Grin Baserunner z9- No power to wheel and indicating error code 2,8 - What should I be looking for

[spectro7]

After running reliably for a good 5 years, my Covid-era project, a Grin based mountain bike setup (CA-3 & Baserunner_Z9 with a cheap 26" Voilamart hub/wheel) has stopped working while actually riding. I didnt change anything in terems of the CA or settings before hand. Specifically, on power up, everything appears normal, but when applying throttle or pedal power there is a tiny jolt of power and then nothing - the system is unresponsive and provides no power to the hub. Power cycling yields the same outcome. The Baserunner led is flashing error code (2,8) and it appears that that code means 'Instantaneous controller under voltage'. This is confirmed in the Baserunner application. I have done some preliminary checks/cleaning of plugs and connections to try and eliminate bad connections at least and hope to check the hall sensors and controller mosfets as per the GRIN guides tomorrow. With that said, I am not sure what to look for or what that specific error message means. I'm hoping someone may have experienced this error and/or offer a suggestion as to what I may be looking at. Thanks for any help!

 

[slaphappygamer]

How many volts are registered when powering up the bike? Compare that to the voltage when you apply throttle. Is there significant voltage sag?

Seems like a battery issue, given the error code.

The BaseRunner is fully potted and you can’t access anything inside.

 

[spectro7]

Thanks for your suggestion.

The battery voltage is 50.4 and there is no noticeable drop (at least on CA Display which might not be fast enough to register the change). The battery is as old as the bike, so yes, when I was drawing high currents/accelleration when the bike operated normally there was noticeable voltage sag but this problem never occurred.

Right now, the power use indicated is quite low before the problem occurs. Maybe a few watts. I will try with the baserunner app connected but must head off to take care of other things right now. Will follow up later...

 

[E-HP]

The battery voltage is 50.4 and there is no noticeable drop (at least on CA Display which might not be fast enough to register the change).

On the CA, one of the stat screens includes voltage sag. If the CA is staying on, you could check to see what’s going on with the input voltage.

 

[amberwolf]

The battery voltage is 50.4 and there is no noticeable drop (at least on CA Display which might not be fast enough to register the change).

Before you retest, press and hold the CA's right button until it resets the trip stats. Retest, then beofre doing anything else, press the right button several times (6 or 7, I think) until this screen comes up

What does the Vmin on this screen read?
If it shows a reading lower than whatever was set in the BR for LVC, then that's what is causing hte problem.

If it doesn't, then you might try connecting to the BR with the phaserunner setup suite, and read the info there. Any error codes should be listed from the last power cycle, IIRC. It may actually state the voltage it detected.

If the CA is powered from the BR rather than a direct connection to battery bus, then any vdrop in the BR should also be expereinced by the CA--otherwise, the CA may not see the drop the BR sees,.


You can also verify your power connection to the BR itself; if it has a high resistance connection for any reason, it could cause enough voltage drop at that point to cause such a problem, without the rest of the system seeing an issue.

 

[spectro7]

Damn! wrote almost the entire reply and then restarted thei lappy after updating the FTDI driver because while I could access the BR via USB FTDI cable it is not successfully connecting to the CA. Anyway...

Thank you for your assistance with this Amberwolf. Much appreciated. RE your queries:

After following the steps you outlined the Vmin is equal to the Battery voltage - currently 50.6 - not 50.4 as I indicated in previous post - that is much higher than the LVC in the Controller (29 V high).

The CA is powered via the BR and I have taken a screenshot of the Phaserunner App. Despite the lack of power issue Both the CA and BR do not appear to lose power at any point.

I have checked and cleaned the Battery and cradle terminals which couple the battery directly to the Baserunner. They look ok and are a snug fit. No obvious way of detecting any resistance in that path however.

Unfortunately as mentioned above I don't seem to be able to successfully connect the software to the CA, even though I'm using the same laptop and cable with upadated driver so any LVC parameters available through the setup utility are not obvious - perhaps there is a way to check in the CA in the but havent found that yet.

Edit: Further t the last point about finding the Low Voltage Cutoff on the CA UI directly I did finally locate it (MISC settings page) and it was set to 39V.

 

[lnanek]

FTDI drivers have always been super buggy. Back when I worked somewhere that had a product that needed them I always kept a spare laptop with an exact version of Windows and the drivers that I knew worked and where I'd messed around in the device manager long enough to get them functional. I'd then never update it and just brought it new firmware via USB stick.

Amusingly, sometimes even using a different USB port on the computer helped (since sometimes the USB controller chip is different for different ports). Other times connecting through an ancient USB2 hub to "downgrade" the ports helped.

 

[amberwolf]

Just to be clear: since the CA and BR cannot communicate, there is no association with the CA LVC and the BR LVC and any messages the BR provides, or any faults it indicates.

Checking the CA's Vmin is just a way to see what the lowest voltage detected during the incident might've been (since this doesn't seem to be logged by the BR).

It is still possible there is a voltage dip happening, but it is too fast for the CA to catch, even though the BR does catch it. The BR probably checks everything on every motor commutation cycle (very very often, to ensure no motor drive issues) while the CA only has to ccatch things at more or less a user-compatible rate, so it makes sense the BR could catch something the CA can't, if this is the case.

If you haven't yet, I'd still recommend verifying your power connections to the BR--not just looking at them, but at minimum disconnecting and reconnecting them, and if possible examining the contacts and the points the wires enter the back of them, etc.

 

[spectro7]

Thanks for your input Inanek - Aside from the possible failurre of the connection to the CA-3 via a 3pin minijack receptacle, you are probably right. Unfortuantely it is not at all easy to check the connections as the receptacle housing is molded. I did try a different usb port (and different Computer - both macs) and still had no luck. Still a bit strange that the Phaserunner suite works fine though. At some point I'll set up a pc I have currently packed away and see how I go with that.

Amberwolf: Point taken re CA and BR LVCs. I have disassembled the controller cradle/housing and removed the BR and checked the wiring. As far as i can tell with meter the connections are good. I have also done the controller mosfet test and they are all ok.

When I next get time I will check the internals of the battery re connector issues and do the hall tests and if that comes up ok the time will come to look further into the hub, quite literally!

As Im juggllng a few commitments over the coming days and beyond (and just pretty slow even when doing this stuff) it may take some time to get the above done - though its now notable how dependent i have become on this bike as a key to my 'urban workflow', so hopefully it wont take too long to get back up and running...

Thanks again for all the suggestions.

 

[amberwolf]

I have disassembled the controller cradle/housing and removed the BR and checked the wiring. As far as i can tell with meter the connections are good.

FWIW, a regular meter probably couldn't read the difference betgween a good connection and a bad one that still lets everything power on. They jsut don't read low enough resistance...and the probes only touch one tiny part of the connection--they dont' actually check the connection itself, unlss you are checking the resstiance wiht the connectors plugged into each other, via the wires that come out either side.

What seems like a low resistance to us, and the meter, etc., can still be high enough relative to the rest of teh current path to cause significant voltage drop across it under load. (for instance, a contact can read "zero" ohms on a regular meter but stil have so much resistance compared to waht it should have that it will heat up enough to melt the plastic housing it's in, and then betgin disconnectinfg, and arc between them, and start a fire....almost certainly not the kind of problem you have there, but it does happen)

 

[amberwolf]

Thanks for your input Inanek - Aside from the possible failurre of the connection to the CA-3 via a 3pin minijack receptacle, you are probably right. Unfortuantely it is not at all easy to check the connections as the receptacle housing is molded. I did try a different usb port (and different Computer - both macs) and still had no luck. Still a bit strange that the Phaserunner suite works fine though. At some point I'll set up a pc I have currently packed away and see how I go with that.

fwiw, the ca is almost certainly not causing any of the problem you have, so since the pr suite does work, tha'ts good because almost certainly any problem you have is somewhere within the motor/controller section--you could disconect the ca entirely and it'd probably still have the issue.

 

[spectro7]

Resurrecting this old thread - been a long time. Tried both a different wheel and finally, a new battery. Been a slow and inefficient process (and a few dollars in!) getting to this point, but I can now confidently confirm the problem lies somehwere within the Baserunner. I haven't bothered to try and open it - if that is possible at all? Will probably just have to replace it.