View Full Version : regenerative braking article (update)..
okay, this is an open source-please add corrections and edits-article.
this is a first cut, so check it out.
http://www.bookofseg.com/regenerate/
cheers,
pt
Brooster
02-01-2003, 05:00 AM
I'd love to know more about it, PT. Braking requires at least as many HP as acceleration ... so, how could this actually store energy?
Brooster
when you're going downhill breaking, you get to keep some of that energy. i think i see more of this due to my hilly commute, for most folks i don't think this will as extreme.
cheers,
pt
http://www.bookofseg.com
emanresu
02-01-2003, 06:22 AM
Brooster, regenerative braking transfers the mechanical energy of going downhill back to the batteries. Instead of using energy to "apply" brakes like you do in your car (in the form of using up brake pads, using muscles in your leg to push the pedal, and using fuel even while you are braking) the gears are set up to "hold you back". While they are doing that, they charge your batteries. It's not a 100% return (i.e. you usually can't get a mile of travel uphill for a mile of travel downhill) because of mechanical and electrical inefficiencies, BUT people here on this forum seem to be indicating it works pretty well on the Seg.
emanresu
02-01-2003, 06:27 AM
It would be fun to test by taking your seg to a high mountain in your car and see how far you could go on a charge.
i've been able to arrive home on almost a full charge after a 4 mile trip due to the hills i've taken, for route planning and experiments i've tried to optimize so i have more than enough battery and still travel very far.
cheers,
pt
http://www.bookofseg.com
emanresu
02-01-2003, 07:07 AM
You're right about that being a lot of travel in a year, let's hope they last longer, though. My experience with rechargeable devices is that it is most desireable to fully discharge them before recharging. So the real question, from a practical standpoint, may be how long the battery life is when they are subject to repeated PARTIAL charges. This is what most of us will do- we'll go out for a couple of two milers, and then worry about getting caught with our charge down, and recharge often. PT- have you had, or will you have the opportunity to let your Seg sit for a period of days, and then report to us on the "standby" life of the charge, unit not hooked up? I'm curious about that.
GlideMaster
02-01-2003, 01:43 PM
If my memory serves me correctly I think the Honda Insight has regenerative braking.
<center>The GlideMaster</center>
<center>http://www.geocities.co.jp/Athlete/1267/gif/segway.gif</center>
<center>Glide On</center>
motleyorc
02-01-2003, 02:45 PM
The Segway people tell new owners not to let the batteries go down to empty if possible. Since there is no memory effect, they are to be topped-off as often as possible.
http://www.segwayceleb.com
BruceWright
02-01-2003, 02:51 PM
A whole bunch of points here.
The problems with repeating partial charges to batteries is confined to the old Nickle-Cadmium rechargable batteries. They would aquire a "memory" or a new baseline when they would partially drain. Nickle-metal Hydride (Segway) and Lithium-Ion batteries have no such problems.
As long as you're going downhill, you could ride your Segway for hundreds and hundreds of miles. THAT would be fun! Drive one to Pike's Peak in your car!
Regenerative Brakeing is used in every commercial Electric and Electric/Gas hybrid car being sold today. It's cheaper than bigger batteries!
Regenerative brakeing works because electrical motors are electrical generators operating in reverse. It's the same thing going on. In an electric motor, electrical energy is converted into mechanical energy. Spinning motors are moved by pulsating electromagnets that are powered by electrons, or if the spinning is faster than the motor is made to drive it, the electrons flow from the generator/motor toward the battery. Mechanical energy is converted into electrical energy and stored in the battery for when they are needed. (Electrical engineers can help me out with descriptors here.)
-Bruce Wright
Segway: Vehicle of Dream
quote:Originally posted by emanresu PT- have you had, or will you have the opportunity to let your Seg sit for a period of days, and then report to us on the "standby" life of the charge, unit not hooked up? I'm curious about that.
i've left the ht unplugged for a couple days and there was not a noticeable loss (at least that is what the gauge reported).
cheers,
pt
http://www.bookofseg.com
motleyorc
02-01-2003, 03:12 PM
I wonder if somebody will come up with a more accurate battery meter someday. Didn't somebody say that the key area is a very minor power source. If so, it would probably have enough juice to run a small voltmeter.
http://www.segwayceleb.com
motleyorc-
i've never had any accuracy issue so far, it's been really good (60 days, 200 miles) heavy use.
cheers,
pt
http://www.bookofseg.com
quote:Originally posted by GlideMaster
If my memory serves me correctly I think the Honda Insight has regenerative braking.
<center>The GlideMaster</center>
<center>http://www.geocities.co.jp/Athlete/1267/gif/segway.gif</center>
<center>Glide On</center>
Yes, and so does the Prius.
Pam, a proud Honda Insight owner
BruceWright
02-01-2003, 03:47 PM
Yes, and the Hybrid Civic, the Hybrid Accord and the Electric Toyota Rav-4 and the Ev-1 and pretty much every electric vehicle (why not, when it's so easy to do!)
-Bruce Wright
Segway: Vehicle of Dream
okay, this is an open source-please add corrections and edits-article.
this is a first cut, so check it out.
http://www.bookofseg.com/regenerate/
cheers,
pt
http://www.bookofseg.com
Brooster
02-01-2003, 10:41 PM
Looks good PT.
Brooster
2totango
02-02-2003, 02:53 AM
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Thanks again pt. We do indeed appreciate your passing on these tibits and largebits. We'll almost feel like experts when we finally get ours.
pdantic
02-02-2003, 07:27 PM
quote:Originally posted by emanresu
It would be fun to test by taking your seg to a high mountain in your car and see how far you could go on a charge.
Hey, if someone wants to bring their Seg out to Colorado this summer, we'll go to the top of Vail Pass and then see how far east we can cruise on a single charge. There's a bike path that goes from the top all the way over to Silverthorne/Dillon, and it's downhill most of the way. Of course, you'll have to let me ride it at least part of the way!!!
Steve
www.pdantic.com
Automobiles:
"They contained the seeds of their own destruction. Eighty million steel juggernauts, operated by imperfect human beings at high speeds, are more destructive than war."
-- Robert Heinlein, "The Roads Must Roll"
CVINTON
02-02-2003, 07:41 PM
Regenerative braking would only apply if the Seg were turned OFF or coasting in such a maaner as not to engage ANY electronics. If you brake at all during the downhill ride, as the seg does, it probably wouldn't get you all that much charge.
Brooster
02-02-2003, 08:02 PM
Welcome to the board Cvinton. Mind sharing your source of information on Segway's regenerative braking capabilities? Many of us are kind of curious to learn more about this.
Brooster
Deviant
02-02-2003, 08:12 PM
One of the Segway employees said that she glides to work downhill, but charges her HT at home before leaving. Because the batteries are full, the regenerative breaking causes the speed to be limited. Otherwise it wouldn't have any way of braking if you went at full speed, since there would be no load on the generator to cause the momentum to slow down.
CVINTON - If you ride the HT at full speed, then lean back to cause braking, the HT has to charge the battery to cause braking to happen. i.e. the unit is on - braking is performed by the friction of the generator which charges the battery.
i don't that that could be accurate, i lose 1/4 to 1/2 of my battery going up a very steep hill in seattle each day, and i get most of it back going down.
cheers,
pt
quote:Originally posted by CVINTON Regenerative braking would only apply if the Seg were turned OFF or coasting in such a maaner as not to engage ANY electronics. If you brake at all during the downhill ride, as the seg does, it probably wouldn't get you all that much charge.
http://www.bookofseg.com
GadgetmanKen
02-02-2003, 10:04 PM
The regenerative braking technique has been around I believe since the early telephone. Crank the handle to make a call and talk into the mouthpiece on the wooden box type. Soldiers since at least WWII have been using the wind up boxes to generate electricity to make radio transmissions to call the base, correct? Same technology as what the Seg does in a way. Only you're not winding the handle, the wheels are doing that. Funny how things sort of come back around after time. There's new flashlights, radios and cell phones out that you wind up for about a minute to get your time spent on the device with out buying batteries. Who would of thought?
"Wouldn't it be cool, if?...is like Folgers in my cup"
CVINTON
02-03-2003, 12:15 AM
My esperience with regen is through my experience with builing Battlebots (combat robots) When a DC motor is spun it becomes a generator and sends current back into the system it is connected to and consequently the battery(s).
This only takes place at "coast" and not if power is applied to the motor.
On a seg, you never actually "coast" since the motors are constantly responding. Hence my comment that the Seg would have to be "off" and coasting to get regen braking.
BruceWright
02-03-2003, 01:09 AM
There are two brushless DC motors that act as 4 independent circuits. Thus you can regen at the same time as you are powering.
-Bruce Wright
Segway: Vehicle of Dream
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