Will this combination work?

[d8veh]

Battery question:
In the interest of light weight, I would like a 36v8Ah battery for short trips (wt: 2kg), and to use a second 36v8Ah for longer trips (i.e. use the second battery for the second half of the trip).
http://www.bmsbattery.com/36v/514-36v-10ah-lithium-ion-electric-bicycle-battery-pack.html

That would allow me to be light and quick for shorter trips (80% of the time), and have the option of going longer on those days when I needed that.

Or is there a power disadvantage with using a 36V 8Ah 15amp battery vis a 36v 12Ah 15amp battery?
(I am avoiding the bottle batteries there, as they look to be only 10amp sustained).

You can't use these batteries with any motor more than 250w. They can't give enough current. The lightest weight options are the 15aH shrink sleeve battery for 350w kit and 20aH version for 500w.
http://www.bmsbattery.com/36v/445-36v-15ah-lithium-ion-electric-bicycle-battery-pack.html
http://www.bmsbattery.com/36v/165-36v-15ah-lithium-ion-electric-bicycle-battery-pack.html

The 350w CST motor gives much less torque than the 500w one - even if you run it at the same current. The size and weight are the same as the 500w one, so no real advantage. The torque difference is less noticeable with the BPMs. The main difference with the kits is the 22amp controller with the 350w kit and 30 amp one with the 500w kit. The 350w motor is strong enough if you don't weigh too much, or if you don't have extremely steep hills. If you weigh 100kg, 500w is more comfortable.

 

[chas58]

Thanks d8veh

I think I am missing part of the equation. Is the amount of current some way related to the Ah?

Both the 36v8ah and 36v20ah are rated at 15amps continuous current. But you are indicating that the larger Ah battery can supply more current? Is there a formula relationship to help me understand that relationship?

 

[friendly1uk]

We all want code 11 BPMs, but they're not easy to find. Luckily, I got one when BMSBattery used to list them.

Friendly1uk, did you order a set of 210mm spokes. If not, see if you can add them to your order without extra postage. Send them an e-mail rather than use the ordering system.

Here's a battery I made with a Frog Case.

Why 210mm spokes? They told me 186mm, so that's what I ordered. Are you telling me my kit won't fit together?

Thank you for the frog box pics. I was disappointed to see them removed from other threads by the picture host. It is a very neat install indeed. I ordered the box too, but with no real idea what it was. Perhaps my 3 4s packs will fit after splitting them up a bit. With enough room for my bms too. If not, it might end up holding a larger controller than the modded ku65 I have compromised with for now. Once I have a better idea what I actually want.


Chas, the constant discharge rate is related to the Ah capacity, but you need a third number. These cells get a C rating. Mine for example is 20c. The figure is a multiplier you use on the Ah capacity. I have 5Ah so the sum is 5X20 giving me 100 Amps. Your batteries can either state the discharge currant, or this multiplier, So you have to work it out yourself.

As it's Amps that create the magnetic field, They are very important. 250W controllers are 15amp, like the pack your looking at. 450w controllers are 22amp and there is nothing in-between on bmsb. This is why I'm building small 20Amp battery packs. I want to mod a ku65 for now, but with two of my 20 amp packs side by side, I have 40 amps for future upgrades.

D8veh, how fast did your Q100 fast wind bike go, when you had two motors in your 26" wheels. I think it's the kind of speed Chas will attain before the motor is starting to loose it's usefulness. Even if he can do 400w of work himself, 200w more at these speeds is not a great deal. I expect a single fast wind+Chas would be marginally better than two fast winds.
Chas, do you have hills were even with the wife on board your dropping below 15mph? It seems the fast wind does not like full power below 15mph, and that is when the 'overheat' clock is ticking.

 

[d8veh]

210mm is the size I used for 2 cross. Your size must be for 1 cross.

With 2 201 rpm Q100s at 36v, the speed was no different to one motor - about 18mph. It climbs well and is quite efficient. Also traction is very good on difficult surfaces.

With two 328 rpm ones at 36v, it was pretty fast - about 25 mph on the flat. You could feel the motors working all the time, and the wattmeter showed 26 amps most of the time. It was good fun, but dificult to conserve power. Both controllers got so hot on a long hill that the thermsl overloads tripped. I thought this setup would be good, but now think that a single 500w would be better.

 

[friendly1uk]

Phew. I think the right expression here is tfft lol I don't know a lot about this stuff, I could easily of made a mistake if I did not ask. Last double crosses I did were the laces of my trainers, in the 80s lol


I think Chas might be one of the best fits for a 36v 328 26" wheeled bike. It could do half the work at 25mph, and he gets to keep his £92 battery/bms/charger combination. Total conversion under 5kg and freewheels well. He does the trek without help anyway, and has no meaningful hills it would appear. I bet he spends little time below 15mph with the throttle wide open. Just reasonable acceleration time-frames.
It is temptingly cheap, this £180 package. If only p&p then duty was not going to double it.

 

[chas58]

yeah, small battery small fast wind motor (36v 328rpm) sounds like just the ticket. I just wouldn't use the motor less than 15mph; motor would be used for speed assist at 15-25mph. Could work. Especially since I figured out how to put a Q100 on a 120mm wide frame.

 

[docnjoj]

I doubt there are more than 2 different gear ratios. Maybe windings are different x3 but maybe not. Way too much work for cheep motors. JMHO
otherDoc

 

[friendly1uk]

I doubt there are more than 2 different gear ratios. Maybe windings are different x3 but maybe not. Way too much work for cheep motors. JMHO
otherDoc

24v gears are straight cut, and the 36v one's helical. I have not been able to count any though. Jury seems to be still out.

 

[friendly1uk]

yeah, small battery small fast wind motor (36v 328rpm) sounds like just the ticket. I just wouldn't use the motor less than 15mph; motor would be used for speed assist at 15-25mph. Could work. Especially since I figured out how to put a Q100 on a 120mm wide frame.

I think you will be happy. I think I should of stuck with this choice too.

My move to 500w cst is an uneducated one. I just want a benchmark from which to judge. If the 350w has less torque, it stands to reason it might be faster. I want fast. I reckon I ordered slow in the form of the 500w. Which I'm currant limiting to it's 44v full speed currant of 15amp anyway, although It would happily pass much more or lower speeds. I just hope the 350s comparative lack of torque means it can't get too the same top speed, so I chose correctly. I will see in a few months when it gets here. Lets hope I was not to silly, andI'm not heading towards building a motorbike instead.

Edit: Be sure to let us know

 

[chas58]

The price doubles for most things from china with shipping (to us). So a $125 wheel costs $250 with shipping. A $75 hub costs $175 with shipping.

Green bike kit can stick a spare hub (not a built wheel) in the same box as the wheel kit without increasing shipping, so I think I’ll just get a spare Q100 hub so I can have both low and high speed motors. D8veh says they are pretty easy to swap out the motors.

From what I see, your Bafang 350W36V low speed motor is a code 12 motor (per GBK) which has a no load speed of 250rpm, where the low and high speed Q100 motors turn at 230 and 273 rpm respectively. The big difference is that the Bafang motors are bigger and can take more current.

The Bafang is going to be ~3mph faster than the low speed Q100, while the high speed Q100 may be even faster with pedal assist, but it will be unhappy trying to pull at speeds much under 15mph.

Here is a speed/motor chart from papa motors
Motor Type - Top Speed - Top Range - Battery
24V/500W 16mph (26KM/H) 17 M (28KM) 24V20AH
36V/500W 19mph (31KM/H) 19 M (31KM) 36V15AH
48V/500W 26mph (43KM/H) 26 M (43KM) 48V15AH
48V/1000W 32mph (52KM/H) 26 M (43KM) 48V15AH
24V/350W(Geared Motor) 14.29mph (23KM/H) 12.42 M (20KM) 24V9AH
36V/350W(Geared Motor) 16.77mph (27KM/H) 19.25 M (31KM) 36V9AH

 

[wesnewell]

Please go to the User Control Panel, select Profile, and then enter your city, state/province, and country into the Location field (country minimum). This will help people help you. Example: Wylie, TX, USA. Without knowing what country you are in it's hard to make any recommendations and you will waste your time and others. Thank you.

 

[chas58]

Ok, to experiment a little, I ordered both a 201RPM and the 328RPM Q100 motor. GreenBikeKit can stick the second motor in the box with the wheel kit for no extra shipping charges. That saves about $100. So, I'll be able to try both motors just by swapping out the core. And if/when I go to 48v, I may be better off with the 201 motor anyway. The next trick will be to see if I can build the bare motor to a single speed/FG wheel with a 120mm dropout. Wish me luck on that, as no one has ever done that before! :-O I like the idea of a 20lb 350watt bike (or 700watt if you include my legs).

 

[friendly1uk]

And so the wait begins
Mines the 36v cst, so a 270rpm wind they claim. Running at no more power than yours. well, maybe a few volts(44v). It's still being processed. I wanted to clarify just which motor I wanted, as I suspect it's manufacture might be the delay. I just didn't understand this 'code' business till very recently. I expect a code 11, which seems be mean 5.5tpv. Really quite low.

 

[chas58]

Good luck on that code 11, I bet you get a code 10 (250rpm @ 36v). But if you are running 44volts, that is going to be 300rpm. You will have more current than the Q100 which probably runs at 12-14amps. Certainly a Q100 speed-wind won't run a 26"/700c wheel at 270rpm without a lot of help from the rider.


Bafang BPM & CST motor code for 36v
Code 08 is 378 rpm frt. and rear 48V slow-winds motors are Code 8
Code 09 is 335 rpm (motor code 16(9))
Code 10 is 300 rpm BMS: 48V 500w rpm393, rear, code 10 .
Code 11 is 280 rpm BMS: 48V 500w rpm393, Front. code 11.
Code 12 is 250 rpm
Code 13 is 230 rpm BPM 36V 350W front 201 rpm 26 (13) motor
Code 14 is 215
Code 15 is 205 rpm
Code 15 is 192 (BPM 36V500W 201rpm (code 15) )
For speed at 48V, use factor of 1.33 increase in motor speed.

 

[chas58]

OK, with shipping (greenbikekit) that $115 wheel/motor suddenly becomes $300. That kind of blows my expectation to get a 26" wheel and a 700c wheel for $250 - now it is more like $600 for a pair. And bumping up to a CST might not be a bad idea, but I love the tiny stealth aspect of the Q100.

Just to update this:
For the price of shipping for one wheel, Greeen Bike Kit can ship two front wheels, a rear wheel with spare motor (not on wheel), but not two rear wheels. So, I got a rear wheel and spare motor.

If you ask nicely, then it is possible to put a front 100F motor kit and one 100R motor kit in one box.

 

[chas58]

d8veh wrote:
“With 2 201 rpm Q100s at 36v, the speed was no different to one motor - about 18mph.”
“With two 328 rpm ones at 36v, it was pretty fast - about 25 mph on the flat.”

18mph is slower than I go with no motor. That isn’t helping me, I don't want to totally overpower the motor with my legs. 25mph sounds better, with my legs providing 300 watts, and the Q100 providing ~300watts. That is my goal.

 

[friendly1uk]

Good luck on that code 11, I bet you get a code 10 (250rpm @ 36v). But if you are running 44volts, that is going to be 300rpm. You will have more current than the Q100 which probably runs at 12-14amps. Certainly a Q100 speed-wind won't run a 26"/700c wheel at 270rpm without a lot of help from the rider.


Bafang BPM & CST motor code for 36v
Code 08 is 378 rpm frt. and rear 48V slow-winds motors are Code 8
Code 09 is 335 rpm (motor code 16(9))
Code 10 is 300 rpm BMS: 48V 500w rpm393, rear, code 10 .
Code 11 is 280 rpm BMS: 48V 500w rpm393, Front. code 11.
Code 12 is 250 rpm
Code 13 is 230 rpm BPM 36V 350W front 201 rpm 26 (13) motor
Code 14 is 215
Code 15 is 205 rpm
Code 15 is 192 (BPM 36V500W 201rpm (code 15) )
For speed at 48V, use factor of 1.33 increase in motor speed.

Thank you Chas.
If I get a code 10 I will be happy having seen this. Even a 9. I don't particularly want the 11 that was suggested to me elsewhere, but it will do. I will be gutted if it's a 12. It's on it's way now though, so fingers crossed

 

[friendly1uk]

Anybody know how I should lace my wheel? Here is a pic showing a radial spoke barely enters the rim. If I move the spoke to draw an arc, It perhaps reach's 3 holes, Although one of them is for the other flanges spoke.

Uploaded with ImageShack.us

I'm using bmsbattery bits. There 26" rim and the 186mm spokes they say they use. The rim is rough 531mm internally, and the cst motor spoke holes about 83mm from center.

I can't seem to find a realistic 'how to' for 1 or 2 cross, So I'm a bit stuck. I was going to trial a 1 cross fitment, but can't see any photo's with enough detail. Well.. there was one but I'm quite sure the spokes crossed wrongly and would move apart under load. So promptly lost the link.

Also, I ordered the widest rim for my mountain bike, but upon arrival it looks like a racer wheel. Can I stick some 2.15" big apples on a 22mm wide rim? Or should I scrap them and find some 28mm one's, and new spokes I imagine.


I'm going to go and stand over it for another hour.
Save me! lol


Edit: There are drawings of both 1 and 2 cross here http://www.troubleshooters.com/bicycles/wheelbuilding/
However, they have paid no attention to which side of the flange the spokes thread from. There all on the outside. I expect one of the pair inside, and one outside, but which leads I dunno...

 

[friendly1uk]

1 cross. Not what I was expecting.

I closed all the 'how to' windows because they were just confusing. I have spent hours trying to work out what any of them were talking about. Just looking at the wheel was much easier.

Well, it seems easy with only half the spokes in. I will no doubt be back lol

 

[wesnewell]

Don't waste your time with that rim. It's not wide enough for a 2.125 tire. I wouldn't even put 1.95's on it. You need a 25mm ID rim minimum imo for 2.125" tires, and 32-35m ID rims would be better. You will likely need spokes about 3-5mm longer for a wider flatter rim.
See chart towards bottom of page.
http://sheldonbrown.com/tire-sizing.html

 

[friendly1uk]

Oh Bother. Thanks for the link wesnewall. I now have two new rims and two new tyres, a set of spokes, and half of it is useless. Measuring the inside diameter of my rims, it gets worse. The new ones are 18mm, and originals 21mm. The link leads me to scrap both.

The 186mm spokes seemed very short. With each nut on just a turn, some slop about, and others play a tune. I would of liked 187mm as it is a double wall rim anyway.

Quick look on the bay finds these 32mm one's. There double wall so perhaps my rear spokes would fit. http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=330854901299 They don't actually give the important dimension. I have wrote to see what they actually are. One way or another, I will need a set of spokes as my rear ones expect a double wall rim, and the front wheel is single wall at the moment.

Next step.. I will find the brakes don't fit round it.

 

[wesnewell]

That ebay rim looks more like a 32mm outside width rim which would make inside width 25mm. Subtract 7mm from outside width to get inside width. It will work ok for up to a 2.3" tire, but barely. I use these and they are great for tires 2.0-2.5". I run 2.4" Cyclops and they ride really good with this rim
http://www.weinmanntek.com/Products/DOWNHILL/DH39.htm
These would also be a good choice for 2.125-2.75" tires.
http://www.weinmanntek.com/Products/CHOPPER/DHL42.htm
Anything much larger than this will probably not work with rim brakes on a standard bike.
These rims are hard to find for some reason. I bought 2 front wheels with the DH39 rims and took one off to use with my hub motor.

 

[d8veh]

Oh Bother. Thanks for the link wesnewall. I now have two new rims and two new tyres, a set of spokes, and half of it is useless. Measuring the inside diameter of my rims, it gets worse. The new ones are 18mm, and originals 21mm. The link leads me to scrap both.

The 186mm spokes seemed very short. With each nut on just a turn, some slop about, and others play a tune. I would of liked 187mm as it is a double wall rim anyway.

Quick look on the bay finds these 32mm one's. There double wall so perhaps my rear spokes would fit. http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=330854901299 They don't actually give the important dimension. I have wrote to see what they actually are. One way or another, I will need a set of spokes as my rear ones expect a double wall rim, and the front wheel is single wall at the moment.

Next step.. I will find the brakes don't fit round it.

I've got those rims on nearly all my bikes, and so has my neighbour. We use a range of tyres from 1.95 to 2.10. and we've never experienced any problems in thousands of miles on and off-road. Maybe they're not the best, but they're perfectly adequate. I've done two CST builds with those rims, and I used 210mm spokes in a 2 cross pattern. I did tell you before that the ones you ordered looked a bit short and would only be able to do a one-cross pattern if anything. I think I read somewhere that 2-cross is better for high-torque motors like the CST.

 

[friendly1uk]

I really didn't expect lacing to be such a big deal. Quick copy of other peoples work I thought. BMSbattery build this way, and I heard no complaints. Now looking for myself I wouldn't of chose 1 cross. I would of liked 2 cross, but settled for 3 cross as it is all over the web. Using a few spoke calcs, they all agree 186mm is not long enough for 1 cross. There over 3mm short and I'm not sure they will ever be any good. As I said before, with just one turn of the nipple, some spokes are fully tensioned. I believe I'm going to be pulling threads off if I tried to finish the job. Meanwhile, other spokes have over a mm of free movement left. The rim is spinning within the spec one wheel builder claims he can achieve, and this is before doing anything at all. This surely shows the spoke&nipple combinations are not very uniform. What with the wheel being round, the nipples all on one turn, yet lots of variance in the fit. It was no 'on your knee' job. I had to pop it in the bike, put the rim against the wall, my knee on the hub, and strain to make some of the nipples reach. Perhaps I should bin both rims and the spokes. Get a fresh start doing it myself. Although I have zero interest, It's just a bothersome job.

I have lost all direction. I could just bin the lot and unregister I guess lol

The Weinmann option looks good. I would love to buy two fronts and a set of spokes to make the rear work. The cost is just to much though. Amazon have them at half the price of everyone else, just $34 a piece, which is great, but I can't fill in 30 pages of 'who are you' to get a shipping quote that is out of this world. I will be paying $180 by the time they are here in the UK. I really dislike amazon and there need to hear my life story to get a quote. Even then they won't take paypal

 

[friendly1uk]

Found the atom labs site. They don't sell them either. However they give External dimensions for there stuff, and internal is 8mm less. Making the 32mm 24mm ID. I have some 21mm already. I don't want to spend money on 3mm. Even if what I have is dirty old single wall stuff. I have never wanted another 3mm.

Rang A large shop, who said there widest was the mavic xm317 but had no actual dimensions. The mavic site says there 23mm, or 17mm ID. That is smaller than the bms wheels, yet they claim there 17mm wheel holds a 2.3" tyre. The chart linked to above says 1.5" max. I'm yet to find any data that is in agreement with any other data.

D8veh, do you know the ID of the 32mm ebay rims? I'm back to looking at 3mm gains, but if they need spokes I will have to jump through amazons hoops and get there quote. I have asked the ebay seller, but the idea of ID Or External went right over his head.