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Discussion Starter #1 (Edited)
When I met JRP3 on Pennock's Fiero Forum, it was all because of a few threads on alternative propulsion and, more specifically, EV concepts and technologies. Despite my skepticism, he chomped down and hung on like an angry pit bull and eventually convinced me of the merits of electric. My original idea was to turn my daily driver/concept car project into a high performance hybrid, with the original ICE powertrain driving the front wheels, and a complete electric powertrain pushing from behind. The problem was batteries. No matter how we sliced it it was going to be too heavy to even consider seriously.

My how things have changed! First, I now have the Inhaler to fulfill my racing and serious performance goals. Secondly, battery technology has come along way over the past two years. It is now possible, for a price, to put together a battery pack that would give good (street vehicle) performance, without turning the whole package into a bloated, waddling, pig of a car.

I am not 100% sold on doing this yet, but I want to do it. I decided to start this thread to, hopefully, get some input and actively track new technologies and ideas that could make it a reality. I am giving serious thought to starting with a stop-n-go traffic booster system. That way I can get some experience with a low-cost, lightweight, system that can be upgraded over time. So far, all I have for it is a Toyota Celica GTS differential. I had a couple 6.7" motors, but sold them because I want at least an 8 or 9" motor. The smaller motor would have been working too hard to move the vehicle. We're probably talking 5-10mph here, for rush-hour city traffic. I'll keep my eye out for a good deal on a used forklift motor, when I have a few extra dollars.

The biggest issue that kept me from doing this is I will have to build a new subframe for the rear of the car, and cut out some of the factory structure, to fit the electric powertrain. I will also most likely have to build a new gas tank, in a u-shape, to fit the motor between the rear seats (I plan to switch to rear bucket seats). I'll probably extend the tank up a bit higher under the seats to regain the capacity. None of this is really a problem for me to fabricate, I just don't have the time to do it right now. I am currently working on Tailfeather's concept bodywork, and on the Inhaler's chassis, so I don't need to add anything to my plate right now.

Here's what it's going to look like, someday:



The biggest issue I have to figure out is how the two powertrains will be controlled and meshed. I have been toying with the idea of converting the ICE to drive-by-wire. That would allow me to have a switch that can toggle between ICE, electric, or combined. In heavy traffic I can switch the ICE throttle pot off and creep forward with the e-motor, while the ICE idles, keeping all the ancillary systems operational. When the pace picks up just select the appropriate gear and switch over to ICE. With some practice I could probably get pretty smooth with the transistion - plus I have a clutch pedal to ease the ICE back in. Eventually, as I built up more power and range in the battery pack, I can start doing more speed and longer distances with the electric powertrain. Ultimately, it would be nice to have the typical 40-50 mile range on electric, then switch to gas.

Eventually it would be nice to have an electronic control unit to determine what powertrain should be doing what, but that's a long-term goal. I have no problem with manually controlling both systems for a while.

As for weight, I would like to have no more than 400-500lbs in the complete electric powertrain. I have at least a couple hundred extra pounds of fiberglass composite body plugs on the car now. I will shave almost all of that off when the final carbon fiber/composite bodywork replaces it. I think I can remove the other half with more composite panels, careful design of the new subframe, and lots of aluminum suspension pieces. The factory subframe and rear suspension look heavy (all steel).

The car gets 25-30mpg around town, and 35 highway, even with the extra weight and rough bodywork. If I can keep the weight the same or lighter I could continuously improve that with increasing use of the electric powertrain. It should be under 3000lbs total - I'm aiming for about 2800. The reason I can come in that light with two powertrains is it's a 1991 model that was 2700-2800lbs new. The new cars this size are substantially heavier due to crash standards and ever-increasing amounts of creature comforts.

I'll post some pictures of the bodywork being developed if people want to see them. I also have some CAD work I'll dig out and post of a chassis I was working on, and some parts.

Did you really just read all that? :eek::D
 

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i recall a link someone posted a while back when i started on here. there is a company that sells electric motors that are housed inside the bell housing. that might be worth looking into. if i recall right they were touting a 30kw motor in the bell housing.
 

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Discussion Starter #3
i recall a link someone posted a while back when i started on here. there is a company that sells electric motors that are housed inside the bell housing. that might be worth looking into. if i recall right they were touting a 30kw motor in the bell housing.
I want a separate system driving the rear wheels so it will be AWD, and it will justify having big meaty-looking tires in back to match my bodywork. :cool::D

I will likely start with an old forklift motor, but have my eye on an AC-50 system. If I am able to drastically inflate the budget, the 100kw system on Dave Kois' site looks pretty nice. Hmmm, I could put a race-prepped 11" series motor, with a 2K controller for that price! :)
 

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Nice one Todd.

If you use 'drive by wire' you could have the throttle switched from the gearshift. When it goes in neutral the ICE is disconnected both mechanically and electrically and the throttle then controls the motor.
Over rides would be needed though.

You could use a small motor, with low ratio gears, to drive it at such low speeds. A freewheel or sprag clutch would prevent it being overspeeded when driven by the ICE.
You would need to use the ICE for reverse though.

The other week when I picked up my welder the seller showed me some IRS diffs with forward and reverse selection built in. He said they were used for racing and allowed quick swapping of cogs for ratio and a lever on top to change direction either during a diff swap or via a control mechanism during use.
One of those would be good with a freewheel between it and the motor The motor would then be safe from overspeeding and yet still provide slow speed drive in both directions.
Unfortunately I didn't need one and so didn't check out the manufacturer or ratio options.
 

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Discussion Starter #6 (Edited)
Nice one Todd...
Thanks Woody. As I said, this was my original plan it just didn't make a lot of sense until recently. I've been toying with the idea off and on for the past two years. When I did the real numbers on the Inhaler's proposed A123 pack I realized that it is actually possible - for a price.

There is a guy that posts on the NEDRA Yahoo Group that is building a 2000 amp, 345v, pack that will weigh under 150lbs! I think he said he would only have about 25 miles of range, but he is building a dedicated drag racer not a street car. That still caught my interest though because, money being no object, I could build a 50-mile pack with awesome performance... I've since left that Yahoo Group so I don't have any additional info on his pack. I think they're pouch cells.



...If you use 'drive by wire' you could have the throttle switched from the gearshift. When it goes in neutral the ICE is disconnected both mechanically and electrically and the throttle then controls the motor. Over rides would be needed though...
That's an interesting idea. It would take some mental adjustment though, because I am used to being able to rev the motor when in neutral. I might accidentally give it a little blip - right into the car in front of me! :eek::D An override button would solve that, but I would stil have to figure out a practical way to tell it I'm in neutral (car doesn't have a neutral indicator, or switch).



...You could use a small motor, with low ratio gears, to drive it at such low speeds. A freewheel or sprag clutch would prevent it being overspeeded when driven by the ICE...

...The motor would then be safe from overspeeding and yet still provide slow speed drive in both directions.
Unfortunately I didn't need one and so didn't check out the manufacturer or ratio options.
I hadn't thought about motor speed either - good point. My Honda (base vehicle) can easily do 100+ mph. Even though the motor wouldn't be working then it would still be spinning. I need to figure out the sizes on the rear tires I plan to run, gear ratios in the current and future diffs, and see where it will put the motor. I prefer a bigger motor because I want to increase the amount of work the electric does over time. The stop-n-go traffic system is a "cheap" way to get it together and start testing the idea. Ideally, it would be nice to be able to drive on electric for all my errands, eventually. Probably either a 9 or 11" motor would be good for that, considering the weight of the car. Running on 48, then 72, then 96, then 144, etc it would be capable of growing with the system. The other thing is I wouldn't have to redesign any of the hard parts - just upgrade the pack and controller.

The other thing I forgot to mention is this is the vehicle I would like to pull the Inhaler around with. I was considering a turbo for hill-climbing power, but this fits the concept better. If I was towing the Inhaler, I woud be able to tap into its pack too, extending the range...
 

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That's a good idea, the electric capability of the car can grow as battery technology does. The pack may keep the same maximum physical parameters and just increase energy stored.

If yoiu set up with a motor on a low voltage then it will happily drive at slow speeds anyway, creeping up as the pack improves. If the maximum speed of the car is within the safe limit of the motor then it won't matter what it is doing when the ICE is running.

The neutral gear switch can also control a big 'idiot light' on the dash indicating motor drive when the appropriate relays close on the throttle pot.

A loud electronic voice saying 'Warning! Electric drive engaged!' would be fun but annoying!:D
Just thinking of the film Alien where Mother, the Nostromo mainframe, does the count down to self distruct.:D
 

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Discussion Starter #8 (Edited)
That's a good idea, the electric capability of the car can grow as battery technology does. The pack may keep the same maximum physical parameters and just increase energy stored...
Exactly. ;)



...The neutral gear switch can also control a big 'idiot light' on the dash indicating motor drive when the appropriate relays close on the throttle pot.

A loud electronic voice saying 'Warning! Electric drive engaged!' would be fun but annoying!:D
Just thinking of the film Alien where Mother, the Nostromo mainframe, does the count down to self distruct.:D
Idiot light probably (maybe not so big though); loud voice - no way! :mad::)

Some electronic safety features would be a good idea though, like a switch to disable the motor when the brake pedal is being used. I would also want a manual override switch for the neutral switch, to allow me to experiment with combined power.
 

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Todd, why don't you look into the multi-plate systems the soft-roaders are using to switch drive to the rear wheels. Setting something like that to disengage the motor above a certain speed to protect the motor should not be too difficult.

Dawid
 

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GM did a car in 2005 called the Precept , it was alum , electric front drive , diesel 3 cylinder rear drive , 95 mpg , they claimed no one would want one , 4 door , Impala like,I had never heard of it until a automotive engineering mag showed it .
 

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Discussion Starter #12
I had to kidnap this information from the HPG AC30/31/50 owner's thread, for future reference on this project.

Something you might be interested in ...

I have not seen a DC/DC converter in this range, but I run a surplus 5 HP 208V three phase VFD from a 300V (or so) battery pack.

The VFD outputs an pulsed AC wave, but it is easily converted to DC with a three phase diode bridge and a couple of capacitors. There is some AC ripple on top of the DC, but my batteries don't seem to mind

In simple Volts/Hertz output I can vary the output voltage from about 50VDC to around 280 VDC.

Since the VFD is also changing the frequency when it changes the output voltage, the voltage is not as 'clean' below 50 VDC.

I use a 4 - 20 mA signal to the VFD to set the voltage output, sort of a programmable power supply.

Just a thought this might help ...

thingstodo

Hi again,

Sorry about that. I'm a techie at heart. Let me try that again.

A VFD can be used to drop the voltage from it's DC bus voltage (which would be the 300V battery pack you talked about) to a lower voltage, similar to a DC to DC converter.

The VFD sends out pulses at between 2000 and 4000 hz. The amount of time between the pulses lets the voltage 'average' to an lower voltage, but it's AC.

If you connect that three phase AC through diodes, a pack of 6 diodes that's referred to as a diode bridge, out of the diode bridge you get a positive and a negative terminal that can be connected to your secondary battery pack.

To filter the output of the diode bridge, since it is not nice smooth DC, a filter can be connected across the positive and negative terminals. I don't use a filter when charging my 48V battery banks from the VFD. I charge two banks in series so that the VFD voltage is stable.

VFDs of various sizes can be purchased surplus or used from many sources - ebay, auctions, even craig's list. Just make sure that the rated output current is high enough for your application. The 208VAC VFD I have fits well into the 300 VDC range, so that's why I suggested it. My 5 HP VFD is rated for 17A. Multiply by 1.73 for three phase versus DC. It's just under 30A.

I've used my VFD as a DC power supply and in my testing, I found that it does not work well below 50VDC. The range does not quite go up to 300 VDC when I have a 300V battery pack. It only goes up to about 290VDC.

Hope this explanation was a bit easier to follow.

I guess it does boil down to - yes, it's possible, and it doesn't have to be expensive.

thingstodo

To get a bit better response at lower voltages, tell your VFD that the nominal motor voltage at 50 Hz is Vdc(required)/1.73. That way it will generate the desired voltage with high enough frequency that you do not have to go overboard with filters to get it to work. This would allow you to generate really low voltages.

I like your idea - this is really a bit of lateral thinking. Thanks for the tip

Dawid
 

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Discussion Starter #13 (Edited)
GM did a car in 2005 called the Precept , it was alum , electric front drive , diesel 3 cylinder rear drive , 95 mpg , they claimed no one would want one , 4 door , Impala like,I had never heard of it until a automotive engineering mag showed it .
That name sounds familiar, I'll Google it.

I was just outside walking my dog, and a Prius pulled up and stopped, waiting to pick someone up. It sat there perfectly silent, other than the annoying rap music booming inside it, then silently glided away. I could hear the sound of the tires squeaking on the cold, damp, asphalt. Knowing that Tailfeather would be able to do that made me smile, and gave me a little more incentive to go forward with this project. :)

I've been observing a lot of things over the past few days, and thinking about this idea. I like the idea of starting with the traffic creeper system and working my way up. One of the things I love most about electric is there is no real penalty for having more power. I can eventually end up with the equivalent of a few hundred horsepower without sacrificing economy and efficiency.

Okay, one compromise in efficiency because of the meaty tires needed to apply 300hp... :D
 

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I was just outside walking my dog,
Pics?:)

Okay, one compromise in efficiency because of the meaty tires needed to apply 300hp... :D
Thinking silly and a little off the wall here.
How about a central tyre inflation system as used by the military?

When travelling in economy mode the tyres are over inflated and presents a smaller contact patch to the road. When you want to apply the 300hp the tyres are deflated until they squish down to give a bigger contact area.
 

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Discussion Starter #16
Of what the dog?



...Thinking silly and a little off the wall here.
How about a central tyre inflation system as used by the military?

When travelling in economy mode the tyres are over inflated and presents a smaller contact patch to the road. When you want to apply the 300hp the tyres are deflated until they squish down to give a bigger contact area.
H1 Hummers used that type system, I think. Sounds expensive. :)

My other thought was about the wear pattern in the thread. Have to remember to go by the tread depth in the center to not run 'em down to the belts! :eek::D
 

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Of what the dog?
Yeah, dogs are nice.:)




H1 Hummers used that type system, I think. Sounds expensive. :)

My other thought was about the wear pattern in the thread. Have to remember to go by the tread depth in the center to not run 'em down to the belts! :eek::D
That caught me out trying to hypermile into the 80mpg range. Wore away my tyre tread centres and had to get new tyres. Cost lots more then I saved in fuel.:eek:
 

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Discussion Starter #18 (Edited)
My little buddy, he's been with me through thick and thin. He was actually my ex's dog, but I kept him when we split. It was supposed to be until she got on her feet, but we kind of bonded in that time. She has a 4lb Yorkie now.


He appears to be a Terrier/Dachshund mix. He has the spunk, and hunting inclination, of a Terrier and the body length, slew-footed stance, and facial expressiveness of a Dachshund (espcially the big paraniod-looking eyes).
 

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just remembered something about charging batteries with pulsed power . it can run into micro cycles that wear out the battery best I remember .
 

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He is lovely!:)

This was my Mollie.


She was my dog but went off with my ex when we split up but I had visiting rights in the divorce.
She passed away over a year ago now (Mollie, not the ex) and I still miss her.
I've been thinking of getting a Jack Russell type for company (and it would mean my 'honey seat' can be smaller;)) but I don't have a regular home routine so it wouldn't be fair.:(
 
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