# Audi A4 Avant buildup



## !George (Jun 9, 2009)

Yes, it isn't the lightest car on four wheels. Nor is it the most aerodynamic. But I own it, and I am really quite tired of the pain in the ass electrical gnomes that infest it.

It weighs about 3350 lbs as it sits. I believe I can knock that down to around 2900 lbs with some creative weight loss. It currently has a little 1.8 liter turbocharged 4 cylinder that churns out a rather anemic 150 BHP. Why do I call that anemic? Because my last 1.8T engine put out 350 BHP, then 450 BHP plus a large hole in the block.

What are my goals?

Range: 20 miles. I believe that with my actual planned trip which is 9 miles the DOD on the cells should not too bad.

Budget: Still working on that. Perhaps $10K, but I can spend more over time.

Performance expectations: I would like it to be faster than when it was stock, but I would settle for "getting out of it's own way".


I believe I'll be starting out with AGM or even flooded cells due to cost. In my first thread, someone recommended the Solecta AC55 motor/controller. I'm sure that would be a great setup, but that would require a higher pack voltage than some of the DC motors I have seen which means more cells & more weight. I have looked at the Warp 11 or Warp 13, and a Zilla 1K controller. I have read that there is a Warp 11 HV on the horizon but not readily available for public consumption. I have even thought about going to two motors, one for the front and one for the rear, for better performance.

I have spent hours with the EV Calculator, but I am not sure what the areas for Motor A, B, C, D, K, or N are refering to. I don't see any motor other than the Warp 9 on there.

I am keeping as much of an open mind as possible in regards to this project. I will be keeping the stock 5 speed trans, the air conditioning will be going away (it's not like it works anyway). Also the car is all wheel drive so I'm sure that will equal more drive-train losses but won't waste time baking tires (or maybe it will).

So, if you would be so kind, please throw in your thoughts on this. About 99% of this is still up in the air for me. My requirements are not too terrible I believe and while I know the car is not the ideal candidate for making into an EV I'm using it as a learning platform.


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## madderscience (Jun 28, 2008)

Hello and welcome.

Your car isn't a terrible choice for a midsize/large car conversion, but as you already acknowledged you can do better in terms of weight and aero. Doing so would mean more range and better acceleration with the same components and the same cost.

If the audi is only a few years old and still in good shape it might make sense to just sell it, buy a cheaper (non-running but better conversion candidate) car and apply the difference to the components.

Your range goals are no problem, even with lead acid.

Your performance goals might be a bit more of a challenge. A typical flooded lead acid conversion using flooded lead and a curtis controller has peak power of about 80 to 100 horsepower in a car that probably ends up weighing 500 to 1000lbs more than original.

To get to at least 150hp peak, in DC land, you will probably want to find a 1000 amp controller and mate it with a warp 9 motor which can take it. Going much past that level of performance and you get into zilla and dual motor territory which significantly increases complexity and cost. In AC land the AC55 is a big motor and it will probably deliver similar performance to the above, but you will need a different battery setup (higher voltage) to keep it happy. It is also less possible to mix and match components with AC (motors, controllers) to optimize performance. 

The only lead acid batteries that can intermittently dump 1000 amps without being wrecked are AGMs such as hawkers and odysseys. These are really nice batteries but are at least double the cost of flooded and require some sort of BMS for maximum lifespan. They also don't last as long in terms of cycles vs. flooded. To keep your performance up, you will want to keep weight down, which would mean more stress on these batteries and less overall range.

Your 10K budget would do a DC/flooded lead conversion on that car, but for the performance you want you will probably need a bit more due to the more expensive batteries, mainly. AC (unless you find a great deal somewhere) would make it even more expensive.

The torque curve you will experience is significantly different than a gas engine, basically maximum torque is at zero RPM and torque stays high until it starts to drop off at higher RPMs. With the gas engine you would see maximum torque probably around 4000rpm I am guessing.

Good Luck.


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## etischer (Jun 16, 2008)

I converted a B5 Passat. Depending on the year of your A4, we might have the same car. Mine is early 2001.

My range is about 25 miles, that gets me down to 305 volts, or 12.2 volts per battery with Optimas. I could probably push it to 30 miles, the voltage drops about 1 volt per mile. 

You will have a tough time matching the power of the 150 hp turbo motor. I am currently at 4010 lbs. The most power I have put into the controller is 87kw, and 0-60 is 16 seconds. It is still fun to drive, and I've even hit 98 mph on flat ground. The car is very aerodynamic, about the same as a corvette and civic.


I'm upgrading to lithium. If you wanted to go A.C. I have batteries, cables, regulators, and battery racks which might bolt right on.

http://etischer.com/awdev/ click on battery link.

I don't regret converting such a large car, it is a nice car to commute in, and has plenty of battery space. 

If you later on decide you need stiffer springs in the rear, I had custom springs wound 500lbs stiffer. These were for a sedan, but could have them made for the wagon.


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## !George (Jun 9, 2009)

madderscience said:


> Hello and welcome.
> 
> Your car isn't a terrible choice for a midsize/large car conversion, but as you already acknowledged you can do better in terms of weight and aero. Doing so would mean more range and better acceleration with the same components and the same cost.
> 
> ...


The Audi is a 1999. It has about 106K on it. Since it's a wagon, I can probably use some of the back area for batteries, perhaps even tub the cargo area since there will not be a fuel tank anymore.

I think the torque peak with the 1.8T starts around 2000 RPM's due to turbocharging, but it's over pretty quickly as the stock turbo falls off rather fast.

I was thinking the Zilla controller, but would the Warp 9 be enough? I know that I can always change to different batteries/increase to higher density batteries in the future but I would rather get the motor/controller nailed down first. DC definitely is more appealing due to the easily interchangeable nature of the parts. I see they have up to a Warp 13, but the specs are not terribly clear to me. Are there larger DC motors than those? And how do you go about interfacing them with the transmission. I know there is a place on the West coast that makes adapters, but I would like to find someone closer.


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## !George (Jun 9, 2009)

etischer said:


> I converted a B5 Passat. Depending on the year of your A4, we might have the same car. Mine is early 2001.
> 
> My range is about 25 miles, that gets me down to 305 volts, or 12.2 volts per battery with Optimas. I could probably push it to 30 miles, the voltage drops about 1 volt per mile.
> 
> ...


Wow, I can't believe the amount of information you have on your site! What made you pick the Siemens motor versus one of the Warp motors? You definitely seem very into the whole EV thing.


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## madderscience (Jun 28, 2008)

!George said:


> The Audi is a 1999. It has about 106K on it. Since it's a wagon, I can probably use some of the back area for batteries, perhaps even tub the cargo area since there will not be a fuel tank anymore.
> 
> I think the torque peak with the 1.8T starts around 2000 RPM's due to turbocharging, but it's over pretty quickly as the stock turbo falls off rather fast.
> 
> I was thinking the Zilla controller, but would the Warp 9 be enough? I know that I can always change to different batteries/increase to higher density batteries in the future but I would rather get the motor/controller nailed down first. DC definitely is more appealing due to the easily interchangeable nature of the parts. I see they have up to a Warp 13, but the specs are not terribly clear to me. Are there larger DC motors than those? And how do you go about interfacing them with the transmission. I know there is a place on the West coast that makes adapters, but I would like to find someone closer.


Motors bigger than the warp 9" are extremely torquey but don't have a very high RPM peak. This means their behavior is pretty comparable to a truck engine; probably not what you will want. The 9" motor is probably the best compromise between RPM (typically around 5000 RPM peak, stock) and torque. I've only seen a couple of 11" motors in pickup conversions, and I don't think I've ever seen a warp 13" in the wild. That is a monstrous motor.

A 156V Zilla 1K (Or logisystems, etc) will support a maximum of 156KW of power into the motor, which works out to a theoretical peak of about 210HP. A warp 9" should be able to handle this on an intermittent basis. So the car will be able to get out of its own way. You can have dual 8" or 9" motors built by people like Jim Hustead; and back them up with a Zilla 2K; but as I implied before once you start going into that territory it gets much more complex and expensive; this is basically drag racing territory and you aren't going to be doing it for any $10K budget.

If your car is a stick shift, interfacing the motor to the tranny is just a matter of getting an adapter plate. There are only a few places that make them; and it sounds like you've already done your research. If you are a semi capable machinist or welder you can make one yourself as well. (If your car is an automatic, then find a stick shift version of the same car, or plan on swapping out the transmission, then go back to the start of this paragraph  ) You should keep the clutch as this is a larger car. Smaller cars with small motors can get away with losing the clutch, but it's a bad idea with larger cars. 

If you are set on using this car, start researching anything you can do to shave weight. It's probably the cheapest way to improve performance.

Oh, and plan on flying out and camping in etischer's front yard and going over his car with a fine tooth comb, if it is indeed very similar to yours.


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## etischer (Jun 16, 2008)

I picked the siemens motor because of the flat power curve. Even at 12,000 it still retains 50% of its peak power. I have been using AC drives and motors for about 10 years now, so Im more familiar with AC. I also have a 2 mile long, 6 to 8 grade to go up and over every morning, so I wanted regen and enough power to maintain 65 up the hill. 

If you need help with an adapter plate, I have made one that fits a 2001 passat to warp 9. my car was a 1.8 turbo, I attached a sketch of the adapter plate. The adapter is pinned in 3 places to the tranny, a centering ring centers the motor. 

http://etischer.com/awdev/coupling/adapter.GIF

this is just the adapter plate, my customer made his own coupling. Of course if you could find a siemens motor and controller, I can also sell you the adapter plate and coupler I designed and am using.





!George said:


> Wow, I can't believe the amount of information you have on your site! What made you pick the Siemens motor versus one of the Warp motors? You definitely seem very into the whole EV thing.


this was actually my first conversion, im just getting started =)


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