# Planning a 1983 Z28 Camaro AC drive conversion.



## RIPPERTON (Jan 26, 2010)

Get rid of all the back to the future mad science capacitor microwave shit,
Get rid of the industrial vfd shit and the 30km range nonsense
And start learning about automotive electrical engineering and design
Give it some time you will find its essentially different to what you know.
Just trawl through some of the on line shops and ponder some of the hardware.


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## Duncan (Dec 8, 2008)

Also: 
lose the flywheel nonsense - honestly it won't gain enough to be worth the weight
Lead acid won't hack it either

DC - 
Comms do wear - 200,000 miles and you will need a service
Comms are NOT inefficient - crude, yes, old fashioned, yes - but not inefficient

I'm not real up on Camaro's - 
but I though that most were "sheep in wolves clothing" - except for the Z28
which did have decent performance - 

in which case it seems a shame to sheepify a Z28


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## ElectroCamaro (Mar 12, 2014)

No, No, and no again. High energy caps are crucial to the design of this car. Capacitors are used for delivering high currents when the load goes up. Lead acid batteries CAN provide the energy necessary to give an EV a moderate range, but can't provide the peak currents because of their comparatively high series resistance. That's what capacitors are for. I'm going to stick to the original design I had planned for this car, sorry.


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## ElectroCamaro (Mar 12, 2014)

If the momentum of a weighted flywheel can cycle a two-tonne press without losing any momentum, a smaller one can strip the shit out of your tires in first gear- Sorry, won't agree with you on that one.


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## Ivansgarage (Sep 3, 2011)

ElectroCamaro said:


> If the momentum of a weighted flywheel can cycle a two-tonne press without losing any momentum, a smaller one can strip the shit out of your tires in first gear- Sorry, won't agree with you on that one.


I have to agree with Ripp and Duncan on this one.

Here is a good thread on flywheels.
http://www.diyelectriccar.com/forums/showthread.php?t=63935&highlight=super+caps

Here is a good thread on caps.
http://www.diyelectriccar.com/forums/showthread.php?t=88559&highlight=super+caps

Ivan


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## palmer_md (Jul 22, 2011)

ElectroCamaro said:


> Has anyone done something similar to this?


Not that I know of in the DIY community. Sounds like you want a KERS system.

http://www.motorauthority.com/news/...-kers-flywheel-hybrid-prototype-what-its-like

I agree with the other comments, that it is much easier to stick with what is known to work, but if you want to try another route it would be interesting to follow your progress. Please keep a build progress thread up to date.


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## Tesseract (Sep 27, 2008)

ElectroCamaro said:


> No, No, and no again. High energy caps are crucial to the design of this car. Capacitors are used for delivering high currents when the load goes up.....


The laws of physics say you are about to get whacked about the head and neck with a stick...

I = C * (dV/dt)
Energy = 0.5CV²


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## ElectroCamaro (Mar 12, 2014)

I knew the formula for energy calculation on a capacitor, but thanks anyway. The HV ones will net 7.2kj @600v, and the low voltage will net 4kj total. Like I said, I know what I'm using them for, and I know what to expect.


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## crackerjackz (Jun 26, 2009)

Tesseract said:


> The laws of physics say you are about to get whacked about the head and neck with a stick...
> 
> I = C * (dV/dt)
> Energy = 0.5CV²


Lol your comments are always funny except when your the one there directed to lol ... This one made me laugh ...


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## frodus (Apr 12, 2008)

That's the total energy in them. The issue is, you're only using them at close to pack voltage. Caps discharge energy linearly, so if you have them tied to the pack to take large current spikes, there's just not much energy stored between the pack voltage and sagged voltage. Its a very small amount of energy.

But by all means, have fun and try to prove it all wrong.



IMHO, you'll get better results using a decent lithium pack and cramming more capacity into the car than the losses you'd see from using lead. I bet you'd use less room with lithium than lead acid and a large enough capacitor pack to matter.


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## dougingraham (Jul 26, 2011)

EC:

You are talking about 75kw peak (basically 100 HP.) That will result in a fairly wimpy Z28. Caps can be used but they are bulky and the electronics needed to extract the energy at usable voltages is going to cost as much as everything else. Clearly you are interested in some performance or you wouldn't be talking about caps and flywheels. Lithium weighs about 1/6 for the usable equivalent energy of lead acid. Lithium displaces about 1/3 the space for the usable equivalent energy of lead acid. Because of this considreing lead acid plus caps is silly. You can make a lithium pack at least 6 times larger at the same weight as a lead pack. And if you make the pack 6 times larger you don't need the caps because you won't get any sag at the power level you are considering.

If performance is your goal there are lots of ways to get there. Since the electronics don't exist in a form that you just buy I would look into alternatives. You can just parallel caps across the batteries but you gain almost nothing if you do this and they take a lot of space.

Look at what the successful drag racers are doing with their EV's and scale it to your application.


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## RIPPERTON (Jan 26, 2010)

The only thing you said right ElectroCamaro was Brushless AC, because they do regen better than anything.
If you read my Mira thread you will see that regen braking is the closest anyone has come to free energy since Nikola Tesla.
I can harvest 2.3kWh out of every 8.5kWh I use and reuse it again. Its like a triple expansion steam engine.
27% free energy. I think that would be interesting enough and all you have to do is fabricate a regen pedal with a potentiometer. too easy.


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## RIPPERTON (Jan 26, 2010)

Ivansgarage said:


> I have to agree with Ripp and Duncan on this one.
> Here is a good thread on flywheels.
> http://www.diyelectriccar.com/forums/showthread.php?t=63935&highlight=super+caps
> Ivan


The safest way to store energy is Lithium.
Sure theres fire hazard IF you puncture a cell but theres hazard in any way you want to store energy.
Flywheel could centrifuge
air pressure or vacuum tank could ex/implode.
Fuel tank could rupture explode
Hydrogen tank could leak or explode....


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## Frank (Dec 6, 2008)

What you want to do - can be done. Not for your budget though.


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## Tesseract (Sep 27, 2008)

ElectroCamaro said:


> I knew the formula for energy calculation on a capacitor, but thanks anyway. The HV ones will net 7.2kj @600v, and the low voltage will net 4kj total. Like I said, I know what I'm using them for, and I know what to expect.


Not to be a beat a thoroughly dead thoroughbred, but...

...there ain't no way you can store 7.2kJ of energy in six 3500uF/450V capacitors. No matter how you connect them the most you will get is ~4.5kJ.

That said, 7.2kJ would only be able to supply 75kW for less than a tenth of a second - and that also assumes you have a lossless means of extracting energy from the capacitors all the way down to 0V.

But like I (and frodus) always say: feel free to spend as much time and money as you like trying to prove us wrong...


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## Vhclbldr (Feb 8, 2014)

E.C., 

As a fellow V8-to-EV converter, I admire your enthusiasm.
I have not started my '69 El Camino project yet, but my research and planning - as well as education - in the field of Electric Vehicle power systems has begun and I will tell you that these senior members (Major, Duncan, Dougingram, Ripperton, and Tesseract) who have replied to your post have decades of experience that will save you money, time, and frustration.

Listen to them, my friend.


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## ElectroCamaro (Mar 12, 2014)

As I put more load on that motor, and the current spikes. Mind you though, that this peak current happens only at the top of each phase cycle of the VFD. Just like on an audio system, I think the capacitors will be able to compensate, and be able to recharge between phases from the transformer, and the battery. I will need to go with caps that hold at least 600v. My initial idea of overcharging 450v caps to 600v has the potential to fail catastrophically, although I have done it before whilst testing step up circuits. 

The lead acids are definitely not there to stay, I know I should have mentioned it earlier, but I will eventually replace them with a string of 140 40AH cells wired in series. The SLA are there just to get things rolling early. 

The VFD however, is one thing that will stay, because a 75kw constant duty vfd has a peak power capacity of 150%. With good cooling this can be sustained for a useful amount of time, which with a good battery would put it's power output close to equal the camaro's stock rating of 169hp. Also, the nifty thing about the VFD is that it can redline an ac motor to crazy rpm's. I'm hoping to get 15k+ from a squirrel cage 3ph induction motor. 

The issue then becomes the torque drop you get at running an ac motor that fast. Which is why I need that flywheel. It's the original flywheel that the camaro came with, except with an additional 1/3" tungsten disc between it and the second ram clutch plate.


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