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Makes And Models => Zero Motorcycles Forum | 2012 and older => Topic started by: ZeroSinMA on March 24, 2012, 09:35:12 AM

Title: 2012 Zero regenerative charging
Post by: ZeroSinMA on March 24, 2012, 09:35:12 AM
Appreciate hearing from 2012 owners about experiences with the new regenerative braking and coasting. How quickly do you slow when coasting in either sport or eco mode? Does it feel anything like engine braking on a ICE bike when in gear?  Does the regen braking feel natural or does the braking feel weird? Thanks!
Title: Re: 2012 Zero regenerative charging
Post by: protomech on March 24, 2012, 10:49:20 AM
Regen braking in eco mode feels a little bit lighter than [engine braking for] my 500cc gas bike, but it's enough that I can generally let off the lever and slow to 10 mph or so with no problems. Regen braking in sport mode is very light, almost unnoticeable.

Generally the braking feels quite good. Sometimes there's a bit of hysterisis if you have the throttle not quite resting on the neutral stop, eg the bike will do a pulse of regen then let off, pulse and let off, etc. Otherwise, I like it.
Title: Re: 2012 Zero regenerative charging
Post by: Marshm on March 24, 2012, 11:11:04 AM
I would prefer a selection for regen braking so the rider can choose.  I can see how higher regen braking in sport mode might be desired. 
Title: Re: 2012 Zero regenerative charging
Post by: flar on March 24, 2012, 02:25:02 PM
Not knowing much about the bike other than my seat of the pants feel on a test ride, I came to the conclusion (as I ran out of juice on 2 of their bikes during 1 test ride ;) that the rear brake lever was hooked up to a regenerative braking switch.  At least on both the S/ZF6 and DS/ZF6 that I was riding it felt very anemic as a brake and I could hear a very machine like whining as I applied it.  When I was on blinking lights trying to make it back to the dealership I tried to extend the range as much as I could by using only the rear brake to slow down (and I had to help with the front brake to get it actually stopped when I couldn't cheat and roll through).

Does anyone know where I could look at an owner's manual online or confirm with their documentation that the rear brake triggers regen?  Or was I just imagining things in my range anxiety?
Title: Re: 2012 Zero regenerative charging
Post by: craigq on March 24, 2012, 06:00:05 PM
The XU manual shows regen braking active when the throttle is in the fully closed position. No idea for the S/DS...
Title: Re: 2012 Zero regenerative charging
Post by: Richard230 on March 24, 2012, 09:10:17 PM
Quote from: flar on March 24, 2012, 02:25:02 PM
Not knowing much about the bike other than my seat of the pants feel on a test ride, I came to the conclusion (as I ran out of juice on 2 of their bikes during 1 test ride ;) that the rear brake lever was hooked up to a regenerative braking switch.  At least on both the S/ZF6 and DS/ZF6 that I was riding it felt very anemic as a brake and I could hear a very machine like whining as I applied it.  When I was on blinking lights trying to make it back to the dealership I tried to extend the range as much as I could by using only the rear brake to slow down (and I had to help with the front brake to get it actually stopped when I couldn't cheat and roll through).

Does anyone know where I could look at an owner's manual online or confirm with their documentation that the rear brake triggers regen?  Or was I just imagining things in my range anxiety?

Flar, If you PM me with your email address, I will shoot you a copy of the 2012 S and DS 120 page owner's manual. It is about a 4 MB-size file.

On my bike, I find the regen in Sport mode to be barely noticeable. When in Eco mode though, it is much more noticeable, feeling more like a 4-cylinder IC motorcycle in 3rd gear with the throttle shut. I do not notice any increase in regen effect with the brakes on, compared with the effect with only the throttle closed, in either mode.   ???

Title: Re: 2012 Zero regenerative charging
Post by: flar on March 24, 2012, 11:32:29 PM
Quote from: Richard230 on March 24, 2012, 09:10:17 PM
On my bike, I find the regen in Sport mode to be barely noticeable. When in Eco mode though, it is much more noticeable, feeling more like a 4-cylinder IC motorcycle in 3rd gear with the throttle shut. I do not notice any increase in regen effect with the brakes on, compared with the effect with only the throttle closed, in either mode.   ???

Just to be complete, you did say "with the brakes on" plural.  Have you tried just the rear brake?  Is there any way to measure that?  (I didn't see any "regen braking" light on the small dashboard so it was mostly seat-of-pants feel that I was going on.)

On the two bikes I rode the rear brake had a very odd feel to it which led me to that hypothesis.  To be sure, the bikes do have rear rotors and pads, but the pedal feel gave me no impression of the typical feel of pad against rotor and the response was the most anemic I've experienced.  Granted, rear brakes are usually not that beefy and are usually adjusted a bit low to prevent lockups, but this seemed to go beyond that.  And, I could stop the bike with the rear brake, but I had to press really hard to do it (harder than it would take to lock the rear on any other motorcycle).

(Keep in mind I've only owned 2 motorcycles and test driven or borrowed only about 7 or 8 others...)

One thing I would like to see is a 3rd mode, sport + heavy regen braking.  I don't see why I should have to give up max power to get good regen - the two should be independent variables.  Some electric cars allow you to control the regen braking settings which seems to be because new drivers can be thrown a little by the effect when rolling off the throttle, but in my test drive of a Tesla Roadster, which has fairly effective regen braking in all modes, I actually loved the behavior and grew into it nearly immediately.  (And, yes, I'll admit that I'm shopping electric motorcycles as a nod to have a poor-man's Tesla. ;)
Title: Re: 2012 Zero regenerative charging
Post by: Richard230 on March 24, 2012, 11:49:46 PM
Hello Flar. Yes, I have tried both front and rear brakes, individually and in combination. I couldn't tell that the regen effect had increased when using the brakes.

The Hayes brakes seem to have very hard pads and feel "wooden" in their action, when compared with the Brembo brakes on my BMW motorcycles. However, if you press on them hard enough, they stop OK.  The "Tiger" brand brakes on my GPR-S feel very similar in their action, however I had the controller programmer for that bike and could alter the regen effect from 100% to 0%, which made a dramatic difference, naturally.  On that bike, the regen is activated by the stop light circuit. Getting the right level of regen took a lot of trial and error. Frankly, the Zero is not bad in that respect. A lot of regen can be fun for a while, but then it becomes something of an irritation as you will slow down more than you really want to.

A Zero employee told me that they are working on a way to allow customers to alter some of the programming of the controller, which would likely include increasing the regen effect, but he didn't indicate if or when this may actually happen.

I received your PM and will be sending you a message shortly.
Title: Re: 2012 Zero regenerative charging
Post by: flar on March 25, 2012, 01:08:15 AM
Thanks for the manual!  It seems to indicate that it is controlled by a switch that activates when the throttle reaches the home position ("to coast without the regenerative braking, hold the
throttle just off of the fully closed position").  The salesman I went on the test ride with seemed to imply that the brakes would kick in regen braking.  It would certainly be nice to have the rear brake kick it in so that you had that option to coast effortlessly (without having to maintain pressure on the throttle) or to bleed off some speed with regen by just pressing lightly on the rear brake...
Title: Re: 2012 Zero regenerative charging
Post by: RickSteeb on March 25, 2012, 10:13:12 AM
I think the throttle needs to be the exclusive mode of invoking the regen, as the motor physically can't do both drive and regen at the same time.

I like the idea of customer-adjustable regen effect; e.g. I think it would be logical to have a stronger regen in sport mode, to compliment the stronger drive when you twist the grip the other way!
Title: Re: 2012 Zero regenerative charging
Post by: Lipo423 on March 25, 2012, 12:29:30 PM
I have only tested a ZF9 once and I found the regen braking very light...I would agree with the suggestion of having in controlled by the throttle, as it makes a lot of sense -a different aspect is to find the right combination of switches & sensors between the throttle, motor & brakes.
I also found -as Richard pointed out- the brake pads a bit hard -you definitely stop the bike, but you need to brake a little hard for my taste.
I had the opportunity of driving a Tesla a few times -and the genen braking is very hard- but you get real energy back to the battery.
I guess that when thinking in a two weel drive vehicle you need to find a good compromise as if the rear wheel slips you could find yourself having a ride at the ground level  :-\
In any case, I would definitely like to see more control from the user side on the regenerative braking.
Title: Re: 2012 Zero regenerative charging
Post by: flar on March 25, 2012, 03:01:34 PM
Quote from: RickSteeb on March 25, 2012, 10:13:12 AM
I think the throttle needs to be the exclusive mode of invoking the regen, as the motor physically can't do both drive and regen at the same time.
Since it is controlled by a switch anyway, and thus is "regen by wire", this would really just be two switches.  If the throttle switch isn't engaged, it won't do it anyway, but once the throttle switch is engaged then the rear brake switch can trigger either yes/no regen or low/hi regen depending on the mode or the rider's independent preference.  I could see it configured by default so that in ECO you get strong regen with just the throttle and the brake switch doesn't have any more to add and then in SPORT mode it gives light regen from the throttle (simulating what a typical rider might expect from engine braking on an IC motorcycle) and then the rear brake kicks it up to max regen.
Title: Re: 2012 Zero regenerative charging
Post by: ZeroSinMA on March 25, 2012, 07:53:27 PM
Thanks everyone for the replies and thoughts. One additional question: Does the regen make a sound? flar mentioned a whining sound. Any owners hear that?

All in all I'm of a mind to wait until the 2nd gen of the new Zero battery and regen tech... after they iron out the bugs ala the wooden feeling rear brake. And I expect they will add user adjustable capabilities that are programmable by iPhone via wifi, including the power curve and regen behavior. And I hope they add one gear. They don't need more than one to move the torque curve out beyond 45MPH.

(http://i39.tinypic.com/33ol25d.png)

Title: Re: 2012 Zero regenerative charging
Post by: Richard230 on March 25, 2012, 08:14:29 PM
I don't notice any unusual sound when the regen is activated. But then I wear earplugs all of the time while riding.

The wooden brake feeling could most likely be resolved by installing more aggressive HH brake pads, which would improve the braking power also.  My guess is that hard brake pads were chosen because Zero thought that the assistance of the regen would allow them to us harder pads and thereby extend their life.  (It is also possible that the pads chosen were a little cheaper than more aggressive brake pads. It is also possible that different pads are not available for Hayes brake calipers.  I need to do some research on this company. )
Title: Re: 2012 Zero regenerative charging
Post by: trikester on March 25, 2012, 10:53:22 PM
On my 2012 DS ZF6 I have wondered if I can get more distance in town in SPORT or ECO? As far as I can tell there is no regen braking in SPORT mode, just the normal drag of the motor being turned by high gearing (big rear, small front). ZERO lit would also indicate that there is no regen in SPORT no matter whether you are braking or throttle at rest. It would seem intuitive that with regen in ECO one could get more distance (I'm speaking urban riding here). However, what I notice is that when I'm riding SPORT mode I can get off the throttle farther back from a stop and coast to where I do the final brake stopping. In ECO mode I'm on the throttle longer getting closer to the stop because the bike slows so quickly when the regen kicks in. Since ZERO says that only 25% of the energy is returned to the battery in regen (ECO) mode, my experience is beginning to indicate that the extra coasting distance I get in SPORT mode may balance out the energy return to the battery I get in ECO mode. This of course assumes that I do the same acceleration curve, in either mode, as I leave a stop. "Jack Rabbit" starts can really eat up the energy in SPORT mode, so that has to be made equal in both modes for the question I'm asking to be valid.

It would be interesting if a number of city riders would do mileage tests in both modes. My guess is that there would not be much difference but that is only from the small amount of testing I have done so far.

On the open highway there would obviously be no difference in the two modes, unless it was a lot of very steep hills where you could actually coast all the way down in ECO mode. I haven't found a hill that steep yet.  :o

Trikester


Title: Re: 2012 Zero regenerative charging
Post by: protomech on March 26, 2012, 01:09:32 AM
I coasted down a .. probably 15% grade today @ 25 mph, regen was useful for holding my speed down the grade. Suspect it has little real effect, but need some better instrumentation to verify.

Even riding the same route twice under the same conditions, the regen effect will probably be lost in the instrumentation margin of error. Maybe you could use distance to the disappearance of a certain bar, although I don't know how repeatable that is.
Title: Re: 2012 Zero regenerative charging
Post by: flar on March 26, 2012, 02:08:21 AM
Quote from: ZeroSinMA on March 25, 2012, 07:53:27 PM
flar mentioned a whining sound. Any owners hear that?
That could probably have been just as easily explained by really hard pads on a drilled rotor come to think of it, so don't read too much into that comment...
Title: Re: 2012 Zero regenerative charging
Post by: flar on March 30, 2012, 01:14:22 PM
I just found this on the Zero S "features" page:

Quote
  • Quad-level regenerative system recharges the power pack when decelerating
  • Re-gen level is increased during brake application vs. “neutral” deceleration
  • Both braking and “neutral” re-gen levels are set higher in Eco vs. Sport mode

It would be nice to see a breakdown of when the "quad" levels come into play.  Does that mean that there is regen while coasting on Sport?  Does braking induce more than one additional level of regen?  I could see the easiest breakdown would be based on the 2 switches (eco/sport vs. brake light) simply being 2 binary bits that choose a level with the throttle switch being an enable switch:

T = throttle switch on
E = echo switch on
B = brake light switch on

T- E* B* = no regen
T+ E- B- = regen level 1
T+ E+ B- = level 2
T+ E- B+ = level 3
T+ E+ B+ = level 4

Or maybe the middle two could be the other way around?
Title: Re: 2012 Zero regenerative charging
Post by: protomech on March 30, 2012, 06:36:10 PM
There's at least two levels of regen braking before you hit the actual brakes IIRC. Sport does regen while throttle is in the neutral position, but the amount of regen is no more than half that in Eco mode.

It's difficult to distinguish regen braking from normal braking.
Title: Re: 2012 Zero regenerative charging
Post by: dkw12002 on March 30, 2012, 06:59:27 PM
What would convince me regeneration was working was if a bar CAME BACK as I was braking going down a hill. My battery displays regenerative stopping. If I have 4 bars, stop and turn off the bike, then in 20 min. start up again, I have 6 bars. I'm convinced this is no quirk either cause the 2 bars I gained do not suddenly disappear. Something has happened in the chemistry that has produced some more energy from the batteries, I think. By the way, this happens with my e-bikes and even an electric weed wacker but to a much less degree. After a rest, you gain some energy. If I ever thought I was going to run out of battery and had 10 miles to go, I would stop the bike, wait a while, then continue. I think this might give you some extra electricity to limp home although I don't know if it would be good for the battery.
 
Title: Re: 2012 Zero regenerative charging
Post by: Richard230 on March 30, 2012, 08:35:33 PM
Speaking of regen, yesterday I had my bike fully charged when Ieft my home. I live at the top of a 1/4 mile long hill and keep the throttle closed all the way down. I had my bike on Eco mode and noticed that the regen drag jerked off and on down the hill. It did the same thing while coming to a stop at an intersection a short distance further. But on my way back home, after draining the battery pack of a couple of bars, as I was riding down another steep hill, I did not notice the jerking any more.  My guess is that the fully charged battery pack was not happy accepting the current created by the strong Eco mode regen until the pack had discharged somewhat. It appeared that the controller was cutting it on and off until pack had been partially discharged.

I might add that I do not notice the same jerking, under the same circumstances, when in Sport mode.

Having owned an electric motorcycle without regen, I can tell you that the Sport mode does generate drag (and I assume power at the same time) when the throttle is closed. My first non-regen GPR-S would really coast with the throttle closed and felt very much like a two-stroke with the throttle off - or a standard motorcycle coasting with the clutch pulled in. There is definitely more drag, even in Sport mode, compared with coasting in "neutral".

Finally, I can tell you that regen provides very little power replacement during your ride, compared with not having it.  My second GPR-S had regen set at 100% and the most I ever saw was a 3% power generation over a long ride with lots of hills. Most of the time the power generated was less than 2%. So don't expect regen to extend your range by much. Mostly what it does is to cut down on your brake pad wear and make the bike feel more like a 4-stroke IC motorcycle. 

Keep in mind that the vast majority of your ride is with your throttle open and not closed. Even when the regen is activated, the amount of power produced is much less than the amount of power consumed by the motor. Regen helps some, but not much.
Title: Re: 2012 Zero regenerative charging
Post by: Lipo423 on March 30, 2012, 09:23:21 PM
The BMS is definitely "managing" the situation here, and avoiding potential over-charging your battery.
As I have said in a different post I own 2 Tidalforces (Electric bicycles) these bikes were made in 2002-2004 and they did have regenerating braking, cruise control, and probably the quietest electric motor I have ever seen in my life.
Regerating braking is more a "marketing thing" or braking thing than a real advantage, you normally get around 10% back to the battery, no more. When designing the system you have to be carefull as the current raises suddenly, and drops the same way...it is very difficult to manage such changes without putting the battery at risk, so you end up with little current back to the battery.
I only remember once when I was riding this bike (it had two regenerating settings, one when riding over the max. set speed and another one -harder- when braking)recovering 20% of energy in a +20% grade 7 Km downhill.
Title: Re: 2012 Zero regenerative charging
Post by: protomech on March 30, 2012, 10:48:17 PM
My bike doesn't regen at all in Eco mode when it's pulled hot off the charger. It takes maybe a half mile before I start to notice regen effects. The same thing applies to the Nissan Leaf btw - part of why the Nissan Leaf has two piston front brakes (http://blogs.insideline.com/roadtests/2011/03/2011-nissan-leaf-suspension-walkaround.html) that in normal use are barely used.

An electric motorcycle (540 lbs with rider) with a 8 kWh pack can tolerate a much higher regen current than a e-assist pedal bike (300 lbs with rider) with maybe a 200-500 Wh pack.

Compare an EV car vs EV bike, vehicles start from rest, accelerate to 40 mph, then regen brake (50% KE back into pack).
1. Nissan Leaf uses 300 Wh for the mile. KE = 256 kJ (http://www.wolframalpha.com/input/?i=0.5+*+1600+kg+*+%2840+mph%29%5E2) or 71 Wh. Say 35 Wh back into the pack or 12% regen.
2. Zero S ZF9 uses 100 Wh for the mile. KE = 39 kJ (http://www.wolframalpha.com/input/?i=0.5+*+245+kg+*+%2840+mph%29%5E2) or 11 Wh. Say 5.5 Wh back or 5.5% regen.

The controller, motor or battery may be a further limiting factor. The EIG cells I think Zero is using have a maximum recommended 0.5C charge rate .. though they may be able to accept a higher charge pulse from regen braking.

Without a tool like a cycle analyst I think it's hard to say how much you actually are getting back. I suspect it's on the order of 3-5% at best.
Title: Re: 2012 Zero regenerative charging
Post by: dkw12002 on March 30, 2012, 11:31:05 PM
Even then, if the slowing down results in a slight charge, this may not equate to more distance because had you not slowed down, the bike would have gone faster and used less energy getting up to speed at the bottom of the hill.  It is only if there is a stop sign at the bottom of a steep hill, or with stop and go traffic that you would actually gain anything from regenerative braking.

Speaking of e-bikes. I get really great range with mine because I seldom stop at stop signs and I cut across parking lots making the distance and stopping time shorter than if I were riding a motorcycle or car. While riding an e-bike in this manner is not legal, I have never yet seen anyone stopped on a bicycle for anything. They ride on the sidewalk, don't stop at stop signs, do U-turns, cut across parking lots, etc.  Even if you did get stopped, you would not lose points on your license because you don't need a license for an e-bike. The police could still fine you and confiscate your bike of course, but this is very unlikely. The fact bicycles are ridden by children and still thought of as a toy works to your advantage in this regard.  Something to think about if you do a lot of in-town riding only.
Title: Re: 2012 Zero regenerative charging
Post by: flar on March 31, 2012, 12:06:18 AM
Quote from: protomech on March 30, 2012, 10:48:17 PM
The EIG cells I think Zero is using have a maximum recommended 0.5C charge rate .. though they may be able to accept a higher charge pulse from regen braking.
With 3 accessory quick chargers you end up charging the ZF6 pack in 1.8 hours.  Given the non-linear nature of the charging, it is probably a bit higher than 0.5C for that first hour, no?
Title: Re: 2012 Zero regenerative charging
Post by: protomech on March 31, 2012, 12:46:02 AM
My onboard charger typically charges between 850-950W and appears to be ~93% efficient, so probably delivers 800-850W to the pack.

Three additional accessory chargers would bump the charge rate to 3.2-3.4 kW.

For a 5.3 kWh battery that's a 0.64C charge rate (0.43C for the 7.9 kWh battery).

I would suppose Zero has either qualified the battery pack for those charge rates beyond EIG's specifications, has a slightly tweaked chemistry for higher charge, or limits the chargers when 4 are connected.

@dkw, you're correct that you're most efficient by slowing via coasting instead of regen. In a world of stop lights and traffic you don't always have the option to coast to a stop. The gate I go through each day is on a 55 mph restricted-access road and has posted 35 mph and 25 mph speed limit signs approximately 0.25 miles before the gate. In practice traffic moves at 60-65 mph and in morning traffic people will ride on your ass at that speed until the 25 mph speed limit sign.

If traffic permits, my Honda Insight can slow from 55 mph through regen only by starting approximately 0.35 miles out from the gate. It has a maximum regen of 50A (144v system voltage), or about 7 kW slowing ~2000 lbs. Probably around 7C into the ~6 Ah pack.

The Zero can slow from 55 when I hit the 25 mph sign (maybe 0.15 miles from the gate?) .. maybe 4 kW + drag slowing 540 lbs.
Title: Re: 2012 Zero regenerative charging
Post by: Richard230 on March 31, 2012, 03:38:10 AM
I might have mentioned this before, but my sepex GPR-S was programmed from EMS with 100% regen and came with a Cycle Analyst display. I once got the bike up to 70 mph (that big motor was not happy about that) downhill, touched the brakes to activate the regen and the CA showed that the motor was producing 60 amps (at 80 volts) into my 50 Ah battery pack. But that generation only lasted a few seconds until the drag slowed the bike down to 50 mph (30 amps) and then 10 amps at about 30 mph. The problem is that this power is only generated when you are slowing down and you just don't do that for very long, compared with the length of your typical trip.