 or 3 c.

In a 10 ah size, 2c discharge rate is 20 amps.

In a 15 ah size, 2c rate is 30 amps. So a 15 ah battery pretty much insures that you won't pull 2c spikes with that setup.

If you get the 10 ah one, it will work, but I would not expect 3-4 years out of it. But like I said, it's possible to ride so you don't use the motor till you are going faster. But cruising fast, even pedaling hard, you will still pull more like 12 amps, and 15-18 if you have a big headwind. So a 10 ah would be ok on a perfect day. But in bad weather, it starts to be real close to being too hard on the battery.

Remember, when you size your battery, you will ride that bike out in the world, in the weather. Not in a lab. When it gets cold, your battery will not perform to it's max potential, and headwinds can double your need for power. With a 10 ah size, that day your ride uphill, into the wind, in the cold, will punish the hell out of your tiny battery.

 

[dogman dan]

Re the 48v comment.

Yes a slower motor and 48v would then cruise at the same speed as the fast motor on 36v. But it would pull less amps leaving stop signs, and be more efficient and pleasant to ride in a city where you might have to stop 5-10 times per mile.

There are some nice selections of motors in a wide variety of rpms on EM3ev. He also sells some nice batteries as well.

 

[chrisbr]

seems that my problem here is 22Amp going through my controller, so what if I drop the KU93 and go for a controller with less peak Amp...didn t do the research but something like

Battery 36v 10AmpH
controller 15 amp peak
same motor 350w 328 rpm

i understand that my torque will suck but since it s not a big concern, would that combinaison do the trick ? 15 amp max controller would mean 1.5C, and ping battery would handle this better... and i ll make sure not to push it full blast to long i guess


right ?

little by little, grasping what the deal is with ebike....thanks

 

[TheBeastie]

2x HWBS (Hidden Wire Brake Sensor) are good, but remember the only sleeve onto the brake cable one way, if you install them the wrong way they send a constant brake signal to the controller.

 

[d8veh]

If you want to run at 15 amps you don't need a BPM motor. The smaller SWX series of motors all handle 15 amps easily, and so does the Q100. If you're not too heavy and like to pedal, a 36v 201 rpm SWXB or QSWXK5 at 48v and 15 amps will give about 24 mph, but won't have the torque of the BPM.

The BPM motor is a high-torque motor that can drag you up hills without pedalling if you give it enough current. There's a close relationship between torque and current. From what you described, the 350w one with a 22 amp KU93 will give you what you want, but you need a battery that can give 22 amps, which is too much for the 10aH Ping. The decision about the battery amp-hours is for its capability to deliver current - nothing to do with range. The 12 aH battery I linked to above is a special high-current battery, which can give 60 amps, so will be totally unstressed by the BPM at 22 amps.

 

[heavymetalthunder]

I would advise to invest in Kevlar tires and puncture resistant tire tubes. I know first hand they make a huge difference.

Nothing more annoying than getting a flat tire on the way to work.

Best of luck!

I'll second that. I was always worried about getting a flat. So when I wore out my Bell street tires (which actually performed well and uses Kevlar), I switched to a couple of Michelin City using puncture resistant tubes and went as far as installing some tire liners. 400+ miles so far and no problems.

 

[dogman dan]

I agree, running the 328 rpm bpm in a large wheel at only 15 amps would result in very very poor performance leaving the stop signs. If you will use less power, then a smaller motor would handle it fine.

However, it depends on what you want from the motor. If ALL you want is some assist at full speed, the fast motor on 15 amps will work fine. You never use the throttle till you are going 15 mph, and it works great with a 15 amps controller.

It's just that 90% of us want the exact opposite. We want as much assist as possible getting started, especially those dreaded stop signs on an uphill grade.

I think if you just commit to a slightly larger battery, you will be happy in the end. You WILL like having a motor that helps you get going with 22 amps on the stops, and you will like having the extra range.

But if your riding is inner city stop and go, I strongly discourage the choice of the 328 rpm. Find something else in 250 ish rpm ( at 36v) for that size wheel. Or even just go for the really slow one, and commit to 48v. Volt up that slower one and it will be fast enough.

 

[chrisbr]

Before adding to much here, i did read a bit more, and this tread did answer a lot of questions.

(You guys actually mention pretty much was being said here, but deeper details is always welcome)
https://www.endless-sphere.com/forums/viewtopic.php?t=49691

SO, this open up my eyes a bit more and my choice will probably be a Q100, 24v, 201rpm, running on a 36v 10(or 15Amps) = 300rpm from what i read. I did post a question on that tread also so I'll not double it here but you can always go there to answer for sure . Battery ping or not , depending on my controller and C rate (the one d8veh (BMS battery) at 12 am or even 15 is actually pretty nice).

If for whatever reason (size of the ping battery, is 15cmx15cmx10 = actually 100 cm3 less then the one on BMS battery...IF their sizes are right...) i go for the Ping 36V 10A, is there a way to drop down the ku93 to less amp so i do not "punish the shit out of a 10 ah battery" because of the C rate? I know squat about opening a controller (for now) but i have a friend that would have no problem with that... I'm always sticking to that controller because of two main things:
-cruise control after 6 sec hold
-capacity of using HWBS
is the ku93 the only way around if i want plug and play simple connection for those two ???

I'm so much in that project that the reading is starting to take over eating and sleeping time will still do it but always thinking about the concepts....pretty fun !

 

[chrisbr]

Also one other thing: i've chat with BSM battery and asking about the Q100 power

on their web site they announce: Q100 24v 250-350W

What the hell does that mean ? is it 250 or 350 ?

The lady that answer me told me that it's because some countries doesnt allow the use of 350W

So I toll her: OK, well, when ordering, where can i tell u guys that i want the 350W ?

Her answer: i don't understand.

And: It's all on our website....


which is not.....so any clue here ? Maybe i'm not getting something....aaaa newbs...

 

[d8veh]

The 250w and 350w Q100 are the same. Some of mine have 250w to 350w written on the labels. They have the same power as a typical 250w hub-motor fronm Bafang. From my own experience and others on the forum, they run fairly safely at 17 amps 44v (12S lipos) and 15 amps with a 48v battery, or any other combination that takes about 750w from the battery, as long as you don't labour it up hills at low speed.

You don't need a KU93 controller unless you get a bigger motor like the BPM. The standard current drom the KU65, KU63, S06P and S06S is 15 amps. If you want more, you can take them past 20amps by soldering the shunt. I run one at 22 amps, and I've gone as high as 24 amps.

The Q100 goes very nicely with the 10aH bottle battery that has the integrated controller, which makes a very simple and neat installation, but I don't know if you can solder the shunt in them. I'll let you know shortly because I have one on order. Other ones I have have encapsulated controllers to waterproof them because these batteries get all the spray from the front wheel.

 

[chrisbr]

I'll let you know shortly because I have one on order. Other ones I have have encapsulated controllers to waterproof them because these batteries get all the spray from the front wheel.

perfect, give some news when you tried it, thanks !