CA2.3 / 'Regen' Ah

[footloose]

Recently my system has begun doing something strange.
Motor = Mac 10T
Controller = Infineon 9FET from EM3EV
CA V2.3
Battery is hot off the charger, ~58v

In past, I saw only minor Regen, typically when coasting downhill.

Today, noticed for first time something strange.
When bike is sitting still, on display screen #4 of CA:
Fwd Ah remains steady (as expected).
Regen Ah is slowly increasing (strange).
% Regen increasing in tandem with Regen Ah.

Believe this is new behavior.

Thoughts?

 

[amberwolf]

Check your CA shunt connections--unplug and replug them a couple times if nothing else. Sometimes a bad conneciton causes a problem.

Then you might need to go into setup and Zero Amps.

 

[footloose]

Thx for suggestions.
Have unplugged/replugged all connections.
And zero'd the amps in Setup.

Behavior persists.

As I've watched it over past hour, the rate of "regen" has slowed substantially.
Still happening, but Regen Ah increasing now at a much slower rate (started at ~.0001 Ah /second and has now decayed to ~.0001 Ah / minute change rate)

Could it be related to battery being hot off charger, and perhaps going through a post-charge period of stabilization?
IHypothesis seems kind of dumb, but who knows... only thing that has changed in system over past hour is passage of time.)

The amounts of power involved are trivial, but seems strange this should happen at all.

 

[footloose]

Update.

I took the bike out and rode a few miles. No problems. Saw trivial Regen, as per usual. Depleted the battery voltage a bit.

After the ride, I reset the CA screen for Forward and Regen Ah, and watched behavior.

Same behavior I noted earlier: Regen figure increasing while bike was motionless, and at a higher rate than before the ride (when bike had sat idle for 90 minutes).

So, that shoots my hypothesis re battery being hot off the charger. (I suspected it was wrong, but hey, great science sometimes arises from 'dumb' hypotheses )

Current hypothesis and plan:
- Hypothesis: this behavior is really just an artifact of some charge remaining in the controller after each use, and the behavior slows as the charge decays over time.
- Plan: ignore it, just ride.

 

[Mordan]

Yes I've experienced this problem once myself (two days ago), Zeroed Amps no more problem
Have not seen it since, keep us posted and let us know if you find a fix

 

[bowlofsalad]

Are you going down hill faster than your bikes top speed?

 

[footloose]

Are you going down hill faster than your bikes top speed?

Mordan, Bowlofsalad... Please excuse me while I make this irresistible reply and then I'll get serious:

"No, my bike and I are generally travelling downhill at same top speed." :wink:

Anyway, serious answer...

My CA top speed is set to 30 mph.
I may at times exceed that slightly going downhill, but not by much... a couple mph, for a very short time.

I've watched this for a couple days. Don't completely understand it, but appears to occur only in the period of say
30 minutes after I've ridden bike. During that period CA reports a slight and gradually slowing rate of regen.

While I was originally hopeful that regeneration while bike was parked might hold the key to perpetual motion,
In fact I think it is probably just a gradually decaying residual voltage within controller.

If anyone has good alternative thought, please chime in!

 

[Mordan]

Mordan, Bowlofsalad... Please excuse me while I make this irresistible reply and then I'll get serious:

"No, my bike and I are generally travelling downhill at same top speed." :wink:

Good one :lol:

I think Bowlofsalad was asking if you were going faster than the max RPM of your motor
But this happens after the ride, Am I correct?
Finish ride, jump off notice negitive Amps
go to regen screen watch %Regen and RegenAh climb up at steady pace (mine reached 999.9%)

 

[itchynackers]

zero amps. its in the manual.

 

[teklektik]

...Don't completely understand it, but appears to occur only in the period of say 30 minutes after I've ridden bike. During that period CA reports a slight and gradually slowing rate of regen.
...
In fact I think it is probably just a gradually decaying residual voltage within controller.

Please try Zeroing Amps at the end of your ride when the battery is at the lowest.

I think this might be what is happening and it may be related to exactly when you Zero the Amps:

If your controller has a resistor to bleed capacitor charge then there will always be some small discharge current in addition to the small current used by the controller 5v regulator and logic. This small current will vary with voltage and will be highest hot off the charger when the battery voltage is highest. As the battery voltage decreases, this small drain will reduce as well. Zeroing Amps hot off the charger will set the largest discharge current as zero amps. Relatively speaking, the reduced discharge current later in the ride from a reduced battery voltage will be interpreted by the CA as a positive current since a discharge rate less than at Zero Amps must be 'charging' (think 'double negative' = positive). This positive charging current is reported as regen.

Other small resistive loads that you might have on you bike that are wired in after the shunt will have a contributing effect.

By Zeroing the Amps at the lowest battery voltage, the larger quiescent discharge hot off the charger should be reported as such and the small phantom regen should disappear.

Hmmm - re-read the thread and this doesn't explain the rate change issue you report, but give it a try anyway just for the heck of it....

 

[footloose]

Teklektic --
Interesting 'double negative' theory, thank you.
I tried what you suggested -- waited until battery was at a low state of charge, then zero'd the amps.
Recharged the battery, took bike out for a short ride, parked it and watched the regen numbers.
Showed same general pattern: slight regen reported initially, rate of reported regen decreased over time, eventually stopped.
Doesn't affect operation of the bike at all, so I'll just chalk this one up to "strange and sort of intriguing, but one of life's mysteries."
-Steve

 

[teklektik]

Showed same general pattern: slight regen reported initially, rate of reported regen decreased over time, eventually stopped.

Ah well - worth a shot. Why don't you shoot Justin an email at ebikes.ca? He is very good about responding to technical questions and this one is puzzling... maybe you could post back if the mystery is resolved.

 

[docnjoj]

Maybe a dumb question but how do you get regen out of a geared hub? Don't they freewheel when coasting?
otherDoc

 

[footloose]

Docnjoj --
Yes, geared hubs freewheel when coasting so theoretically can't regenerate power.
Mine shows a slight regen when I'm coasting (I was surprised at this.)
I figure that one of two things is actually happening.
First possibility: the freewheel isn't 100% friction free, so there is a bit of drag, causing some slight actual regen. (Anyone out there think this makes sense? Or is it completely bogus idea?)
Second possibility: the regen that shows when I'm coasting is a spurious figure, related to the spurious regen that shows when the bike sits still after riding.
-Steve

 

[alsmith]

My CA 2.3 does the same. I ignore it in general but when the regen amps start to creep up I zero it. It happens almost all of the time, and often when I swap batteries over. Both batteries are supposedly identical.

I now have regen switched off -never noticed it when it was on. I was probably only getting 2 - 5% regen depending on my route but the wheel axle flats wore a bit and the steel forks opened and were damaged enough to need replacing- despite 2 torque arms. I use 2 ebikes.ca torque arms now with no regen and all looks well. I don't think the amount of regen was worth risking damage for.