Bionx conversion of scorpion recumbent trike battery Kaput?

[jonnie_m]

Hi
I've just bought a trek ride plus and a scorpion recumbent trike (both from ebay) so that I can blend the two and make an assisted trike for my daughter. The trek ride plus is great in that it has a 350W motor, but when I ride it with full assist the battery indicator goes from full to empty in the first 5 minutes or so. Only recharging the battery restores the battery indicator. The battery looks like an R320 which as I understand it should be 48v, 6.6Ah, 320Wh and should contain 39 Li-Mn cells, mine showed 42.8V when empty the other day (after a shortish ride) and shows 45.5V, both on the bionx diagnostics tab, when fully charged. I've tried charging it, letting it rest and charging it again, but it only gets to 45.5V on the screen. Does anyone know whether this means my battery is knackered and if so could I replace the cells? I've had a look inside the battery casing and there are no glaring faults on the pcb. Thanks in advance for any help you might be able to contribute, cheers. jonnie

 

[Deleted member 4366]

You have to check the voltage of each of the 13 groups of 3 to show what's wrong. There should be a multi-pin connector to the PCB where you can measure them. If you're unsure, take some photos and post them here.

 

[jonnie_m]

wow, thanks for the quick reply - it'll be next week before I get to take it apart again. Thanks for the pointer.

 

[jonnie_m]

Hi again
just pulled the battery casing apart - there are 3 wires come out of the battery pack red, black & yellow which are soldered into the smart connect 5.2 pcb. The battery pack itself has a BMZ (the battery experts) sticker on it stating Nominal/charge voltage: 39.6V/46.2V, Energy/Capacity: 253.4Wh/6.4Ah. It looks to be made up of 44 18650 cells so must be 4 parallel blocks of 11 in series. I suppose that means my voltage looks ok and maybe it's an electronics issue causing the voltage indicator to drop from full to empty?
cheers
jonnie

 

[Deleted member 4366]

Those numbers don't quite compute. 39 lithium cells 13S3P would make 48v. Your maximum voltage of 45.5v is too low for that. It's about right for 11S4P, but that would make it a 39.6v battery. Can you check the cell count again and make sure there's no dummy ones in there. I wonder if somebody recelled it with the wrong pack or replaced a 46.2v battery with a 39.6v one, so that your system is using the wrong low voltage cut-off?

 

[jonnie_m]

I'm pretty sure it is a 44 cell battery - the voltage seems consistent with a charged 11S4P (I've learned a new designation today) and with that shown on the sticker. When the battery is charged and fitted to the bike (at 45.5V) the battery level gauge does show full, it's just that it seems to go straight to empty at some point. I need to do a little more riding - so far I've been trying it at full assistance most of the time ( which is where I think my daughter might need it initially) . I wonder if for some reason I'm causing too large a current draw leading to the controller switching into a safe mode? The bike is fitted with the 350W motor and the owner before me has changed some of the control parameters with a german aftermarket programming device. You'll notice that I'm still learning about the system at the moment - I'm in the process of dismantling a spare motor to study the pcb. Thanks for your continuing input - much appreciated - have you much experience of the bionx system?
cheers
jonnie

 

[Deleted member 4366]

The only experience that I have is second hand from reading about them. There's lots of stuff on Endless-sphere about them and the secret codes. There's also threads on how to convert the motor to use an external controller with any battery you want and other good stuff like that.