HELP! Grin RH212 hub + ERIDER T17 BB + Phaserunner only producing <250W in PAS

[kurtster]

Shot in the dark perhaps, but I'm struggling to troubleshoot a lack of PAS power in my recently finished build.

Basically, regardless of whether the PAS configuration is set to "Basic Power" (i.e., cadence PAS) or "Torque" in Cycle Analyst, I'm only getting ~250W output max. Moreover, I even tried setting the "Start level" power as high as 1500W in Basic Power and the Scale Factor up to 10 Watts/Human Watt in Torque mode, but still the power delivery doesn't increase.

Is there some setting in CA that's limiting the power output? Could it alternatively be a setting in Phaserunner?? FWIW, power output via the throttle works fine.

RH212 rear hub
Erider T17 torque-sensing BB
Cycle Analyst (v 3.15)
Phaserunner v6
72V 15A battery

 

[Mongo]

What's your assist level (via the "Digital Aux buttons" handlebar control) currently - max? I completed a similar build recently (here), and am still trying to get a handle on the CA3 setup / settings interactions.

I'm currently running a scale factor value of 15 (on the first preset). then set the bar control to 3 (out of 5). Also, in my case Grin did not preset the PAS device "Device Sensor Type" to ERider - dunno if you've done that:



A tweaker's delight the CA3 is, but I've by no means got a handle on it.

 

[kurtster]

What's your assist level (via the "Digital Aux buttons" handlebar control) currently - max?

Yes, set to max. In fact, I've now disabled the Digi Aux buttons entirely just to take them out of the equation. Setting the scale factor (in the "Torque" configuration) as high as 10 didn't help.

Not sure if it's relevant, but in the "Basic (Pwr)" configuration, the assist power is delivered as an intermittent pulse, instead of a steady power, regardless of how fast I pedal.

I was just reading another thread in which the OP recommended grounding the battery negative to the frame. Does that sound relevant to my issue?

 

[E-HP]

Not sure if it's relevant, but in the "Basic (Pwr)" configuration, the assist power is delivered as an intermittent pulse, instead of a steady power, regardless of how fast I pedal.

I was just reading another thread in which the OP recommended grounding the battery negative to the frame. Does that sound relevant to my issue?

I read the same post and took note of it for when I get unlazy enough to install my ERider. Anyway the pulsing behavior appears to be similar, due to noise on the line, so grounding may help.

 

[Mongo]

Grounding the battery negative to the frame doesn't seem like a solution to me, but I'm a neophyte at this and dunno the context. Update - never mind, I watched the video @E-HP linked ...

There may be slightly easier grounding pickup points via the Phaserunner / Baserunner unused plugs, or via the programming plug up near the display.

I will try to attach my config file to this post (wheel size 20"), if you want to try it out.

 

[kurtster]

There may be slightly easier grounding pickup points via the Phaserunner / Baserunner unused plugs, or via the programming plug up near the display.

I will try to attach my config file to this post (wheel size 20"), if you want to try it out.

yeah, I wonder if there's an easier way to achieve the grounding. I should take at the Phserunner manual. Might be something in there.

Anyway, appreciate the config file. It's getting late here, so I'll take a look tomorrow.

 

[Mongo]

I wonder if anyone has reported blowing the fuse, 'cause fusing a ground strikes me as, well, half-assed. What's being tamed by grounding? Static buildup, RFI, what?

While I don't think I'm having the sensor problem, I'm having a few other issues, and who knows. One of the quirks is, when trying to brake on the first big downhill sometimes the regen cuts out as does the throttle and PAS. I then need to repower the CA to wake the motor system back up. Another just one time so far, the CA wouldn't power up after an extended ride break. I could see the display darken ever so slightly, but it kinda as if if the CA wasn't booting correctly. After a few tries, it did - beats me why it was then happy.

I'm looking at my battery tray as I type this, thinking of a ground wire addition "up" to one of the water bottle boss screws.

 

[kurtster]

Here's what my PAS settings currently look like in CA. Preset 1 is Torque, and Preset 2 is Basic Power (i.e., cadence PAS)



Here's a quick video showing what I mean by the lack of power. Notice how the output only reached 230W.

EDIT: I just noticed that Grin also recommends grounding the frame.

NOTE: Certain ERider setups are succeptible to electrical noise from the controller causing intermittent cutout behavior. This can be solved by grounding the bicycle frame.

I guess that really is the solution. So my next question is what's the easiest/foolproof way of going about this?

 

[Mongo]

... what's the easiest/foolproof way of going about this?

Grin sells a fused cable: PAS Grounding Cable

 

[kurtster]

Grin sells a fused cable: PAS Grounding Cable

Well spotted.
Would the M5 ring in that cable be soldered to all 6 wires?

 

[E-HP]

I

Grin sells a fused cable: PAS Grounding Cable

Interesting that the noise issue mainly affects ASI based controllers.

 

[Mongo]

Well spotted.
Would the M5 ring in that cable be soldered to all 6 wires?

NO, just to the ground pin, which per this Baserunner reference page is as follows:

Also make sure that the M5 screw and threaded boss makes a good frame connection (not insulated by paint, etc.)

I've added a grounding wire to my battery tray.

 

[kurtster]

Just wanted to add that the grounding wire worked like a charm. Power output is now steady and at whatever power level I set in CA. Considering that I was on the verge of uninstalling and RMAing the torque sensor back to Canada, I'm relieved to have found such a simple fix.

The wire runs from the 6-pin HiGo plug of the Phaserunner to an M5 bolt in the bike frame but doesn't have a fuse. If I were to add one, what kind of fuse should I use? My battery is 72V.

 

[E-HP]

Just wanted to add that the grounding wire worked like a charm. Power output is now steady and at whatever power level I set in CA. Considering that I was on the verge of uninstalling and RMAing the torque sensor back to Canada, I'm relieved to have found such a simple fix.

The wire runs from the 6-pin HiGo plug of the Phaserunner to an M5 bolt in the bike frame but doesn't have a fuse. If I were to add one, what kind of fuse should I use? My battery is 72V.

Great news! How do you like the torque sensor? I'd better get on with installing mine.

 

[kurtster]

The torque sensor is amazing...pedal assist now feels more natural and organic imo compared to the normal cadence sensor and makes me wish I put one on earlier builds. Used in conjuction with the DigiAux controller, I can vary on the fly how much power is added to each pedal stroke, so I feel encouraged to actually pedal as opposed to ghost pedalling.