bionx battery replacement

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Last seen: 12 years 5 months ago
Joined: Tuesday, May 27, 2008 - 10:26
Points: 64
bionx battery replacement

I use my Bionx bike as my commuter and put a lot of miles on it. I go through the equivalent of 4 complete charge cycles a week. Since the 36V Li-MN battery is rated for about 500 cycles, that means I would need a new battery in 125 weeks of use, or about 2 and 1/2 years.

A replacement battery from Bionx costs around $950. So battery replacement is going to be a huge operating expense for me. It's costing me about $1.50/day in battery cost. That's only slightly less than the gasoline would cost ( at current price of $1.75/gal) if I used a car instead of the bike.

I'd like to reduce this cost, if possible.

My first question, to any knowledgeable people out there, is whether there are just batteries in the Bionx battery case or whether the control electronics are also in there. If the latter, shouldn't Bionx or a 3rd party group replace just the batteries at a lower cost than a complete battery box replacement? I tried to contact Bionx about this, but no luck.

My second question is whether anybody knows of any 3rd party agencies that might do this. I noticed that OHM Bicycles, which are based on the Bionx, must have their own batteries as one of their bikes uses a 36V 12Ah battery that is not offered directly by Bionx.

I might even try to do the battery replacement myself. For instance, I could purchase a 36V, 10Ah LiFePO battery pack, plus a fast charger, from one supplier for about $625. This would result in a superior battery pack, as the LiFePOs have a much higher charge/discharge rate and are suppose to be good for 2000-3000 cycles at the Bionx discharge rates. Plus you can charge them much quicker than the Bionx batteries. You can safely recharge them in 20 minutes with the right charger, although the charger being offered would take 2 hours.

davew's picture
Last seen: 8 years 5 months ago
Joined: Monday, November 20, 2006 - 20:13
Points: 85376
Re: bionx battery replacement

You can pop the cover on the battery fairly easily and have a look. There is quite a bit of electronics inside. Clearly some of it is BMS. The controller is probably in there too, because I can't think of where else it might be.

I understand that you'd like to reduce cost, who wouldn't, but the Bionx is still a deal. A car would have cost for more with maintenance, insurance, taxes, and feeling like a complete tool all the time.

I have a LiIon battery that's a few years old now, but I don't use my electric as much as you do. I'm planning on sucking it up and replacing it with another Bionx battery when the time comes. I've had a few ebikes and this has been far and away the most reliable. I wouldn't want to screw with that. Not even for a couple of hundred bucks. I'm also hoping prices will drop by the time I need a new one or they'll have a Lithium Iron Phosphate battery by then.

"we must be the change we wish to see in the world"

Last seen: 12 years 5 months ago
Joined: Tuesday, May 27, 2008 - 10:26
Points: 64
Re: bionx battery replacement

Thanks for the reply. BTW - the battery pack I looked at had the BMS in it, although apparently it's not as critical with the LiFePo. I'd like to update to these batteries one way or another.

I'd be seriously interested in Bionx switching to the LiFePo battery, both because it would essentially last the life of the bike for most people and it has the potential of very fast charging. With a 30 minute charge you could use the Bionx for bike touring or for trips at the far end of the battery range. Just stop every 30 miles or so and have a coffee while the bike charges. You could go all day this way and cover nice distances. It would essentially make the range of the bike infinite.

Last seen: 11 years 11 months ago
Joined: Friday, May 16, 2008 - 06:31
Points: 21
Re: bionx battery replacement

I know that a guy whose battery NiMH collapsed qfter 2 and a half years (9920 km) has ordered from maximus (a chinese company ?) a new battey and is going to try to adapt it on his old one. He is giving news on this french web site
He should receive the battery after christmas..
The problem with bionx seems to be that the electronic is in the battery case and that there is a misterious blue wire, probably a temperature sensor. You can find photographs of the dismantles battery on the cyclurba site.

Last seen: 13 years 2 months ago
Joined: Sunday, December 9, 2007 - 01:20
Points: 22
Re: bionx battery replacement

We recently made a video on how to replace Bionx battery. Here is the link, enjoy!


Last seen: 14 years 11 months ago
Joined: Saturday, August 8, 2009 - 21:05
Points: 2
Re: bionx battery replacement


A half a year later, and there still doesn't seem to be any progress on the battery replacement ease or cost!

I bought a P-250 in 2006 - it must be down to about 30-40% of its original charge capacity. Then, I bought a PL-350 just this summer - love it even more! I put the old P-250 on my wife's bike, but now I find the power/discharge difference (between bikes) so much different that I now want to buy her a PL-250 battery so that she has more charge/range.

The thought of spending another $600-800 for a PL-250 is just heartbreaking, despite going on a spending spree with the PL-350 (I'm now at a point where I cannot afford a replacement battery). Oh how I wish there was a $100-200 solution, involving swapping some of the innards, as you (cyclepete) bring up.

Anyone find anything yet?

proton's picture
Last seen: 12 years 7 months ago
Joined: Wednesday, June 20, 2007 - 04:47
Points: 125
Re: bionx battery replacement

I may be able to replace the cells with LiFe type, 26650's
the bionix liMn bms is differant, so, probably need to replace that as well
I also have 10Ah LiMn cells if they will fit
If u want to give it a shot, let me know
contact email on

The LiFepo4 BattMan

Last seen: 8 years 6 months ago
Joined: Friday, January 16, 2009 - 11:45
Points: 54
Re: bionx battery replacement

Just tried to link up to that video, and the site said "video has been removed by user." It would be good to see. I'm trying to replace batteries on my Bionx right now. I'm taking pictures as I go.

Last seen: 14 years 10 months ago
Joined: Thursday, July 2, 2009 - 07:45
Points: 50
Re: bionx battery replacement

I wouldn't be at all surprised to see Magna start making it's own batteries for the BionX system after seeing this article.

I hope that as our BionX batteries become worn down, we can return them to the dealer to have new cells insalled for a reasonable price. I'm hoping that there is a big savings based on large volume production and that these savings will be passed along to us end users.

Last seen: 14 years 10 months ago
Joined: Saturday, August 29, 2009 - 08:26
Points: 16
Re: bionx battery replacement

Hi theres this link on ebay someone will do the battery change for you hope its ok to link that.

Monkey see, monkey do, so get the monkey to do it.

BobotheDestroyer's picture
Last seen: 14 years 10 months ago
Joined: Wednesday, March 5, 2008 - 21:30
Points: 9
Re: bionx battery replacement

I have close to 5000km on my battery and it's almost dead (1.5 yrs. old). There's no way I'm buying a replacement Bionx battery for a grand, so I've been researching alternatives. I have the following objectives:

1) Replacement cells must fit into the Bionx hard-case
2) Use the same charger
3) Have similar capacity
4) Low cost

I've been researching this for over a year and I think I've finally found a solution. Below is a link to a reseller with Ni-Mn cells for sale:

An 8Ah pack can be constructed that will easily fit in the hard case, be compatible with the Bionx circuitry and battery charger and is low cost. This will be my winter project if nothing better comes along.

What do you think?

Last seen: 14 years 7 months ago
Joined: Saturday, January 17, 2009 - 10:24
Points: 12
Re: bionx battery replacement


I presently run a Bionx PL-350 on a Catrike 700 Recumbent. I added another 36 V. 20 A/h battery pack (LiFePo4) in parallel with the the original 36 V. Li-Mn battery, thus tripling the original Bionx range. I opened the Bionx battery case and soldered black and red 12 AWG wires to the two heavy blk. and red. wires coming out of its battery pack. Led the wires out of a hole drilled in the side of the case via a spst toggle switch and 0-10 Amp DC ampmeter (both shoe-glued at a 45 degree angle to the top rear of the case,) and a 30 amp fuse, to the LiFePo4 battery pack sitting in a Sears canvas tool case strapped to a rear luggage rack. The switch was necessary to simultaneously, yet separately, charge the 2 battery packs with the two different chargers.
Since the Li-Mn battery pack has a lower internal resistance than the LiFePo4 battery pack it discharges slightly before the latter. I live in the Mohawk River Valley in Utica, N.Y.where are roads are mostly rolling hills. With the present set-up I get, at assist levels 3-4, approximately 80 miles range and 4-4.5 hours of riding time at an average speed of 20 mph. Using assist level 1, w/o using regen. mode except for braking at stop signs, I could theoretically ride 120 miles at 15 mph for 8 hours. I'm 70 years old, at 133 lbs.
Catrike is 30 lbs., batteries 30 lbs. and motor 8 lbs for total weight of 68 lbs. The ammeter indicates a max. draw of 10-15(approx.) amps on a steep 12% incline 3 miles long at max speed of 6 mph. On a steep decline bike, owing to the hysteresis effect of the motor, with fairing, reaches only 39 mph. While I can beat the bike Club's A riders up that hill by 1/2 a mile, they overtake me on a long down hill going 45 mph. However I usually catch up with them and beat them at the end of a typical 40 mile ride. My average speed on the same course riding a Titanflex Tri-bike averages only 16 mph.
One slightly annoying problem with my bionx system is that about every 3rd ride, after about 1.5 hours of riding the counsel freezes up and none of the control buttons work. I then have to disconnect the 6-pin plug at the console for 1 second and reconnect it to be able to start off again. Bionx wanted me to ship everything back to them but the hassle wasn't worth it. With the 2 battery packs in parallel all of the functions of the counsel work even when the original L-iMn battery is discharged.
I purchased the LiFePo4 duct taped pack, with BMS and charger from Lau Chan (chan71 [at] in China by winning an EBAY bid at about $340. Received it about 6 weeks later. Bionx is now 2 years old w/about 1300 miles.

p.s. I purchased the Catrike 3 wheeled recumbent as an aid to recovery after being side-swiped and run over by 2 cars at age 68. Was 2 months in hospital w/a compound fracture of a humorous, ruptured diaphragm, broken collar bone, pneumothorax, crushed ulna, radial and medial nerves, 6 broken ribs, 2 crushed vertebrae, and severed quad muscle. Intubated 4-10 days, and tracheotomy followed by 2 months PT and OT and I was back riding even though right bicep and triceps are 90% nonfunctional. Nerve re-inervation from a traumatic brachial plexus injury is 1 mm/day. Surgeons gave me a 60% chance to live but I guess that 55 years of running marathons built up a few extra vessels in my heart.
Any questions? I'm at srg1941 [at] Good luck w/the mod if you use it!

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