Sabvoton regen current setting is inaccurate?

[Adrian_]

I have a Sabvoton SVMC72150-M with a QS 273 V3 5T motor. I'm trying to get regen working when braking not to recharge the battery but mostly for braking assistance and to prolong the life of my brake pads. I have a 20S14P Panasoic NCR18650GA battery, rated charge current of those cells is 1.45A with 14P, I'm looking at just over 20A max charge current so that's what I set the "Regen current" in the Sabvoton app to.

I test rode it and honestly at first I thought it wasn't working, it was so weak that I disregarded it as wind resistence, only at 30+ MPH I noticed that it's working just very weakly. I had 48v 1500w bikes that had 20x stronger regen at 15mph than this. I did accelerate to 20 MPH on a flat surface and regened, according to UKC1 display which I'm not sure how accurate it is, I was only generating 410w of regen which is just over 5A (my battery voltage was 80v at the time) which with a 260lb bike is hardly noticeable.

I don't want to damage my battery or cells by putting too much current into it but I also want a harder regen. Is this a known issue with Sabvoton controllers and their regen current setting not being accurate? Or does this current setting do something else?

 

[dominik h]

On the sabvoton the regen current is depending on
the RPM the motor is making. The more RPM the more current you get.
I think the regen current you set in the app is the phase current the motor will see during regreneration.

 

[Adrian_]

On the sabvoton the regen current is depending on
the RPM the motor is making. The more RPM the more current you get.
I think the regen current you set in the app is the phase current the motor will see during regreneration.

Thanks for the response. That would certainly make more sense. I just can't find any info on this online. Either people says to set the regen current depending how fast you want your motor to slow down which is terrible advice or I see people running 40A or 60A for regen current with no battery specs. You would need a ridiculously beefy battery to handle 40A or 60A of charge current which is possible but unlikely but if this setting uses phase current, then those numbers make more sense.

 

[E-HP]

On the sabvoton the regen current is depending on
the RPM the motor is making. The more RPM the more current you get.
I think the regen current you set in the app is the phase current the motor will see during regreneration.

Thanks for the response. That would certainly make more sense. I just can't find any info on this online. Either people says to set the regen current depending how fast you want your motor to slow down which is terrible advice or I see people running 40A or 60A for regen current with no battery specs. You would need a ridiculously beefy battery to handle 40A or 60A of charge current which is possible but unlikely but if this setting uses phase current, then those numbers make more sense.

I don't think the regen current is a big issue, since when the regen current is high, the bike slows so quickly that it won't be sending that high level of current for more than a few seconds. I never worried about that, but the heat from regen is a factor, when you're motor is already warm from climbing the hill, and descend right afterwards. I'd stop the bike to let the motor cool more often during a descent than during a climb.

 

[DogDipstick]

Thanks for the response. That would certainly make more sense. I just can't find any info on this online. Either people says to set the regen current depending how fast you want your motor to slow down which is terrible advice or I see people running 40A or 60A for regen current with no battery specs.

I am in some of the same confusion. Same controller, and initially it was set up to regen when you left off the throttle.. and it would push 15-20A back into the battery when rolling downhill from speed... Just fine.... but now I have it set " Regen Off" and " Ebrake On" cause I want the brake triggers to start the regen....

....and now nothing is happening at all. I have it set for 25A ( 1C for my pack) and RMP(rpm?) is set to 50... it was set to 100 before. Should I set the regen amps to 50A? Should i lower or raiser the rpm setting?

My pack can handle 50A ( 2C) charge rates just fine. But I want to understand how the regen / ebrake works on this controller.

 

[dominik h]

On my scooter I set 100A regen current. But I have neuer seen more than 55A on the fisplay from the BMS until I changed to a motor with a lower KV this Motor gives me now upt to 75A regen current, but only with a higher E-RPM .
My 21S100Ah scooter battery can take a lot of more current, so there is no limiting factor on the battery side.

 

[Adrian_]

Thanks for the response. That would certainly make more sense. I just can't find any info on this online. Either people says to set the regen current depending how fast you want your motor to slow down which is terrible advice or I see people running 40A or 60A for regen current with no battery specs.

I am in some of the same confusion. Same controller, and initially it was set up to regen when you left off the throttle.. and it would push 15-20A back into the battery when rolling downhill from speed... Just fine.... but now I have it set " Regen Off" and " Ebrake On" cause I want the brake triggers to start the regen....

....and now nothing is happening at all. I have it set for 25A ( 1C for my pack) and RMP(rpm?) is set to 50... it was set to 100 before. Should I set the regen amps to 50A? Should i lower or raiser the rpm setting?

My pack can handle 50A ( 2C) charge rates just fine. But I want to understand how the regen / ebrake works on this controller.

From my understanding the RPM setting (they misspelled it as RMP in the app) is only for the regen when you let off the throttle and it doesn't do anything with the e-brake function. E-brake regen will trigger whenever you apple brakes no matter the motor's RPM.

I would do a continuity test with a multimeter on your brake lever trigger signal and make sure they are working, if they are, see if they are plugged into the controller correctly. Maybe the regen is so weak that you can't tell it's working, that's what happened to me, it was so weak that I disregarded it as wind resistence intially and you might need to bump up the current. If the setting uses phase current like the other user stated then these current settings should be 2.5 or 3 times higher than what you want.