Bafang 8fun CD 36v or 48v ?

[Rohloffboy]

This may be a dumb question, but here goes.

I have been considering the Bafang 8fun Crank Drive unit for some time, the 500watt BBS02 is probably what I will be going for, as the unit can be de-tuned to 250w and the plate on the motor case states 250w which I guess keeps it all legal.

I also understand, that there a lead and software available, should I ever choose to put the motor into 500watt mode.

But my main question is about the motor voltage, as it can be ordered as 36v or 48v, now this has me a little confused, as to why there are two voltage options, can one offer more torque over the other?, the only thing I can think of is that maybe the 48v version may produce more RPM.

I am sure the folk on here, can help explain, and give a reason for and against, why I should choose 36v or 48v.

In my mind I am thinking 36v, but I have no reason why.

 

[Andy88]

You may or may not have seen this article on reddit in case you haven't here is the link

https://m.reddit.com/r/ebikes/comments/38fpjo/8fun_48v_750w_or_36v_500w_middrive_for_hilly/

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[trex]

the 36V is optimized for torque, the 48V for speed.
If your heart can hold on to 120 RPM, then 48V.
If you are old and well built, then you need torque, 36V which maxes out about 86RPM.

 

[Andy88]

That more or less summarises the article. Def 36 for me.

BTW trex I couldn't see the sundowner on the woosh site but great pictures of it on fb has it been discontinued?

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[Rohloffboy]

Thanks folks, I found the Reddit link informative having not seen it before. I got the speed bit if using 48v, and I get that a higher voltage draws less amps.

I am not really after speed, just need help to get up the hills, so for me it is more about torque at relatively low speed, so I guess I was on the right track in thinking 36v and not 48v

I have one particular hill round here, which although only maybe less than 500m road distance, is a killer, and sees me collapsing at the summit for a 10 minute breather!

I am probably lucky to keep above 3mph whilst peddling up the said hill, although I do see other folks pushing there pedal bikes up.

The only reason I can get up the hill at all, is no doubt down to the fact that my 26" Wheel all rigid Hybrid is running a 14 gear Rohloff with 17T rear sprocket and 41T chain ring up front.

If my gearing was any lower, I would struggle to get past 20mph on the flat.

20mph is about my sweet spot on the flat.

It would just be nice to pedal up the hill, without almost killing myself, and I am hoping that going electric will provide this.

 

[trex]

the 36V BBS02 maxes out at 1,000W - you'll climb pretty much any hill with it coupled to a Rolhoff. Max speed derestricted is about 24mph.

 

[Deleted member 4366]

All the 250w marked ones are 36v.

All the 500w and 750w ones are illegal, regardless of how you set them. If you're going to get an illegal one, get a 750w 48v one.

 

[trex]

BTW trex I couldn't see the sundowner on the woosh site but great pictures of it on fb has it been discontinued?

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that bike is a classic Dutch design, so it won't be discontinued but woosh have no spare storage from now to June/July, unlikely to see a new batch before July.

 

[Andy88]

This may be a dumb question, but here goes.

I have been considering the Bafang 8fun Crank Drive unit for some time, the 500watt BBS02 is probably what I will be going for, as the unit can be de-tuned to 250w and the plate on the motor case states 250w which I guess keeps it all legal.

I also understand, that there a lead and software available, should I ever choose to put the motor into 500watt mode.

But my main question is about the motor voltage, as it can be ordered as 36v or 48v, now this has me a little confused, as to why there are two voltage options, can one offer more torque over the other?, the only thing I can think of is that maybe the 48v version may produce more RPM.

I am sure the folk on here, can help explain, and give a reason for and against, why I should choose 36v or 48v.

In my mind I am thinking 36v, but I have no reason why.

Can I ask which bike you would attach the motor to?

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[Artstu]

I have one particular hill round here, which although only maybe less than 500m road distance, is a killer, and sees me collapsing at the summit for a 10 minute breather!

I am probably lucky to keep above 3mph whilst peddling up the said hill, although I do see other folks pushing there pedal bikes up.

Has it got a Strava segment? (probably several) it's always interesting to see the hills that people have to tackle on their e-bikes.

 

[Rohloffboy]

Yep Andy88.
The bike is none branded as such which I got back in 2004, but came from Tilon X'CND in China X'ian Provence.

Got the Rohloff from a LBS, bargain price back then 2004, although there was 5 of us each ordering Rohloff's at the time, which helped with the price.

Not worked how to do a Linky on here, but the Tilon website is worth a look, they even do Ti exhaust systems for cars etc!

All the parts for the bike, are Titanium Brushed finish, 17.5" MTB style c/w Ti rigid forks and Ti handle bars with integral Stem you get a choice of Stem angles, I even sent them a FSA alloy isis crankset, and they made an exac copy in Ti, although I will loose the crankset to another bike when I get the Bafang.

Tilon did a very nice job, especially the OEM style Sliding Drop-Out's for the Rohloff.

They even did me a Ti bottle cage.

 

[Andy88]

Thanks for this

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[Rohloffboy]

My pleasure Andy88.

d8veh, I was wondering about the legals on the 500w model, according to the supplier the 500w motor can be factory set to 250w and despatched as such, also the motor case is badged as 250w even if they set it to the full 500w spec.

With that in mind, if the motor is factory set to 250w and the controller is set to 15.5mph cut of for assist, surely it would still be legal, as the motor in electronically fixed to 250w.

Artstu.
Strava is a bit of a mystery to me, although my cycling buddies are always jibering on about it.

I got given an Epson Runsense SF-810 watch last year, it has GPS, and I was hoping to get it to work with Strava, but I gave up in the end, the whole setup just seemed to complicated, I am bit of an analog bloke in a digital world!

 

[Andy88]

Yes, I hear conflicting stories on the legality side as well as I am just looking for a bike that I can use throttle only up to 15mph but seems id need to buy a pre 2016 model for it to be legal.

Actually your post gave me food for thought as if it were a conversion and the frame was 2015 but the motor was 2016 and the components were a mix or vice-versa re motor and frame then how does that stand from a legal stand point?

By the way where are you going to buy the motor from and will you be doing the conversion yourself?

Andy

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[Rohloffboy]

Yep Andy88, no problem using a Throttle on my conversion, as there is no way of establishing when it was done.

As for the build, yep will be doing that myself, we have a fully equipped workshop, as we do bike repairs, long story but you get the picture.

As for the legals on the 500w motor, in my mind if it comes as de-tuned to 250w, from the supplier then even in the eyes of the law it is a 250w motor.

Probably will be buying from em3ev over in China, not sure what to do about the battery and charger, but will probably get that from em3ev as well.

I am in no rush, and will probably leave it until the new year.

 

[trex]

the throttle has always been and still is allowed on all converted bikes. Don't worry about it.

 

[Andy88]

So surely all manufacturers/sales outlets need to do is either sell a throttle separately but leave wiring in place or use a control panel that can be configured by the user for road or private land use.

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[trex]

sellers are divided into two camps: half leave you with the socket to plug your throttle in, the other not. The latter tend to fit a torque sensor as a substitute. However, a torque sensor requires you to pedal even more than bikes with a simple cadence sensor so it's not really a substitute.
If you want a throttle, just buy a bike with a throttle socket or a bike with a throttle that only requires you to push the plug in.

 

[Andy88]

How do woosh stand on this one? Or u cannot comment?

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[Deleted member 4366]

My pleasure Andy88.

d8veh, I was wondering about the legals on the 500w model, according to the supplier the 500w motor can be factory set to 250w and despatched as such, also the motor case is badged as 250w even if they set it to the full 500w spec.

With that in mind, if the motor is factory set to 250w and the controller is set to 15.5mph cut of for assist, surely it would still be legal, as the motor in electronically fixed to 250w.

Artstu.
Strava is a bit of a mystery to me, although my cycling buddies are always jibering on about it.

I got given an Epson Runsense SF-810 watch last year, it has GPS, and I was hoping to get it to work with Strava, but I gave up in the end, the whole setup just seemed to complicated, I am bit of an analog bloke in a digital world!

If a motor is stamped 250w, then it's a 250w motor. You can't set any motor to 250W. What does that mean? Is it 250w from the battery, 250w from the back wheel, 250W at the crank, peak power, average power, power at what speed? It's a complete meaningless nonsense.