BionX P250 max speed and 36V battery question

[francoisr]

Hi,

This is my 1st post to the forum. I'm about to invest in a e-bike. BionX seems to be the best system around but I can't afford $1500 - $2000 for a new system this year. My thought go toward buying a used one. I can see a few available for around $800. Most seem to be in good shape, being sold by seniors that have to give up biking.

My main interest for an e-bike is to cut a 35k commute from 2h down to about 1h. This implies an average speed of 35+ km/h (23MPG) (that I can't sustain for long without assist.). I hope couple of hundred watts from a BionX would help compensate for my physical limitations...

I understand the P250 is now out of production but more importantly the smallest motor available. And that batteries age. I read about the 3773 code to unlock the max limit.

I also understand that there is a physical limit (V/RPM or something) for any engine/wheel/battery configuration after which the system goes into regeneration. I read it is around 38km/h for a P(L)350/36V system but couldn't find similar number for the old P250/24V system. Has anyone evaluated it?

On the other hand, I know I might have to replace the battery pack. Is getting an new 36V battery on the P250 an option that is possible and has already been tried? Will this give me a new max speed closer to my expectations.

Thanks in advance for your suppport.

Francois.

 

[morph999]

Getting a new battery for a Bionx is probably possible. You could probably put some LIPO in it instead and it would be about $400. LIPO doesn't last as long as lifepo4, though but it'll last about 500 charges.

Most people on this forum don't really buy Bionx. It's much cheaper to just buy a kit and install it on your bike. You can still pedal along with the assist if you really want to get exercise.

 

[dogman dan]

Not that simple Morph. Bionx has a lot of proprieretary electronics in the battery box. So you can't just yank the controller and replace it with a 36v one. With bionx, you are pretty much limited to zero modifications, and must use the battery they provide.

I'm not saying bionx sucks, but if you want more watts, you better buy the highest wattage and largest battery they offer.

It's true, we don't discuss bionx much on this forum, since we can't tinker with it unless we are electronic geniuses. Some have put their own battery on a bionx, but it's beyond the skill of most of us.

 

[deardancer3]

I have two bionx, one for sale. Lots of friends have bionx and are quite happy. but its not the best for everyone.
Bionx does not offer open source or self service battery options, and batteries are a service issue on most systems.

BUT FIRST, lets back up and determine why you think bionx is best for YOU. What are your needs.

A thousand dolllars new can get you some nice system parts these days.

d


PS Forgot my manners; welcome to The forum and the world of Ebikes!!

d

 

[slayer]

Hi Francois ,

I don't own a bionx bike.
But i did tried one 36 volts at a bionx dealer. that guy disabled the speed limiter, i reached 38 kmh very fast, i was impressed, it is also very light. that was last summer. If you are willing to peddle bionx is a very good choice. if not it is a bit weak on throtlle only.
i have seen from jvbike the guy using a 36 volts bionx pack on a 24 volts system ask him http://www.jvbike.com also he does sell used ones.

For the battery being proprieretary with electronics... it is not true. you could swap any kind of battery pack in there providing you are a bit carefull.

for the half the time it could be possible depending on a lot of thing.

here is a video of a foldable birdy bike against a racer cutting the time in half...but it is always going uphill wich would give tha advantage an ebike... if you dan't have many uphills in your commute it will be harder to cut the time in half i would think.

http://www.veoh.com/browse/videos/category/autos_and_vehicles/watch/v6358634f2Be7RPD#

 

[francoisr]

Thanks you slayer and all.

I've shot jvbike an email and will wait for his anwers.

Cheers!

 

[dogman dan]

Yes, it's possible. Just wanted to keep a newbie from thinking its easy as pie as Morph said. And you do have a few issues to deal with if the new batteries don't fit in the bionx case. I should have been more specific, but am I wrong that there are needed electronics inside the battery case? It wouldn't matter too much where the battery was actually stowed as long as the wires went into the electronics, wherever they may be located.

The biggest complaint I've seen on bionx wasn't service or breakdowns, but simply that the batteries are too small in capacity. Bionx ought to offer a secondary battery that plugs into the first if they don't allready.

The biggest rave I see on bionx is that it keeps the bike feeling and riding like a normal bike. Some folks really have a huge aversion to having to deal with a throttle.

I agree with DD though, that the prices and good dealers to buy from in north america for regular ebikes makes a regular kit a pretty good choice, unless you just can't adjust to a throttle.

 

[Russell]

If I were to buy a BionX kit I would get the model with the battery in the rear soft trunk bag which would make a future battery upgrade easier.

-R

 

[DahonElectric]

The only advantages of owning a Bionx bike is the fact that it is currently one of the lightest, well packaged and all around ebike retro-fit kits out there. There is a computer that is governing the assist level, which is why the thumb throttle switch provides only an on (full assist)/off (no assist) assist switch. The reason why Bionx is not discussed much, or sometimes being dissed a lot is because it is very much a closed expensive system. This is good for people who don't want to mess with electronics, but loves to pedal. If you are an avid cyclist and plan to keep cycling without thinking of how much assist you need to give, then the Bionx system is for you. Bionx benefits mostly on the flat, especially with a P350 system. It is somewhat lacking on the hills -- 9 Continent or eZee 350 geared motor are better.

 

[alan]

the thumb throttle switch provides only an on (full assist)/off (no assist) assist switch.

It's been my observation that my PL350 BionX has a fully adjustable throttle assist level. Sure doesn't get used much, but when I use it, I can ask it to help me creep at a few MPH, or go full out, or anything in between, with no pedaling.

If the controller is set to diagnostic mode, the assist level is displayed digitally between 0 and 64 (much higher resolution than the normal assist "dial" readout), and you can see that there is some hysteresis such that the thumb input is slightly dampened, in a very useful way. That is, it seems to ramp up/down your input to avoid motor jerk/current spikes. I though I read elsewhere that throttle input overrides pedal input, but I find they work together, with the higher input of the two being the actual control.

-- Alan

 

[DahonElectric]

Alan, you are correct that all Bionx system's throttle control provides a ramp up to the maximum assist speed and this is a smooth computer controlled operation, which behaves like you have a variable throttle control. It is adjustable somewhat in the control panel too. But it is not the same as a hall effect throttle switch connected to the Cycle Analyst where you can manually regulate how much Watts output the motor should give. The Bionx does this automatically and also takes in input from your pedal feedback through a multiplier effect, so there's very little manual control you can do with it.

 

[kriskros]

as Deardancer says ,there are better kits that cost less money e.g holmes hobbies....bafang geared front motor[lotsof torque, free wheel,easy to pedal] $300.00 mounted in a rhyno lite rim[ i have one myself]good reliable little motor...6lbs....try a ping lifepo4 36v,12amp battery.[10lbs]...add a cycle analyst and an infineon controller from ebikes.ca and you are under $1000.00,,,put these on any bike you want i have gone 43 miles on this combo with some pedaling ... good riding

 

[alan]

Alan, you are correct that all Bionx system's throttle control provides a ramp up to the maximum assist speed and this is a smooth computer controlled operation, which behaves like you have a variable throttle control. It is adjustable somewhat in the control panel too. But it is not the same as a hall effect throttle switch connected to the Cycle Analyst where you can manually regulate how much Watts output the motor should give. The Bionx does this automatically and also takes in input from your pedal feedback through a multiplier effect, so there's very little manual control you can do with it.

This is not my experience. There is a ramp to the set point, but it is pretty quick, and it ramps to where your thumb is. If I press a little, I only get a little power, and will go slow. If I back off full throttle a bit, it will slow down a bit. I have no idea if it is a hall-effect sensor, or a simple potentiometer, or a variluctor, or whatever kind of throttle switch that is used, but it is a variable input throttle, and it seems to give continuous control from off to full power, and it is filtered to smooth out any rapid thumb twitchiness.

The difference I notice between my BionX and the half dozen other electric bikes with throttles that I have ridden is that I can't make the BionX jerk on or off. I have tried the Ultra A2B, and I believe it has a some filtering as well. I have also ridden bikes that have a lot more power than mine, but that is another topic (except the filtering would be even nicer on those)!

Another difference between the BionX and other thumb throttles I've tried is that the BionX engages with a very comfortable press forward motion (as your thumb moves when gripping something), where most other thumb throttles are basically a twist motion (moving the thumb up/down). If I were always using the throttle, I might prefer a twist grip, but definitely not a twist motion thumb switch. The BionX throttle is very comfortable to use, and, more importantly, it is very much out of the way when only using the pedal assist. That is, I can move my thumb off the switch without moving the rest of my hand.

-- Alan

 

[DahonElectric]

Alan,

I would be curious to hear what generation Bionx system you currently have. Mine is early 2008 and as much as I would like to do variable throttle control, it either does on or off and nothing in between. It does however detect terrain and environmental changes (headwind) and react to it so I think it is monitoring speed fluctuations in relation to the throttle control. I remembered that I asked that very same question to a Bionx rep during a bike show a few years back and he confirmed that it is only an on/off switch designed not to be used like a conventional ebike, rather it is there to provide a backup in the event your chain broke or a rear hub failure, which happened to me during the 2nd month of ownership. Without throttle control, it would be a very long walk home at least for me. However, you are right in saying that the throttle control algorithm to me is one of the best I've used thus far compared to many ebikes I test rode. It definitely has a smooth transition from low to high power and back rather than the jerk on and off or pulse and glide, though I'm used to that now on my 9C setup.

DE.

 

[alan]

Alan, I would be curious to hear what generation Bionx system you currently have.

Mine is about 18 months old (late 2008; with over 6K miles so far), and uses the previous generation I2C bus (not the new CAN bus). Perhaps the difference is between the P250 (which I believe is a NiMH system; is that what you have?) and my PL350 LMn system.

-- Alan