Newbie Questions and cheap Chinese motor kits?

[gatorboots]

Sorry for the newbie questions but i’m finding it hard to get any specific answers.
Anyway i’m planning a build, probably start with a mountain bike frame, drop it (for lack of a better term) and add some carbon fibre\ fibreglass elements for a clean, slick look.

before i can go ahead and design it i need to settle on a battery motor set up.

Anyone have any experience with these Chinese hub motors?
http://www.alibaba.com/product-detail/100kph-electric-bike-conversionk-it-3kw_60018853103.html

Now the main question i have is how does a motor like this interface with the battery? Is it as simple as buying and connecting positive and negative wires to a terminal on the battery like this?
http://www.ebay.com/itm/48V-3000W-Electric-Bike-eBike-Bicycle-Lithium-20Ah-Battery-BMS-Alloy-Charger-/181573529659#rpdCntId

I live in New Zealand so i don’t exactly have a huge amount of set ups to choose from.

Thanks in advance.

 

[amberwolf]

Anyone have any experience with these Chinese hub motors?
http://www.alibaba.com/product-detail/100kph-electric-bike-conversionk-it-3kw_60018853103.html

Now the main question i have is how does a motor like this interface with the battery?

Well, what yiou link to says it is a whole kit, motor battery and controller, etc., so if it is properly done you just plug everything together per it's instructions, and it would just work.

Unfortunately you won't know till you receive it, since vendors on these sites may or may not supply exactly what you see in the ad, or may not bother to supply plug-and-play compatible parts/connectors (or instructions).

Is it as simple as buying and connecting positive and negative wires to a terminal on the battery like this?

If you mean, directly connecting the motor to the battery, then no. If you use a brushless motor (which is most hub motors sold these days), you'll need to use a controller of some kind (crude versions made with brushed motors physically linked to brushless motors used as generators hooked to brushless motors used as motors can work, but are large and impractical compared to the standard ESC or electronic speed controller, which most just call "controller").

Most kits would come with a controller compatible with the motor in the kit.


There are quite a few threads discussing various cheap kits, some quite recent (mostly started by other newbies asking this same question), and many with links to information here on ES and elsewhere. I highly recommend you look around and read those first.

If you choose not to, we'll need more informaiion abou how you expect the bike to perform when complete, to help you find the right stuff to build it with. The questions we'd need answers to are also in many of those threads.

 

[dogman dan]

Re mating that particular motor kit with that particular battery, uhh, no. It would murder the battery.

Bear in mind, that however affordable the motor kit may be, a very powerful motor kits controller will eat a cheap small ebike battery alive. You will need a shitload of money for a battery for a 3000w kit.

I would say that battery could run ok on 2c discharge, 40 amps controller. That's about 2000w. Though I'm sure the battery is indeed rated for a 3000w peak, the real world fact is the battery will hate it. 2000w peak more like it if you want it to last awhile. So that motor, but with 48v 40 amps controller, not 72v 40 amps controller for that particular battery.

 

[amberwolf]

regarding he kit link itself:

the first link is titled (on the site) as
"100kph electric bike conversionk it 3kw ebike conversion kit with 72v 20ah lifepo4 battery"
so that means it comes with all the stuff you'd need for the ~$500 price tag.

I don't believe it's actually true, or that any of the stuff promised by that title is actually in the kit; it's probably an empty box without even packing for that price, but tha'ts what the title says you get. :/ (the description below that doesn' mention the promised battery)


I wouldn' deal with the company at all just because of that false advertising; who knows what else is unrue on the page, and if you would get what you order, if anything at all.

 

[dogman dan]

Maybe not quite that sinsister, but I sure see no mention of a battery in that kit other than the title.

Personally, I'd rather open my wallet in the wind than order from Alibaba, unless the item is under 20 bucks.

You should look for a typical 1000w kit, such as from ebay. They have good power and speed for cheap, and run on a more affordable 48v battery.

 

[wesnewell]

That kit does not come with the battery, as I guess you noticed, thus the link to the battery. That's a 48V battery pack and the controller the kit comes with is minimum 60V, so that battery won't work with that controller. I'd recommend a 72V or higher battery pack for that kit if you're wanting 70kph from it. This is how I connect my battery to my controller.

 

[John in CR]

"100kph electric bike conversion kit 3kw ebike conversion kit with 72v 20ah lifepo4 battery"

First year supplier on Alibaba, incredible price, some definite untruths in the info....combine to tell me to be very careful.

 

[Rebelraptor]

Did you buy the kit?

 

[amberwolf]

Hard to tell, since while the OP has logged into ES since the post above, he hasn't bothered to reply to anyone to let us know if we helped or not, or any other results. Unfortunately that's pretty common.

 

[DrChopper8]

I'm going to try a couple different kits. Sensorless hub motors will have just the three phase wires without the extra five hall sensor wires. Less chance of problems. http://www.campsolution.com/electricbikeconversionkit-fronthubmotorwithrimandfullaccessories-1.aspx

 

[DrChopper8]

I'm also ordering 48v 18ah Lithium batteries from Www.conhismotor.com . The O.E.M. cell battery. It's under $500 shipped. And as far as your builds, Direct Drive is so much easier. Just make sure you gather all the specs including the proper torque arms. Ebikeling and Afterpartz have nice innexpensive kits. A nice mid price kit is Mac or Magic Pie. So I've read. I will post the results of each kit within the next couple months when my builds are complete. I'm building ten E bikes and ten E scooters. I'm only keeping the 36v 1000 watt Direct Drive Scooter motors. My Schwinn Stealth 1000 gets me up the steapest hills like it's running on the flats. Very powerful.

 

[d8veh]

I don't mean to jump on you, but you make some interesting statements that some noob might misinterpret or get the wrong impression if he takes them at face value, so I want to voice my opinion on these points.

"Direct drive is so much easier". Easier than what? A crank drive installation is normally a lot easier and a gear motor is exactly the same as a DD. Direct drive motors are good if you want to travel at constant high speed or use very high power (>1000W), but other systems would probably be better if you have hills or a lot of stop-starts.

Sensorless motors have less wires, it's true, but how much extra effort does it take to plug in extra hall sensor connector? Hall sensor problems are not so common these days if you buy a properly developed motor. You won't get a blown hall sensor in a sensorless motor, but, instead, you could get a blown mosfet in your controller when the motor doesn't start properly. To me, the advantages of running with hall sensors (smoother, better starting, more efficient) outweigh the advantages of running sensorless.

 

[DrChopper8]

This is 100% true. But I'm a noob too. I just completed my first two builds. One Direct drive rear hub motor, brushless sensored and one chain drive brush motor. My opinion is only based on the last month of my work I put into making these E bikes work at top performance. Both bikes were used and 10 years old. Setting up the BLDC hub motor was difficult for me because I had no idea if it was even good. The other chain drive brushed motor set up was a lot more mechanical work for me because I had to worry about the chain length, adjustment and alignment. I'd have to say that building my own and adding upgrades is awesome though. Because of the costs of buying an E bike built and ready to go varies from lower price/less power and higher price/more power. Now if money is no object to me, I'd go new brushless sensored rear hub motor set up. So many options..... I recommend to trying to stay with one style set up. It's really been wracking my brain learning how each different set up works at best performance. I will be builing a mid drive Bafang set up very soon. But before I shell out cash that I barely have for the Bafang Crank Motor, I have to find out which brand bike it will fit with minimal work. Plus the thought of have a 7 speed to work with the Crank Drive really sounds amazing. It's like comparing a 2 speed powerglide transmission to a 6 speed transmission. Way more torque and way more top speed. Like a dream come true. (Now if I could only find the list of "bikes that accept the Bafang motor easiest" i will order the kit asap)