Looks like my poor mans Hybrid just might have merit!

[Nerys]

I came up with an interesting idea a few months back. I saw a voyager with AWD and though HUH did not know it came like that.

I thought it might be neat to PUT the AWD rear axles in my voyager but not the T case IE add in an electric motor with a simple relay on off switch to boost MPG.

Well it looks like others are thinking the same thing and even have prototypes built!!!

http://tinyurl.com/4dhyhk

Very cool! and retrofitable to ANY FWD car!

[SVOboy]

Sounds pretty sweet...are you willing to spend the money though?

[Nerys]

$3300 for a kit? NO (plus its damned ugly :-) $400-$500 to do it myself as planned using the AWD axle YES. This just gives me a little extra incentive that if a company is willing to do the R&D to make it happen then that tells me the idea has at least some merit.

[JohnnyGrey]

Simple relay isn't going to cut it. You'll need a specialized control system for this. The MPG increase comes from:

1. Regenerative braking
2. Being able to move without the engine running

[MetroMPG]

The idea (electrically driven rear axles in FWD car) comes up a lot, but I've yet to see anyone implement it, DIY.

I did speak to a guy who did it for fun with an old Tercel 4wd wagon, but it was basically a science project in a junkyard car; I don't think he ever drove it on the road.

JG's right: you'd need much more than a relay. Don't forget batteries too! Either heavy and bulky (lead acid) or super expensive (Lithium).

[cfg83]

Frank -

Originally Posted by Frank Lee

Yet another awesome thing about Tempos: there was an AWD version and it would be SO EASY to power the rear wheels of a FWD model by getting one or two of those hubs!

Ooooooh, and you got the skillzzz to do it!

I really like this because I am "pro-retro-fit". There's too many normal cars out there that could be improved. But the $3300 price tag is steep.

Frank, do you think you could you make this up yourself from your own "kit O'parts"?

Details :



CarloSW2

[Nerys]

No a relay is enough. If I do a 72v system I am thinking 3 speed. 24v 48v 72v 3 buttons.

Press button one when maxed press button 2 when maxed press button 3. IF it has enough torque screw all that and just go 72v from the get go. One button.

I am not looking to make an electric car. I have NO expectation of being able to MOVE a 3700 pound minivan on a junkyard EV motor alone. I want to "assist" the ICE enough to dramatically increase fuel economy. Thats all. MAYBE even enough to let me FAS for miles at a time on nice level or sloping terrain at cruise speed. Who Knows :-)

No controllers no nothing. Just "jack" in the power and GO. the "controller adjustment" is the piece of carbon sitting in the drivers seat with his foot on the accelerator :-) IE I adjust the ICE throttle as needed.

I am thinking sickeningly simple here. AWD rear axle DIRECT DRIVE to the Electric Motor.

Motor connected directly to the batteries simple "on/off" via the button controlled relay. Thats it. Heck the drive wires would only need to be 3 feet long as I would put the batteries in the back cargo area directly above where the rear axle is.

I can get junkyard WORKING car batteries for $18 a pop. So $108 in batteries $125 for the axle assembly (complete) and whatever for the EV motor hopefully another junkyard or freebie find. I already have a good 60amp continuous charger on hand. And whatever that beast of a relay is going to cost. the MOMENT I have to think about "controllers" this project is a non starter. I do not have that kind of money.

No Regen. No Pure EV. etc..

IF and ONLY if it proves itself functional THEN I can look into better quality batteries.

Eventually if the MPG gain is sufficient to warrant it I want to go NIMH powered. IF I can figure out a feasible way to CHARGE it I can build a 30amp hour 72volt nimh pack for $900 - Every time I have an extra $300 I can add another 10 amp hours to the pack.

Lithium is not an option for me. Far to expensive Far to unreliable Far to wasteful and far to short lived relative to there cost.

But first I go the $108 junkyard pack path to see if it will even work well enough to be worth the effort. I am seriously going to attempt to do this over the summer. Just got to find a motor :-)

[i_am_socket]

Cool idea! That kit would be a bit more sexy if you used wheel skirts instead of just an arm.

I kinda miss my Tempo. You never forget your first ;-)

[JohnnyGrey]

Your idea would be more like half car, half EV, not so much a hybrid. A few points to consider...

1. When the motor is assisting the ICE, it's pushing it down into a less efficient part of the BSFC map. You'll be getting considerably less power from the ICE, but it will only be using a little less fuel.

2. Selectively switching battery banks to get different voltages will discharge them at different rates, and has the potential to even reverse charge them!

I would rather see a well-engineered design than you blowing money and time only to half-ass it and give up after disappointing results.

Remember the Accord Hybrid. Same V6 as the regular Accord (not to mention millions in R&D), just with motors added. Economy was worse than the 4cyl version.

[Jetta90GL]

I had an idea awhile ago for an electric motor assist. Rather than add another drive axle I thought of just adding a motor to the engine serpentine belt of my truck. Or on a front wheel drive transverse engine have a long shaft and put the motor over the transmission. It would probably have to be a separate stronger belt and pulley.

[bhazard]

What happens when you are moving without using the electric motor? Are you gonna have some sort of clutch on it so the back wheels dont turn it?

How about an alternator being turned by the wheels too so you can get some recharging when youre not using the motor.

Sounds like something that would really be useful in stop-and-go traffic.

[Nerys]

I am not sure. My original idea was a free wheel like on a bicycle. IE spins freely when no force is applied. I figure "heavy duty" version of that must exist??

[getnpsi]

Ii would love to put an awd axle into my aspire and run a 20hp motor or so. Get the car up to speed, shut off engine or even idle the thing and that would net over 80mpg easy. Scangauges in heavy trucks idling coasting in N say they are getting over 50 mpg over 30 mph. I dont think you'd need all the batteries of a full replacement as you arent using it from a dead stop like OEM hybrids do. Supplementation I think is an angle not many are really considering. Some people with full electric conversions are just charging the batteries and running them down, with no way to recoup power as they drive. You can always just charge your stuff overnight and drain independant of your ICE.

[Nerys]

Exactly. Two completely independent system. To the ice it would be like I am suddenly going downhill or something so I could "let off" the gas a bit as the E motor took up some of the drain.

When I get home or get to work I "plug in" to recharge the batteries.

as for offset draining. No I would always be using "all" of the batteries just in different variations of parallel and series connections.

For example lets say I have 6 batteries. Thats 72v. if there 6 in series. what if I do 2 sets of 3 in series and run those sets parallel. Now I have a 36v pack with twice the amps IE still using ALL the batteries IE still evenly discharging them.

I do not care if I only get a 10mpg boost. I do not care if I get NO mpg boost. the ideal is to see if it WORKS at all at a price that can fit in my nearly non existent budget. Thats why It has to be dead simple I can NOT afford a "controller". as soon as one becomes mandatory this project becomes a non starter. I just do not have the cash. If I had that kind of cash lying around I would not be so concerned about fuel economy :-)

If it works at all then the idea has merit THEN I can safely spend some serious cash to making it work well. 3-4 hundred dollars I can afford on a "seat of the pants test" 3 grand I can not.

[bennelson]

I was thinking that converting an all-wheel drive vehicle to engine powers the front - electric powers the rear, could work well.

I don't know enough about how four-wheel drive systems work to know all the specifics of actually doing it.

A "relay" to control the electric motor is called a contactor. You can have multiple contactors that will switch a pack of batteries so that all batteries are used at the same time, but rigged either in parralel or serial. All batteries drain at the same rate this way, but you can make the motor go a couple of speeds. This is a very old-school way of doing it, and it makes loud "clicks" as the contactors turn on and off. Check out a Commuta-Car/Citi-Car to see how those work.

There are a lot of Geo Trackers out there that seem like they would be a good vehicle to experiment on for this type of a project.

I would simply control both the motor and engine manually. Run on electric only around town, then turn on the engine for highway driving.

The biggest downside is that you are carrying the weight of the engine and motor and batteries at all times.

[Nerys]

thats ok bennelson. So does the Prius :-) you know what would be REALLY funny. I mean hilarious funny in a very serious way? If I managed to get 50mpg with my junkyard 96 voyager with a jerry rigged awd electric conversion and no electronics. I think IF this works that well and IF enough of us did it consumers would start to have some serious questions for the likes of toyota GM and other auto makers.

I'm not holding my breath. If I get 40mpg I will be tickled pink. If I get 35mpg it will have been well worth it.

Even at 35mpg this would save me just shy of $84 a month. That means it would pay for itself inside of 5 or 6 months.!! Lets see a prius pay back like that. At 40mpg it would save me $106 a month paying for itself in 4 months.

If I somehow manage 50mpg it would save me $138 a month. Thats $1656.00 in savings PER YEAR for a $400-$500 investment. So yeah I really really hope it works :-) Even if I have to replace the batteries once a YEAR it will still pay for itself almost triple every year.

also it does not matter how the FWD/4WD works bennelson if your car is already FWD only. IE you change nothing except the rear axle. You do not even need the T-Case. If you already have a T-Case IE already have AWD I am not sure how it would go since you would now be REMOVING a drive shaft to connect the EV motor. When I flip a shaft on my cherokee once it LEAKED fluid when I removed the rear yoke (the part of the shaft that goes into the T Case) so something would have to be done with that.

Since I am already FWD only I do not have a T-Case at all to deal with. I am just going to yank the entire rear axle assembly from an AWD voyager once I find one springs and all and just bolt it on. Mount the EV motor and away I go. (in theory :-) hehe

Just got to find a motor :-)

[NoCO2]

I'm liking the idea, however, one thing to keep in mind. When you are not using the electric motor, make sure you have some way to disconnect it from the drive train otherwise it may become something like the alternator causing more resistance to the ICE's FE then just the wheels would be without the motor attached. If I were to do this I would do it as follows.

3 way relay contact switch like you're planning on doing and a normal foot clutch like a car (mainly to keep the acceleration smooth. Hit button number 1, slowly release clutch to accelerate, then, hit button two. By this time the clutch should be unnecessary for the transition, then button three in the same manner as two. Then once you max out button three, you will need to have a lever of sorts to put it in almost like a "neutral" gear, so the motor is no longer contacting the wheels so the wheels can spin "free-ish" as they would have before. Then proceed like you would with the ICE. This would give you a jerry-rigged type hybrid in a sense. However, my only concern is with the "clutch" mechanism and the neutral lever. Those things are going to be more expensive then if you didn't use them, and they are also pretty complex parts of the drive train so they're going to be hard to install / machine.

Personally, I would do a little research into motor controllers and see if you can't actually just make your own variable speed controller. Not only will it allow you to have a smoother acceleration, but it will also increase battery life since contact type controllers are less efficient.

[Nerys]

at 3700 pounds I think the mass will smooth things out. Any Motor I get is likely not going to be able to effectively move the vehicle on its own (as if I would be so lucky) I am hoping for something like a Bicycle Sprocket thing. IE you can stop pedaling and it "free spins" I am hoping to find a larger heavy duty version of something like this. would eliminate the need for any clutch or lever.

Worst case I am hoping to do what people do with there alternators. IE removed the electrical load and the alternator free spins for the most part.

Sure it will add "some" load but this increased load should be far far less than the benefit I will gain from the electric motor reducing fuel needs.

For now I am just going to try and "get it working" and see what happens. If it proves unusually effective say I manage to get 50mpg. then I would definitely look into both a controller and regen. IE I could just wait a year and use the saved gas money to buy the parts :-)

If the motor proves powerful enough to handle the load I will first go with a larger batter pack. or work on making a NIMH battery pack.

[Coyote X]

The part that I am planning when I put a rear drive in my metro is to modify the largest alternator I can find to put out 70 volts or so to charge the battery pack with the gas engine. That way if the car is able to drive on electric only once up to speed or whatever the gas motor could just be cycled on and off every so often just to charge the batteries. Then just use a single set of optima or similar batteries that can run the car for a few minutes at full load before needing recharged. Gives the car a lot of flexibility that way by charging it at home or on the road.

I am still looking into different rear drive setups though and if the voyager rear drivetrain is easy to find it might be worth looking into. I figure whatever I end up using I want something common and cheap to find replacement parts for.

If you do find a good awd voyager in a junkyard somewhere take lots of pics of it

[Nerys]

Absolutely - I have an obsession with taking pictures :-) hehe