Author Topic: Xiamen Carbon Full Suspension fattie  (Read 2766 times)

carbonazza

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Re: Xiamen Carbon Full Suspension fattie
« Reply #15 on: October 13, 2016, 04:16:18 AM »
I now have questions  ;)
My girlfriend wants an e-bike, and I remembered your post.

I won't go with the Cyclone, but probably with the BBSHD at 1000w.

How does it ride after a few months?

The only testing was in the shop using 34t to 11/36 cassette
What cassette/chain/number of speeds did you put in the end?

a backpack battery holding Hobbyking 1600M ampHr lipo's
eCarbon wheelies very easily at 48v and gets wild with 52v... feels like it could climb a tree
Can't imagine 72v... concerned the huge torque could break something :-\
How do you connect the 1600Ah lipo's together, and what voltage do you use in the end?

element

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Re: Xiamen Carbon Full Suspension fattie
« Reply #16 on: October 13, 2016, 02:55:22 PM »
It is a good idea to safety wire the rear axle nut on the rear 12mm axle... if it get loose it could destroy the cassette freehub

element

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Re: Xiamen Carbon Full Suspension fattie
« Reply #17 on: October 13, 2016, 03:05:30 PM »
58.8v/52v Hobbyking Lipo picture

carbonazza

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Re: Xiamen Carbon Full Suspension fattie
« Reply #18 on: October 14, 2016, 12:16:43 AM »
Thanks !

Jerryno

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Re: Xiamen Carbon Full Suspension fattie
« Reply #19 on: October 14, 2016, 04:58:18 AM »
My girlfriend wants an e-bike

Hi carbonazza, don't invest into LiPo technology and definitely not into Hobbykings own brand batteries. They are cheap with good stats on paper, but that's about it.

Why not Lipo: they are not durable, have short life span (low amount of charging cycles - at best 500) and have to be charged very carefully not to over voltage them with very expensive charger - else their life span drops rapidly.

What to get as powersource - LiFePo: best power to weight ratio (but not as good capacity to weight ratio as LiPo), very good durability - can be overcharged, under depleted, 1000 charging cycles with almost no capacity loss during cell's life, can be charged with cheap chinese chargers so that makes up for their higher price compared to LiPo.

Why not no-brand batteries (Hobbyking, etc): Batteries are made with different grades and are sorted as they leave the factory. The grade is usually determined by the internal resistance of the cell. Low grade cells loose capacity faster, reach less charging cycles, can get puffy easier and they get hotter drawing current from them. These cells usually end up in cheap LiPo packs.

I have very good experience with A123 LiFePo cells. They have also multiple grades, get the A grade as directly from the factory as you can. The longer the battery sits in warehouse the worst it is (some batteries can be old as 2 years then sold cheaper). Make sure all cells in the battery pack are the same age (so the whole pack ages the same and all cells have same properties). Have the cells professionally be welded together (not soldered but welded - some HobbyKing packs are soldered). This way you can have a pack much cheaper than buying it already made.

Now about the voltages and power:

E-bikes are powered by brushless DC motors. The torque of the motor is determined by the current flowing through, the max rpm is kv * Volts. Kv is a constant specific to each motor. So voltage  influences the max reachable speed.

If your pack is connected in series then raising the voltage will not raise the current the pack is able to give.

Each motor has a limit how much current it can handle - else it will get burned. Adding additional cooling to the motor does increase the maximum torque it is capable of (granted the batteries can supply the current needed).

Looks like the Cyclone 3000 uses this motor controller: http://www.ebikes.ca/c-phaserunner.html. It is able to handle 90V max and 40A max current with a 96A peak. These controllers have programmable limits and they have to be paired to the motor with PC (each motor requires different parameters to run smoothly). Maybe there are lower current limits programmed in not to overload the Cyclone 3000 motor.

It is also worth noting that supplying too much current for higher torque can damage the transmission even if the motor can handle it. The transmission has plastic wheels inside: https://endless-sphere.com/forums/viewtopic.php?p=1054349#p1054349.

Increasing the voltage will increase the max speed and the power, but not the torque. The max power happens at half the max rpm: http://motors.vex.com/introduction/.

carbonazza

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Re: Xiamen Carbon Full Suspension fattie
« Reply #20 on: October 14, 2016, 06:36:24 AM »
@Jerryno, it looks I opened a new Pandora Box  :o
Thank you for the advices and providing all these resources to read.

element

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Re: Xiamen Carbon Full Suspension fattie
« Reply #21 on: October 14, 2016, 07:51:46 AM »
Hobbyking batteries are cheap, light, powerful and work good... been using them for many years....
I don't recommend them for the inexperienced novice because they have very high current that can be dangerous
Bottomline, this ain't rocket science but basic electrical and workshop skills are required

carbonazza

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Re: Xiamen Carbon Full Suspension fattie
« Reply #22 on: October 14, 2016, 08:07:44 AM »
Hobbyking batteries are cheap, light, powerful and work good... been using them for many years....
I don't recommend them for the inexperienced novice because they have very high current that can be dangerous
Bottomline, this ain't rocket science but basic electrical and workshop skills are required

I know from playing with quadcopters that Lipo batteries can be fragile to charge/discharge
You have a good charger or do not care that much?

element

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Re: Xiamen Carbon Full Suspension fattie
« Reply #23 on: October 15, 2016, 08:18:42 PM »
I bulk charge them, but watch for heat or swelling...  individual cells are monitored periodically and bad ones are removed.

I have not notice that cell matching is critical as some profess and swelling or heat usually predicts that a cell internal resistance is too high

IMHO, not over discharging HobbyKing lipos is the key to safety. I found little benefit building packs with BMS units so I stopped using BMS.

Commercial packs have one BMS lead monitord 6 to 8 welded cells in series they call one cell. So the BMS can only tell when the larger group is failing, not each individual cell

With HobbyKing packs, generally 6 cells pack have 6 cells and each single cell can be monitor with a cell tester. 

I have some commercial packs, but but for my high performer ebikes I use HobbyKing Lipo's. The cost to performance ration has been excellent

element

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Re: Xiamen Carbon Full Suspension fattie
« Reply #24 on: October 15, 2016, 08:20:00 PM »
The orginal XM Carbon Speed has matured and had a child.

There is a second XM Carbon Speed full suspension and it has gown up to be like its daddy with a Cyclone 3000w.
http://www.xmcarbonspeed.com/Productinfo.asp?f=1402 (FYI, Peter at XM Carbon Speed is a very good person do work with)

IMHO, a carbon full suspension bike with Cyclone 3000w very close to being the ultimate woods bike and here are some of the reasons.

1. Versatile mounting options: Relatively speaking it was easy to make longer/stronger brackets to facilitate inside the frame mounting for improved ground clearance
2. Good power to weight ratio: The BBS-HD feels like it is broken or has dead batteries when compared to the Cyclone 3000w
3. Reasonable noise levels: Few people have noticed or commented on the sound.... the mini cyclone was obnoxious and not useable on public areas
4. Low Cost: When compared to the cost of carbon components, Lipo batteries, BBS-HD the Cyclone 3000w is a bargain
5. Dependable: Maybe it because the mounts are well made, but nothing has broken during deliberate nasty thrashing rides in the woods... that not to say something won't break, but it was surprising that efforts to ride hard and break something... nothing broke

Bottomline, the Cyclone 3000 is awesome, but don't let anyone tell you that weight doesn't matter on ebikes... A full suspension carbon ebike in the woods using a battery backpack is another world when compared to the weight and mass of an aluminum BBS-HD ebike... Bafang is now boring...

carbonazza

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Re: Xiamen Carbon Full Suspension fattie
« Reply #25 on: October 18, 2016, 07:52:00 AM »
There's a lot of wiring going on an e-bike, but in your case they are very well hidden. Congrats!
And thanks for the additional details about the LiPo's.

One thing worries me with the Cyclone 3000w is the rider's leg is quite exposed to the chain/chainring/cog, although they could be hidden by some plastic cover.
And probably 3000w is quite oversized for my girlfriend needs :)

Just curious. How do you attach the engine to the carbon frame?

element

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Re: Xiamen Carbon Full Suspension fattie
« Reply #26 on: October 22, 2016, 11:50:05 AM »
custom made bracket, see picture