Analysis of regen on an ebike

[ZapPat]

Turns out the Infineon has regen braking.
It was there all along. Works great too.

Knuckles - I checked out your tech info threads to look at what can be configured on the infinion, but I couldn't find a current limit for the regen. We usually need to keep the max regen current lower than the max drive current for most batteries. This is doubly important since the batterie's BMS can not cutoff regen current itself because of the internal diode in the MOSFET that automaticaly conducts on reverse current.
Thanks,
Pat

[Knuckles]

I have not yet measured the Infineon regen current in the 72V range.
It appears to be software regulated and a fraction of the programmed drive current.
(Another reason for a home-made dynamometer perhaps?)

The regen works very well, however, on the flat during road testing.
I like the idea of "braking by wire". Very cool feature.

[Roy Von Rogers]

I had wondered if it is possible to engage regen in the same manner as a throttle via hall effect. But since I have never experienced how hard regen kicks in, I'm not sure if such a device is needed. Such a device could be engaged with the brake switch mechanism and the harder you pull the brake lever, the more the regen would operate. I know this would bring about more complexity, but was just an idea I had pondered about.

Roy

[ZapPat]

I had wondered if it is possible to engage regen in the same manner as a throttle via hall effect. But since I have never experienced how hard regen kicks in, I'm not sure if such a device is needed. Such a device could be engaged with the brake switch mechanism and the harder you pull the brake lever, the more the regen would operate.

Regen braking could easily controlled like this via a second hall-effect throttle, if a controller would exist that had a second input for this (in fact I'll add this regen control option to my long term controller build wish list!).

Something close to this setup does exist though:
- When your brake lever switch (on/off) is triggered, you controller is now in regen mode and the throttle now acts as a variable brake instead of a regular throttle.

Other ideas for regen input are:
- Dual direction throttle (center return): One way controls drive current and the other way controls regen current.
- Snap/Roll throttle: Uses regular style throttle, but in a different way; Quickly letting go (snaping back) lets you coast, while slowly rolling back the throttle engages regen and adjusts it's strength.

[Knuckles]

The Infineon has Throttle regen also.
The throttle regen is an option in the software interface.

I have the throttle regen turned off for now but it works very nicely.
Same amount of regen braking at higher speed.
You can ride (accelerate and decelerate) by throttle alone.

As the bike slows down, however, throttle regen turns -off.
The eBrake regen is continuous to a dead stop.
The throttle regen disengages at maybe 15% of full throttle.

[fechter]

That kind of 'throttle regen' is similar to the MCIPC24 controller my Zappy has. I did not like it since it does not allow for coasting unless you hold the throttle just right.

Having the regen activated by the brake lever is much more intuitive.

The old Xooter EX3 had a bi-directional throttle that operated regen in one direction. I don't think it would be easy to implement this kind of feature on the Infineon, but it would be a nice feature.

Using the regular throttle as a regen control during braking could be a problem if you were on full and suddenly let off the brake (it would go from full brake to full throttle). It's also a bit akward to operate a throttle and brake lever with the same hand.

[ZapPat]

The old Xooter EX3 had a bi-directional throttle that operated regen in one direction. I don't think it would be easy to implement this kind of feature on the Infineon, but it would be a nice feature.

Any idea where we could get such a dual-direction twist-type hall throttle (center return)?

Or maybe a lever-style hall throttle (linear) to be used as a regen brake? This might be easy to make with a couple magnets, a metal strip and a linear hall sensor (as used in the twist throttles - A1302 from Allegro, digikey #620-1022-ND) mounted to an old brake lever. The chip's output changes depending on it's position between the north and south magnetic poles. Might be a fun project if nothing exists out there...


On/off type regen braking (meaning single strength) is probably usefull but also kind of limited, although if "pumping" (ramping up/down of regen power) implemented in the controller's software it would be more acceptable since we could then modulate the regen power this way.

Using the regular throttle as a regen control during braking could be a problem if you were on full and suddenly let off the brake (it would go from full brake to full throttle).

I was wondering about this myself, and have read that a number of controllers force you to stop moving before changing modes (golden motors), but then force you into the permanent "engine brake" style drive/regen. No coasting. Does the infinion do regen via throttle in this manner? Knuckles showed us where we can activate it in the software interface, but I think there is also an input that can enable/disable all regen on the fly. It seems to me that to make this type of regen control safe, the controller should only do the switch to/from regen mode when the throttle is droped to zero.


I wish I could do more tests outside with both controllers, but it's about -20oC here and there's tons of snow! I'm looking into a front ski conversion and screws in the back tire to take care of this problem soon!

[StevenR]

Please excuse the excursion from theoretical to practical.

My motor is a C'lyte 5303 and the battery is a Ping v2 48V20aH with a Crystalyte 4840 controller. I enabled regen and saw 5 to 10% regen on the Cycle Analyst over the course of several hundred miles. I disabled it when I blew up the caps. I am considering upgrading the caps on my backup controller and re-enabling it, given this discussion.

When regen was enabled the phase wires to the motor got warm - perhaps even hot. They never seemed at all warm when regen was not enabled.

My question for this wise group is this: Does the C'lyte regen actually work? Am I pushing juice back into the battery or am I just heating up the wires because the voltage is below battery voltage?

On a related note: Can I enable regen on the ebikes.ca model C7248SI 36-72V 48A Start Immediate Digital Controller withIRFB4110 Mosfets in the same way I do it on the standard C'lyte controller (I would put the ebrakes and cruise control on as well)?

If the C'lyte does not work, what is a good regen controller? Curtis? Kelley? Other?

[Knuckles]

It seems to me that to make this type of regen control safe, the controller should only do the switch to/from regen mode when the throttle is dropped to zero.

The Infineon regen appears to be "smart". It follows an algorithm of sorts.

So no problem with WOT while braking and then releasing the brake.

Also no heating effect of motor, controller or harness. Just very nice braking with reverse current to the bats.

The regen works great. I just use it.

Very cool also. I tap on my rear brake handle (right side) and my front DD hub slows me down.

Regen_Test_Setup.jpg

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