An Adorable BionX 22.2V 6.6Ah Battery Teardown and 9Ah Rebuild

I thought I’d covered all the older BionX battery packs in my various previous posts, but I was wrong!  I recently found out that there’s an absolutely adorable little pack I’d never heard of before!  This is a 22.2V 6.6Ah BionX battery, which is notable for being under the 300Wh limit that makes shipping really irritating.  I’d never heard of it before, and the capacity is as cute as the pack (not even 150Wh), but it’s here for a rebuild - which requires pulling it apart first!

This is a companion discussion topic for the original entry at

(Comments from Blogger)

2017-10-08 by Darius

This canbus board, is that what bionX uses in all their packs? And you seem to imply it’s some sort of standard. I searched your blog for ‘canbus’ but didn’t find anything relevant.

2017-10-09 by Russell Graves

The very oldest BionX systems used I2C for communication, but that ran into issues with longer cable lengths (as you’d see on a tandem, or some of the tadpole trikes). They solved this by switching to Canbus, which is a longer distance serial protocol used in cars, though they don’t speak the same dialect (Canbus is a physical layer, what you want to push over it is up to you).

All their newer packs use Canbus, though I understand there may be several different revisions of it in use. In theory, any Canbus BionX setup can use any other Canbus pack.

2017-10-29 by Unknown

Hello, I’ve been thinking for awhile about building a 12v “house” battery out of ~150 18650 cells for my Prius, for the ability to later repurpose into an ebike battery. I’ve seen 4s BMSes for scary cheap on EBay, but was wondering if you would recommend something a bit better built. I’m looking for 60a of charging capability. I’m also trying to figure out how to boost the ~14v from the inverter to 16v.

Joel (I’ve had discussions with you from MM and I think you pointed me towards ADR too!)

2017-10-29 by Russell Graves

A 4S battery is going to be mostly useless for ebike purposes - you want 10S or higher for a modern system. The 48V and 52V packs are pretty standard now.

I’ve got a bunch of the cheap Chinese BMSs to evaluate, but haven’t gotten around to doing so yet - too many projects, too many things that have to happen before winter. I don’t know of a good BMS out there, to the point that I’m working on designing one myself. It’s a big project, though, so no promises on when it will show up, and it’s likely to be a 10S unit (though capable of working on fewer, I’m not sure if it would handle a 4S pack or not - I’d have to check the spec sheet on my frontend).

Why do you need 16V? I’m… a bit confused as to what, exactly, you’re trying to do. A standard 4S lithium pack won’t match an automotive 12V system, though a 4S LiFePO4 will match almost exactly (but not typically built from 18650s).

There’s a contact form in the right column - this would probably be easier over email. Ping me there and we can work out what you’re actually trying to accomplish, then go backwards from there.