Problem with abrupt regen

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Heavendenied
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Joined: 02/01/2015
Points: 86

Hi,
since some weaks i have a second Vectrix VX 1 Li+. As it had some dead cells i bought it mainly to use it to change the bad cells in my first Vectrix. As it was (beside some scratchs from a little fall and the dead cells) completly OK i found it to pity to use it only as donor for spare parts i put it the (now) good battery packs from my first scooter and it works fine now.
So i made some test rides and found out that the "new" vectrix is liitle less noisy than my first one is. Maybe thats because it has only run 2500km while my first one has run about 11000kms but there is one other thing that irritated me much more and thats the regen.
On my first vectrix, espacially on highter speeds when i use regen it begins very abrupt, no matter how smooth i turn the throttle. On the "new" one the regen is begins very smooth, no matter on what speed... After the abrupt beginning of regen the regen behaves absolutly the same on booth scooters.
Firmwares are all the same so i really don't know what can be the reason for this.

Can anyone solve this?

Firmware:
Charger: LiFe40-3
MC: R2042-04
ICM: DIY 1708
BMS: R54

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framuga
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Joined: 10/23/2013
Points: 65
Re: Problem with abrupt regen

It is very strange what you tell us. both bikes have the same chemistry and the same firmware 2042_4? The MC2042 firmware, short regeneration 100A and when it detects overvoltage

Heavendenied
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Joined: 02/01/2015
Points: 86
Re: Problem with abrupt regen

Thanks for your answer. Yes, its very strange to me too, because as i said firmware is all the same and throttle on both scooters is calibrated. Maybe its a hardware problem with the throttle?
Just to clearify how this problem shows:
The abrupt regen is only when i begin to regen brake, espacially on higher speeds, but i think its also there at lower speeds but could not be recognized that much. After that i can dose the regen very smooth. But if i go back to neutral throttle and than begin regen brake again the begining of regen brake is again abrupt...

Hopefully you can unterstand, it's little bit hard for me to explain this in english...

LeftieBiker
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Joined: 07/09/2011
Points: 885
Re: Problem with abrupt regen

You should be able test the throttle hardware theory, at least. Use the Reverse function: if it reverses abruptly, like an on/off switch has been thrown, then it's probably the portion of the throttle used for Regen and Reverse. If it reverses smoothly and controllably, the throttle is likely OK.

R
R's picture
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Joined: 06/18/2009
Points: 1751
Re: Problem with abrupt regen

The abrupt regen is only when i begin to regen brake, espacially on higher speeds

My guess: when you regen, encoder disc of the motor slightly moves forward, and the position of the phases is lost, it system becomes temporarily uncalibrated.

check, with plenty care, the encoder disk. Check if it is loose and can be moved forward and backward. You may also swap entire swingarms with motor, if you don't want to touch encoder...

hybride
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Joined: 08/01/2014
Points: 145
Re: Problem with abrupt regen

I was thinking on a phase issue too. If you recalibrate encoder does that change Regen behaviour?

Hall9000
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Joined: 08/27/2015
Points: 83
Re: Problem with abrupt regen

By the way mates , how do you know if your encoder needs calibration on the vectrix?And wich tools do you need to acomplish that task?

R
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Points: 1751
Re: Problem with abrupt regen
Heavendenied
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Joined: 02/01/2015
Points: 86
Re: Problem with abrupt regen

HI together,
on weekend i managed to switch my good battery back to my silver vectrix and yesterday testet again this thing with the regen. Few Days ago i realized that on the white vectrix i also had this "abrupt" regen, but only when i drive faster than 80km/h and the battery is below 15 bars.
So i now testet again with the silver vectrix and it seems its almost the same. When i have more than 15 bars in the battery the regen is smooth on all speeds. When it wents belos 15 bars and i drive very fast (faster than 80km/s) the regen ist kind of abrupt. On lower speeds again everything is very smooth.

I also did the software encoder calibration an changed the value from 99 to 96 but i think that didn't really change anything.

So i think it must be kind of normal that the regen is a little abrupt or lets say very perceptible on higher speeeds...

R
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Joined: 06/18/2009
Points: 1751
Re: Problem with abrupt regen

What firmwares do you have installed on your vectrix?Your vectrix is original GP lithium?

Heavendenied
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Joined: 02/01/2015
Points: 86
Re: Problem with abrupt regen

Hi, Firmwares on both Vectrix are as mentinoned in first Post:
Firmware:
Charger: LiFe40-3
MC: R2042-04
ICM: DIY 1708
BMS: R54

And both Vectrix are original Li+ with GP cells. Both Vectrix are used with the same battery pack which is switched between the two scooters (I have not enough good cells to build a second pack).
The silver vectrix is from 2012 and had run about 11000km, the white one is from 2011 and had run about 2700km

R
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Points: 1751
Re: Problem with abrupt regen

Firmware:
Charger: LiFe40-3
MC: R2042-04
ICM: DIY 1708
BMS: R54

Oh, really? these crap GP cells are still alive? This changes everything, main suspect now is the battery.
Enable pro mode and check voltage oscillations. What voltage do you get when those strange regen issues happen?

MEroller
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Points: 843
Re: Problem with abrupt regen

Guys, it may just be pure induction at work: I am fairly sure VX1 also uses a permanent magnet synchronous motor, which at any RPM always also works as a generator, and the higher it's speed, the higher is the generated voltage, also known as back-EMF, electro-motive force. Apparently the VX1 controller software uses some more simple programming in it's regen-regimen, thus giving smooth transitions only in a certain battery voltage and back-EMF voltage range. Whenever battery voltage is lower than that sweet spot, and simultanously the motor creates higher back-EMF due to higher speed, that voltage difference is evidenced by a quick jerk when regeneration commences.
I am sure that the VX1 controller is far more refined than the rather primitve block-commutating Kelly in my Thunder, but the latter creates immense jerks when regen sets in at higher speeds. The more refined Lingbo/GoldenMotor vector controller in my Swiss ride uses a trick to cover up that jerk, despite also having fixed regen, not with some modulation such as VX1 provides: It applies a rising minimal current (thus voltage) at increasing speed, both with the throttle as well as with regen, and in the case of regen from there softly increases negative battery voltage up to the programmed regen current, within about half a second. So no jerking there. Possibly technology wasn't that far yet when this pioneer of potent electric two-wheelers was developed?

Or do only some VX1 have this phenomenon, and others not? That would worry me too...

__________________

My rides:
QvR vR one: a Swiss package of pure understatement - innocent and to some eyes (from some angles) exceedingly ugly looks, but with raw and hardly containable electron power up to real 95 to 100km/h! And a literally rock-hard suspension due to a carrying capacity of twice it's unladen weight... Now converted to more controllable and efficient brushless motor and vector-contoller.

E-Sprit Fury (basis is the Erider Thunder 5000) since May 03, 2011. Highly moded - but now in active retirement

Heavendenied
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Joined: 02/01/2015
Points: 86
Re: Problem with abrupt regen

At the moment i don't think that it is really a problem but that it is the normal behaviour. Maybe I'm just a little to sensitive with such phenomenons...

Yesterday i did test what R wrote and i have about 118V on accelerating, 121V while rolling and about 126V when i start regen. Thats almonst the same equal if i rode slower or faster. What is significant is that regen starts whith about 20A when i drive on a speed of 30km/h and starts with about 50A to 60A when I'm driving on speeds of about 90km/h (all tested with battery about half full)
So if i see this high Amps i think it is normal that i can really feel when regen sets in.
But i have to say that it is not to easy to give very exact data of this because the "Live Dashboard" is not really live but only updates one time a second or something like this...

I can't believe that this phenomenon is because of the battery pack. I have managed to get the best 40 cells out of two complete LI+ Battery packs and all cells now give me about 38Ah so thats very close to what they could give if they were new. I know that they are not the best cells, but i just can't afford 3.000 or more € for a new pack.
The only "problem" with this pack i could believe having to do with this regen "problem" ist, that the packs voltage is lower than the pack voltage of the normal NIMh or self made Lithium packs...

LeftieBiker
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Joined: 07/09/2011
Points: 885
Re: Problem with abrupt regen

The only "problem" with this pack i could believe having to do with this regen "problem" ist, that the packs voltage is lower than the pack voltage of the normal NIMh or self made Lithium packs...

That may be it. If the bike's firmware thinks the pack is always low on charge, it may be "trying harder" to keep it charged via Regen.

Heavendenied
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Joined: 02/01/2015
Points: 86
Re: Problem with abrupt regen

Just to be sure you unterstand it right:
Thats not a problem of my Li Pack but a problem of all original Li Packs in the Vectrix, because a li cell has a much more flat voltage curve than NiMh Cells have. So the Voltage of the Li Cells normaly is around the nominal voltage while on a NiMh Pack it is much higher in the beginning and much lower at the End. I think that is one reason many people who converted to selfmade Li Packs used more than 40 cells.
So i think that should be one thing that is programmed right in the LI-Firmware from Vectrix.

R
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Points: 1751
Re: Problem with abrupt regen

Thats not a problem of my Li Pack but a problem of all original Li Packs in the Vectrix

There's a BMS that monitors cells. When you regen, you increase the voltage of all cells. The worst cells of the pack have higher internal resistance, resulting into higher voltage readouts than average.
If they reach maximum allowed voltage during regen, motorcontroller (if it is correctly programmed) would reduce regen intensity to protect these bad cells from over-voltage.
This may lead to strange braking patterns during regen.
Riding at hi speeds depletes de battery, and lowers the voltage. My guess, under this conditions it may be able to admit higher regen intensity.

Heavendenied
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Joined: 02/01/2015
Points: 86
Re: Problem with abrupt regen

No, what you describe is not the "problem" i have.

The behaviour of my vectrix is, that the regen only starts kind of abrupt at higher speeds. Once set in the regen is absolutely smooth! I think the only "problem" is, that the regen starts at a very high curront of 50amps when i drive at about 90km/h. It rises hight to about 90 or 100 Amps if i pull the throttle completly forward. Maybe the current of regen is programmed higher than on NiMh Firmware bikes?

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