8fun crank drive kit
- Thread starter shemozzle999
- Start date
D
Deleted member 4366
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Haven't tried one. You can only test in the hall, so not much point.
I'll find out about 48v tomorrow, but I think that 48v will make the crank turn too quickly, so no point. Better with higher current, so need to find the max current.
Sent from my GT-N7100 using Tapatalk 2
I'll find out about 48v tomorrow, but I think that 48v will make the crank turn too quickly, so no point. Better with higher current, so need to find the max current.
Sent from my GT-N7100 using Tapatalk 2
I did clock that one when they first came out.
Nice pack, but would be very expensive at around £700 shipped.
I'm hoping that a manufacturer will start making the hardcase packs that attach to the water bottle holder. Similar to the Bosch ones, rectangular or triangular but not cylindrical.
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Yes - that Samsung is a 500 cycle pack too, not a long life 1,000+ cycle pack like you get supplied on higher end retail bikes. Makes it equivalent of about £1,400 shipped taking cycle life into account - which is an astronomic amount for a battery pack - especially since the bikes it'll be suitable for at 50V are likely to be pretty power hungry. I like the precharge tho'. Saves making one.
There's not much "in the middle" at the moment battery wise for high capacity batteries that are ready to fit with holders suitable for in-triangle mounting without making boxes. Must be time the market moved on in China soon ....
£520 shipped
That's 500 cycles at max charge voltage and max discharge. Charge to 90% and only do 80% dod's and you'll see 1000 cycles easy.
How does that work then ? Always get completely bamboozled with all this battery thing. I understood you had to manage charging of LiPos, not charge 100% and cut them out before they lose too much charge - but isn't this a Li-Ion battery ? Everything one reads about them suggests they like to be kept topped up.
What's "dod" ?
Don't forget the dreaded import tax on top of that
.... and a charger
Total customs value: £568.97
- Duty: £15.36
- VAT: £116.87
Total import duty & taxes due: £132.23
Total landed cost: £701.20
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Li-ion/lipo are the same chemistry - the distinction is just the solvent - liquid on a li-ion battery and a solid (polymer) on the lipo.
In fact the correct names are Lithium Ion and Lithium Ion Polymer.
DOD is depth of discharge.
Oh yeah :-(
OK. So with regard to the question, why the different advice regarding management to Lithium Ion and Lithium Ion Polymer batteries especially viz topping up ?
Does the Li-Ion BMS on high stated charge cycle batteries see to the top charge capping and dod limiting so as to achieve those results ?
Quite a few li-ion batteries with BMS's - Bosch included - only charge to 4.15v per cell and limit depth of discharge to 80% - which is why they can boast high cycles.
Sadly it would seem that the days are gone when Shemozzle could supply good and decent British citizens with high tech, cutting edge Chinese e-bike solutions and reluctantly we must return to the old windscreen wiper bldcm's and Archimedes Screws of yore.
Shmozzle, if you would entrust me with the link I will endevour not to lose it. hch
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Deleted member 4366
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Bafang showed us the 750w version of their crank-drive that looks the same as the 250w one but is slightly wider at the motor.
Unfortunately, they didn't understand the gear-changing problem that you get with the delay from the controller with pedal speed sensor, so I expect to get crashing gears when I try it tomorrow. They told me that they recognised the problem but not the cause.
They're developing a torque sensor version. Unfortunately, also, from my tests, it appears that all the new Chinese torque sensor bikes are using the sensor as a switch for the
normal controllers, not as a proportional torque device; however the penny has now dropped, so we'll have to wait a bit longer before we get a Chinese bike that behaves like a Bosch.
Sent from my GT-N7100 using Tapatalk 2
Unfortunately, they didn't understand the gear-changing problem that you get with the delay from the controller with pedal speed sensor, so I expect to get crashing gears when I try it tomorrow. They told me that they recognised the problem but not the cause.
They're developing a torque sensor version. Unfortunately, also, from my tests, it appears that all the new Chinese torque sensor bikes are using the sensor as a switch for the
normal controllers, not as a proportional torque device; however the penny has now dropped, so we'll have to wait a bit longer before we get a Chinese bike that behaves like a Bosch.
Sent from my GT-N7100 using Tapatalk 2
Shame that. Thing is both Bosch and Impulse use 3 separate sensors (cadence, torque and speed) to detect what the rider is doing and offer assistance appropriately... to varying degrees of success for an individual rider depending on how the software is programmed to respond. The Chinese seem to be a way away from this and that's the reason I don't think they can supply competing crank drive bikes... they haven't yet got the hang of one set of inputs yet let alone 3.
It's a software thing basically - copyable engineering can only go so far. So for next couple of years at least I think everyone who wants an intuitive crank drive bike is stuck with high priced models with all the spec limitations and price implications that brings when compared to a good kit. A really competent programmer could absolutely clean up.
Once again I realize that if I'd gone into IT I'd likely have made a fortune several times over lol.
D
Deleted member 4366
Guest
It'll be fairly easy to sort. I don't think these guys are good at figuring things out here. They can only copy. All the crank drives had speed control instead of torque control. Then someone probably said that the Europeans use torque sensors, so one has one already fitted and the rest are working on it, but they just haven't thought it through properly.
The old Panasonic definitely had current control for power, where current is proportional to torque in some way, which is logical. I'm sure the Bosch is the same, but the Chinese are using speed control controllers with their torque sensors so that the torque sensor works as a switch without proportional control.
It's not easy to discuss these sort of things with them because their English isn't good enough, but the Bafang guy understands now, and he said that he'll make a solution soon.
Sent from my GT-N7100 using Tapatalk 2
The old Panasonic definitely had current control for power, where current is proportional to torque in some way, which is logical. I'm sure the Bosch is the same, but the Chinese are using speed control controllers with their torque sensors so that the torque sensor works as a switch without proportional control.
It's not easy to discuss these sort of things with them because their English isn't good enough, but the Bafang guy understands now, and he said that he'll make a solution soon.
Sent from my GT-N7100 using Tapatalk 2
I'm not so sure it's entirely that simple - the cadence sensor and speed sensor both play their part in regulating the bike's response as well as the torque sensor. But time will tell. Think the 26V Panasonic ran on a simple cadence sensor ... there is quite an enlightening article on it here :
Kalkhoff Impulse Riding | 50cycles Ltd
Having ridden with the Impulse system under 2 different programming variants, the difference made by the programming is very significant - although it has to be said that within a 0-16mph range there is a limit to the impact and circumstances in which the real potential of a good torque sensor can be put to effective use in generating impressive performance.
Have read that the Bosch uses 3 sensors too. The key is their understanding how to translate the sensor readings into controller response ... and without a blatent rip-off (which would no doubt lead to litigation and they wouldn't know how to tweak or develop even if they did) it's something that the Chinese need to hire in people who understand the programming to really get right to a good standard.
Kalkhoff Impulse Riding | 50cycles Ltd
Having ridden with the Impulse system under 2 different programming variants, the difference made by the programming is very significant - although it has to be said that within a 0-16mph range there is a limit to the impact and circumstances in which the real potential of a good torque sensor can be put to effective use in generating impressive performance.
Have read that the Bosch uses 3 sensors too. The key is their understanding how to translate the sensor readings into controller response ... and without a blatent rip-off (which would no doubt lead to litigation and they wouldn't know how to tweak or develop even if they did) it's something that the Chinese need to hire in people who understand the programming to really get right to a good standard.
i was wondering if the gearshifter had a sensor in it, the same as a brake has, to cut power to the motor,when shifting gear would this not work ,to stop the gear changing problem , or even a sensor on the gear cable, like the hidden brake wire type.
Please don't be put off this kit by all the technical mumbo jumbo, it still remains one of the most simple solutions for a crank conversion kit.
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