BionX 48V 8.8Ah SL 350 HT XL Pack Teardown

I’m kind of a weird person.  I get really, really excited when I get new battery packs in to pull apart.

This is a companion discussion topic for the original entry at

(Comments from Blogger)

2016-12-10 by dude mcginty

How does BionX remotely brick a pack? There’s no communication coming into or leaving the pack…right? Also, if all the voltages were good, then what is the failure point? Thanks for another cool post!

2016-12-10 by Russell Graves

It’s not done over the air - it’s done at an authorized BionX dealer. The dealer plugs the pack into the computer, a BionX tech remotely queries the pack, and if they decide it’s going to be replaced, they issue commands that brick it, and tell the dealer to recycle it locally.

I don’t know why this particular pack is dead, though I know a number of the 48V packs have had problems with output transistors failing.

2016-12-11 by RonF

Physically what happens to a bricked pack? Is it just deeply discharged?

2016-12-11 by Russell Graves

As far as I can tell, the controller is disabled. That’s about it.

2016-12-12 by Anonymous

Have you explored getting a CANbus toggle and software that can connect to a Bionx system so you can view those controller parameters? I saw a link on Endles Sphere by a German poster.

2016-12-12 by Russell Graves

I do have the Canbus interface hardware - I just haven’t had time to get it all set up yet.

2016-12-12 by Anonymous

That is a most interesting insight into the Bionx world of 48V powerhouses! You are enlighten us Bionx enthusiasts about what goes on under the plastic covers. Bionx has done a pretty good job keeping our paws out of their systems to discourage battery rebuilds as you have been doing. It’s a wonder that they have not cemented the plastic battery housing halves together so you destroy it on disassembly. It’s also remarkable that this housing has not change significantly since 2003, except for the contents.

I have been commuting for more than 10 years with the assistance of Bionx and have sampled its many flavours. The very early batteries were of course (heavy) NiMh and I had one sent back to the factory for a rebuild. With the move to Lithium and the horror stories around exploding battery packs we are all now in a straight jacket. Bionx did not and could not “brick” the battery packsk in the early days. That was also when they still built their systems with the Philips I2C communications standard and before the BBI interface that is now part of the the Bosch automotive CAN bus standard. I remember being disappointed at the time when Bionx abandoned I2C in favour of CAN bus as Bionx decided to no longer support the older system and I had to fork out big bucks for a new kit. I think in retrospect it was the right move to adopt CANbus and I have been impressed with the latest 48V offerings and in particular the DV500 series.

Speaking as a user, I like that Bionx has put more of the battery charging regulation in the battery housing in that the charger is no longer this huge fan driven brick that is a pain to take along should one have range anxiety. Your teardown shows me that this arrangement results in a weight saving overall when you factor in the charger weight. I think more than that, integrating the charging electronics in the battery pack has allowed Bionx to capitalize on its advantage of powerful recouperation when in regen while going downhill. With the higher torque of the DV500 for example, recouperation can be quite significant, and perhaps without subjecting the lithium battery to unwelcome votages/currents. I have ridden my DV500 to the 3000 ft elevation on our local (Vancouver) mountain from almost sea level and discovered that the console was again showing full battery charge before I reached sea level again. With this advantage and having 555 Wh in the new battery pack my range anxiety is a thing of the past.

2016-12-12 by Anonymous

Getting back to your teardown! I also like that Bionx is now using more connectors rather than wiring. You were able to strip down the circuit board quite nicely! As you astutely pointed out, these battery packs with internal balancing of cells appear to be designed to accept a larger variety of battery chemistries. Given that Bionx is designing its battery packs to be disassembled more easily (?), would this suggest that they will be more willing to allow Syonyk Enterprises (or a dealer?) to rebuild their battery packs since shipping a case of individual cells does not incur the steep regulator expenses. I hope so! As you also uncovered, these battery packs are coming directly out of China rather than Germany. I’m sure Bionx has a healthy markup on the batteries but their expertise and advantage must be at the motor and controller side. Perhaps in the future battery packs will last much longer, be cheaper to buy and easier to rebuild as with computers of the past.

I have read that long term, Bosch is targeting their CANbus eDrive systems to have the capability to accept batteries from any supplier. Perhaps this is what is driving the decisions in the current Bionx battery designs. I have discovered that the current Bionx-CANbus systems allow a 48V battery to drive say a 24V system. This apparently will even work in reverse, (which I hope to fully test) where the 24V LiM battery operates a 48V DV500 system. Bionx is not particularly open about this as but Bosch has already captured a huge part of the ebike market in a very short time, Bionx has to go with the flow. Bosch must have learned from Bionx since Bionx adopted CANbus some 7 years ago for ebikes. As users we know that the battery cost and life affect our purchasing decisions and ownership costs. Perhaps going forward we will see more options available to us so “bricking” a battery intentionally will be a thing of the past?

Thanks Russell for your explorations and insights into the world of batteries and Bionx. Maybe someone will ship you an expired Bosch ebike battery to tear down?

2016-12-13 by wavelet

Hi Syonyk,
Impressive tear down, as always. it is annoying that companies boast of sustainability while doing business like this. Worst offender is Apple, IMO, who started the trend of consumer devices with non-easily-consumer replaceable batteries on phones and laptops. If it needs specialty screwdrivers, it will put off some consumers, so cause devices which are repairable to be trashed or recycled instead of reused, which is far more sustainable. I’d forbid the manufacture by law of devices like this except for very few exceptions.
Sorry about the rant. Anyway, about the trash can icon, have you really not seen trash bins like this?
That’s the most common residential sort here and in quite a few European countries – the pair of wheels is to allow them to be wheeled from their niche near the building to the road, along which the garbage compactor truck is slowly moving.
~~~ wavelet

2016-12-14 by Russell Graves

Apple isn’t as bad as BionX. You can get replacement parts easily, and the tools are an annoyance, at worst. Your local phone repair shop can replace the battery/screen/etc, and the other bits don’t fail terribly often without some sort of actual abuse.

As far as the garbage can, yes, I’m familiar. I just don’t think the icon has much in terms of resemblance.

2016-12-14 by Anonymous

I’m wondering if one will be able buy circuit boards for the battery system for the Bosch systems like one can for other automotive products. It seems to me that when you buy an ebike or ebike kit the life expectancy of the motor is much longer than the battery with the battery last maybe 5 years if cared for. Given the cost of replacement battery packs from OEM’s it would be good for the ebike business if people like Russel were given the opportunity to become certified to rebuild them. That would also help keep motors out of the recycle heap. Most times a used bike appears for sale, the deal falls apart because one has to factor in a new battery. As we see more ebikes on the market this could all improve. I certainly hope so.

2017-01-21 by Unknown

Hi Syonyk,
I have a similar Bionx battery pack, that has a cell balance issue:the BMS goes in error (blinking green) while charging, in the first 30 seconds. Measuring the voltages on the balancing connector I have the lowest at 2.6V and the highest at 4.2V. What would you recommend? Maybe a discharge/depleting of the pack would level out the cell voltages, and then I could try to recharge it? But in this case what is the lowest voltage I should discharge?

2017-01-22 by Russell Graves

I wouldn’t attempt to discharge the pack - you’ll drive those low cells deep into the damaged region (arguably, 2.6V is already well into that region). If you do anything, you should try to charge the low banks back up to 4.2V, then cycle it and see what the voltages are.

2017-01-28 by Unknown

Following your advice, I recharged the lower value banks to 3.5V (charged with 4V for about an hour), but looks like it’s still not enough as the highest bank is 4.2V. What is the maximum allowed voltage difference for cell balancing?

2017-01-28 by Russell Graves

I don’t know what the BionX controller will tolerate, but an hour probably wasn’t enough to charge that bank. Let it run longer, and try to get it up to 4.2V.

However, pay close attention to the temperature while charging - a bad cell in that parallel group could be responsible for the voltage drop, and dumping more energy into a bad cell is quite unwise.

There’s no valid reason for one bank to be that far off - something has to be wrong inside that bank that exceeds the balancing current’s ability to correct. I don’t have any real speculation beyond a bad cell, but if one bank in a pack I owned was at 2.5V when the rest of the pack was at 4.2V, I’d probably replace that whole bank. I’m normally unhappy if I see more than a few hundredths of a volt difference between banks, and the older BionX LiMN cells, with no balancing gear whatesoever, will reliably maintain a balance to within 0.01V.

2017-06-13 by Miguel

I have an old IC2 Bionx and the battery is still OKish. But after reading your post I’ve tried to find a solution for a ‘bricked’ pack by looking into some German forums (it seems Bionx is quite used/hacked there), but I couldn’t find any. I don’t speak German so I had to use a known translator in my search, which quite often gave incoherent results. But from the little I gathered and understood, there’s maybe a company in Germany that can (apparently) fix this, it’s called Liofit. Maybe I’m wrong. Cheers. PS: I know you’re aware of what ‘Crustulu’ (Endless sphere) did to get his CANbus system to work with a dead BMS. I wonder if his solution would work in bricked pack.

2017-06-13 by Russell Graves

I’m working on some options with regards to failed BMS boards, but nothing fully developed yet.

2017-11-25 by razzputin

Recently exchanged 48v, 11.6 BionX battery under warranty. Although OHM/BionX (OHM makes bikes with BionX systems) claims these “smart” batteries go into deep sleep mode when stored, and can be shelved for 18 months (check the charge every 6? months) my battery was behaving badly six months after purchase. I learned the battery purchased in Feb of 2017 was manufactured in 2015 July. Some experts suggest recently manufactured batteries are preferred. I had no idea where this 18 month old battery was stored or if it was stored with a full charge as recommended.

I could not find anyone to rebuild the “suitcase” battery (case with handle) that came with the 2013 OHM bike. Canbus. Some experts maintained BionX goes to extremes to prevent rebuilding. Your tear down reveals why my new battery has a hump/bump vs tear drop design that went back to BionX. I am referring to that portion of the battery assembly that sticks out. The hump design case is supposedly newer model.

OHM arranged the exchange with a BionX dealer. Dealer upgraded the bike firmware during the swap and told me they are sending the returned unit back to Bionx, which impressed me as strange since I was told the dealer was going to disable the old battery, giving me the impression it was going to be trashed. Is BionX interested in why I was experiencing decreased performance/longevity?

Equally perplexing is the charging suggestions for this new beastly battery, which impress me as contradictory. They suggest recharging after every use while also mentioning charging it after depleted 50 percent (or greater) is advisable. Hmmm. There are 8 bands to reveal remaining charge and each band can achieve 12 to 18 miles depending on power demands by rider. It is referred to as an 80 mile battery. I typically recharge with 3 bands remaining after 60 to 75 miles. My point? It is very difficult for the average rider to deplete this battery below 50 percent on a single ride. I will probably continue to charge after 3 to 4 rides, when the battery is below 50 percent, or should I adopt the charge-after-every-ride method.

Regarding the original suitcase battery that was set aside about 1 year ago. I’ve been hearing an eerie noise for the past few months and was unable to find the source. It sounded like a smoke detector battery running low but that was not the problem. Turns out the original suitcase battery, which had been boxed up to ship to some battery rebuilding service, who offered to buy it but never followed through, was making the noise !! The battery was emitting low charge signal approximately 1 year after it was boxed up for a shipment to rebuilder that never happened. I should toss the old battery and charger but hoarding habits prevent me, despite the fact I swore to smash the annoying noise making device with a sledge hammer when it was discovered. Never imagined that geriatric, 35v? battery maintained enough juice to produce noise one year after it was set aside. It would squeal once or twice every 24 hours. Just enough to be a haunting annoyance but not enough to track down the source.

2017-11-26 by Russell Graves

Your battery charging method is fine, and probably will lead to longer pack life than charging after every ride. Lithium is most stressed when fully charged and fully empty.

I have lost an Annoy-a-tron in my dryer before and taken many hours to find it…

2017-11-29 by razzputin

Thanks for confirming battery charge procedure. This $1,200 battery was the same amount paid for 1968 Chevy Malibu (exc condition with 60,000 miles) in 1972. Absolutely bizarre.

One battery expert was surprised I only charged the battery that was replaced 30 times in approx 6 months, implying it should be charged more frequently. Others suggested either method is OK: after every ride OR below 50 percent, but instinct told me too frequent charging is detrimental.

The dealer who swapped the battery did a firmware? update that changed the function of dashboard controls (not appreciated) and could be responsible for another quirk. The battery case is now super-sensitive and activates the automatic voltage light ring around the charging port, aka touchport, too frequently. This battery has GREEN, ORANGE and RED light ring to provide voltage status. GREEN = 75% and higher I believe. The 48v battery that was replaced correctly activated only when finger was placed inside the receptacle indentation. The new battery activates if the top of case is touched 6 inches from the charging receptacle. I recall reading this feature should not be over-used; more than two or three times in 60 seconds. WHY ON EARTH would they make this feature as adjustable, and why would default setting be high sensitivity. It isn’t a major concern since the battery is covered. It was also mounted upside down, with 3 corners of the case contacting the bike frame benefiting from foam mounts to minimize shock and vibration.

RESPONSE FROM COMPANY…As for the touchport, the sensitivity is adjustable through a dealer meaning you can make it less sensitive or more sensitive. Right now it might be fairly high, it requires you to bring the bike to a dealer though.

2017-11-29 by Russell Graves

You can find my thoughts on BionX’s business practices and actual sustainability elsewhere on this blog.

I’m not particularly familiar with the 48V packs, though. They’re still for sale, and I try to avoid stepping on BionX’s toes. They have to know I’m out here doing this stuff if they have any interest, and they haven’t contacted me to tell me to knock it off. I figure that by staying out of the way of their current pack sales, I’m not directly competing with their systems.

And, sadly, on the 48V packs, most of the failures I know of aren’t actually cell failures. I’ve got a few 48V BMS boards with fried output transistors and the like.

2017-11-30 by razzputin

I’ve covered the entire blog several times. Although it is beyond the scope of my technical prowess there are tidbits which can provide a novice useful insight, such as the complexities involved regarding BMS and the issue regarding transistors. If this battery behaves badly I may benefit from the insight.

This BionX system came installed on an OHM bike. Both companies located in Canada. They generally receive favorable reviews. In 2015 June I happened to search C-List and found a desperate dealer intent on liquidating OHM and BionX stock. He had 2013 OHM Urban XU700 with 36v, 9.6AH battery with handle known as suitcase battery. 350 watt motor. $3,500 MSRP with 37 miles. He let it go for $700 cash and told me a new battery would cost about 500. I got one year of use (800 miles) before the original battery was fading. Several top notch battery rebuilders told me they could not refurb it. It undoubtedly has the same guts as the 36/9.6 teardrop design you dissected. You can have the battery and charger. I only need a shipping label if you have Fed Ex or UPS account.

2017-11-30 by razzputin

There could be a demand for rebuilt suitcase battery. eBay battery rebuilder in Ohio has sold one.

You can include the charger. The Sport XS700 is virtually identical to XU700 Urban.

— Rebuild-service-for-OHM-Sport-XS700-and-XS750-Battery. $475-----

OHM CEO told me “50 percent of older bike owners upgrade to more potent battery”. A costly outlay for battery, charger and mount. $100 installation for those lacking necessary skills.

2017-11-30 by Russell Graves

Are you interested in a replacement battery for it? I know at least some of the Ohm systems use the same brick, and people have successfully installed my brick in Ohm systems.

2017-11-30 by razzputin

No need for a rebuilt suitcase battery after installing 48v, 11.6AH. Your offer would have had greater appeal before ordering new battery in Jan 2017. Do you concur with those who have a suggest getting a newly manufactured battery (ideally less than four to 5 months old) while implying lithium batteries begin to decline from day of manufacture.

2018-03-29 by RonF

I’m just reading old BionX stuff now that they are in reorganization and users are stuck with what they have.

Is there a way to separate the battery from the Canbus controller? To make it a supplier of volts/amps to use on other motors and systems?

I have a 48 volt battery. Yet, the charger is a 26 volt charger. How do they do that? DC to DC converter? I’m really old, and from the early 1970s, the DC to DC converters we built back then were made from ferrite ceramic cores to handle the amp range power. Now?

2018-04-21 by Unknown

Hi Russel,
I have a HT 250 XL Pack here that has lost current over the winter. The BMS wouldn’t charge it therefore I’m looking into recharging it through the BMS Connectors to make sure no single pack gets overcharged. The wiring to the pack seems to be slightly different and also the board is the SMC6.2B instead of SMC6.3B.
Would you have specs for the 6.2B BMS connector pins to make sure i charge the right port?

2018-04-28 by Russell Graves

No, sorry. I don’t have any technical details on BionX packs beyond what I’ve posted on my blog.

2018-05-21 by Unknown

Great post! Especially for me when I have problems with the exactly the same battery. I had a hard time opening it and reading about the adhesive helped a lot. Thanks!

Now to my problem. Last week my battery just died on me from being at good health. I connected to the charger after a long ride as I normally do and the day after it was blinking red. I then reinserted the charger the led just flashed and nothing more. Since it is 3.5 years old (no warranty) I decided to open it up and measure the cells, they were scary low (24V) and I charged them back to 42V with 100mA, hopefully saving them. What I also found was that a mosfet (Q307) on the BMS (SMC6.3B) had burnt. Further investigation I also found Q104 and D102 burnt.

Fixing the board is probably hard/impossible without schematics and stuff so I was wondering if you have any idea were to buy a replacement board or dead battery back from were I can take a board?

2018-05-22 by Russell Graves

I wish I had better news. You’ve suffered the standard 48V failure, where the BMS dies, and takes the pack with it. Since there are no schematics, and BionX doesn’t sell replacement boards, you’re sort of up a creek. Any “bad pack” you can find of the 48V variety almost certainly has a bad BMS board (I’ve got half a dozen of them in my storage unit for research purposes), and BionX isn’t currently in business, so I’d buy a replacement pack quickly, if you can still find one.

Good luck.

This is the sort of reason I rail against proprietary systems so much on my blog…

2018-06-14 by Unknown

Continuing this story I have almost repaired my SMC6.3B BM but still no cigar… Further investigation I found out that the 5V supply had died and was currently 12V, ooops. The 5V is generated with a TPS62110 DC/DC (U103). I managed to replace this using hot-air reflow station, it was really hard because of the thick copper. I also replaced the mosfet Q307 (IRF6668) and Q104 (guessed PNP transistor) and D102 (guessed schottky). After doing this my system is working again except for the charging part… So I did further checking and found that Q309 mosfet also was burnt (lower part of the H-bridge). Together with that the two 4.7ohm resistors connecting the mosfets to the IR2011S driver. And finally I think I found the failing part, the IR2011S driving Q307 & Q309. I have just ordered a new one so next week when I can test it will be exciting!

2018-06-15 by Russell Graves

When they fail, they fail… wow. That’s an awful lot of blown parts.

2018-06-21 by Unknown

Exchanged the IR2011S and it is charging again! This must be what failed causing the H-bridge to short. Don’t know why the 5V failed though. Anyway it now seams to be working however I have some suspicion something more is broke, time will tell. Also while charging it gets pretty hot. Around 75 deg Celsius around the big inductor. Wonder if this is normal…?

2018-07-06 by RonF

I just had to read about your teardown of the 48 volt battery again. I have one that is the same specs as the article except that it is a rack-mount which simplfies construction a bit. I bought this battery as part of a system in October of 2014 and I had good service for three years and over 10,000 miles. Last Fall I noticed that the range was decreasing. And this year the system on the trike was acting funny. Sometimes I had support, I ride pedal assist, and other times no support. It seemed like I had to spin the pedals very fast with a moderate effort to get any assist. Another problem I had was that the system would momentarily shut off (and back on) a few times at the beginning of the ride. I noticed it because there was no assist and I had to start assist again. The daily distance would go back to zero.

I spent time checking all the connections using contact cleaner and silicon grease trying to make them good.

Then the other day I did an experiment. I was on my way back home so decided to use the throttle. Well, the power came on and shut off. On and off, up to almost 20 mph and then coasting below 10 mph before the power came on again. Jiggled wires from the throttle to the control, G2 control console, to no effect.

I have a wimpy 36 volt BionX battery, from a PL 350 HT RR M, 37 V / 6.4 Ah / 237 Wh, and I put it on the trike today. The system was fine, worked like almost new. I ran on the throttle only around a few blocks in the neighborhood. I had to put a charge back into that battery, because I hadn’t used it for a while.

Could the behavior of the 48 volt pack be explained by having the PTCs making and breaking the circuits on the remaining good strings of cells? The cells that are now trying to pump out 350 watts?

2018-07-07 by Russell Graves

I doubt the PTCs are involved. It’s probably, like almost all 48V pack failures, a BMS board on the way out.

2018-12-12 by Unknown

Hi there,

i have a weird problem with my S350DL. Its circa mid-2016 bought brand new on my hybrid bike. 48V 6.6Ah version with 600+ recharge cycles on it.

At this point the motor cuts out when i get a bit of load on teh system e.g. minor hill, seems worse when carry more stuff in my pannier. I am on assist level 2 or 3, getting up to speed and the motor/assist will cut out, with speed going down to 0 km/h but power remaining on the console. I can adjust assist levels but cannot never get the assist to kick back in. I have ot power off the unit and power back on. When on flats on a more difficult gear, generally does not cut out. When using Throttle only , it can cut out more than not.

The store tried a different battery and seemingly the problem goes awaybut they have not put it through my exact ride scenario. I have checked all cables, connections, cleaned them all, etc. What do you think?

2018-12-13 by Russell Graves

It’s a 48V BionX system. Replace it with something you can work on and reason about.

2019-06-16 by occasional Bionx rider

Thanks for the notes which enable to dismantle a 48V, 11.8 AH Bionx battery.
For the balance connector:

pin1, black, GND, 0 V
pin2, brown, 4 V
pin3, pur/wht, thermister?
pin4, orange, 8 V
pin5, yellow, 12 V
pin6, green, 16 V
pin7, blue, 20 V
pin8, purple, 24 V
pin9, grey, 28 V
pin10, white, 32 V,
pin11, grey/wht, 36 V
pin12, RED/wht, 40V
pin13, Blue/wht, 44 V
pin14, red, 48 V

I’ve also found the case was super-glued in a few places so had to cut opened
I disconnected the PCB and use a regulated power supply to recharge the battery up to 50V before the light would turn amber and accept the normal charger. The PCB may be faulty or needing calibration?

Hello everybody! I need help with parameters of missing part - see my photo. Maybe scheme of this board.

Nobody has a schematic I’m aware of.

However, if you look at - it’s the same size as the rest of the capacitors on the board (the orange-yellow things). See if you can read any markings from those and get a replacement. Unfortunately, the conformal coating makes that almost impossible in a lot of cases, if the stuff is labeled in the first place.

It’s unlikely to be terribly critical at that size, you could likely just find something close.