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[Justin Andrews]

To be honest I'm more interested in reducing physical wear and tear on my brake pads & disks.

[cloroxbb]

Trikester, are you not concerned about locking your rear wheel on loose ground or wet tarmac?  I imagine 100% regen is equivalent to pressing quite hard on the rear brake pedal?

Im with liveandletdrive on this one.  I can't imagine that approaching a stop light, for example, at speed and then slowing suddenly with 100% regen will recover more energy than rolling gradually to a stop with 25% regen (or whatever is standard.)

100% regen doesn't mean 100% braking. It means that it will use the max regeneration that the motor can handle, which would not be the same as the output of the motor. So I highly doubt that the wheel will lock up since nothing is actually physically impeding the movement of the tire, just the reverse flow of electrons thru a magnetic field that slows the motors spinning. Or at least that's how it works on the Tesla. Just a guess, I guess

[LiveandLetDrive]

Model S has traction control, though I'm not sure how it interacts with the regen.  (I work there but I'm in the thermal group.  I'll have to ask a friend in chassis.  In other news we have a number of Model S, Volt, and Leaf owners (and some conversions, other brands, and electric scooters), but I think I'm the first with a Zero!)  The FX's regen is absolutely enough to lock up the rear on loose ground as I discovered Sunday.  Deceleration is by definition impedance (in both the electrical and mechanical senses), and you could just as well say the "forward" flow of electrons speeds up the motor's spinning.  Motor and generator are reversibly equivalent, minus efficiency losses.  Next time I ride dirt I will have regen off entirely, unless it is much harder packed than the dust-dunes I was dealing with this time.  It has only rained once in the last 6 months here.  Riding downhill in the loose stuff I wanted less rear brake than I was sometimes forced to have.

As for pavement, I'm still learning what my preferences are and putting 100% regen on only with the brake light certainly gives you more control but my argument is that there are times that you aren't on the brake but are still decelerating and that's the regen you're giving up my making it effectively manually controlled.  Maybe that's not such a common thing as I imagine it to be, or maybe it's just sloppy riding, but it seems to me like regen is more about the many small decelerations and less about the less frequent big ones.  If you're consistently coming down a big incline every time you ride then what you describe is probably right.  I tend to be about 70% fairly flat city streets, 30% steep but rolling San Jose hills.

I'm starting to like having some variation in the regen with throttle-off rather than 100% right away, it would be good to have a linear progression instead of a wall of regen.  I'm test riding a coworker's Vectrix this afternoon so that will be informative.  I'll be open to mods some day (S cast wheels for street tires soon) but I should probably own it for more than a week before chopping up my most reliable vehicle.  Regen all the way to a near stop sounds great.

[BSDThw]

The limit for regeneration is the current you will allow to your battery.

My 2012DS ZF9 has 120Ah it will handle 60A cont - but not more than 1c = 120A max for braking.

To accelerate you would be able to use 1200A = 10C so the 420A is easy for the battery.

[NoiseBoy]

Trikester, are you not concerned about locking your rear wheel on loose ground or wet tarmac?  I imagine 100% regen is equivalent to pressing quite hard on the rear brake pedal?

Im with liveandletdrive on this one.  I can't imagine that approaching a stop light, for example, at speed and then slowing suddenly with 100% regen will recover more energy than rolling gradually to a stop with 25% regen (or whatever is standard.)

100% regen doesn't mean 100% braking. It means that it will use the max regeneration that the motor can handle, which would not be the same as the output of the motor. So I highly doubt that the wheel will lock up since nothing is actually physically impeding the movement of the tire, just the reverse flow of electrons thru a magnetic field that slows the motors spinning. Or at least that's how it works on the Tesla. Just a guess, I guess

Yes i appreciate that 100% only means the maximum allowed by the controller, but that is still a significant amount of braking.  If you unload the rear wheel with the front brake, it doesnt take much to lock the rear.

[Doctorbass]

To accelerate you would be able to use 1200A = 10C so the 420A is easy for the battery.

yes as well but the "big" Powerpole 175 connector to the battery would begin to melt in a minute  as well as for the contactor

btw did i mentionned that i  95% charge my DS9  at 90amp pure DC with only a negligible increase in temp of the battery The nominal measured capacity i have is  exactly the specified Ah (120Ah) wich mean i'm charging at 3/4C and the battery handle that very well. I would not worrie about setting regen to 120A... but the rear wheel would fall in tractoin mode wich might be  a risk for stability..

[trikester]

To address the question of my locking the rear wheel in loose terrain with max regen: That is why I set the SPORT regen, with brake light, at 15% and the ECO regen with brake light at 100% regen (equal to 25%). When I'm riding in loose terrain, where it would be easy to lock my rear wheel, I ride in SPORT mode so that my brake light only gives me 15% instead of 25% (100% ECO max).

Any other time I'm off the throttle I'm coasting which is the most efficient way of slowing.

BTW - In loose sand one never has to hit the brake light. As soon as the throttle is rolled off you are stopping rapidly, in any mode. 

Trikester

[LiveandLetDrive]

Any other time I'm off the throttle I'm coasting which is the most efficient way of slowing.

Again sorry to nitpick, but this is false.  Coasting is more efficient if you don't need to slow down, I will agree with you there, but if you are slowing, recovering some of that energy is always going to be better, for obvious reasons.

[trikester]

Again sorry to nitpick, but this is false.  Coasting is more efficient if you don't need to slow down, I will agree with you there, but if you are slowing, recovering some of that energy is always going to be better, for obvious reasons.

That is exactly what I have been saying in all of my postings on this subject. Go back and read them. I'll even repeat it again for the umpteenth time: If you don't need to slow - coast, if you need to slow use regen. How can you say what I said is false if it is exactly the same thing you just said?

One problem with these forums is that people don't always read them carefully.

Trikester

[LiveandLetDrive]

Any other time I'm off the throttle I'm coasting which is the most efficient way of slowing.

If you don't need to slow - coast, if you need to slow use regen.

Maybe proof-read what you're saying so you don't contradict yourself before you criticize others' reading comprehension. The second quote is consistent with everything else you've said in this thread and I agree, the first is not.  I am disagreeing with the former which is patently false, particularly the phrase I've now underlined.  If it just wasn't phrased correctly, no big deal!  Maybe I'm being pedantic but I wanted to make sure we weren't contradicting physics and confusing anyone.

[Marshm]

I think we understand.  Not everything can be worded perfectly and sometimes on motorcycle forums we are thinking of some real riding situations where we used some of the things discussed on forums, so they have to be understood in context.  On some mountain trails on the way back down I am using engine breaking a lot, so that would be a great place to be using regen instead.  I guess I could pull in the clutch and coast on my gas bike, but actually I seldom ever do it on purpose for the sake of coasting.  So I really do not have a good idea of coasting on offroad trails.  When I do use it, I usually end up going too fast. Like pulling in the clutch down a steep hill will get rid of the engine breaking you had, and if you can't get your foot on the brake pedal to slow that rear wheel, you are probably going to speed up.  There is a tight right hand corner with a cliff on the outside.  It is such a tight turn and so scary that I go so slow that first gear will stall, so I have the clutch in, but it is still steep so I have to stay on the breaks and the front is the only one I can use since my right foot is off the pegs.  I hate that corner.  Still not a rear brake lever on the handle bar for 2014?  That lever would work well for this corner.  Full regen would help also, and I wouldn't have the stalling problem with electric drive.  Not sure how much slowing regen would provide when going at a walking pace.   

[trikester]

     Any other time I'm off the throttle I'm coasting which is the most efficient way of slowing.

I'll explain what I meant. O wish you had included the quote in your first reply and I could have addressed it. I didn't know that statement was what you were referring to.

I wasn't talking about going downhill in this statement. I was thinking about when I'm riding street and approaching a stop sign or light (usually fairly level) in light traffic and I get off the throttle well back from the stop. I will coast and also be very slowly decelerating just like on a bicycle. Then when I get close to the stop I'll come to a stop using regen. That gives me many more feet of coasting than if I had some amount regen going all the time even without the brake light. With some amount regen all the time I would have to stay on the throttle longer.

Since regen has losses and the coasting losses are always there anyway, regardless of regen I stand by the statement and it follows the laws of physics. Coasting is more efficient to cover more ground while slowly slowing.

I say it is more efficient to coast for 500 feet and then use regen to stop in the last 100 feet, than to use the throttle for 500 feet until 100 feet from the stop. Obviously I don't always do this especially if a vehicle is on my tail in heavy traffic, or if I'm in a hurry.

I hope that clears it up. I guess since most of my threads were about going downhill and I suddenly changed to city stop & go riding, I can see how it would be confusing.

I obey all laws of physics at all times. 

Trikester

[WindRider]

It is good to obey physics laws. 

I have also noticed that any post on this forum about regenerative braking is akin to "what is the best oil for my motorcycle?" on one of the ICE motorcycle forums.   

[cloroxbb]

So....about those Regen settings

[trikester]

So....about those Regen settings

My settings: SPORT = no regen with no Brake Light. 15% regen with BL
                   ECO = no regen with no BL. 100% (which is actually 25% regen) with BL

What actually happens is the the SPORT Mode = 0% regen with no BL has to be programmed by a dealer (unless you are Doctorbass and a few others). That dealer can also set the BL regen for SPORT. I personally like 15% for riding where I don't want heavy regen. If I am riding where I'm wanting more regen braking I will switch to ECO to get the full 100% (25%) max, which I have set with my iPod.

When ECO Mode regen is set to 0% it will be whatever the Sport Mode no Brake Light regen is set to. In my case that is 0%. So in order to get no regen with no BL in ECO you have to first have set SPORT to no regen with no BL. ECO will only go down to what SPORT is set to for the no brake light situation. At least that is how it appears to work on my bikes.

Years ago I read about a record gas powered mileage run. The vehicle was on a track, I don't remember the vehicle description, but it could coast free without engine connection. The driver would accelerate slowly to a certain speed and then coast down to a certain lower speed. They did this over and over until 1 gallon of gas was used. The mileage was about 1500 mpg (I don't remember the exact figure).

When I was a teenager a friend and I used this technique to travel many miles when the model A Ford (converted to a desert buggy) we were driving was almost out of gas and we had no money (no credit cards in those days, cash only). We even coasted all the way down the Cajon Pass in SoCal. When I got home I drained the remaining gas from the tank to see how much was left. It was 1/2 cup.

Trikester