The eBike thread

13-08-2019 05:55PM

samih wrote: »

Bit late to this party but I have been commuting for just over two years with a Bafang BBSHD mid motor based setup built on a Boardman MX hybrid. It has been really reliable and as I have about 17 Ah of 48 V battery the range of the bike still about 100 km cruising at slightly above the legal 25 km/h speed limit. I did a first properly long spin on the bike a couple of weeks ago and it took just over three hours to cycle 85 real kilometers and the battery had still enough juice for about estimated 15-25 kilometers. So it has pretty much the range of a L24.

There is currently just under 14k km on the clock since the conversion with no Bafang related issues, just general wear and tear on the bike.

The power and battery specs are bit of an overkill for my daily commute of 42 km return but this gives me plenty of headroom against battery degradation and hurricane level headwinds and I also figured out that a higher rated motor has an easier life and will therefore have less problems at high miles. Some say that bike like this would have enough oomph for about 50 km/h on level ground at full blast but what do I know. I cruise at lower legal(ish) speeds.

Here's an ongoing thread about the experience:

Commuting on a BBSHD

Excellent stuff, the BBSHD is a beast alright but you can't beat the power of a hub with 5 Kw lol, no interruption in power , no gear changing.

Can't beat the BBSHD for slow mega steep trails and efficiency.

What's it like to pedal without power, I've heard there is is a fair amount of pedal resistance ?

unkel · 13-08-2019 06:18PM

samih wrote: »

Bit late to this party but I have been commuting for just over two years with a Bafang BBSHD mid motor based setup built on a Boardman MX hybrid. It has been really reliable and as I have about 17 Ah of 48 V battery

Some battery at just under a kWh! I presume your motor is 1000W?

BarryM · 14-08-2019 07:13AM

unkel wrote: »

Some battery at just under a kWh! I presume your motor is 1000W?

A question for the thread.

Just got a Jorvil trike, nnt for commute per se, I live on an island off the South coast and am attracted by the advantage of not needing fuel,etc.

The terrain is hilly, so, what power should I have? Any tips on riding in hilly terrain appreciated.

TIA

14-08-2019 09:09AM

[Deleted User] wrote: »

Excellent stuff, the BBSHD is a beast alright but you can't beat the power of a hub with 5 Kw lol, no interruption in power , no gear changing.

Can't beat the BBSHD for slow mega steep trails and efficiency.

What's it like to pedal without power, I've heard there is is a fair amount of pedal resistance ?

No noticeable resistance, it's as easy to pedal as a normal bottom bracket after the initial small bit of stiction wore out.

14-08-2019 09:11AM

unkel wrote: »

Some battery at just under a kWh! I presume your motor is 1000W?

The peak amps is 30 A and the battery voltage about 50 V under load when fully charged so can produce more than that. But it's rated at 1 kW.

14-08-2019 09:51AM

The BBS 02 could pull over 1 Kw Peak I believe so the BBSHD is pulling much more 1.5 Kw. Nice.

14-08-2019 10:00AM

BarryM wrote: »

A question for the thread.

Just got a Jorvil trike, nnt for commute per se, I live on an island off the South coast and am attracted by the advantage of not needing fuel,etc.

The terrain is hilly, so, what power should I have? Any tips on riding in hilly terrain appreciated.

TIA

Depends on many things, such as length and grade of hills, if you intend to carry cargo which I'm sure you will, so I would go for the Bafang BBSHD with the 30 amp controller version, about 1500 watts max according to em3ev.

https://em3ev.com/shop/bafang-48v-1000w-bbshd-kit/?currency=EUR

Make sure your battery can handle 30 amps, it will drain your battery a lot faster having higher power but you don't have to use it all but it's dead handy to have it when you need it.

I wish my Bosch from 2013 could give out more than the 50 Nm of torque it's capable of because I have not been on the bike in a very long time and the rare time I go out having 50 Nm now is a lot less than I like but still makes a big difference, it wouldn't be so bad if I could use a throttle to give my legs a break. But the Bosch is super efficient and will go long distance with it's 36 v 14 Ah battery though I don't actually know what it has now after 6 years.

If I were to convert a bike again I'd most definitely have a throttle and much more power for when I need it, more power usually means more weight but anyway, if I could hack the Bosch for throttle use it would do me fine but my legs can get very tired on long hills because I can not get on it regularly to get used to it bit it has drag on the peddles when there is no motor power which I don't like, I believe the 2019 motors don't have this drag, it took them until 2019 to eliminate it lol.

The best motors are Brose. No drag and 120 Nm torque. But come OEM only at a price.

14-08-2019 11:04AM

Any mid drive can tackle hills no problem due to gearing and the more power the higher gear you can use. To give you an idea the bbshd can easily accelerate in a few seconds from 20 to 30 km/h using the throttle on a 15% hill (there are a couple of these on my usual route). And on the same hill a legal 250 W central motor can maintain approx 20 km/h I suspect.

An average cyclist is doing something like well below 10 km/h on the first gear or pushing the bike on these hills.

14-08-2019 11:09AM

I got up mount Leinster with the Bosch , it was very very tough but the difference was being able to do it with the Bosch v not at all without it.

Some of the grades there are over 20% so more power would have been welcome because I was in such a low heat most of the time that I was peddling like mad and it was hard on the legs.

The hearing also allowed me to get up with the sram dual drive 3 gear hub.

I prefer to pedal at a slower cadence than the 2013 Bosch allows so that would mean more power.

I don’t climb mount Leinster every day of course but the same still applies , I like to pedal at a certain cadence not ultra fast.

beauf · 14-08-2019 11:46AM

Deleted User wrote: »

I ....more power would have been welcome because I was in such a low heat most of the time that I was peddling like mad and it was hard on the legs.

The hearing also allowed me to get up with the sram dual drive 3 gear hub.

I prefer to pedal at a slower cadence than the 2013 Bosch allows so that would mean more power.

I don’t climb mount Leinster every day of course but the same still applies , I like to pedal at a certain cadence not ultra fast.

Is that to do with the sensors not measuring actual pedal effort and only pedal speed/cadence?

Isn't that the issue. If it had a speed limiter, but allowed more power up to that speed, that would be idea.

The idea behind limiting power is to limit speed. But they don't measure speed.

beauf · 14-08-2019 11:50AM

I like the idea of the some of the single speed electric bikes with belt drives as a low maintenance commuter, (my route is mainly flat with a slight incline in one direction).

But I think at lot of them cut out a bit early. So I would be spinning out at top speed a lot of the time. Only when tired or slow would I be getting assistance. Maybe thats exactly what I want I don't know.

This discussion about power has me wondering. I guesstimate my speed into work as about a 24 kmph average. Whereas home more like 14 kmph. Against incline and wind usually.

14-08-2019 12:35PM

beauf wrote: »

I like the idea of the some of the single speed electric bikes with belt drives as a low maintenance commuter, (my route is mainly flat with a slight incline in one direction).

But I think at lot of them cut out a bit early. So I would be spinning out at top speed a lot of the time. Only when tired or slow would I be getting assistance. Maybe thats exactly what I want I don't know.

This discussion about power has me wondering. I guesstimate my speed into work as about a 24 kmph average. Whereas home more like 14 kmph. Against incline and wind usually.

The hills and the usual gale force headwind on Friday evening were my main motivators on going electric. Regardless of rain shine wind hurricane floods and hills I always complete my 21 kilometers in 45-47 minutes these days now that I have settled down for less assistance and so less wear and tear on the chain and sprockets and more excercise for me.

I have observed peaks of 800 W continuos power at level ground at particularly hard conditions. Those days I have felt much sympathy towards the fellow commuters that struggle for double digit speeds while I continue at my normal cruising speed.

Edit. And my ideal commuter would have a Rohloff Speedhub (with 14 gears it is a total overkill for an ebike but it's the only IGH that can take the torque from BBSHD) and either a really heavy duty chain or a belt drive. The only problem is that those hubs are double the price of the base bike I have. A one new set of chain cassette and sprocket is about 80 quid DIY and I seem to get a full year and 7k from it so not worth the additional spend of 1k plus the go with the IGH. And my drivetrain is 10 speed which is not as robust as a good quality 8 speed one would be.

krissovo · 14-08-2019 02:37PM

samih wrote: »

Edit. And my ideal commuter would have a Rohloff Speedhub (with 14 gears it is a total overkill for an ebike but it's the only IGH that can take the torque from BBSHD) and either a really heavy duty chain or a belt drive.

Gates drive and Rohloff are on my wish list but I am struggling to find a strong frame like my Surly Cross Check. I don't want to trash my frame either and weld it. I am a big dude over 110 kgs and I do take it up hills and rough tracks so it gets a beating.

I did try a cheap Shimano hub but I stripped that in Ballyhoura.

14-08-2019 03:52PM

The Bafang does put a lot of stress on the bike even on the road and I can only imagine what happens offroad. I only figured out after almost two years of use that the motor is much more comfortable in use when you set the speed limiter to something like 50 km/h which then results in suitable cruising speed at say assistance level 4 of 9. At these lower levels of assistance the maximum torque is much limited which:

a) helps me to stay at the top of the assistance window where I can do plenty of legwork but the motor doesn't constantly want to push you over the speed limiter and then totally kick off which results the speed to constanty fluctuate by about 3 km/h. Now the power delivery seems really sublime and it's easy to stay at constant XX km/h.
b) Less torque puts way less demand on the drivetrain and frame as it usually delivers only up to about a third or so of the maximum power but you can override that anytime using the thumb throttle. The BBSHD is really an overkill for most of the time and I chose it manily for reliability over the smaller versions.
c) All this increases the range per charge a lot due to gentler power delivery.

Yesterday my 48V nominal battery pack was still at just over 49 Volts (down from 54V) when returning home after the commute and there was therefore plenty of charge left for today's commute without taking the pack down towards the lower shutdown voltage of 40V.

krissovo · 14-08-2019 04:07PM

samih wrote: »

The Bafang does put a lot of stress on the bike even on the road and I can only imagine what happens offroad. I only figured out after almost two years of use that the motor is much more comfortable in use when you set the speed limiter to something like 50 km/h which then results in suitable cruising speed at say assistance level 4 of 9. At these lower levels of assistance the maximum torque is much limited which:

I didn't realize the limiter impacts the cadence. Setting 4 puts me at the max limit of my cruising cadence, must be over 70rpm, anything above and its throttle use only.

14-08-2019 04:21PM

krissovo wrote: »

I didn't realize the limiter impacts the cadence. Setting 4 puts me at the max limit of my cruising cadence, must be over 70rpm, anything above and its throttle use only.

I don't think there is a cadence limit as such but my (hybrid) bike with 700c wheels (46T front, 11T top) has a very long gearing already at 8th gear (out of 10) which is ideal at the cruising speeds I use. At downhill sections on the 10th gear the cadence is good at ridiculous speeds.

The controller at level 4 (limiter at 50 km/h) typically allows about 10 Amps (sometimes up to 12) of current which is just right and typically the assistance hovers between 0 and 6 Amps at the cruise. On level 6 with limiter set to 42 km/h the current peaks were about 20 Amps which feels fun off the lights but not very good for mechanicals (or range on the long runs).

BarryM · 15-08-2019 12:03PM

Thanks for all the info. Just so I can compare, I have a Huzhqu Li i battery 36v 10A; and BFSWZB 36v 250w 170R 24-190 1118485 letters and numbers on the motor. What does that give me versus the battery motor combinations mentioned above?

TIA

15-08-2019 05:29PM

beauf wrote: »

Is that to do with the sensors not measuring actual pedal effort and only pedal speed/cadence?

Isn't that the issue. If it had a speed limiter, but allowed more power up to that speed, that would be idea.

The idea behind limiting power is to limit speed. But they don't measure speed.

No the Bosch is a proper pedelec system which measures cadence + torque so the harder you pedal the more power the motor gives, it knows when to apply max power too because of the pedel cadence, if it's much faster in a low gear it will give you more power because it knows you'll be climbing a hill.

But, with 50 Nm of torque you're going to have to drop gears anyway because there isn't enough power for a higher gear and slower cadence.

I would like to try out the current Gen Bosch which have about 75 Nm of torque, still a long way off the Brose which is about 110 Nm.

The Legal bikes do monitor speed and this is how they get away with much more than 250 watts, once speed and acceleration are within spec no one cares about power.

The Bosch speed limit can be hacked with a box or the proper way via software which doesn't effect the speedo and can be activated and deactivated easy.

15-08-2019 05:36PM

BarryM wrote: »

Thanks for all the info. Just so I can compare, I have a Huzhqu Li i battery 36v 10A; and BFSWZB 36v 250w 170R 24-190 1118485 letters and numbers on the motor. What does that give me versus the battery motor combinations mentioned above?

TIA

I can't find any info on that motor.

BarryM · 15-08-2019 08:38PM

Deleted User wrote: »

I can't find any info on that motor.

Neither can I !

Attached is a pic of the data from the front hub.

If it was BB it would be Bafang?

15-08-2019 10:52PM

BarryM wrote: »

Neither can I !

Attached is a pic of the data from the front hub.

If it was BB it would be Bafang?

Probably Bafang alright, that motor is around 35 Nm of torque which isn't a lot, their 500 Watt is about 50 Nm.

If you like hubs, a MAC 8 or 10T with 52 volts and 40 amp controller, would be about 2 Kw. 8T would do about 48 Km/h and the 10T about 43 Km/h but have more torque.

a 35 amp controller would give you 100 Nm torque from 0-10 Km/h and at 20 Km/h you still got 70 Nm torque, that's a lot of torque ! :-)

unkel · 15-08-2019 11:11PM

Deleted User wrote: »

a 35 amp controller would give you 100 Nm torque from 0-10 Km/h and at 20 Km/h you still got 70 Nm torque, that's a lot of torque ! :-)

A 1987 Citroen 2CV had a maximum 38Nm of torque. And that's a car!

15-08-2019 11:26PM

unkel wrote: »

A 1987 Citroen 2CV had a maximum 38Nm of torque. And that's a car!

lol, God bless electric motors and Lithium batteries !

But it's amazing what you can do with a gearbox. Enough HP and that 38 Nm of torque can do a lot.

unkel · 15-08-2019 11:44PM

Deleted User wrote: »

lol, God bless electric motors and Lithium batteries !

But it's amazing what you can do with a gearbox. Enough HP and that 38 Nm of torque can do a lot.

It had 29BHP

16-08-2019 12:02AM

unkel wrote: »

It had 29BHP

Yeah plenty to get from 0-100 in about 50 seconds with the wind in it's back.

unkel · 16-08-2019 12:07AM

I think I remember from my youth that some of the earlier models did not have an official 0-100km/h acceleration timing, as they couldn't make it

Mind, they could be driven faster than most people drive their Nissan Leafs even today :pac:

krissovo · 16-08-2019 12:48AM

unkel wrote: »

A 1987 Citroen 2CV had a maximum 38Nm of torque. And that's a car!

I spent the best part of a 4 week European summer road trip with 3 friends in my teens trying to tip over the 1980’s 2CV we had. Every sharp bend or roundabout we were hanging out the rag top and leaning over. Impossible to tip and great fun were my lasting impressions.

Another impression is that my e-bike has far superior acceleration and it can actually climb a hill without getting off and pushing.

BarryM · 16-08-2019 06:35AM

krissovo wrote: »

I spent the best part of a 4 week European summer road trip with 3 friends in my teens

you wild thing....:)

Another impression is that my e-bike has far superior acceleration and it can actually climb a hill without getting off and pushing.

Have you a spec?

BarryM · 16-08-2019 06:36AM

Thanks for that, I am in contact with Jorvik for a swap.

16-08-2019 07:46AM

tldr alert.

The Bafang BBSHD has a maximum (output) torque of 160 Nm at the cranks. As it has an internal reduction ratio of 1:21.9 it means that the electric motor itself has about 7.3 Nm. As my particular bicycle has gear ratio of 46:32-11 it means that the torque at the rear wheel hub on the 10th gear would be about 40 Nm and on the 1st gear 111 Nm.

The 1979 2CV has 1:1.47 gear ratio on the top gear which means that the 2CV has only about 10 Nn more torque at the driving wheels on the top gear than my bike. Which is not a lot :-) The first gear torque is on 145 Nm and the fully loaded car with 3 grown ups and their luggage weighs easily 800 kilograms vs. about 110 kg for my bike and me. And the bike also has pedals to assist it uphills. And the peak torque from a 40 yo 2CV might be less than the stated figure and in any case only appears at one particular point at 3750 rpm.

The 2018 LEAF has about 2900 Nm of wheel torque so it's the overall winner of these three on the sprint to Sally Gap.

PS. a 1979 2CV has only 28 Nm of torque so it fares even worse than my calcs using the given figure of 35 Nm.

Above calcs also omit the wheel size which helps the cars 15-17 inches instead of 28 on my bike.

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