PAS mode working oddly-geared hub motor - CA3.1

I have an eZee cargo bike with a front geared hub motor. Awhile back, I replaced the led control box with a CA 3.1. I have been working with the setting and things keep getting better except for one thing. While the throttle works as expected, the PAS behaves oddly. When I up the PAS setting, and start pedalling, the motor kicks in and then stops a couple of seconds later, repeating the over and over again. While this is making my battery last longer, it is, I suspect, hard on the motor and annoying. I have no idea why this is happening.

if you can post up your settings (as screenshots of the setup program, for instance), it might help to narrow it down.


the most likely culprits, since it only happens with pas and not throttle, are the pas-specific sections regarding how long the ca waits for the next pas magnet signal, or how quickly it stops providing assist when not pedalling, etc. i don't recall the specific setting names atm.

it could also be the magnet ring is not quite close enough to the sensor, so taht the sensor is not picking up all the pulses, or not all of the time, so the ca doesn't always detect the spinning cranks. this can be eliminated by checking for the icon at the lower left that shows two lines, one going up while the other goes down, that represetn spinning cranks. if these appear to match your crank movements/speed, then this is unlikely to be the problem.


additinally, the throttle overrides the pas. so if you get a pulse on the throttle that would give a much lower throttle value than the pas is at taht moment, then that throttle pulse will appear to "cut power" until it goes away, then the pas will take over again. such a pulse can be a connection issue, like a ground floating a little bit, etc. these types of connection issues will be unlikely to affect throttle-only operation in a noticeable way, so throttle appears to work perfectly but pas doesn't.

I can't communicate with the CA from my laptop. The PAS setup information from the device display are a couple of responses down.

i just get a black screen for the link. if you can attach the image directly to the post then anyone taht can see the post can see teh image too.

alternately you can save the settings as a file, then attach the file itself (as a zip file if necessary) to your post, and then we can look at the settings directly in the setup program.

I can't seem to connect to the bike using the setup utility. Here are the readings from the PAS setup displays:

Setup PAS Device - 4.96V - Basic - Note: The PtDt display doesn't change when I pedal the bike.
PASD-> Sensor Type - Basic PAS
PASD-> Poles - 12 Poles
PASD-> Signal Type - 1 wire
PASD-> Dir Plrty - 5V = Fwd
Setup PAS Config - Basic - 500 W
PAS-> PAS Mode - Basic (Pwr)
PAS-> Start Level - + 500 Watts
PAS-> Scale Fctr - +30.00 W/rpm
PAS-> Strt Thrsh - 0.45 sec/pole
PAS-> Stop Thrsh - 0.29 sec/pole

I'm not sure why the software stopped talking to the CA. I did do a software upgrade on the CA. The problem may have started then. The PAS is working, but not properly. When I start pedaling, the PAS kicks in and then kicks out. If I pedal very fast, then it continues working.

RschDev said:

I can't seem to connect to the bike using the setup utility. Here are the readings from the PAS setup displays:

Setup PAS Device - 4.96V - Basic - Note: The PtDt display doesn't change when I pedal the bike.
PASD-> Sensor Type - Basic PAS
PASD-> Poles - 12 Poles
PASD-> Signal Type - 1 wire
PASD-> Dir Plrty - 5V = Fwd
Setup PAS Config - Basic - 500 W
PAS-> PAS Mode - Basic (Pwr)
PAS-> Start Level - + 500 Watts
PAS-> Scale Fctr - +30.00 W/rpm
PAS-> Strt Thrsh - 0.45 sec/pole
PAS-> Stop Thrsh - 0.29 sec/pole

I'm not sure why the software stopped talking to the CA. I did do a software upgrade on the CA. The problem may have started then. The PAS is working, but not properly. When I start pedaling, the PAS kicks in and then kicks out. If I pedal very fast, then it continues working.

Click to expand...

Can you post a pic of the PAS itself? Sounds like possibly the sensor and disc may be too far apart to get a consistent signal.

RschDev said:

I can't seem to connect to the bike using the setup utility.

Click to expand...

ok. that could be an indicator of a different problem.

you said it might've started after the ca firmware update. which version did you start with, and which did you update to? and which setup software version are you using, on which computer os?

Note: The PtDt display doesn't change when I pedal the bike.

Click to expand...

does the "human power display" marked in this pic have the two bars going up and down? if not, it means the ca isn't detecting the pas device itself rotating, which means there is an issue with the hardware of the sensor/magnet. could be distance of magnet from sensor, or fault in sensor, etc.

PASD-> Sensor Type - Basic PAS
PASD-> Poles - 12 Poles
PASD-> Signal Type - 1 wire
PASD-> Dir Plrty - 5V = Fwd
Setup PAS Config - Basic - 500 W
PAS-> PAS Mode - Basic (Pwr)
PAS-> Start Level - + 500 Watts
PAS-> Scale Fctr - +30.00 W/rpm
PAS-> Strt Thrsh - 0.45 sec/pole
PAS-> Stop Thrsh - 0.29 sec/pole
<snip>
The PAS is working, but not properly. When I start pedaling, the PAS kicks in and then kicks out. If I pedal very fast, then it continues working.

Click to expand...

i don't see anything in those settings that should prevent it from at least just working (even if not at the assist amount you want; that usually requires tuning once it's basically working).

but if you are getting "toggling" of the "human power display" bars (meaning the sensor is working and being detected correctly), then you could try adjusting these two settings as noted below, from here:
https://www.ebikes.ca/product-info/cycle-analyst-3.html

[ PAS->Strt Thrsh ]
Sets the threshold minimum time between pedal sensing events to cause the CA to assume that the rider is 'pedaling' and activate motor assist. If set to a long period, assist will begin sooner when starting from a standstill, but there will also be a longer delay before the motor cuts out if pedaling stops within a single revolution.

Sensors with more poles give brisker response because the CA gets sensor pulses more quickly, and can use shorter threshold times.

[ PAS->Stop Thrsh ]
After the first complete crank revolution, sets the minimum time that must be maintained between pedal sensing events for the CA to assume that the rider is still pedaling. If the time between pedal events is longer than this threshold, the CA will assume that pedaling has stopped and will cease power assist. Short values result in a more immediate cutout in power, while longer values allow for pedal assist even at slow pedal speeds. Sensible values are usually between ' 0.5x-1.0x the StrtThrsh.

Click to expand...

the other thing to check is your throttle input and output settings, and try watching the throttle on the diagnostics screen

with no throttle input, only the pas, the leftside should stay exactly the same and not change from whatever value it normally rests at. but the rightside should output whatever voltage is needed to maintain the power level you set it for in the pas settings.


something also to note, is that the power and current limit settings of the ca are always active...so you will need to set them so that they are high enough to allow the ca to actually output the power demanded by the pas (or throttle) or else it will limit the system, and depending on the rest of the settings in the limiting menus, can make for some strange behavior.

if power or current (or speed, etc) limits *are* in-action at any moment, you'll see their letter go capitalized in the diagnostics screen. so if you see a capital letter there in that row, but you don't think it should be limiting at that point, you need to change the settings in whichever section is capitalized.