Pint Power Surges and Wheel Slip Detection (Or rather not)

[cba20k]

I experienced my first power surge this evening but it was not under circumstances I've seen reported in the forums and so thought it was worth mentioning and to see if any other Pint riders had experienced it.

Riding on level ground, with a battery level of 85% at about 8mph, I experienced a rather jarring surge that forced the tail down to the ground briefly, then the pint see-sawed forward to the nose and I managed to outrun my fall.

I heard the wheel skid/slip and yet when I gathered my senses and walked back to the board and looked at my phone, no notification of wheel slipped had been logged. I sent in a diagnostic report, but for all intents and purposes, the board thought everything was normal.

That got me to thinking, I don't recall ever seeing a notification for wheel slippage on my pint (I previously had a OW+), which is something that routinely happens when I simplestop on grass.

The reports of surges that I have seen on here appear to be happening with the full size OW's with very low battery levels, so it makes me wonder if maybe it's a firmware issue I'm dealing with? I'm on Gemini of course and keep things redwood (I'm not a thrill seeker, I enjoy slow, smooth, sublime rides) for what it's worth. Not sure if it's possible to reflash or not.

Anyway, just wanted to see if anyone else has experienced this on a pint with plenty of charge left.

[blkwalnutgrwr]

@cba20k said in Pint Power Surges and Wheel Slip Detection (Or rather not):

a rather jarring surge that forced the tail down to the ground briefly, then the pint see-sawed forward to the nose

Sounds to me like regen/overcurrent cut-out -- that quick and dramatic nose-rise/ tail-down pushback followed by immediate cut-out, which becomes slam nosedown because of the weight of a foot on the nose. To me this has happened on a V1 when I connected a CarvePower booster without turning on the board first. It also happened when the BMS of my V1 had had water damage and was registering almost any regen as overcharge.

[cba20k]

@blkwalnutgrwr interesting. Now in theory, I should get a notification about that too right? Something to the effect that the board is nearing 100%? If the board is sending data back to the app (which seems to be working normally aside from the lack of notifications) then the app should take that info and notify me right?

Maybe it's an app issue? Haven't seen updates to that in some time.

I've only ever ridden over sprinkler-wet sidewalk on my Pint. I live in Los Angeles where rain is a dream/wish your heart makes.

[cba20k]

I figured I would throw this idea out there and am unsure if there's ever going to be a way to prove if it works unless I never experience another surge for as long as I ride, but I've opted to switch on the 90% notification in the app to remind me to unplug my Pint before it reaches 100%. The app states this is a good idea if someone lives on a hill, but I think sacrificing 10% battery to prevent the BMS from thinking it has overcharged (again, in theory) might be worth it?

I don't know, but I did read somewhere on the internet (so it must be true) that an iron law of thing is that peak battery efficiency is typically achieved with an 80% charge anyway.

Again, not sure if this will do any good, but just throwing it out there.

[stinkyface]

@cba20k no prob with only charging to 90%. Just make sure that you regularly do a balance charge (overnight) to let the BMS balance the cell voltage. I commute daily and do a balance charge same day every week. More or slightly less frequently would be fine.

[hattifnatt]

I had a surge this morning that sent me backwards onto the asphalt when my Pint went full-speed ahead. I was riding on my new Hoosier wet-weather treaded tire, just logging some kms to get used to it, so I had my upper body pads on, in addition to the wrist guards and helmet that I always have. Lucky thing – tore my coat on the elbow, but the pads did their job. Hopped up and rode another 6km* in a mild state of shock. lol.

I was at 38% battery, and I never felt any surge like that on the stock tire on that much battery (2400 km on that one). OTOH, this new tire is very soft and very energy inefficient compared to the stock slick tire. May well be that I won't be able to ride it like the old tire due to the additional drag all the time. I'm 85 kilos and run with it at around 22 psi, so far.

Headwind; soft tire, cold temperatures, low battery – it all seems to play into the possibility for drama in the form of surges/nosedives.

*Note: Yep. Range extender, but I've got 1000 km riding with that, too, and it's never been an issue.

[hattifnatt]

Had another surge this week. They’re just diabolical! Tail down, then nose down, then a relatively light tumble. 🙁