# Poke holes in my plan please



## O'Zeeke (Mar 9, 2008)

Hi Cricha5 and welcome to the insanity, IMHO those ideas sound good but would be more practical if your car was totally electric and currently using drivebelts for the A/C, ps etc. If you want to get off cheap and Lo Tech with your A/C you may want to look at 
http://www.instructables.com/id/Portable-12V-Air-Conditioner---Cheap-and-easy%21/
and use your car's A/C as a backup. Mine lasts for more than an hour in Florida and cost less than 50 $ to make. Takes some time to dump it out and add new ice but much less time than takes to do those modifications. Good luck with your project


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## cricha5 (Jun 21, 2008)

Thanks for the ideas. I'd really like to go all electric, but I just can't afford it. All I can afford is about 1K for a project to help me save some gas, some carbon, and some money and have fun doing it.


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## Woodsmith (Jun 5, 2008)

I know some heavy trucks have had electric retarders installed on the transmission/prop shaft. Consists of a rotor on the shaft spinning in a set of coils. Whether they apply current to retard or dump current that is generated when retarding I can't remember (25 years is a long time for the old grey matter to remember) but it might be a good place to start looking.


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## cricha5 (Jun 21, 2008)

Interesting. I will definitely look there. Thanks!


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## cricha5 (Jun 21, 2008)

I checked out those electric retarders. They look almost exactly like the the thing I was first thinking of. But the commercial ones are HUGE. http://www.zelusl.com/ These guys made an excellent 80's dance/scifi video about retarders and you can see how big they are.


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## cricha5 (Jun 21, 2008)

I've seen you guys put together two electric motors to make one that switches the way the current connects, like in that drag car. So there must be a motor out there with a shaft that goes all the way through to the other end. I'd like to put something similar but smaller on my driveshaft. Know what kind of motors these are?

I don't really think this will end up working btw. I think the more likely situation is putting a chain or a belt on my drive shaft and turning a motor from that.

Either way, what kind of motor could handle the energy required to brake a 2500 pound car? Think I'd have to run the power through capacitors to capture all that energy, or will charging the battery take all the load?


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## Woodsmith (Jun 5, 2008)

cricha5 said:


> I checked out those electric retarders. They look almost exactly like the the thing I was first thinking of. But the commercial ones are HUGE. http://www.zelusl.com/ These guys made an excellent 80's dance/scifi video about retarders and you can see how big they are.


Well they need to be to slow down 40 tons of commercial vehicle! 

You could have one on the transmission open circuit and just apply a load on it when you want to slow down. I am sure you can find a motor with a shaft on each end but that will be difficult to fit and support. Better would be a pulley between the drive flange on the back of your transmission and the UJ on the prop shaft. You can then install the motor to the same mounts as your transmission so that they move as one unit.

Is isn't really a practical solution really and you would be better off just going for a full EV with regen breaking.


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## cricha5 (Jun 21, 2008)

http://www.electricmotorsport.com/store/ems_ev_parts_motors_ac-induction.php

This looks like it would fit my needs. Might be possible to get these parts, or similar, a lot cheaper used. That with a chain connected to the driveshaft near a driveshaft bearing that connects to the chasis. Put a wheel on the driveshaft big enough to keep the motor under it's max rpm's, or vice versa. I do wonder, however, if I'll get enough power out of braking to keep the car running off the batteries without having to turn the alternator on (at least in the city). I've also gathered that the car actually runs on around 14 volts rather than 12, so that would be an issue. I also am starting to worry that the imbalance to the driveshaft due to a connected chain might make this all an impossibility. Maybe if I add another driveshaft bearing...


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## Bugzuki (Jan 15, 2008)

I think that this would work, but would probably be least expensive by using an alternator instead of a motor. You could just have the larger alternator connect to the drive shaft and not to the engine. Then it would only run while the wheels were turning. It should be able to produce enough power while moving to keep everything running while stopped.

The only reason that there is 14.4 volts in the car is because that is what it takes to charge a 12volt battery to capacity. Everything works perfectly at 12volts.

It would probably be best to have a clutched alternator attached to the engine incase the batteries were dead. If you only had the driveline setup with dead batteries you would not be able to start and idle the car until you were moving. You could probably still push start the car.


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## coil_nine (Apr 22, 2008)

cricha5 said:


> I would like to get enough power from this to switch to an electric water pump, fan, a/c, etc.


THERE is your heart's desire, to make your system more efficient. Powering those units is the critical parameter. HOW you do it is secondary.

OK, regen braking. Any time you or I touch the brakes, we are losing. If we can drive by touching the brakes very little, then we gain overall efficiency. Hypermilers get their results by using the brakes as little as possible. (Yeah, I have read the articles that describe max eff. by going up and down in speed for regen, but that is only a hybrid drive vehicle)

So, regen gains you almost nothing on highways, very little in open suburbs, and most in total city driving. I have a very large Grand Caravan and have changed from 18 mpg up to 23 mpg just by gentle accel and almost no braking. Decide on your driving habits.

The fan designs in water pumps are very inefficient, total crap. You will get significant changes in efficiency by replacing the stock pump with a high efficiency pump and perhaps a different pulley (larger pulley that makes it turn slower.) Also very helpful are electric water pumps powered by your existing alternator. Here is a catalog: http://www.stewartcomponents.com/Stewart_faq.htm

Fluid power steering is always a drag on your motor. Search for electric power steering, which uses energy only when needed. Toyota used this. Your current alternator and battery can probably manage it. The electric assist motor is right on the steering shaft of these units. Replacing your current wheel and steering shaft is a problem if you can't find a 1:1 drop-in. Search the net for examples of electric power steering units, and then get a used one.

I think the AC compressors in cars are very well designed, but cars are un-insulated metal boxes. The best way to get more AC efficiency is not to use it. Consider a belt-drive AC. It has an electric clutch which cuts in ONLY when needed, other times it is simply a low-friction pulley. If you go to electric and re-generator, then you have generator and motor losses. That is actually less efficient than the mechanical setup.

You can greatly increase the overall system efficiency of an IC vehicle. *Wanna almost double your mileage with almost no cost and no tricks? Real, not a hoax.*

*Carpool with a friend.*

Think about it. If two people go to the same destination, then the vehicle is getting nearly twice the mileage. Sure you have a social cost. I think we will have to get used to that cost.


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## BigAlum (Jun 12, 2008)

Here's something I believe is relevant to the _current_ discussion:

http://www.motortrend.com/features/editorial/112_0803_technologue/index.html

This was an article in _Motor Trend Magazine_. It also contains information on the British Company that makes this system. I've never bought the notion that all-electric is more efficient than mechanical regeneration braking. There is an inescapable loss in conversion from mechanical to stored electric energy, as well as reconversion from electric back to mechanical. I've thught about this being a good way to use expended braking power to operate your air conditioning system while at a stop?? BTW - The most efficient electric retarders for trucks was a system with LARGE generators mounted on the trailer axles. These, IIRC, were not used for regeneration, as the current used to brake the rig was simply shunted to the frame to provide the load. These were abandoned as being too heavy and (at the time) too complex to control from the driver's seat - I'm thinking it was too much technology for the drivers to adapt to without extensive retraining in driving practices. They were quite powerful, though: 500hp (250hp on each axle) worth of braking power is a lot, even for big trucks.


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## cricha5 (Jun 21, 2008)

I don't buy it either that switching to electric gains anything in the long run. I think it wastes energy. My car already has a clutch on the ac compressor and a viscous clutch on the fan and the alternator only draws what it needs, and the water pump pumps what it needs.

I'd like to put all that on electric and power it from braking, but if I just powered it with a larger clutched alternator, I think I'd lose.

Regarding the flywheel F1 thing. I think it's great. It's a really great simple solution. I would totally get one for under 2K in a second. If they were available.... I have a feeling that this is one of those things that looks like it's just around the corner, but never actually makes it to us.


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