The eBike thread

unkel · 22-07-2019 7:34pm #1

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?

cojomo2 · 22-07-2019 8:27pm

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.

beauf · 22-07-2019 8:46pm

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

unkel · 22-07-2019 8:52pm

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

I guess it very much depends what other uses I will have for it and what kind of quality I will go for.

unkel · 22-07-2019 9:07pm

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...

ted1 · 22-07-2019 9:20pm

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

beauf · 22-07-2019 9:21pm

Electric Brompton is ideal for that.

Lumen · 22-07-2019 9:40pm

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

bunderoon · 22-07-2019 9:52pm

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.

eddhorse · 22-07-2019 10:15pm

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

22-07-2019 10:27pm

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.

krissovo · 22-07-2019 10:27pm

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.

22-07-2019 10:39pm

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......

22-07-2019 11:06pm

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.

unkel · 22-07-2019 11:07pm

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.

Wtf ? · 22-07-2019 11:10pm

After all your hard work.....https://www.dublinlive.ie/news/dublin-news/scooters-dublin-gardai-video-seized-16147126
Careful now....

22-07-2019 11:23pm

Wtf ? wrote: »

After all your hard work.....https://www.dublinlive.ie/news/dublin-news/scooters-dublin-gardai-video-seized-16147126
Careful now....

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.

22-07-2019 11:34pm

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.

unkel · 23-07-2019 12:05am

Deleted User 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.

macnab · 23-07-2019 1:18am

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.

unkel · 23-07-2019 1:25am

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...

23-07-2019 7:36am

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 !

23-07-2019 7:40am

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.

Lumen · 23-07-2019 10:35am

Deleted User 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!

insular1 · 23-07-2019 10:40am

Deleted User 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.

23-07-2019 11:18am

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.

xckjoo · 23-07-2019 11:18am

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

xckjoo · 23-07-2019 11:21am

Deleted User 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

23-07-2019 11:32am

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.

23-07-2019 11:37am

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

xckjoo · 23-07-2019 12:12pm

Deleted User 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

insular1 · 23-07-2019 1:14pm

Would love a crank drive, but I think what really appealed about the hub motor was the ease of set up and low price. This would make it harder for me to screw up and at the same time wouldn't be a huge amount lost if I did screw it up. Still my commute would be pretty hilly, and I also have an off road trail I'd like to use it on if possible so I'm now thinking probably mid-drive is the way to go. Plenty of hills with gradients up to 7% and one that must be at least 10% for about 600meters climb.

On the legality issue is it possible to get a set up where I can limit it to peddle assist and 25km/hr for commuting but then remove this restriction easily for the off road trail if I need/want a bit more power?

unkel · 23-07-2019 4:23pm

xckjoo wrote: »

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.

All that is important to me. I live in a fairly flat area anyway. It's just a project for fun.

So all I would need is the kit (in my link above) plus battery (and charger)?

23-07-2019 4:50pm

xckjoo wrote: »

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

Most if not all so called legal ebikes are not legal if you want to look strictly at power, Bosch for instance are more like 750 watts. Most others probably too.

Power is overlooked because acceleration and top assisted speed is severely limited.

I guarantee 250 Watts wouldn't pull a heavy ebike + heavy rider up many hills without serious effort.

You don't need much power on level ground until you start climbing hills then add a heavy rider and you will indeed need much more than 250 watts.

unkel · 23-07-2019 5:01pm

Or not make the battery myself, but use a pair of hoverboard batteries in parallel. Built in BMS, 3C discharge rating (that's more than I need to charge the car at 860W) and come with XC60 connectors installed. $58 for a 0.3kWh (8Ah) lithium pack, that's very cheap :eek:

Linky

Slight issue is that it is a 36V pack. I saw last night that there are 36V hub motors. That's not the issue. And my daughter has a kids electric scooter which I think is also 36V, so could use that charger. More complicated to find a 36V inverter that can power a 1kW AC appliance

Any ideas welcome...

23-07-2019 5:02pm

unkel wrote: »

All that is important to me. I live in a fairly flat area anyway. It's just a project for fun.

So all I would need is the kit (in my link above) plus battery (and charger)?

Yes, that's all you need but I would advise against a front hub if you use aluminium forks, steel forks will be fine.

Depends on the torque, how hard you are with the throttle and how heavy you are + Bike.

The kit should come with torque washers and these are suitable on older bikes where the little groove will fit into the drop out, if your dropouts do not have this then you need to buy separate torque arms, for this motor 1 might be enough.

If you do not use torque arms or if there are supplied torque washers then as soon as you hit the throttle the axle will spin in the droupouts and break the wires, you can rewire it but it's a pain in the ass.

On a similar kit I had many years ago I think I got about 28 mph full throttle level ground and it could climb some hills but a geared hub will be more efficient giving more range and better torque for the same power.

Ebiking is fun.

23-07-2019 5:11pm

unkel wrote: »

Or not make the battery myself, but use a pair of hoverboard batteries in parallel. Built in BMS, 3C discharge rating (that's more than I need to charge the car at 860W) and come with XC60 connectors installed. $58 for a 0.3kWh (8Ah) lithium pack, that's very cheap :eek:

Linky

Slight issue is that it is a 36V pack. I saw last night that there are 36V hub motors. That's not the issue. And my daughter has a kids electric scooter which I think is also 36V, so could use that charger. More complicated to find a 36V inverter that can power a 1kW AC appliance

Any ideas welcome...

That ebike kit will run at 36 volts no problem, it's top speed will be lower and less torque. But here's the thing, the controller will have a low voltage cut off for a 48V battery , you'd need the software and cable to adjust the low voltage cut off to make it work with a 36 V battery.

4 ah battery x 2 would be 8 x 3c = 24 amps so it should handle the motor kit but I feel the peak power would be more.

23-07-2019 5:16pm

Hobby King 20 C 5 ah would be the job, LiPo, dangerous if abused or cells punctured but I never had issue. You need to know what your doing and there won't be a BMS. And you need an RC charger + power supply to connect the balance leads up to which will equalise all the cells if they are out of balance but in general LiPo does not go much out of balance unless it's ran down to a low voltage. But you can make high power cheap batteries.

unkel · 23-07-2019 8:50pm

Yeah I've decided I'm going to buy cheap already made up batteries (with BMS) like above. And I think I'll abandon the idea of the "petrol can" for the EV. I guess a single 36V 4Ah battery be good with a 500W motor?

My bike is a Raleigh, probably about 5-8 years old. Model AL6061 "aluminium tubeset airlite", so yes aluminium. Not sure if fork is aluminium too. And yes, I am a fairly big lad, just under 6'2 and about 100kg

kiely182 · 23-07-2019 9:10pm

I bought one of Andy Kirby's ebike kits. He's a youtuber I've done over 2500miles on it in 6 months and it's been faultless. 1500w with a 52v 17ah battery range varies from 20 to 60miles depending on speed and amount of pedalling.

unkel · 23-07-2019 9:50pm

It was one of his videos that gave me the idea of converting my bike. Didn't even know kits existed. That machine of yours is a beast, but not cheap

kiely182 · 23-07-2019 10:29pm

It wasn't cheap. When you compare it to a factory built model that can do the same it would be around 4 grand. Iam planning in building a 52v 30ah battery using vruzend kit and cells from nkon.nl. I do 50 miles a day 3 or 4 days a week.

23-07-2019 10:37pm

unkel wrote: »

Yeah I've decided I'm going to buy cheap already made up batteries (with BMS) like above. And I think I'll abandon the idea of the "petrol can" for the EV. I guess a single 36V 4Ah battery be good with a 500W motor?

My bike is a Raleigh, probably about 5-8 years old. Model AL6061 "aluminium tubeset airlite", so yes aluminium. Not sure if fork is aluminium too. And yes, I am a fairly big lad, just under 6'2 and about 100kg

I would avoid the front motor, rear hubs are harder to fit but still easy. Few mins job. Snapping forks crossing a busy road is something to avoid.....

The 36 volt battery won't work on the 48 V controller because of the low voltage cut off ( LVC ) , you'd want a 36 V controller. Most of my controllers could be set via software but you might not be able to get it or cable for this controller.

The battery you linked to would likely die fast, it would be 4 ah x the c rate of 3 which is 12 amps and this ebike kit would kill it fast, it's way too much. You have to also think of the peak power.

Lipo is your man for this kind of job, small battery , big power. Or buy a dedicated battery one that you can use on a higher quality kit in the future, ebiking is a lot of fun.

unkel · 23-07-2019 10:51pm

kiely182 wrote: »

It wasn't cheap. When you compare it to a factory built model that can do the same it would be around 4 grand. Iam planning in building a 52v 30ah battery using vruzend kit and cells from nkon.nl. I do 50 miles a day 3 or 4 days a week.

You'll save a fortune compared with commuting in an ICE car. But if I were you with that sort of commute I would go for an EV, not an eBike. For safety alone.

I was about to pull the trigger on a Vruzend kit, but they ain't cheap. And I only needed two full kits. I guess for your 30Ah battery you would go for something like a 13s10p pack. That will need 5 full kits. That's €200 plus a good €500 in batteries (3Ah?) before you even add a single BMS. About a grand in total for just €1.5kWh. That's madness!

Would it not be better and even cheaper to buy a ready built battery? Warrantied and all?

One of these fellas 2.4kWh is about €900 + VAT

unkel · 23-07-2019 11:11pm

Deleted User wrote: »

Or buy a dedicated battery one that you can use on a higher quality kit in the future, ebiking is a lot of fun.

I hear ya. Still in two minds about it though. Now I have abandoned the idea of the petrol can, I could go either

-24V and a tiny 250W motor. This not only would be very cheap, but I could also safely go for a FWD. Fully legal too. And I have a single east facing solar panel on my shed, not connected to my grid tie inverter. It's currently charging a couple of leisure batteries in series, so 24V too. Could charge the bike pack on this with solar for free in no time with my existing basic PWM solar charge controller

-On the other hand I could get a more powerful and versatile 48V battery (much more expensive) and go for a high power eBike. I would have to get a charger, which would not run on solar

24-07-2019 8:40am

kiely182 wrote: »

It wasn't cheap. When you compare it to a factory built model that can do the same it would be around 4 grand. Iam planning in building a 52v 30ah battery using vruzend kit and cells from nkon.nl. I do 50 miles a day 3 or 4 days a week.

Have you a link to the kit ?

xckjoo · 24-07-2019 9:26am

Sorry in advance if I miss some stuff here. Only having a quick scan so will be short on info but I think my experiences have been a bit different from Mad_Lads so want to present that side. His technical info looks sound but I think his power requirements are overkill for most :pac:.

insular1 wrote: »

Would love a crank drive, but I think what really appealed about the hub motor was the ease of set up and low price. This would make it harder for me to screw up and at the same time wouldn't be a huge amount lost if I did screw it up. Still my commute would be pretty hilly, and I also have an off road trail I'd like to use it on if possible so I'm now thinking probably mid-drive is the way to go. Plenty of hills with gradients up to 7% and one that must be at least 10% for about 600meters climb.

On the legality issue is it possible to get a set up where I can limit it to peddle assist and 25km/hr for commuting but then remove this restriction easily for the off road trail if I need/want a bit more power?

I wouldn't bring a hub motor off-road as they are applying forces to the fork that isn't technically designed for them. It's fine on roads but not for rough treatment. You'd probably snap it pretty quick.

The motors are generally more than 250W so it's the controller that limits the power output. I've never bothered messing with mine but they are generally programmable so you could potentially reprogram for different situations but not sure how convenient that would be. Again I'd go mid-drive if I wanted to start looking at higher power.

unkel wrote: »

All that is important to me. I live in a fairly flat area anyway. It's just a project for fun.

So all I would need is the kit (in my link above) plus battery (and charger)?

I think front hub is the best fit so. By far the simplest to set up and no major bike mechanic skills needed. I'll give a bit more detail below.

Deleted User wrote: »

Most if not all so called legal ebikes are not legal if you want to look strictly at power, Bosch for instance are more like 750 watts. Most others probably too.

Power is overlooked because acceleration and top assisted speed is severely limited.

I guarantee 250 Watts wouldn't pull a heavy ebike + heavy rider up many hills without serious effort.

You don't need much power on level ground until you start climbing hills then add a heavy rider and you will indeed need much more than 250 watts.

Ya it's technically 25kmph and 250W isn't it? Really don't understand the power output limit. Abysmally low and irrelevant to safety etc. I might not be fully compliant in that regards :pac:

Deleted User wrote: »

I would avoid the front motor, rear hubs are harder to fit but still easy. Few mins job. Snapping forks crossing a busy road is something to avoid.....

I had a disaster of an experience getting my first ebike going as it was rear hub. There's a decent level of bike knowledge needed to do it as you're messing with things like gear hubs. When I built it there was only freewheel

gear hubs that were compatible with the rear hub motors so first I had to track down one of them, then it was spacing issues and the gear alignment was a disaster. Full disclosure though, it was an MTB frame and in hindsight not suited for the conversion. It literally took weeks and involved an angle grinder for a brief period

. A few years later I decided to build a fresh one and went for a front hub. Took me an afternoon and have had zero issues since.
Here's the advice I'd give anyone thinking of doing a conversion. If you're a casual cyclist and just looking for a commuting bike on a route that's mainly city or decent roads, go front hub motor. You want a fairly robust bike. Forget your carbon fibres, suspension and all that. You won't miss it (well maybe the suspension with the state of our roads

). Steel frames are ideal but it's the fork that's most important. You can switch them out if you needs to. Potentially just buy and old beater bike off donedeal as it could be cheaper and easier than trying to do changes yourself. Dropouts on the fork are the other factor. Some more modern designs use shorter dropouts for quicker tyre changes. You don't want that. The longer the better so they can provide more purchase. Don't skip on the torque arm either. You're applying forces in ways the bike wasn't set up for. It'll be fine as long as you take care. I've had zero issues with mine and have been using it near daily for the last few years. Also, get the PAS that doesn't need you to remove the bottom bracket of the bike if possible. Those things are a nightmare to remove and require special tools.

With the front hub set up, you only really need to know how to change a bike tyre, wheel and brake levers. If you're the kind of person that loves tinkering with a bike I'd go rear or mid-drive. They are mechanically superior set ups, but again I think this is overkill for most people. I use mine for commuting so can't afford too much down time and never fully got to grips with all the gear alignment stuff on a bike. TBH I rarely change gears on the bike since putting the motor on so set-and-forget appeals to me.

beauf · 24-07-2019 9:29am

xckjoo wrote: »

S... I use mine for commuting so can't afford too much down time and never fully got to grips with all the gear alignment stuff on a bike. TBH I rarely change gears on the bike since putting the motor on so set-and-forget appeals to me.

With the front motor do you find you rely on it, or actually still get some cycling in. (sorry this is slightly off topic from the OP requirements).

24-07-2019 9:29am

unkel wrote: »

I hear ya. Still in two minds about it though. Now I have abandoned the idea of the petrol can, I could go either

-24V and a tiny 250W motor. This not only would be very cheap, but I could also safely go for a FWD. Fully legal too. And I have a single east facing solar panel on my shed, not connected to my grid tie inverter. It's currently charging a couple of leisure batteries in series, so 24V too. Could charge the bike pack on this with solar for free in no time with my existing basic PWM solar charge controller

-On the other hand I could get a more powerful and versatile 48V battery (much more expensive) and go for a high power eBike. I would have to get a charger, which would not run on solar

Just think about what you want, cheap or good ? Buying a cheap kit and upgrading later is a waste of money and you'll likely have to sell the existing kit on ebay and that's a lot of hassle. Selling in Ireland will be difficult.

The first link you posted to will do the job but be a b1tch to pedal without power, get it in rear wheel setup, it won't be any more expensive. You will need to add a cassette to match the gearing on your bike.

It's a 48V controller so you need a 48V battery and one that can handle at least 25 amps of current. You should be able to find a 36 volt version on ebay handy enough.

Steer well away from unknown battery sources, em3ev builds his own and has a fantastic reputation in the DIY ebike community, check out endless-sphere.

The Mac 8T with 30 amp controller would do the job nicely, even 40 amps with 48V will be around 2 Kw and a lot of fun.

Or get the Bafang BBS02 or BBSHD crank drive, they are not very difficult to fit and you have tonnes of power for all terrain, put the bike in the boot of the car and take it to some trails, it will be a blast and it's a bike that can do anything.

The crank drive will be easier on the battery too as they are more efficient because they can use the bikes gearing.

The BBS HD can be set de-tuned to 25 amps or to the full 30 amps on em3ev when you buy it. I would go with the 30 amp, you don't have to use all the power.

You're talking around 1 K or more if customs get you, they never did get me from em3ev but then again that was several years ago.

You could spend 500 euro's on a kit that is not so good but the choice is yours, the BBSHD would be better than many electric bikes sold that cost thousands more.

xckjoo · 24-07-2019 9:37am

beauf wrote: »

With the front motor do you find you rely on it, or actually still get some cycling in. (sorry this is slightly off topic from the OP requirements).

I find I'm cycling it more often than not. It's a bit hard to explain unless you try it but basically you start pedaling and the motor kicks in and speeds you up. When you hit 25kmph it turns off and your doing all the work to keep the momentum going. If i want a bit more help I'll slow my pedalling back down until I drop below 25kmph and it'll kick in again. You can get a decent heart rate going if you want or take it easy so you don't arrive too work covered in sweat. I find 25kmph a little slow but I can push that up above 30 with some effort and it's probably a fine speed anyway. Your average speed will probably be higher than on a standard bike unless you're a decent cyclist already

24-07-2019 9:42am

Direct drive motors are an absolute pig to cycle without power.

Geared hubs can be got in front wheel format also. ( but I would not use more than 500 watts max )

Fitting a rear hub the first time tok me 20 mins max because I had to get the spacers aligned properly and really bend the frame to get it in, that was back in about 2009/10 they fit a lot better now depending on where you get the kit, Paul from em3ev gets his direct from the factory and deals with them directly. I had 0 issue fitting a mac 8t back in a bout 2011, I really miss that motor.

Next motor I got was a Golden Motor magic Pie II, built in controller, about 750 watts but it wasn't enough for me so I ripped the controller out and put in a 40 amp and boy did it fly haha. Those were the days, but due to it's size it was even worse to pedal without power.

The Golden motor kits are actually pretty decent, easy to fit and built in controller.

All the direct drive hubs, ( without internal gearing ) are designed for those who don't want to pedal or peddle very little, if the battery runs down you will have a very hard time peddling home so my advice is for anyone who likes efficiency or any form of peddling to avoid direct drives like the plague.

Also the crank drive motors are not actually designed solely for high power use, on the contrary , they are better for lower power because you can use the bikes gear and choose a lower gear when the motor starts to struggle.

Crank drives are harder on the chain , gears etc but all this is really a doddle to repair and if you don;t constantly hammer the throttle they will last a lot longer.

The eBike thread

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