Spoke Supplies in the UK?

[tongxinpete]

Using the Roger Musson Spoke calc I need 226mm spokes (left 226.8, right 225.8) it says + or - 1 mm so I was going with 226mm
Best deal I find so far for this unusual size is price 30p ea inc nipple. I am building a Q100 into a 24'' rim.
This is UK based. Chinese cheaper but shipping a killer!!
From a bench test (with a Con61 controller) the 201 rpm quoted is at 5A load, unloaded rpm is 249.
A footnote re the instructions on the Con61, joining the blue loop limits speed to 160 rpm @ max throttle,
joining the white loop engages a cruise function (the instructions have the coulors reversed for these.
Also a throttle from bmsbatteries had two wires in the plug the wrong way round, I changed these to match red red, black black & all was well. Anyone know what a rotor alnico number of 20 means?

 

[Deleted member 4366]

Alnico = magnet, so 20 magnets in the rotor.

 

[tongxinpete]

Actually the alnico number was 16, but this is the case in both the Q100 & Q100H, both also 14A max rated, both 20.4 Nm, however the gearing is 8:1 on the 100 but 12:1 on the 100H - this would lead me to think the 201rpm is a max unloaded on the 100H in other words it runs slower in use. This is the only place the the 30% extra torque can come from. So building the std Q100 into a smaller rim comes to the same place. If I get all running I am going to try the halfway soldering of the shunt to give 18A, is all I am risking a £12 controller? doing both things should give 40% more torque

 

[Deleted member 4366]

I had a bike with two 201 rpm Q100s in it. I changed them both for 260 rpm Q100Hs. Result: No significant difference in torque, but a proportional increase in speed. The Q100Hs have a higher power rating, so I guess they can handle more current, which I believe is where the claimed increased torque comes from.

The gearing thing doesn't add up. If they changed the gearing from 8:1 to 12:1 on the 328 rpm Q100, the new speed would be 219 rpm, so where does 260 rpm come from unless everything has changed?

 

[drsolly]

30p per spoke looks cheap to me, who's the supplier?

 

[tongxinpete]

Supplier is unicycle UK, I think some other hubmotor guys have used them in the past, from memory.
Thinking that the Q100 size motor has a huge Asian market, & that the average Chinese guy weighs about 150lb while the average western guy about 200 lb + I guess the real answer to all this is the Q128 or similar @ 500w (says 40Nm) or 800W (50 nm) - Trouble is you then need a costly higher C rate battery to run it.
Again looking at stuff available on the mass market would it be possible to discharge two Frog batts in parallel (maybe diodes to prevent one discharging into the other & upsetting the BMS?) out of my depth here!
Charging would be by an individual supplied small charger to each Frog.
I found a supplier putting 2p 10s pouches into Frog cases rather than 4p 10s cylindrical. He does sea shipping for 10+ batts. Unit price $150 per batt (less for bigger orders). Idly wondered about possibility of a group buy?

 

[drsolly]

I had a look at unicycle.uk.com. The problem I'd have, is that they don't offer anything between 191mm and 225mm, and I needed 213mm. I got mine from http://www.tillercycles.co.uk/
They cost me 85p each for "apim Strong 13/14g, but they cut them to whatever size you want. They also do Sapim Leader 14g for 60p. I'm happy with my purchase from them, plus they gave me useful advice when I phoned them to order.

 

[tongxinpete]

Thanks, drsolly, have noted them down. I read further & see the Q128 is not a good motor (better off with the Q100 modded) & no match against the Bafang BPM provided you get the right code for you. I also see that there is much confusion over the speeds & torque of motors from many suppliers. It has been stated that faster motors have no more torque than slow ones, they make the same torque at higher speeds, maybe but if you look at Crystalyte charts from 10 yrs ago you will see 36v 15A controller with say a 406, & then a 4011, & the torques differ massively inversely proportionally to max speed in each case, this tends to show that more poles do increase torque. I used to think that these gearmotors were all wound same but had different gear ratios according to the rim size they were destined for. Now I think that gears are common & pole pair numbers vary???

 

[Cyclezee]

I had a look at unicycle.uk.com. The problem I'd have, is that they don't offer anything between 191mm and 225mm, and I needed 213mm. I got mine from http://www.tillercycles.co.uk/
They cost me 85p each for "apim Strong 13/14g, but they cut them to whatever size you want. They also do Sapim Leader 14g for 60p. I'm happy with my purchase from them, plus they gave me useful advice when I phoned them to order.

When it comes to wheels, spokes, cycle repair, rebuilds, Bromptons, etc., etc.,
Graham Tiller is number one in my book.
Knowledgeable, friendly and helpful.

 

[Deleted member 4366]

Now I think that gears are common & pole pair numbers vary???

When you get lots of different speed versions of the same motor, like the MAC and BPM, it's the turns of wire per pole that determines the speed. The less turns, the higher the speed.

 

[jhruk]

For unusual length spokes at a reasonable price I've found these plain 14g ones from SJS to be good value and problem free so far:

http://www.sjscycles.co.uk/british-made-14g-stainless-steel-plain-gauge-spokes-and-12-mm-brass-nipple-pack-of-6-prod3145/

Most sizes from 120mm to 298mm at £1.84 for six, plus p&p.

 

[drsolly]

Thanks, good source.

 

[flecc]

For unusual length spokes at a reasonable price I've found these plain 14g ones from SJS to be good value and problem free so far:

http://www.sjscycles.co.uk/british-made-14g-stainless-steel-plain-gauge-spokes-and-12-mm-brass-nipple-pack-of-6-prod3145/

Most sizes from 120mm to 298mm at £1.84 for six, plus p&p.

Agreed, I've used them often and my hub motor rear wheel is built with them, no failures and in it's seventh year now.
.

 

[tongxinpete]

Do more turns per pole then give more torque? If the wire cross sectional area remains the same I would imagine more turns = more resistance & hence less current flows? but then we come to star & delta connections to further muddy the water. Kenny of Xlyte was doing something to get a torque vs speed trade off from the same 15A @ 36v controller.
A bit OT but Caterpillar are experimenting with a Diesel electric transmission on their D7 sized Dozer, uses I genny, 2 controllers & 2 brushless motors (1 per track) In the past these have always had mech multi gear transmissions & often fluid torque converters. If it works it tends to come down against elec cars (or bikes) needing gear boxes to get more out of them.

 

[trex]

Do more turns per pole then give more torque? If the wire cross sectional area remains the same I would imagine more turns = more resistance & hence less current flows?
..

yes, more turns per pole give more torque using the same wire.
http://en.wikipedia.org/wiki/Motor_constants
KM is the motor constant, P: resistive power loss
torque = KM * SQRT(P)
Increasing P causes increased torque.

 

[Deleted member 4366]

If the wire cross sectional area remains the same I would imagine more turns = more resistance & hence less current flows?

The cross-section of the wire doesn't always remain the same. You can have a higher number of turns with thicker wire. It depends how they wind the coil because they can use multiple strands in each turn. As an example, you can have 8 turns of 6-strand or 12 turns of 3 strands with thicker wire, so the overall resistance could be the same.

 

[tongxinpete]

OK thanks I am getting it now.
I did build the std Q100 into a 24'' rim (3x dished, my first rear) I now have a bike with the 175rpm Tongxin in the 26'' front, & the Q100 in the rear. Test results are :- Q100 unassisted gradient 1 in 11.5 (8.75%) @ 7.5 mph & 12A
pulling a total weight of 278 Lb (rider, batts, bike, motors) I would normally assist but this was for the test, as the sweet spot for the motor hill climbing seems to be between 8 & 10 mph.
As my rear wheel radius is 12'' then converting Nm to Lbf would give the actual 'rimpull' at the interface between the tyre & road. It is generally stated that 2% of all up weight is needed to overcome rolling resistance & keep a 4 wheeled vehicle moving on a smooth level road (maybe say half this for a bike with its two wheels & ball hub races)
Then 1% of all up weight per 1% of gradient climbed, this works out that the motor is about 30+ Nm short term rather than 21 as shown in a goldenmotor graph. I did find this Xlyte mini motor @ 29 Nm - it looks pretty generic & similar to many, (I doubt they built it) http://shop.crystalyte-europe.com/product.php?productid=16592&cat=314&page=1

Anyway I am glad I went for the 24'' rim as with this I have the improved torque I was after over the tongxin, Had I built it into a 26'' then I would have had faster speed but no torque improvement. Both motors top out @ about 14.7 mph, the Tongxin cuts off at this point, but the Q100 would go on up to a theoretical 17.6, but it makes very little effect beyond about 15.5 mph.
I feel the Q100 has a wider torque band & better pick up from very low speeds. The Con61 controller was topping out @ 12A 36v so I did the shunt mod (carefully in two stages) & have got it up to 15A. I do not want to go past this so as to protect the clutch & leave the option of running off a 10Ah Frog batt (1.5C in short bursts) Thus there is about 30 Lb to shave off in total (18 Lb from batts, 5 Lb from putting a plain front wheel in, & hopefully 7 Lb off me!)
The tongxin was a bit weaker tending to bog on the above test hill (to be fair they recommended 160rpm for the 26'' wheel but solarbbq was only selling the 175 & a faster one as a compromise). In short I have gone from just about acceptable, to quite acceptable. If I had a better batt system I would be able to see what bringing in the front motor would add (I could just about do it on the flat before the shunt mod, but not on hills as the LV would cut in on the Tongxin) Westerners are that bit heavier than the Chinese, so by dropping a rim size I am about getting the motor as it's designer would have intended. Not bad but I would think another 100w continuous (thus 700w peak) keeping the same max speed would make for a very rideable single speed bike able to tackle pretty well anything Pete

 

[Deleted member 4366]

I've got loads of spare frog cases if you want to experiment with lipos. You can have one or two for the cost of postage. A 5aH 12S pack fits in easily, and a pair of 8aH 6S bricks can just be squeezed in. You don't have to change anything else - just clip the battery on like the normal one. You get an instant 20% improvement in speed and torque, which the Q100 can easily take. You can even solder the shunt up to about 18A, which turns the motor into a firebreather (not literally of course!).

 

[tongxinpete]

Thanks for the offer d8veh, maybe one for the future, if I could track down some suitable cells at a cheaper price than the 5A LiCoMn @ bmsbatts, because actually these work out dearer as cells than a complete frog pack with charger would. I built a batt from 7070260 cells a while ago but could never get it to work. It proved to be a dodgy bms in the end, (they did offer to replace if I returned it,) but cheaper to buy one off the HK ebay guys (& shipping much cheaper) fitted this & now pack balance charges & discharges hurrah - for a bit I was beginning to doubt my competence or think I was jinxed. The charger puts out 42.5 as OCV but cycles with the batt @ 41.8v.
(12x3.55v I presume) Could I also use same charger for LiCoMn as they say 4.2v +- 0.05v /cell (I make this 42.5v for 10s) If ever I built another pack I would like to use a shunting bms such as this http://www.bestechpower.com/37v10spcmbmspcbforli-ionli-polymerbatterypack/PCM-D178.html pity it does not have LED's to show when all cells shunting, some have per cell LED's to show other states I think. Sorry have been away for few days.