Bionx - attempting 48v rebuild

[g1nko]

I know there's lots of advice on here saying you can't rebuild a 48v canbus Bionx battery, but hey, what's the deep end of the pool for if not jumping in foolhardily. My battery wasn't holding a charge anyway (from full charge to discharged in about 3 miles), so I figured "What do I have to lose?"

I took the battery out of the case. This was surprisingly easy. Two screws held the case together. There was some hot glue on one side of the battery and on top, but most of that had released from the case anyway, and gentle pressure with a small pry bar made quick work of the rest.

I'm posting these pics since I figure this attempt to rebuild might be of general interest since I've only found info on the 36v systems. It's a 13s4p pack arranged in 3 tiers of 17 cells with an extra tacked on the side. There are 20 leads to the BMS. I need to figure out how the 13s packs wire together in series; I'm going with the white wires, but I have to figure out the specifics before going much farther.

The 3 tiers have a semi-rigid plastic separator between them. I'm not sure if this is functional or just to help hold things together. I wouldn't have suspected it to be functional, but it's coated with what looks like conductive lithium grease. Anybody have any ideas on this?

 

[Manny]

good luck with the rebuild.

I am wondering what are those yellow things in the black heat shrink on the J4 connector.

 

[amberwolf]

Probably PTC or self-resetting "fuses" so that if something goes wrong on the BMS or balance wires, a short between cells / etc won't happen.

 

[madin88]

Many asking me if i could take a look at theire faulty Bionx 48v battery, but only two out of about 20 !!! i was able to repair. The reason was the electronic board was faulty (on a few i had in hands even the battery cells had been in good condition).
Most of them had board rev 6.2b or something like this, so there is a good chance that yours is OK.
However, before you invest hours in building a new battery, you should really make sure that there is no problem with the electronic.

check following:
does it charge to 100% or 4,2V per cell? It could stop chargig for instance at 50V without any reason..
does the display show accurate s.o.c.? like 100% if the cells are at 4,2V, and empty if the cells are really empty

good luck^^

 

[circuit]

Hi madin,

How many BionX batteries do you get for repairs? There might be a solution for this...
We should be able to modify our BMS to work with BionX I2C / CAN, and completely replace the board.
Here is the BMS: https://www.energusps.com/shop/product/tiny-bms-s516-30a-16

 

[Syonyk]

Posting to follow.

I've torn apart a 48V downtube pack, will be publishing my post on it this next weekend. Haven't tried to rebuild it yet, as the 48V packs are still in production and my current spot welder won't deal with the goofy layout on the downtube packs.

The BionX packs definitely have a weak BMS on some of the pack generations.

 

[Joachim]

The 48v bionx rebuild can wurk out ok....the bms/pcb must be 100% ok!

i rebuild 4 48v bionx packs and one fail(discharge not lower as 48V) the other 3 wurks perfect,only the indication-battery state is not correct so after 25km in the boost setting it shows empty.The system doenst shut down and give 45km assist in the boost setting.

11s packs are easy and rebuild 20x 100% succes.

The brand Trek bikes already go to bosch system/yamaha/impulse like most big bike brands like koga-gazelle-sparta-batavus.

The bionx-gazelle innergy pcb boards are al crap! i have almost every day people in the shop whit problems...mostly the pcb.

last weak i read out a gazelle innergy(48mnd old) with proper bms from BMZ :lol: 1 cel was verry bad and takes only 2.9V-ful charge(already to low) the
missing voltage on the 42v 10s pack was just pumpt in the next cell charged to 4.9V :lol: they use always good green sony cells....just a waste i think if you put a pcb that doesnt wurk propper and just kil the battery pack

 

[madin88]

11s packs are easy and rebuild 20x 100% succes.

typo?
you must mean the 36V 10s packs which come with no real BMS

they use always good green sony cells....just a waste i think if you put a pcb that doesnt wurk propper and just kil the battery pack

the 36V packs came with Sony V2 Cells (1600mAh i think), but i believe they decided to use those due to the fact the BMS has no single cell voltage monitoring and Sony cells are known to stay balanced very well.
most of the 48V packs i've seen had Samsung cells (don't remember the type, but they had purple color).

 

[Syonyk]

you must mean the 36V 10s packs which come with no real BMS

BionX has used both 10S and 11S packs - the Trek Ride+ has a 4P11S pack, the normal downtube 36V batteries are 10S6P or 6P10S, I've seen a 3P11S pack...

the 36V packs came with Sony V2 Cells (1600mAh i think), but i believe they decided to use those due to the fact the BMS has no single cell voltage monitoring and Sony cells are known to stay balanced very well.
most of the 48V packs i've seen had Samsung cells (don't remember the type, but they had purple color).

Yup. US18650Vs, 1600mAh. They stay very, very well balanced. I recently did some analysis on the "not totally dead" ones I've seen, and they're within 0.01V after years of use and hundreds of cycles.

https://syonyk.blogspot.com/2016/12/a-tale-of-3-bionx-packs-self-balancing.html

 

[Joachim]

i never wurk on a 36v bionx pack.