will the scooter run without BMS?

Pudding 7 months ago updated 7 months ago 8

Hi everyone, I am a newbe here. Nice to meet you all. I got myself a second hand vx-1 as good as new (<500km!) and want to start using it as a commute for my new job. It has a dead battery's of course so I am slowly starting to learn about this machine. There is so much info on the web that I don't know where to start.... For now I would like to know if the scooter will  run without the bms being connected. Charging will be a problem of course but just as an idea, a step by step understanding of the machine, does the engine control needs to have "a green flag" from the bms? I will have a lot more to ask (and to read) but for this saturday afternoon this will do... :-) I hope to contribute as well to this forum later on. Thank you, greetings from Haarlem NL

Hi, yes the various firmwares allow the bike to run in case the BMS is broken (or missing if that's the case). It is an emergency mode. On the other hand as you pointed out it makes little sense as charging will be fairly problematic.

Thank you Azzuro, that means I can start thinking about a battery system&charger from other vendors. I do have the original 2012 battery packs (lifepo?) they were still build in. But getting replacement cells the right size is hard...(and expensive) Will it mean that I have to change the firmware before I can drive? in the couple of weeks coming I want to "feed" the bike 130 volt and see what happens, if I can spin the rear wheel I will know that bike is ok for the rest...

If your new battery will be some sort of LFP as well with 40 cells in series then you can keep the current BMS and firmware. In case you prefer Li-ion instead which typically means 36S then it will require much more tweaking. Same applies to non-Vectrix chargers, that is only recommended for experts. All options will be expensive, depending on your requirements. The good news is the components of the VX-1s are very reliable apart from the old batteries (80% of the problems) and sometimes the chargers give up (10%).

will the much more tweaking be concerning the battery systems or the motor controller? for me, a new (or used) li-ion systems is easier to build then tweaking the current charger... So can I see the motor controller and the battery+charger as two separate systems?

The challenge is the CAN, all the components namely the MC, the charger and the BMS must speak the same language (the ICM and the display are less relevant). If you want to go with a 36S system you'd need to replace the firmware accordingly. Keep in mind the Vectrix charger is much more than just a charger, it is also providing auxilary 12V and keeps track of the SoC allowing range estimation, interprets the cell voltage data from the BMS when the bike is running etc.

In summary the "tweaking" would be addressing the complexity of the MC, charger and BMS to work together. On top of this the firmware changes require a special dongle and software (we can share it) as well. 

Wow. Ok. Thanks for all this useful info. Sounds like I have to think over if I can do this myself or should I hire someone to do that for me...or stick to the 40s lifepo system that it has now.. choices choices :-) 

Hello, Are you sure batteries are dead?

I got the same as you. NimH 500KM, rested 1é years in a car park. Charger dead but, I slowly reload the pack (less than 1A) from Zero to 133V. Could not test in real (no insurrance) but it moved forward and backward for a few meters.

no I am pretty sure that most of the cells are dead. I managed to charge e few of them and they keep their load, a little voltage drop but not too bad. I keep them for testing purposes, how else can I get 133 volt to test the can bus... :-) But a least 25 or so become hot when charging and the voltage drops within a few minutes to almost zero....so those are dead for sure...