Rebuilding a BionX 36v 9.6AH Battery Pack - upgraded to 13.5AH

A month or so ago, I posted a teardown of a BionX 36v 9.6AH battery pack.  Some of you may have guessed that I was going to rebuilt it!  You were right!

This is a companion discussion topic for the original entry at

(Comments from Blogger)

2015-10-11 by kmpres2015

Thanks, man, this is just what I was looking for. I will soon do the same to my BionX 36V rear mount pack but will use the new LG HG2 3000 mahr cells instead. I hope to nearly double the range I had before which was never what the company advertised (20 miles). Two years ago, when my pack was new, it once got 16 miles, and that only because I stuck to torque assist mode and kept my thumb off the throttle button. I’m now lucky to get more than 6 miles in the hilly neighborhood where I live with much less hill-climbing ability and acceleration than I once had. It’s odd that BionX doesn’t use a BMS so I think I will add sense wires and some kind of connector so I can use a true balance charger. That way I can monitor the condition of the six parallel modules and get a better idea of the pack’s overall condition.

2015-10-11 by Russell Graves

It’s not that odd that the pack doesn’t use a BMS - the LiMn chemistry used is slightly self balancing, as the charge efficiency drops at higher state of charge. So, set up in the strings like this with high quality new cells, it actually does a decent job of staying balanced. If you go to a different chemistry as you’re planning, you lose this capability, and you’ll have to install your own BMS. I’m not sure where you’d put it, TBH - this pack is surprisingly tight on the inside, and you’d have to wire it up differently to make good use of a BMS. If you go with the newer US18650V3 cells, you get about a 40% gain in range without having to completely re-engineer the pack.

If you are going with LiCo cells, build a more standard pack arrangement with the parallel groups first, then put those in series. That’s easier to deal with for your BMS (and you’ll have to wire the charge connector to go through the BMS). I’m not entirely convinced it’s worth the effort, but it’s your project!

2015-11-17 by Unknown

I have 2 Trek Ride+ electric bikes which use the Bionx components. Both batteries for these bikes are dead, i.e. they will not hold a charge. I would like to have these 2 batteries rebuilt with new,similar but higher capacity cells. I bike in Florida which is very flat, but I want to use the ebikes as an equalizer so that friends of different skill or fitness levels can ride together. The 2 batteries which I have are the same part number, 01-2090, and are LiMn 40.7V/6.4Ah/260Wh. These batteries slide into a rear bike rack. Can you please rebuild these for me?

2015-12-30 by Unknown

HI Russell! Great post. My Bionix 36v has only 40 cells. It is only 6.5AH.
Made in 2013. Down to 6 volts and won’t hold a charge. Several people have said for some reason the newer CAN BUS Bionix Batteries can not be rebuilt.Yet it is the same positive negative 36-40 volt set… Like to get your input. BIONIX Dealers want $1200 to get a new battery unit. Yet I can source 40 lithium Ion 4.5 v cells for under $200!
Will it restore the system? -Dirk in Vancouver BC

2017-01-29 by Guru

I have an old 24V Bionx system. The battery is half dead! I added 2 lawn mower batteries (6DZM-20)
to provide additional power. it lasts more than 2 hours* at full throttle (30~32Km/h)going up hills etc
very cheap, but heavy!
* hours is my limit, not the bike!
I buy my batteries at a recycling place, about 6$ ea

2017-01-31 by Guru

To Dirk
Will it restore the system?
Only God can answer that question
All the batteries that are said to “contain a chip” are actually a complete computer!
That computer (the battery management system, or charge controller) continually draws current from the battery
This is the root cause why batteries in storage MUST be recharged once in a while
My recommendation, at least twice during the winter, once a month when the battery is older
It is also important to not overcharge the batteries (they don’t like that) Again, charge at least 6 hours, but not more than about 20 hours.
For in-depth understanding how batteries work, I recommend that you visit Battery University
Unfortunately, in my shop, what I often see is poorly designed chargers that cook batteries!
Also there are some that some component failed and the outcome was to deep fry the battery pack

2017-06-27 by Unknown

Hello - My 2010 36V LiMn battery measures 40v on the meter. When mounted on the system, it won’t turn on, however, if you hold the power button down the display shows information and chirps. I opened the battery pack up and sprayed contact cleaner on the circuit board and wire connections. But no luck. The Bionx dealer mounted a 48V battery on the system and it turned on normal. Anyone else experience anything like this or diagnose whether it’s the batteries or circuit board? Thanks

2017-06-27 by Russell Graves

That’s probably the battery management board, then. There are no replacements available for them, and they’re generally not easy to repair. Sorry. You might just buy a 48V battery for your system.

2017-11-22 by Maverick

Hi Russel,
I have a 48 V DX 350 with 260 cycles left. The range is ok (1/2 or 1/3 of new) but it still works

I know you mentioned that you were experimenting with 48 V cells. Have you rebuilt one?


2017-11-22 by Russell Graves

I haven’t. They’re a much more complex pack to rebuild, and they’re still sold, so I haven’t felt the need. Try running your pack until it actually turns off (and then recharge it) - BionX has a capacity loss calibration algorithm that is excessively pessimistic.

2017-11-27 by Jim

Do you know any thing about the bionx 37v battery it

2018-06-26 by Mark

Yep, I one of those who forgot to keep the battery charged over winter…Dead.
It’s a canbus rear rack mounted 37v/6.4 Ah 236.8 Wh (max charge voltage is 42v).
I think it’s maybe 4 years old??

Have you done of these? The replacement from Bionx (in liquidation/bankruptcy? now) is a 45V system that is backwards compatible with my 36v system (Bionx website says) only if I get their new charger. Looking a close to $2grand, ouch! My is easy to access, just some nuts and bolts.

The new 45v battery from Bionx uses a charging management system, while mine is the old self balancing type. So I’m thinking either an upgrade using my unit would be nice, but I assume it still has to be self balancing batteries to work?. Not so sure if a 45v upgrade from 36v would work as Bionx’s did? (they may have some software that allows the recognition). Bionx really loves their little snitching software to make it hard just replace the batteries.

Well, I’d appreciate your suggestion on the batteries I could use to upgrade from what I have now.

2018-08-24 by Unknown

Russell: Do you rebuild Stromer batteries?

2018-08-24 by Russell Graves

No. I have one to tear apart at some point but I don’t rebuild them as of yet, and since they’re still being produced, it’s less likely that I’ll bother.

2018-09-06 by Unknown

@ Russell : I have the same BionX 36v 9.6AH Battery Pack.
Is it possible to make this assembly (10S6P) with Panasonic NCR18650B 3350mAh, to get a pack of 20.1 Ah?

2018-09-06 by Russell Graves

You could, but you’d need some sort of external balancing BMS to even things out - the Panasonic cells don’t have the same self balancing behavior as the Sony cells.

2018-09-16 by Unknown

Re: bionx ic2,36v,350w,(9.2)10a
I can’t get to 1st base on a battery. I have knowledge on battery design. Would like to have 20 miles range(flat terrain). Has anyone have a blueprint either lead acid vs lion? Willing to pay something for this. Regards…crankshaft louie

2019-03-17 by Unknown

Do you know where i can find the BSM/PBC card for BionX batterys; I searched evrywhere, the compagnie made a banckrupt and it seams nobody can find it ? My battery is a 24 volt, but I think it’s the same card then the 36 Volt.