Buy parts from Ebay for first time conversion

[Eidel]

Hi!

I've been looking on Ebay for cheap parts to convert my mtb into an ebike and have found a motor, controller and battery, but I am not sure if these components will work together, so I greatly appreciate if someone with more experience could enlighten me

I have the following demands on my setup:
Desired max speed: 25 kph (15.5 mph) with 250W controller, 35 km/h (22 mph) with 500W controller
Desired max range: 40 km (25 miles)
Wheel size: 26"
Breaks: Unsure
Rider weight: 70 kg (154 lbs)
Terrain: Mostly flat, some hills here and there
Budget: around $600

The parts I'm interested is the following:
36V 500W Front wheel hub motor
36V 20AH LiFePO4 with charger and BMS
36V 250W Controller

I've chosen a 250W controller since it is the maximum power I can give the motor legally (EU-law). However, I thought it would be nice to buy a 500W motor if I in the future want to register the bike as an electric moped (if thats even possible), then I can just buy a new controller with 500W throughput. I also read that it is more healthy for the motor to not use 100% of its capacity.

Regarding the hub motor, I think it is very nice to just buy the motor and not a wheel with an already installed motor, because I want to learn how I can install motors in wheels and be able to build customized ebikes. I am however unsure how I will deal with the spokes since I probably will have to buy new ones to fit my 28" wheel.

Are these components okay? What I'm most worried about is how to connect the motor with the controller, it seems like the power cable is extremely thin. Will it really be able to handle almost 7A at full power? (250W = 36V * 6.9A).

I am not looking for the best products available, but also don't want these components to break after 6 months of use (even though I want it as cheap as possible :wink. Btw, I am aware that I need a throttle and brakes, I just haven't researched that area yet.

-- Eidel

 

[Eidel]

I get paid with 20EUR per hour so to repair and not to teach others as electrician.

But you may do your job with out paying by searching the forum for what you are looking for.
The problem is that you have hundreds of questions and not just one which is my limit when helping for free.

This post was very odd. If you don't have time to help me, you don't have to post and tell me. I bet there are several people in this forum who gladly want to help me. I just received a PM with some really good advises from a person who I guess want to be anonymous.

 

[Drunkskunk]

Welcome to the forum. The motor looks good, but it will be greatly under served by the 250 watt controller. That's not a problem in one sense. However, it's a direct drive, and needs a fair amount of power to make any torque. a geared drive like most 250-500 watt motors might actually be more powerful at low speeds and under acceleration at such low power levels.

If you want to use a motor like that, it's best to feed it properly with a 1000w or higher controller. many users also find they prefer 48 volts or more, as those direct drive motors are pretty anemic at 36 volts.

You'll save money getting the big motor now instead of buying something else now, but you'll likely be better served buying a geared motor.

The battery is the heart of your ebike. While the difference between the best and worst motors is minimal, the difference in batteries is great. Buying an unknown battery off ebay is a huge gamble. Sometimes you win and get exactly what you need. But there are plenty of posts in the forum of people having a large array of trouble with cheap batteries.
My best advice is only gamble money you can afford to lose.

 

[Eidel]

Welcome to the forum. The motor looks good, but it will be greatly under served by the 250 watt controller. That's not a problem in one sense. However, it's a direct drive, and needs a fair amount of power to make any torque. a geared drive like most 250-500 watt motors might actually be more powerful at low speeds and under acceleration at such low power levels.

If you want to use a motor like that, it's best to feed it properly with a 1000w or higher controller. many users also find they prefer 48 volts or more, as those direct drive motors are pretty anemic at 36 volts.

You'll save money getting the big motor now instead of buying something else now, but you'll likely be better served buying a geared motor.

The battery is the heart of your ebike. While the difference between the best and worst motors is minimal, the difference in batteries is great. Buying an unknown battery off ebay is a huge gamble. Sometimes you win and get exactly what you need. But there are plenty of posts in the forum of people having a large array of trouble with cheap batteries.
My best advice is only gamble money you can afford to lose.

Thank you I will definitely go for a geared motor since I'm not going to use full power that often. It also seems like geared motors are better if I want to be able to use the pedals without using the motor. I chose a 36V since I felt that I don't want my bike to go very fast and it seemed unnecessary to have those extra 12V because batteries and motors were more expensive. I have to read up on the difference if I'm using a geared motor.

The battery issue is really hard... A Ping-battery costs twice as much as a no name brand from ebay. If I'm lucky I can get two good batteries for the cost of one. But whats the ratio of good and bad batteries from sellers like Sunthing28? I've heard some bad reviews and some good, and is it possible to fix a battery if it not works as described? I want to believe that I can get help from the forum . Nowadays there is also PayPal buyers protection with 180 days time limit, so I'll have plenty of time to test the battery - if this protection is working in practice, I don't know.

I got an advice in a PM that the controller I linked to is made for a brushed motor, so I need to find another one (if the geared motor I choose is brushless, I don't even know what brush/brushless means right now - going to read up on that). I got some other really good advice in the PM, but I'm waiting for the users approval to publish them in this thread.

-- Eidel

 

[Drunkskunk]

Brushed VS brushless is easy: When possible, get brushless.

Brushed motors run on straight DC power. But a motor needs it's magnetic coils to switch off and on at the right time as they pass the magnets, so a brushed motor has a mechanical distributor like an old car, called a commutator on the spinning shaft, and some solid blocks of carbon that press up against it to feed it power called brushes. the brushes stay still while the commutator spins, so they slowly wear out and put just a tiny amount of drag on the motor.

A brushless motor skips all that nonsense. Their coils aren't on the spinning part, and the coils are switched off and on by a computer, much like a car's electronic ignition. There is only 1 moving part in the motor, and no parts to wear out. They also run more efficient, with less noise.

Not all motors use the same connectors or the same color codes for the sensors and phase wires, so it's best to get the controller and throttle form the same source as the motor.

 

[dnmun]

you should avoid buying the Vpower packs. sun-thing28 guy has the cheapest pouch pack from lifepo4. i just posted up a link on that other newbie thread about his battery choices.

http://www.ebay.com/itm/48v-15ah-LiFePO4-Battery-5A-Charger-BMS-Electric-Bicycle-Kits-Sea-8-Weeks-Gift-/171320560736?pt=LH_DefaultDomain_0&hash=item27e3804c60

 

[999zip999]

The heart of E.S. is to help as we have helped kirako with many of his question here for free. Mainy he would like to sale his E.S. free advise to you for a pot of Gold.
48v does wake up a electric motor, but 36v is good for a flat ride no hills. I guess there is import fees to Sweden ?

 

[Ch00paKabrA]

When I joined this forum I thought the same way you do. Why should I get higher voltage when I just want to cruise around at 15 mph or so? The reality is that if you want to go slow, you can use less throttle but if you need the speed, then, with the higher voltage you will have it. Getting a 48v battery was good advice and should save you money in the long run when you want to up the volts.

The controller you linked to will not work with that motor because it is a brushed controller but I believe that has been said before. Many people here have so much more knowledge than I do but I would impart one piece of wisdom to you: Spend a bit more money and get a programmable controller. I have a box of cheap controllers of various volts and wattages that I wasted money on and spent more on them that if I had just bought a good programmable controller in the first place. If you do, you will be able to customize your settings and if you do decide to change voltage, it is only a few key strokes away. I thought it would be complicated because I am a simple man with less than proficient computer skills but With the creation of XPD software, it is dead simple. Paul at EM3EV has a controller that would fit your build for around $100.00 and it is probably the last one you will have to buy.

Good luck to you with the build. I am running a MAC which is a geared hub and although it is a bit pricey compared to others, it is tough as nails.

Paul at EM3EV has the MACs for for just about $300.00 and change.

If that is too much money, then the best price on the larger Bafang rear 500w motor that I could find is here @ $200.00:

http://www.aliexpress.com/store/pro...otor-rear-wheel-7-speed/612941_629079638.html

If you want the 250w bafang, they sell it as well for around $130.00.

I have bought from them before and they turned out to be a good seller with good communication and reasonably fast shipping. Don't buy from AliExpress sellers unless they have feedback.

I would bet that you would enjoy the larger Bafang with EM3EV's 9 or 12 fet programmable controller and that battery that you linked. Both controller and motor can be used with either 36 or 48 volts. For a few bucks more, get the programming cable and a 3 speed switch. It will push the budget over $700.00 though.

I set my switch at 40%, 65%, and 100%. At 40% I just cruise around at 14 or 15 mph but if I am coming up on an entrance to a highway or need to go with the flow of traffic, I just click it up a level and the bike accelerates to the desired speed. It is a great little addition.

Good luck with you build and enjoy!
'Cal

Edit: One more thing, if you buy the MAC and controller from Paul at EM3EV, everything with just plug right in and work, If you buy from different vendors, then the phase wires and Hall sensor colors fromt eh motor and controller might not color coordinate and it can get a bit frustrating figuring out what wire goes where. Just and FYI.

 

[wesnewell]

I think you misunderstand the wattage ratings of controllers. It doesn't mean that's the max wattage it will put out. That's the 24/7 wattage rating you can use without damage to the controller. A 250W controller could actually put out more wattage than a 500W controller. It all depends on the max amp rating of the controller. And there's no practical advantage to a geared motor except the freewheel capability. A direct drive motor is the most reliable by far since it doesn't have gears and clutches to break and it can provide regen braking. The motor size has absolutely nothing to do with the battery pack. You need a battery pack capable of the max amp draw of the controller, period. Forget the motor size when choosing the battery.

 

[Eidel]

Brushed VS brushless is easy: When possible, get brushless.

Brushed motors run on straight DC power. But a motor needs it's magnetic coils to switch off and on at the right time as they pass the magnets, so a brushed motor has a mechanical distributor like an old car, called a commutator on the spinning shaft, and some solid blocks of carbon that press up against it to feed it power called brushes. the brushes stay still while the commutator spins, so they slowly wear out and put just a tiny amount of drag on the motor.

A brushless motor skips all that nonsense. Their coils aren't on the spinning part, and the coils are switched off and on by a computer, much like a car's electronic ignition. There is only 1 moving part in the motor, and no parts to wear out. They also run more efficient, with less noise.

Not all motors use the same connectors or the same color codes for the sensors and phase wires, so it's best to get the controller and throttle form the same source as the motor.

Thank you for your explanation, I will go for a brushless motor. It is really interesting to learn new things like this.

you should avoid buying the Vpower packs. sun-thing28 guy has the cheapest pouch pack from lifepo4. i just posted up a link on that other newbie thread about his battery choices.

http://www.ebay.com/itm/48v-15ah-LiFePO4-Battery-5A-Charger-BMS-Electric-Bicycle-Kits-Sea-8-Weeks-Gift-/171320560736?pt=LH_DefaultDomain_0&hash=item27e3804c60

I saw them on ebay during lunch the other day and thought they were suspiciously cheap, this explains it I guess. I take it as these so called pouch pack's are good property of a battery pack. I learn new things every day

I guess there is import fees to Sweden ?

Yes there is. Think at least around 3% toll-fee and 25% duty, so It's a lot. The best would be to buy from a EU country, since I don't have to pay toll and tax then.

When I joined this forum I thought the same way you do. Why should I get higher voltage when I just want to cruise around at 15 mph or so? The reality is that if you want to go slow, you can use less throttle but if you need the speed, then, with the higher voltage you will have it. Getting a 48v battery was good advice and should save you money in the long run when you want to up the volts.

It makes sense, especially in hills. I was overtaken by a really slow moped in a hill today and thought "I do not want my ebike to go that slow", so I'll probably buy a 48V battery. Regarding batteries, I was looking at Ping-batteries today and saw that two 24V batteries costs 2/3 of the price of one 48V battery. Shouldn't I be able to wire them in series to obtain 48V? Two 24V batteries is even 5.3 kg (11.7 lbs) lighter than one 48V battery... strange?

Edit: I just read that it amp hours does not add when wiring in series, only voltage. Rookie mistake!

Spend a bit more money and get a programmable controller. I have a box of cheap controllers of various volts and wattages that I wasted money on and spent more on them that if I had just bought a good programmable controller in the first place. If you do, you will be able to customize your settings and if you do decide to change voltage, it is only a few key strokes away. I thought it would be complicated because I am a simple man with less than proficient computer skills but With the creation of XPD software, it is dead simple. Paul at EM3EV has a controller that would fit your build for around $100.00 and it is probably the last one you will have to buy.

I thought about this too, but regular controllers are so much cheaper. However, I am very interested in customizing and tweaking things until every parameter is perfect (I also work as a programmer ). I really appreciate your advice on brands by the way, I know nothing about brands since I've been browsing no-names at ebay. Going to do some more research on those you linked.

I think you misunderstand the wattage ratings of controllers. It doesn't mean that's the max wattage it will put out. That's the 24/7 wattage rating you can use without damage to the controller. A 250W controller could actually put out more wattage than a 500W controller. It all depends on the max amp rating of the controller. And there's no practical advantage to a geared motor except the freewheel capability. A direct drive motor is the most reliable by far since it doesn't have gears and clutches to break and it can provide regen braking. The motor size has absolutely nothing to do with the battery pack. You need a battery pack capable of the max amp draw of the controller, period. Forget the motor size when choosing the battery.

Aha, I had no idea. Good that you mentioned it.

 

[fellow]

I also live in Sweden. About taxes: If you order things from China, you pay nothing extra under 13USD. Over 13 USD you pay 25% moms (thats VAT for you outide of Sweden) and a 50 SEK to the post company for their service. Usualy they send you a "inbetalningskort" (=payment form) 2 days after you receive the gods.

 

[Eidel]

I also live in Sweden. About taxes: If you order things from China, you pay nothing extra under 13USD. Over 13 USD you pay 25% moms (thats VAT for you outide of Sweden) and a 50 SEK to the post company for their service. Usualy they send you a "inbetalningskort" (=payment form) 2 days after you receive the gods.

Actually, according to swedish customs, there is no taxes if the total cost is < $162 (1400 SEK). I bought a pressure canner from the us three months ago for over $230 but I didn't have to pay anything else, so if I'm lucky I don't have to pay extra fees.

 

[fellow]

I've payed tax few days ago for a front suspension bicycle fork from China declared at 30 USD. Payed 50 sek service fee to the DHL and 62 SEK MOMS/VAT. 0 SEK tull/custom fee. I guess the 0 SEK part is correct in that case. I see it as a kind of gamble, you never know if you are going to pay or not . You can see list of parts that may fit your project in my signature.

 

[Eidel]

I've payed tax few days ago for a front suspension bicycle fork from China declared at 30 USD. Payed 50 sek service fee to the DHL and 62 SEK MOMS/VAT. 0 SEK tull/custom fee. I guess the 0 SEK part is correct in that case. I see it as a kind of gamble, you never know if you are going to pay or not .

Haha, very odd. They do write "you might avoid taxes the value is below 1400", so yes gamble indeed.

Edit: Your bike looks awesome! Very clean, you sure have hid everything in a good way.

 

[fellow]

About your project: 13s pack (48V nominal, 54,6V charging) is the very good start point voltage. It wont kill you, and it will not disappoint you. I'm considering move to 18s (67V nominal, 75,6V charging voltage) for my next project.

 

[Eidel]

Update: I'm considering building my own battery from either used or new laptop cells. I've seen some youtube clips where people are doing this. It requires a lot of extra work and researching how to do it (at least for me), but this is exactly what I want to do (at least the researching part). When I build my own battery I can make sure all cells are of good quality, and that the BMS is of good quality as well.

 

[fellow]

The alternative (and much better) cells are Panasonic NCR18650PF from http://www.nkon.nl/ or https://www.akkuteile.de . With those cells you don't need a complicated Battery Menagement System (BMS), only LVC cutoff that is already provided in S06S controller. Every cell is internally PTC protected. Cells cost about 4€/piece to 6€/piece depending on order quantity. It is not very hard to do your own pack.

Cells prefer not to be charged over 4.2V/cell, and not under 2.5V to 3.5/Cell, 3.5V/cell being the prefered lowest value. Under 2.5V/cell they risk permanent damage, but NCR18650PF can survive even this if you are lucky. It is the only known LiPo cell that can do that. Laptop cells are NOT very good for this purpuse because of their low I_max value. Laptop cells don't like a lot of current, they are better at capacity. NCR18650PF takes I_6_sec_burst=18A, I_cont=10A, laptop cells can only dream of this.

You can buy improoved S06S controller (48V version, 40 USD) here http://www.aliexpress.com/item/Regeneration-Electric-Bicycle-Brush-less-Controller-48V-6-MOSFET/1749495210.html . The mosfets inside are 80NF70, 68V, 10mOhm, capacitors are 63V rated so i would not use this over 54,6V without heavy modifications. Resistor inside is 270 0hm. If you want older 36V version, you can buy it here: http://www.bmsbattery.com . Resistor inside this one is 83 Ohm, one capacitor is 63V and the other one 50V. Resistor and capacitor values are for future reference, some people may found it useful when planning "Frankenstein" mod.

 

[999zip999]

There was a post in the " New for sale " section of E.S. of a person making new battery packs for sale in Norway. He was going to Sweden to drop ship as he thought it would be cheaper. I looked but couldn't find his thread. Maybe someone could chime in ? Get a good battery. Used lap top cells, hard enough getting good new cells, plus tons of work for a low performing battery.
Lot's of junk batteries on ebay ( vpower ) ect. Don't waste your time or money.