Phaserunner V6, PAS, CA3 & GMAC (Grin) settings help: power cutouts under high load at low speeds.

[dialing_wand]

I'm hoping someone with some experience tweaking settings can help out.

I recently completed a Grin build with a Phaserunner V6, GMAC 8T and a 23Ah 52v battery (~50A continuous BMS circuit), in also has a torque sensing bottom bracket.

I'm having an issue where, from a stop, in certain conditions, there is either no power to the motor after starting from a standstill, or power drops to 0W to the motor very shortly after assist starts (within a second or two). I can usually see motor power go very high (1000W+) on the CA3 readout and then drop to 0W.

My PAS and Torque multiplier is set at 1 and 2.5 respectively. I have a 5W mode for steep hills. Even at 2.5W per human Watt, I can regularly get it to stop powering the motor from a standstill while pedaling hard. I'm not sure where to begin debugging the settings to solve the issue.

Each preset in the CA3 head unit is set to 90A and 2000W as per the default that shipped from Grin.

Now I get that at a stoplight, up a hill, I might be able to briefly demand more power than the system could provide, but I always assumed that the motor would just run up to its limit and not simply cut out. It feels like there's another setting there somewhere that's causing the drop-outs. The strange thing is that I can't always bring it back, sometimes I have to power cycle the bike while riding.

In "normal" riding where I start in a totally appropriate, not-grinding, gear on a relatively flat road I don't have this issue. However, it's often very different at a signalled intersection where I might have even taken the lane to make a left turn and thus put my own power down hard to get moving.

Even if I'm "doing it wrong"—I wonder if there's a setting that will let the motor get up to its limit and stay there while I accelerate instead of cutting out.

Just to cover my bases, the same thing seems to happen if I attach and use the throttle. If I demand too much power from the motor via the throttle, the motor just cuts out (CA3 display goes to 0W).

Edit: Some grammar.

 

[AHicks]

To me, it sounds like you are running into a voltage sag issue and either your battery BMS or controller LVC is shutting you down. Like there's a bottleneck in your power delivery - somewhere?

 

[mclewis1]

1) I'd really dig into the CA and look for any error messages and the ramp of watts used (looking for a specific point where it reverts to 0W). I'd also put a meter on the battery connections and look for the possible voltage sag mentioned under load.
2) When you connected the throttle did you also run the bike without the TS bottom bracket connection? (to see if the TS or it's cabling is somehow causing the problem)
3) I'd post the same question on the Endless Sphere board (https://endless-sphere.com/sphere/ ) ... where there's even more experience in troubleshooting CA configurations
4) Have you asked Grin for some guidance? they will likely help you focus your troubleshooting
5) Do you have a totally original (the way it came from Grin) configuration saved for the CA settings?
6) When you start off more slowly can you then get the failure if you then run it hard without a stop ... like uphill?

 

[tomjasz]

@linklemming is another astute user.

 

[dialing_wand]

@AHicks & @mclewis1 thanks!

Responses in order

1) Dig into CA3:
Will do. I had looked at the Phaserunner and didn't see any faults listed there but didn't think to check the CA3 itself.

2) Run without TS BB:
Haven't tried that either. Thanks.

3) Endless sphere:
Thanks! Will do.

4) Contact Grin:
Sadly they have yet to respond over the last 4 business days - but it was a long weekend here and people are often away beyond the stat holiday so I'm giving them the benefit of the doubt. I'm following up today with copies of my current Phaserunner and CA3 settings to help expedite things.

5) Original settings:
Yes, I saved them. Will give a restore it a whirl. The odd thing is that I had only lowered power and amperage settings.

6). Start more slowly:
Indeed, I can get it to fail at any speed if I'm moving along and then run it hard. I mentioned "from a stop" because it's pretty consistent in that use case. Previous long rides I had no reason to try to surge the system so hadn't noticed until I was commuting about in heavy traffic.

Will report back with more updates! Appreciate you all.

 

[dialing_wand]

No word from Grin. :/ Sent a follow-up today finally.

1) No errors listed on the CA3 that I can see.

5) Will play around with original settings today. I've been away enjoying some gravel riding.

 

[tomjasz]

3) Endless sphere:
Thanks! Will do.

Endless_sphere is owned by Justin Elmore is also the owner of Grin/ebikes.ca. You can find the unofficial guide as well as pretty decent support by way of ES.

 

[JRA]

Assuming you got a RTR kit from Grin they should have synced your system before delivery. If you have adjusted any of the settings in either the CA3 setup or Phaserunner suite, given you have the proper TTL cable then you should be able to go back to the default settings? Given that it worked at first that is before adjustments.

I have to admit that their customer support isn't what it used to be when dealing directly with Justin or Robbie but I understand that they have grown, I started getting stuff from them in 2016, and have other aspects of the business to attend to and have to depend on hires to help out with that aspect. In fact I have been wrestling with them on an issue with my baserunner/All Axle build here recently and it has taken some time. But they aren't the only ones that are slow to respond that I deal with.

 

[dialing_wand]

Sadly it wasn't an RTR kit - but they did sync my system and I kept the original files before I added a few presets and tuned the motor response. In every case though, I "softened" things instead of pumped up performance. But that's neither here nor there.

There were some hiccups with Grin that would make me hesitant to recommend them. I totally get the growing pains, but they seem to be at the uncomfortable stage where they're pretty successful (orders were taking WAY WAY longer to ship because of volume they claimed), but post-sales support and follow-up are seemingly non-existent at this point.

I won't air all my grievances here, but suffice to say they have a lot of "we'll help" or "we'll take care of you" pre-sales and that has not proved to be true once I hit the buy button and they had my money. I did get what I ordered and my bike is far more functional than not. I ride it often and despite the above hiccups, it's fine.

Overall though, it's too bad because I love supporting Canadian businesses... and I love that they're trying to do something a bit different, but I'm definitely concerned at the post-sales radio silence when the systems are (even in RTR kits) relatively bespoke.

 

[dialing_wand]

Update: Issue fixed. It was my error.

The throttle was faulting at 3.7V in the Phaserunner. The recommendation to watch the CA3 throttle in/out screen helped me solve it. Under hard load (at a stop light) the PAS would request throttle beyond the Phaserunner max setting and fault. I'd argue I was misled by the manual, but that doesn't change that I was responsible for the issue.

Easy fix in the end and all is well.

On the Grin front sadly support remains pretty questionable, which is disappointing. Justin wrote me directly after a third "how come no one's answering after two weeks" message.

He provided the same advice here (to look at the CA3), which did work. However, Grin didn't reply to my follow-up (which was before I put all the pieces together and fixed the throttle mapping myself). Grin claimed that they weren't getting my messages. :/ If, as a company, you're going to push people to email you as the point of contact, you better have that nailed.

Oh well, still enjoying the bike.

 

[tomjasz]

Oh well

I’m an 8 year Grin addict. And an 8 year BBSxx groupie. After Bafang support Grin is stellar. Almost true.

I find endless_sphere.com, owned by Justin Elmore (Grin) to be a good place for support.

 

[INSJBLM]

Update: Issue fixed. It was my error.

The throttle was faulting at 3.7V in the Phaserunner. The recommendation to watch the CA3 throttle in/out screen helped me solve it. Under hard load (at a stop light) the PAS would request throttle beyond the Phaserunner max setting and fault. I'd argue I was misled by the manual, but that doesn't change that I was responsible for the issue.

Easy fix in the end and all is well.

On the Grin front sadly support remains pretty questionable, which is disappointing. Justin wrote me directly after a third "how come no one's answering after two weeks" message.

He provided the same advice here (to look at the CA3), which did work. However, Grin didn't reply to my follow-up (which was before I put all the pieces together and fixed the throttle mapping myself). Grin claimed that they weren't getting my messages. :/ If, as a company, you're going to push people to email you as the point of contact, you better have that nailed.

Oh well, still enjoying the bike.

"I had the same issue and the support was terrible. I ended up returning the equipment before Justin got involved. I wish I had his help earlier, as he seems to be the only person there who knows about the equipment and cares enough to provide real support. I work in operations, and if I ran the support team there, I would have to clean house."