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The eBike thread

  • 22-07-2019 8:34pm
    #1
    Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,915 CMod ✭✭✭✭ unkel


    A quick look seems that this doesn't really seem to fit in the cycling forum. So starting a thread here about all things eBike

    I'll get the ball rolling. I have zero experience with eBikes. But I was going to build myself a battery anyway, for various reasons (like in bringing with me in my EV as a "petrol can")

    I'm going to buy a solderless kit to make the battery (with 18650 cells I have removed from dead / old laptop batteries). This kit cah handle 20A max, and I would like the battery pack to produce 1kW constant. P=V*I so 1000W = 50V * 20A

    This dictates that my battery needs to be nominal 48V (was thinking of making a 24V battery pack, but that won't be able to charge my car)

    A quick browse on eBay and Amazon shows that you could buy a powerful 1000W bike conversion kit with everything needed except the battery for about GBP120 (a bit more from Amazon but peace of mind)

    What to buy though, front wheel or rear wheel kit? Pros and cons? Any other advice?

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022

    Post edited by unkel on


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Comments

  • Registered Users Posts: 3,212 ✭✭✭ cojomo2


    unkel wrote: »
    A quick look seems that this doesn't really seem to fit in the cycling forum. So starting a thread here about all things eBike

    I'll get the ball rolling. I have zero experience with eBikes. But I was going to build myself a battery anyway, for various reasons (like in bringing with me in my EV as a "petrol can")

    I'm going to buy a solderless kit to make the battery (with 18650 cells I have removed from dead / old laptop batteries). This kit cah handle 20A max, and I would like the battery pack to produce 1kW constant. P=V*I so 1000W = 50V * 20A

    This dictates that my battery needs to be nominal 48V (was thinking of making a 24V battery pack, but that won't be able to charge my car)

    A quick browse on eBay and Amazon shows that you could buy a powerful 1000W bike conversion kit with everything needed except the battery for about GBP120 (a bit more from Amazon but peace of mind)

    What to buy though, front wheel or rear wheel kit? Pros and cons? Any other advice?

    Fyi, anything over 250w will not be road legal. It also needs to be setup in such a way that the motor only gives assistance while the user pedals and cuts out as soon as they stop.


  • Closed Accounts Posts: 22,676 ✭✭✭✭ beauf


    If it's something for the boot consider the weight when lifting it in and out.


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,915 CMod ✭✭✭✭ unkel


    beauf wrote: »
    If it's something for the boot consider the weight when lifting it in and out.

    Battery is going to be tiny and light weight. I'm thinking of a 13s4p setup, so just 52 cells (which are a bit bigger than an AA cell, for people not familiar with the 18650 cell)

    The 48V inverter - that's a different story :p I guess it very much depends what other uses I will have for it and what kind of quality I will go for.

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,915 CMod ✭✭✭✭ unkel


    cojomo2 wrote: »
    Fyi, anything over 250w will not be road legal. It also needs to be setup in such a way that the motor only gives assistance while the user pedals and cuts out as soon as they stop.

    That's the kind of info I need too, thank you! So all those electric scooters you see everywhere are also not road legal then? Why is nobody stopping them? Is it likely this legislation will be changed soon?

    So if this kit had just a 250W motor it would be road legal, it seems to have the sensor that does what you describe?

    Linky


    I don't really want a bike that's not road legal, but how would a Garda know what wattage the motor is?

    I don't particularly want or need a 1000W motor, but my battery has to be 48V and most 48V conversion kits seem to have motors of 500W and over...

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 21,618 ✭✭✭✭ ted1


    unkel wrote: »
    That's the kind of info I need too, thank you! So all those electric scooters you see everywhere are also not road legal then? Why is nobody stopping them? Is it likely this legislation will be changed soon?

    So if this kit had just a 250W motor it would be road legal, it seems to have the sensor that does what you describe?

    Linky


    I don't really want a bike that's not road legal, but how would a Garda know what wattage the motor is?

    I don't particularly want or need a 1000W motor, but my battery has to be 48V and most 48V conversion kits seem to have motors of 500W and over...

    The three rules are:

    Engine no bigger than 250w
    Engine stops assisting at 25kmh
    Engine only assists when pedals are being turned.

    Gardaí are seizing scooters https://www.google.ie/amp/s/amp.independent.ie/irish-news/escooters-seized-as-gardai-warn-riders-to-stay-off-streets-38330934.html


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  • Closed Accounts Posts: 22,676 ✭✭✭✭ beauf


    Electric Brompton is ideal for that.


  • Registered Users Posts: 30,515 ✭✭✭✭ Lumen


    Are you sure that making a battery pack from mixed old batteries is safe? I thought they had to be matched.


  • Registered Users Posts: 563 ✭✭✭ bunderoon


    Lumen wrote: »
    Are you sure that making a battery pack from mixed old batteries is safe? I thought they had to be matched.

    You can match them by testing their nominal voltage and capacity first, then grouping like for like.
    A good 18650 BMS will handle the charging / balancing of them.


  • Registered Users Posts: 5,694 ✭✭✭ eddhorse


    Interesting thread, I have lots of 18650s , will follow this with interest.


  • Registered Users Posts: 21,406 ✭✭✭✭ Mad_Lad


    unkel wrote: »
    That's the kind of info I need too, thank you! So all those electric scooters you see everywhere are also not road legal then? Why is nobody stopping them? Is it likely this legislation will be changed soon?

    So if this kit had just a 250W motor it would be road legal, it seems to have the sensor that does what you describe?

    Linky


    I don't really want a bike that's not road legal, but how would a Garda know what wattage the motor is?

    I don't particularly want or need a 1000W motor, but my battery has to be 48V and most 48V conversion kits seem to have motors of 500W and over...

    A Guard can't know and will most likely not care unless you're not peddling......if you peddle or pretend to peddle there isn't a lot they can do but don't ride around making it obvious, it's a lot easier for me living in the country, I could do what I want but used caution in town, don't ride at 50 Km/h in cycle Cough Cough, I mean "BUS Lanes" and you'll be fine.

    One of my first kits I built back in about 2010 used I would pretty much guarantee this exact motor you linked to.

    I ended up hacking the controller and running about 5 Kw through it and boy did I have a hell of a time, the acceleration was mental !

    Anyway the advice is avoid this motor, they are fine as throttle only setups on more level ground with some small hills but it's all Crank drive these days because crank drive is more efficient for hills, much more in fact.

    The downside with these motor kits is they are not really designed for peddling without motor power and there can be some mad resistance when peddling without power.

    The kit you linked to, that motor is an absolute B1tch to peddle without power, it's a direct drive motor and the motor magnets create a hell of a drag when no power is applied.

    If you want a hub motor kit then the internally geared hub motors such as the MAC motors are one of the best, they have gearing for better toque and efficiency but they are noisier.

    This is probably the best place to buy ebike kits, https://em3ev.com/ this guy is called Paul and is from the U.K living in china and has direct contact with the factory that makes the motors and is very well respected on endless-sphere.com

    Paul also builds his own battery packs, I advise against building your own from old laptop packs , ebikes have vastly higher power requirements + different cells will have aged more than others and have different internal resistance and you need closely matched cells in a pack, believe me.

    I used Hobbyking Lipo in the past and it's great, https://hobbyking.com/en_us/zippy-compact-6200mah-6s-40c-lipo-pack-xt90-1.html

    LiPo is great as it can provide massive power from a tiny pack but it is volatile and can not be stored in the house ( absolutely can not be stored in the house )and needs to be charged on a RC balance charger, LifeP04 is safer, much safer but can't give out as high power and also needs RC balance charger, is heavier and bulkier than LiPo, once you know how to handle LiPo it's great and you can build a very cheap pack, the downside is that you need to buy an RC charger and power supply, so I recommend buying the pack from em3ev.

    2 in series of the packs I linked to in hobbyking will give you 44 volts and another 2 in parallel will give you 10 ah and double the same for 20 ah of battery or 880 Watt hrs of storage.

    The Mac motors are available in 8T windings, 10 and 12T, the 8T is good for level ground and some hills, 10 and especially 12 T are better for steep hills.

    8 T will do 28 Mph on 44 volts, 10T probably 20 and 12 T probably 15 Mph.

    They are geared hubs and really great for peddling without power because they got a clutch that disconnects the motor mechanically when no power is applied creating 0 motor drag.

    Hub motors need torque arms at each wheel nut to prevent axle spin in the dropouts, if this happens under load it can be quite dangerous and break the wiring to the motor and it is a right pain in the ass to connect it all back up again and I'm speaking from experience..........Torque arms are essential.

    If you got lots of hills then the Bafang BBS02 or BBSHD from em3ev will be the man for the job, motors are more efficient at higher RPM and the Crank drive motor can use the bikes gearing, a hub motor can not and so when on steep hills the hub motor "can" bog down and most of the power turns to heat and can kill a motor fast but I've climbed pretty steep hills on motor alone with the 8T mac motor @ 48 Volts and roughly 40 amps or 2 Kw pulled from the battery.

    For slow steep trails the Crank drive is the best. I've got up Mount Leinster with a Bosch Crank drive @500 watts , but it was very tough and the gearing helps a lot. Some of this was 22% grades !

    With motors Current gives you torque and voltage gives you speed.

    And I repeat........1860 cells from various sources and different packs, different ages is a recipe for disaster and fire and a potential to burn the house down or block, 18650 need a BMS ( as with most lithium cells ) and to be correctly wired and correctly welded tabs with proper fused links, do not do it.


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  • Registered Users Posts: 2,645 ✭✭✭ krissovo


    I bought a mid drive kit (bafang) from Green Bike kit with a 52v 14.5 ah samsung battery.
    It’ was not compliant to EU rules in its raw state as its 500w and did nearly 50kmph at full pelt and would easily overtake mopeds. I have since limited it to a more reasonable 25kmph using the controller. Anything over speed 4 on the controller and my legs cannot keep the cadence to drive it.

    The mid drive is really good as it drives the crank and not the wheel so its more natural feeling and also as it drives the gears I can literally ride up the side of a mountain without stressing the motor or battery and I am a big bloke.

    Ships from Asia somewhere via Rotterdam so no import taxes and it also came with lights that are powered from the battery. I get can get similar range to some early Nissan leafs but 60 to 80k’s is normal with plenty of assist.


  • Registered Users Posts: 21,406 ✭✭✭✭ Mad_Lad


    krissovo wrote: »
    I bought a mid drive kit (bafang) from Green Bike kit with a 52v 14.5 ah samsung battery.
    It’ was not compliant to EU rules in its raw state as its 500w and did nearly 50kmph at full pelt and would easily overtake mopeds. I have since limited it to a more reasonable 25kmph using the controller. Anything over speed 4 on the controller and my legs cannot keep the cadence to drive it.

    The mid drive is really good as it drives the crank and not the wheel so its more natural feeling and also as it drives the gears I can literally ride up the side of a mountain without stressing the motor or battery and I am a big bloke.

    Ships from Asia somewhere via Rotterdam so no import taxes and it also came with lights that are powered from the battery. I get can get similar range to some early Nissan leafs but 60 to 80k’s is normal with plenty of assist.

    the bafang kit you mentioned is probably the BBS02 and more like 750 watts, they are good kits but they have the issue of resistance without motor power which I doubt is an issue for most as I expect they will ride with some power.

    Even the Bosch ebikes are well known for resistance with no power, my 2013 has it and it's only very recently Bosch have addressed this issue.

    One of the best are Brose motors but they are expensive, made in Berlin, the best ebike motors come from Deutschland and are unfortunately OEM motors.

    One of the best bikes I built was an rear internally geared MAC 8T I got from em3ev.com. I lost 20 Kg with this kit believe it or not, over 3 months..... then I had 2 Children, started working shift and put it all back on and have no time for cycling any more and can't bring the lads out because Irish back roads are extremely dangerous and Ireland lacks proper cycle lanes.

    Anyone into cycling should go to Deutschland, it's amazing......


  • Registered Users Posts: 21,406 ✭✭✭✭ Mad_Lad


    Most of the commercial ebikes "Bosch to name a few" are well above 250 watts, they are more like 750-1Kw , how do they get around this ? well mainly because they limit speed and acceleration which is how they can still receive their certification.


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,915 CMod ✭✭✭✭ unkel


    Nice posts there, keep them coming :)

    I guess I should have clarified my position a bit better.

    The battery pack that I'm planning to build is not for long term or frequent use. It is a project for playing with, with the aim it could charge my car enough to give it an additional range of maybe 2km in case I ran out of juice on a long (unknown) journey. I rarely make long journeys beyond the range of the car anyway. I like that idea (EV petrol can). I don't plan to spend much money on this project. The Vruzend kit costs a bit, but should keep its value well in case I want to sell it on. The batteries I'm using are recovered from laptop batteries, so didn't cost me anything. I'm not expecting more than say 100 cycles from them. Very low expectations, just a project for fun. Wasn't even considering a BMS as a must for this project. Charging car: 15 minutes and that's it, unplug and recharge on slow charger later. Running eBike: a few minutes here and there. Not enough to ever run down the battery before I got home and slowly recharge it. But of course safety is very important. I was not planning to store the battery in the house (or in the car for that matter)

    As I'm planning to build this battery anyway, for very little extra money I could electrify my old mountain bike (that I don't really use). I don't plan to use it much, I won't speed on it and it is stored outside (not even in the shed). I don't care about range either. 10km would be more than plenty.

    So to summarise: project must be extremely cheap, yet safe. Don't care about performance or longevity.

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Banned (with Prison Access) Posts: 343 ✭✭ Wtf ?




  • Registered Users Posts: 21,406 ✭✭✭✭ Mad_Lad


    Wtf ? wrote: »

    Scooters are different, with ebikes all you got to do when in town or in dublin city is pedal and not cycle like an idiot and you'll be fine.


  • Registered Users Posts: 21,406 ✭✭✭✭ Mad_Lad


    unkel wrote: »
    Nice posts there, keep them coming :)

    I guess I should have clarified my position a bit better.

    The battery pack that I'm planning to build is not for long term or frequent use. It is a project for playing with, with the aim it could charge my car enough to give it an additional range of maybe 2km in case I ran out of juice on a long (unknown) journey. I rarely make long journeys beyond the range of the car anyway. I like that idea (EV petrol can). I don't plan to spend much money on this project. The Vruzend kit costs a bit, but should keep its value well in case I want to sell it on. The batteries I'm using are recovered from laptop batteries, so didn't cost me anything. I'm not expecting more than say 100 cycles from them. Very low expectations, just a project for fun. Wasn't even considering a BMS as a must for this project. Charging car: 15 minutes and that's it, unplug and recharge on slow charger later. Running eBike: a few minutes here and there. Not enough to ever run down the battery before I got home and slowly recharge it. But of course safety is very important. I was not planning to store the battery in the house (or in the car for that matter)

    As I'm planning to build this battery anyway, for very little extra money I could electrify my old mountain bike (that I don't really use). I don't plan to use it much, I won't speed on it and it is stored outside (not even in the shed). I don't care about range either. 10km would be more than plenty.

    So to summarise: project must be extremely cheap, yet safe. Don't care about performance or longevity.

    By all means experiment , but you need cells close in internal resistance and age, if not they will discharge at different rates and have different voltages at different charge and discharge rates and you got to know at what C rate they can charge and discharge at.

    Keep an eye on heat, the whole pack should not get hot.

    A BMS is a must unless you can monitor the cell voltages yourself, if they get too low or too high then you got a real fire potential and Lithium fires are not nice lol , you really can't take safety for granted here mate.


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,915 CMod ✭✭✭✭ unkel


    Mad_Lad wrote: »
    By all means experiment , but you need cells close in internal resistance and age, if not they will discharge at different rates and have different voltages at different charge and discharge rates and you got to know at what C rate they can charge and discharge at.

    Keep an eye on heat, the whole pack should not get hot.

    A BMS is a must unless you can monitor the cell voltages yourself, if they get too low or too high then you got a real fire potential and Lithium fires are not nice lol , you really can't take safety for granted here mate.

    Yeah I'm inclining towards using a BMS. From the reading up I have done, I'm getting the impression you don't really need cells close in internal resistance / age / capacity from a safety point of view though if you use a BMS.

    Before I would even start building the pack, I would make sure every cell I use will charge up to 4.15-4.20V and not have abnormal self discharge rates.

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 1,502 ✭✭✭ macnab


    unkel wrote: »
    From the reading up I have done, I'm getting the impression you don't really need cells close in internal resistance / age.

    The efficiency of the pack depends on the characteristics of each individual cell. Li-Ion cells are very robust in my experience but internal resistance is very important, and very hard to test without the correct equipment. A good BMS will not counteract or correct a miss matched battery pack.


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,915 CMod ✭✭✭✭ unkel


    macnab wrote: »
    The efficiency of the pack depends on the characteristics of each individual cell. Li-Ion cells are very robust in my experience but internal resistance is very important, and very hard to test without the correct equipment. A good BMS will not counteract or correct a miss matched battery pack.

    Aye my thoughts too. I'm not interested at all though in the efficiency of the pack, nor its performance, nor its longevity. A perfectly managed LiFePo4 pack will easily last 50 years and tens of thousands of cycles in the Irish moderate climate and still have 70-80% capacity, but that is not something that I am aiming for

    Just 100 cycles and poor capacity are fine with me. As long as things are safe...

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



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  • Registered Users Posts: 21,406 ✭✭✭✭ Mad_Lad


    macnab wrote: »
    The efficiency of the pack depends on the characteristics of each individual cell. Li-Ion cells are very robust in my experience but internal resistance is very important, and very hard to test without the correct equipment. A good BMS will not counteract or correct a miss matched battery pack.

    Absolutely !


  • Registered Users Posts: 21,406 ✭✭✭✭ Mad_Lad


    unkel wrote: »
    Aye my thoughts too. I'm not interested at all though in the efficiency of the pack, nor its performance, nor its longevity. A perfectly managed LiFePo4 pack will easily last 50 years and tens of thousands of cycles in the Irish moderate climate and still have 70-80% capacity, but that is not something that I am aiming for

    Just 100 cycles and poor capacity are fine with me. As long as things are safe...

    No harm in trying but don't expect a lot just make sure you use fuseable links , one mistake and the whole lot can go up in smoke, again lithium fires are scary and they smoke like hell and you have to make sure if it does ignite that you can vent the smoke it's highly toxic and it's unlikely you can out the fire out with ease.


  • Registered Users Posts: 30,515 ✭✭✭✭ Lumen


    Mad_Lad wrote: »
    No harm in trying but don't expect a lot just make sure you use fuseable links , one mistake and the whole lot can go up in smoke, again lithium fires are scary and they smoke like hell and you have to make sure if it does ignite that you can vent the smoke it's highly toxic and it's unlikely you can out the fire out with ease.

    Fill the bath before charging! :D


  • Registered Users Posts: 123 ✭✭ insular1


    Mad_Lad wrote: »
    Quoti g Mad_Lad "They are geared hubs and really great for peddling without power because they got a clutch that disconnects the motor mechanically when no power is applied creating 0 motor drag."[/B]

    Great post. Been saving to build my own ebike for a while but money keeps disappearing into other projects. Was thinking maybe of just starting with one of those cheap hub motor kits for my first build so I can get started sooner but after reading this I'm thinking I'm better off waiting for a better kit as the ability to cycle without power is an important factor for me.

    Looked into ordering a kit from em3ev but when I got to the order page there were so many different options I wasn't sure which were essential and which were just nice to have. Any one know any good resources, blogs/YouTube etc that I could use to learn the basics? I have an engineering background in an unrelated field so not afraid of technical detail but has been nearly 15 years since college and that was the last time I did anything involving the electrical side of things. Bit rusty to say the least.


  • Registered Users Posts: 21,406 ✭✭✭✭ Mad_Lad


    insular1 wrote: »
    Great post. Been saving to build my own ebike for a while but money keeps disappearing into other projects. Was thinking maybe of just starting with one of those cheap hub motor kits for my first build so I can get started sooner but after reading this I'm thinking I'm better off waiting for a better kit as the ability to cycle without power is an important factor for me.

    Looked into ordering a kit from em3ev but when I got to the order page there were so many different options I wasn't sure which were essential and which were just nice to have. Any one know any good resources, blogs/YouTube etc that I could use to learn the basics? I have an engineering background in an unrelated field so not afraid of technical detail but has been nearly 15 years since college and that was the last time I did anything involving the electrical side of things. Bit rusty to say the least.

    Keep the money for a much better kit it will be worth it !

    Yes these days options are confusing on em3ev.

    What are you looking to achieve , assistance for hills, will these hills be steep and very long ?

    The crank drives are better for long steep trails and are more efficient which is important because it's easier on the battery , steep hills on hub motors causes more heat but you can get more efficient hub motors for hills such as the Mac 10 or 12T speed at 48-52 volts with a 12 T will be about 15 mph max , it's wound for torque, the 8T gives a good balance between speed and torque and will do 28 Mph on the flat with 48-52 volts, I would go for the higher voltage if you can 52 volts.

    The battery is also very important so you will have to size it correctly for your needs but also make sure it can supply the amps.


  • Registered Users Posts: 3,168 ✭✭✭ xckjoo


    insular1 wrote: »
    Great post. Been saving to build my own ebike for a while but money keeps disappearing into other projects. Was thinking maybe of just starting with one of those cheap hub motor kits for my first build so I can get started sooner but after reading this I'm thinking I'm better off waiting for a better kit as the ability to cycle without power is an important factor for me.

    Looked into ordering a kit from em3ev but when I got to the order page there were so many different options I wasn't sure which were essential and which were just nice to have. Any one know any good resources, blogs/YouTube etc that I could use to learn the basics? I have an engineering background in an unrelated field so not afraid of technical detail but has been nearly 15 years since college and that was the last time I did anything involving the electrical side of things. Bit rusty to say the least.
    I'm going to add some confusion by saying that I disagree with Mad_Lad and think hub motors are the way to go :pac:. I think a front hub motor will work for 99% of commuters. Simplest to install, no major maintenance and changes to the mechanics of the bike. Just make sure you include the torque arms and have a steel front fork (no suspension). They do make your bike heavy and you won't want to cycle it with no power, but once it's under way you don't notice. I'd say >70% of my commute is pedal powered due to the motor cutting out at 25kmph (road legal). The motor is mainly for getting me moving and taking the pain out of hills and wind. I haven't used a mid-drive, but I think they might only needed for "fancier" cycling like off-roading.



    To get you started, I think this is what you need for a front hub conversion:
    • Front hub motor and rim (buy them pre-spoked so you don't have to do it)
    • Torque Arm
    • Controller
    • Battery pack (match power to hub motor) + charger
    • Brakes with motor disconnect cable
    • PAS (Peddle Assist Sensor) - Get one with the ring you can clip open to save yourself the nightmare that removing the bottom bracket can be
    • Ebike computer (the little screen to see what's going on)
    Wires and stuff should be included. I like to have a throttle too because my PAS is a bit hit-and-miss but I think this might not be technically road legal so keep that in mind


  • Registered Users Posts: 3,168 ✭✭✭ xckjoo


    Mad_Lad wrote: »
    Keep the money for a much better kit it will be worth it !

    Yes these days options are confusing on em3ev.

    What are you looking to achieve , assistance for hills, will these hills be steep and very long ?

    The crank drives are better for long steep trails and are more efficient which is important because it's easier on the battery , steep hills on hub motors causes more heat but you can get more efficient hub motors for hills such as the Mac 10 or 12T speed at 48-52 volts with a 12 T will be about 15 mph max , it's wound for torque, the 8T gives a good balance between speed and torque and will do 28 Mph on the flat with 48-52 volts, I would go for the higher voltage if you can 52 volts.

    The battery is also very important so you will have to size it correctly for your needs but also make sure it can supply the amps.


    This is good advice if you're going to be encountering long, steep hills daily. My commute is relatively flat with only a few hills


  • Registered Users Posts: 21,406 ✭✭✭✭ Mad_Lad


    xckjoo wrote: »
    I'm going to add some confusion by saying that I disagree with Mad_Lad and think hub motors are the way to go :pac:. I think a front hub motor will work for 99% of commuters. Simplest to install, no major maintenance and changes to the mechanics of the bike. Just make sure you include the torque arms and have a steel front fork (no suspension). They do make your bike heavy and you won't want to cycle it with no power, but once it's under way you don't notice. I'd say >70% of my commute is pedal powered due to the motor cutting out at 25kmph (road legal). The motor is mainly for getting me moving and taking the pain out of hills and wind. I haven't used a mid-drive, but I think they might only needed for "fancier" cycling like off-roading.



    To get you started, I think this is what you need for a front hub conversion:
    • Front hub motor and rim (buy them pre-spoked so you don't have to do it)
    • Torque Arm
    • Controller
    • Battery pack (match power to hub motor) + charger
    • Brakes with motor disconnect cable
    • PAS (Peddle Assist Sensor) - Get one with the ring you can clip open to save yourself the nightmare that removing the bottom bracket can be
    • Ebike computer (the little screen to see what's going on)
    Wires and stuff should be included. I like to have a throttle too because my PAS is a bit hit-and-miss but I think this might not be technically road legal so keep that in mind

    It depends on what you want to achieve, and what power you want, too much torque and the front forks can break.

    Front or rear mounted motors, torque arms are essential.

    Again, direct drive hubs are a b1tch to pedal with no power.

    Crank drives are more efficient for hills, Hubs are great but they like power.

    Front hubs are fine but can spin wheels in the wet and they are not suitable for higher power setups and I'd certainly never consider a front hub because I like a bit of power.

    My Bosch bike is very efficient but it only provides 50 Nm of torque but unlike a bub this torque is available at a much broader range because I can use the bikes gearing. They're up to 75+ Nm now and the better bikes provide 120 Nm from the German motor manufacturers , but they're well above 250 watts which is only a continuous limit anyway the peak can run well beyond this.

    The worst about legal ebikes is that they provide no assistance beyond 15.5 Mph or so which can be a right pain in a strong headwind but the limit can be removed.

    Swings and roundabouts for all setups.

    The crank drives are also neater to install because the controller is built in to the motor, less fiddling with wiring and trying to hide wires.

    Also ebikes are a target for thieves. You can't buy an expensive enough lock.

    At the end of the day I would love a Brose ebike system but they are very expensive, it's crank drive and has no resistance when peddling with no power.

    I really miss my 8T Mac motor , it gave me lots of power and I could use the throttle to give my legs a rest if I got tired and no pedal resistance, you will always notice the extra weight but that's what the motor is for at the end of the day.

    I also used slick tyres pumped to 90 PSI which makes a big difference.


  • Registered Users Posts: 21,406 ✭✭✭✭ Mad_Lad


    xckjoo wrote: »
    This is good advice if you're going to be encountering long, steep hills daily. My commute is relatively flat with only a few hills

    The 8T mac would be the motor for you then, great motor. You can choose a 36 V battery if you want a lower top speed, 28 mph is pretty fast.

    48-52 volts 28 Mph max in a 26 inch wheel a bit higher in a 28 inch.

    36 volts about 20 mph 26 inch wheel.

    Here's a very handy tool, have a play with this.

    The controller you choose will determine the torque/acceleration, the more amps the better battery you need.

    https://hobbyking.com/en_us/zippy-compact-6200mah-6s-40c-lipo-pack-xt90-1.html


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  • Registered Users Posts: 3,168 ✭✭✭ xckjoo


    Mad_Lad wrote: »
    It depends on what you want to achieve, and what power you want, too much torque and the front forks can break.

    Front or rear mounted motors, torque arms are essential.

    Again, direct drive hubs are a b1tch to pedal with no power.

    Crank drives are more efficient for hills, Hubs are great but they like power.

    Front hubs are fine but can spin wheels in the wet and they are not suitable for higher power setups and I'd certainly never consider a front hub because I like a bit of power.

    My Bosch bike is very efficient but it only provides 50 Nm of torque but unlike a bub this torque is available at a much broader range because I can use the bikes gearing. They're up to 75+ Nm now and the better bikes provide 120 Nm from the German motor manufacturers , but they're well above 250 watts which is only a continuous limit anyway the peak can run well beyond this.

    The worst about legal ebikes is that they provide no assistance beyond 15.5 Mph or so which can be a right pain in a strong headwind but the limit can be removed.

    Swings and roundabouts for all setups.

    The crank drives are also neater to install because the controller is built in to the motor, less fiddling with wiring and trying to hide wires.

    Also ebikes are a target for thieves. You can't buy an expensive enough lock.

    At the end of the day I would love a Brose ebike system but they are very expensive, it's crank drive and has no resistance when peddling with no power.

    I really miss my 8T Mac motor , it gave me lots of power and I could use the throttle to give my legs a rest if I got tired and no pedal resistance, you will always notice the extra weight but that's what the motor is for at the end of the day.

    I also used slick tyres pumped to 90 PSI which makes a big difference.
    I presume you're not too worried about it being road legal? The relatively low limits on ebikes makes higher powered motors unnecessary IMO.

    25kmph max speed is slower than I'd probably do on a decent normal commuter bike but my overall travel time is down because my average speed is higher. I quite like that I'm still getting some exercise from pedalling, but if I'm tired I can drop the pedal speed to virtually zero and let the motor do the heavy lifting. Again, I'd stress my opinion that a regular, road-legal, front hub motor setup is perfect for the vast majority of commuters. It's also the cheapest and easiest setup to build.

    Regarding thieves, I tend to take my battery with me when I lock up the bike. They can still steal the rest but good luck to them pedalling off with that and the battery is the most expensive part anyway :D


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