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why does no one do this?
By donald77777, Section Homebrewed Electricity Posted on Thu Apr 24, 2008 at 04:28:23 PM MST
just throwing it out.

I was just wondering why no one makes a setup for when they are driving to take the energy that is being used to spin the wheels, to charge up batteries. Think how much better the hybrid cars could be. I was just wondering so do not mock me to hard. I was thinking of doing something like this as an idea. All I need is money. Lol the problem of the world.

why does no one do this? | 22 comments (22 topical)

Re: why does no one do this? (3.00 / 0) (#1)
by AbyssUnderground on Thu Apr 24, 2008 at 10:30:12 AM MST

Remember, you can't make energy from nothing. There is always a loss when extracting it too.

If you extract it from the wheels, whatever is moving the vehicle has to work harder to provide the energy you're extracting. If its a combustion engine then what you have basically made is an over-complicated generator...

http://www.repowered.co.uk - My Renewable Energy site.
msn[at]m3ezw.co.uk - my msn if you want a chat.

Re: why does no one do this? (3.00 / 0) (#2)
by wooferhound on Thu Apr 24, 2008 at 11:05:39 AM MST

-quote-
"take the energy that is being used to spin the wheels, to charge up batteries"

The Alternator does this already . . .
W o o f -={(

Re: why does no one do this? (3.00 / 0) (#10)
by Ungrounded Lightning Rod on Thu Apr 24, 2008 at 07:44:45 PM MST

In particular, hybrid cars do EXACTLY this. That's the whole point.

When accelerating they pull power from the batteries and put it into the wheels to assist the engine. (They may even not run the engine.) This lets them work with a smaller engine, which is thus running at a more efficient part of its RPM range most of the time. (It's also less weight to haul around - which helps to make up for the weight of the batteries and motor.)

When braking they pull power from the wheels and put it in the batteries, rather than wasting it as heat in the brakes. Most of this power can be used to get the car moving again later, letting stop-and-go driving have mileage nearly that of highway cruising. Ditto when going down hills to recycle power for going up the next one.

When cruising they can run the engine a little harder if the batteries are down and store the power for later, use power from the batteries to fight a wind or go up hills if the engine would otherwise be running fast enough to have an efficiency drop, or even shut the engine down and run on batteries for a while. Again the engine usually runs close to its maximum efficiency - or not at all.

And if it's a "plug-in hybrid" (i.e. a hybrid with a lot of battery capacity and an onboard charger) you can plug it in at night to top off the batteries and do a small amount of commuting the next day without even running the engine. Just like an electric - except that when the batteries get too run down the engine starts, rather than the car stopping.

(You can also limp to the repair shop or gas station on pure battery power if you have engine trouble or run out of gas.)

Electric or electromechanical transmissions can also simpler and lighter than ordinary manual or automatic transmissions. (The one on the Prius is especially cute: One permanently engaged planetary gearbox (compared to one per "gear" plus a torque converter and lots of other stuff for an auto, one set of gears and synchronizers per gear" plus a clutch and shift linkages for a manual) plus a second electric drive motor.

[ Parent ]

Re: why does no one do this? (3.00 / 0) (#3)
by zeusmorg on Thu Apr 24, 2008 at 11:13:04 AM MST

Think about it,, where is that energy coming from? Put a heavier load on the "wheels"
you'd need a larger engine to have any forward momentum.. ya can't get something from nothing,, that's called over-unity.

Re: why does no one do this? (3.00 / 0) (#4)
by kurt on Thu Apr 24, 2008 at 11:51:30 AM MST

you better be careful you keep up this line of thinking we will have so send someone after you with a "clue hammer"

IRC inst.
just a personal rant carry on.

Re: why does no one do this? (3.00 / 0) (#5)
by Jon Miller on Thu Apr 24, 2008 at 12:52:13 PM MST

donald77777,

do you mean along the lines of regenerative brakes that use generators as brakes?

Jon M

www.otherpower.co.uk "I am certainly not a perfectionist, the thing is to know where you can take short c

Re: why does no one do this? (3.00 / 0) (#11)
by donald77777 on Thu Apr 24, 2008 at 09:03:06 PM MST

Yes, this was mostly what I was thinking. Eg. For instance, let us take a pickup truck, big lots of unused space in the back. You would use regenerative breaking when stopping to recharge the battery. in the back of the truck you could remove the part of the liner and run lets say belts from your wheels to power a generator ( not very tough gears, would kill your gas mileage)gears that are kind of low do not interfere. In addition, a row of batteries that would be being charged from driving and braking that could be used to help offset the gas usage.
I might just be needing to be whacked by a clue hammer (wink) but I have had this in my mind for at least 10 years, and just was thinking it could work.

[ Parent ]

Re: why does no one do this? (3.00 / 0) (#16)
by wooferhound on Thu Apr 24, 2008 at 11:29:33 PM MST

It would be much simpler to just charge the second battery from the alternator. It is designed to do exactly what you are talking about. It wold present a larger load to the engine and use more gas. All of your ideas here will use more gas. Using gas to charge batteries is really expensive. It would be way cheaper to charge the batteries with a battery charger plugged into the wall outlet.

W o o f -={(

[ Parent ]

Re: why does no one do this? (3.00 / 0) (#19)
by richhagen on Fri Apr 25, 2008 at 02:25:22 AM MST

For braking, not a problem, my hybrid does this now to some extent. If you are going to induce drag on the wheels spinning a belt and turning an alternator while driving down the highway, and then use some of that energy captured to spin a motor to help propel you down the road, you will find that in every conceivable scenario at a steady speed you will be using more additional gas to keep spinning the alternator because of the added drag than you will save by using the energy captured in a motor to help propel you. It is basically only worthwhile if you want to take the kinetic energy of the vehicles motion and turn some of it into electrical energy rather than the thermal energy of normal breaking, or if you are going to use a smaller gasoline engine in general and supplement the peak acceleration with an electric motor, which is what hybrid cars do now. Now if you were going to charge the batteries from another power source, kind of like a plug in hybrid, that would be a different analysis. Rich
'A Joule saved is a Joule made'
[ Parent ]

Re: why does no one do this? (3.00 / 0) (#21)
by electrak on Fri Apr 25, 2008 at 10:55:33 AM MST

Donald
look up transwarp motor ( not from trek ) it's a dc motor with drive shift flanges on it to do where ( no man has gone before ) part of the drive shaft goes, then you use electric power to help get you going, and idealy help you stop and recharge, NetGain is the company that makes them but the do not offer a controller that does regen, yet

[ Parent ]

Re: why does no one do this? (3.00 / 0) (#6)
by GeeMac on Thu Apr 24, 2008 at 02:18:29 PM MST

I've wondered why there are not magnets in cars and coils in the pavement. But your idea might help to recharge a battery.
Jesus is coming. Try to look busy. GeeMac

Re: why does no one do this? (3.00 / 0) (#17)
by wooferhound on Thu Apr 24, 2008 at 11:31:39 PM MST

Magnets in the road and coils on the car would create magnetic drag and you end up charging the batteries with gasoline again.

W o o f -={(

[ Parent ]

Re: why does no one do this? (3.00 / 0) (#7)
by asheets on Thu Apr 24, 2008 at 03:09:17 PM MST

Probably a better idea to try is building a linear generator into your shock absorbers. , then drive exclusively on bumpy roads.

I'm only half kidding, as somebody tried it once... Google "bose linear generator suspension".
_____________________________

Alan Sheets

Re: why does no one do this? (3.00 / 0) (#8)
by joestue on Thu Apr 24, 2008 at 03:33:49 PM MST

Actually i thought of this, after seeing first hand what kind of movement is there, even on a relatively flat road.
It wouldn't really extract any useful energy, u'd get better gas mileage by having an adjustable shock, and driving on aircraft tires @100psi.

Watts compared to horsepower, its a 1-2% savings on a 20% efficient engine...spend your effort on the biggest problem.

[ Parent ]

Re: why does no one do this? (3.00 / 0) (#14)
by Ungrounded Lightning Rod on Thu Apr 24, 2008 at 09:21:36 PM MST

Actually the power turned into heat in the shocks is a significant part of your "rolling friction".

It's why auto designers work so hard to keep the "unsprung weight" (the part that bounces up and down) low. Every time you hit a bump a bunch of your forward momentum is stolen to accelelerate the wheels and associated stuff (brakes, control arms, axles, ...) vertically. This energy would then make them (and/or the car) oscillate on the springs until it is dissipated as heat. The job of the shock absorbers is to initially let the wheels jump up (but snub them before the suspension bottoms out), then quickly throw away that energy so the car stays stable. As a result, the more unsprung weight the worse your mileage on not-slick-as-glass roads. It's NOT trivial.

So, just like regenerative braking, active electrical shock absorbers could potentially scavenge essentially all of this energy while simultaneously doing their shock-absorbing function. (And if the electronics is right they could do the shock-absorbing function even better than a passive hydraulic system.) Result: Just as regenerative braking makes stop-and-go mileage approach that of cruising, this could make bumpy-road mileage approach that of operation on smooth roads. You might also be able to cruise down a corrugated road at speed as if it had just been regraded.

Downside: If you thought the power levels involved in electric propulsion and regenerative braking were enormous, hold onto your hat when considering the energy dissipation rates (i.e. power level) in a shock absorber. (Fortunately they're short duration.) No batteries here - supercapacitors are the way to go.

[ Parent ]

Re: why does no one do this? (3.00 / 0) (#15)
by Ungrounded Lightning Rod on Thu Apr 24, 2008 at 10:27:28 PM MST

You might also be able to cruise down a corrugated road at speed as if it had just been regraded.

Indeed, the power-driven hydraulic system that Chrysler experimented with a few decades back worked just about that well. The techie accidentally drove the thing off a cliff when demoing it for a visiting exec and the exec thought it was part of the demo. B-)

Worked really well - or so it was claimed. But about a complicated as an auto tranny (or several of them). And it made the car bank into curves. B-) Distracting other drivers by banking into curves was the official reason they shelved that system. But I bet it was really mothballed because the complication of all that active mechanical-computer hydraulics (and potential problems if it failed, with two flexy-hoses per wheel) made it too expensive and risky even for a luxury car.

[ Parent ]

Re: why does no one do this? (3.00 / 0) (#9)
by spinningmagnets on Thu Apr 24, 2008 at 06:20:01 PM MST

On the electric bicycle forums, a few enthusiasts have gone to the extra trouble to get a controller and motor that allow the "Regen" function.

This is where on a downhill (or when just slowing down) the motor begins functioning as a generator to recharge the battery, and recover some of the energy that was used to get up the hill.

Regen adds so much resistance, you almost dont need to use the brakes. In fact, the amount of regen is adjustable, as using the max regen will snap you to an abrupt halt.

Driving with regen "on" at the same time is like driving with the brakes on a little, no free lunch, and a lot of wasted heat.

"Here, the streets are made out of a special material that we pay extra taxes for, it is called "pot holes" -Deronmoped @ VisforVoltage.com

Re: why does no one do this? (3.00 / 0) (#12)
by donald77777 on Thu Apr 24, 2008 at 09:05:37 PM MST

lol my old house in the country where I lived was cold rolled. In addition, we had potholes so big, because the city will fill them with asphalt and it would kill the road further when it broke down within 3 days. It was fun lets say.

[ Parent ]

Re: why does no one do this? (3.00 / 0) (#13)
by donald77777 on Thu Apr 24, 2008 at 09:07:52 PM MST

Or in your wheles put magnets and make a generator out of all 4 wheels eg like a wind genny, but on the road.

Re: why does no one do this? (3.00 / 0) (#18)
by donald77777 on Thu Apr 24, 2008 at 11:39:39 PM MST

Well thankyou everyone for crushing my hopes. (lol) Now I just need a new idea to get stuck in my head besides automated christmas displays and RE projects lol.

They do it this way (3.00 / 0) (#20)
by Norm on Fri Apr 25, 2008 at 03:29:40 AM MST

You can actually do this with a home brew EV
an electric motor hooked to the wheels thru a
variable speed transmission from a snowmobile
add a small 8 or 12 hp engine to charge the batteries.
Your speed is controlled by the transmission ....
the higher the ratio the faster
and slowing down you downshift and regenerative
braking....basically it's that simple.
Popular Science had plans to build an EV
with variable ratio like this ....regenerative
braking helped increase the range....especially
city stop and go driving.
That was back in the 70's....
There is even a gas engine car that uses basically such
a variable transmission made from wedge shaped
cross sections of steel strung together with 2
strands of steel cable running in an oil bath.
( :>) Norm

Re: They do it this way (3.00 / 0) (#22)
by elvin1949 on Sun Apr 27, 2008 at 11:33:36 PM MST

Subaru Justy cvt,I started to buy one in 1989.
later
Elvin

[ Parent ]

why does no one do this? | 22 comments (22 topical)

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