# Audi Quattr-ohm



## somanywelps (Jan 25, 2012)

This:


quattrogreg said:


> The budget for this build is $5000 or less


And This:


quattrogreg said:


> have brisk acceleration and decent top speed with about a 30 mile range (at first).


Are not compatible.


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## drgrieve (Apr 14, 2011)

The only way to build a budget performance EV is to use a small pack of A123 20ah pouch cells.

Even then you'll need to use a forklift motor and a DIY controller. Neither of which would be high performance.

A short range EV using lithium is possible on a low budget but forget using off the shelf parts.


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## mora (Nov 11, 2009)

Increase your budget or decrease your goals. 5000$ will barely get you motor and lithium batteries for 30 mile range. Don't bother with lead if range is important. But if you are satisfied with 70kW peak power you could use cheaper and smaller motor. Kostovs are pretty cheap already but forklift motors could be close to free. And build motor controller yourself (OpenRevolt) for ~500$. You can always add batteries later for more range and performance.


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## quattrogreg (Oct 5, 2012)

Well thanks for the warm welcome... 
I could double my budget to about 10 grand, then using the kostov and about 45-48 LiFePo4 batteries I would have about $2500 left for the other needed items...
What charge controllers, DC-DC converters, Throttle signals, BMS etc. would you guys recommend for this build?


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## gravelydude (Sep 6, 2008)

$2,500 isn't going to do it for the rest of the conversion. You need a controller, a battery charger, a motor adapter and coupling, a dc/dc converter to get 12volts from the pack, and the incidentals that add up quick (cable, connectors, relays, cooling systems for some controllers), etc., etc. BMS is debateable. If you are willing to monitor your batteries with a good meter, you probably don't need it. Some people on this forum think that they generally do more harm than good. I would think that you need to determine your motor and battery pack first. Charger and controller are a function of vehicle weight, power available from your pack and voltage, and your motor specs. Actually, you might be able to do it for $2,500 or a little more. Build your contoller from a kit, Elcon charger that won't be useable for a different voltage pack, make your own motor adapter, use a computer power supply for your dc/dc, or just use a 12V battery, and charge it while charging the pack. Do some reading and poking around in this forum, on EVAlbum, and EVTV. Good luck!

JACK


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## mora (Nov 11, 2009)

2500$ will do fine for rest of the components in my opinion. Maybe even less is needed. You could get both 400W DC/DC and 1500W charger from TCcharger for ~600$ (didn't check actual pricing) including shipping. 500$ for OpenRevolt controller, 500$ for motor/transmission adapter plate and shaft coupler. 900$ is left for contactors, potbox, cabling, fuses, maybe heater and whatever you need. Oh and miniBMS is cheap. It will fit into that 900$ too. I say you need one (BMS). Others may say you don't need it. I've been using it for over two years without problems.


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## dtbaker (Jan 5, 2008)

I think you will need to re-budget to meet your goals.... probably closer to $12k in parts+batteries. You should not skimp on controller/batteries or you'll end up with something you don't enjoy driving.

You don't need an 11" to get a very drivable vehicle. I'd shoot for:
Warp9 motor
Soliton Jr. controller
144v of 100ah CALB (calibpower.com) or Winston (balqon.com)

all the other bits fall into line behind that... you have a great retailer right in your hometown. Go visit EvolveElectrics.com down on 28th st and build up the rest of your list. Some stuff you might collect on sales here in classified section, or on ebay.

Fixed voltage chargers like Elcon are just fine as long as you don't intend to fiddle with pack voltage 'later'. You really don't NEED a BMS if you decide to go top-balanced and do a good initial balance in parallel; thats saves at least $1k and a lot of wiring.


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## Ace_bridger (Nov 22, 2011)

I would suggest getting your requirements fixed down and then beg, borrow or steal to make the build work within budget.

Have you monitored your 'normal' daily drives to see how many miles you do each day? If your needs are modest you could convert within your budget with sensible purchasing and keeping an eye out on eBay and secondhand sources.

Build an Open Revolt controller (kit from PaulandSabrina $600). 500A 144V.

If this is to be a 'car' rather than a short term project for fun then try your absolute upmost to buy lithium batteries of the type suggested above.

One thought...do you really want to convert the Quattro? Would a two wheel drive be better for range?

Good luck and go for it!!


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## quattrogreg (Oct 5, 2012)

Thank you all for the info!
I have been to Evolve Electrics website but i didn't realize they are in boulder! I will have to check them out and bother them with questions as well .
I am thinking I am going to use the Kostov 11" over a WarP 9 because for $500-600 it seems to have a whole lot more performance potential...
and with the 6000 RPM limit that will give me about 120mph top speed (with no rolling resistance or wind resistance)... which is faster that the car currently could go .

What am I forgetting in this formula for wheel torque = (Gear ratio * Final Drive ratio) * motor output torque
How would I calculate energy lost through drive train.
because (4.11 * 3.6) * 53.8 lbft = 796 lbft constant AWtorque in first gear seems a bit much, if that were the case I would definitely need to go with the stage 5+ clutch...


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## quattrogreg (Oct 5, 2012)

Ace_bridger said:


> I would suggest getting your requirements fixed down and then beg, borrow or steal to make the build work within budget.
> 
> Have you monitored your 'normal' daily drives to see how many miles you do each day? If your needs are modest you could convert within your budget with sensible purchasing and keeping an eye out on eBay and secondhand sources.
> 
> ...


I think I can raise a budget (I will just need to flip a few more cars) My daily drive is about 10-12 miles each way to school and then 2-3 times a week to work an additional 10 miles round trip.
I do really want to convert the Quattro I am well aware of the benefits (in EV) of 2wd. But I want to also try to rally and icerace this car (I am aware that you can do this with 2wd but it wouldn't be as awesome.)


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## Tesseract (Sep 27, 2008)

mora said:


> ...500$ for OpenRevolt controller....





Ace_bridger said:


> ...
> Build an Open Revolt controller (kit from PaulandSabrina $600). 500A 144V....


Guys, how about let's first determine if the OP has *any* electronics knowledge and/or the ability to solder before recommending he build a controller kit. A poorly or incorrectly assembled motor controller is literally an accident waiting to happen.

I'm not saying don't recommend the kit at all, just that you all find out if the person knows which end of a soldering iron to hold before telling them to build a potentially lethal device. Even adding a proviso such, "If you are good at soldering and know which end of a diode is which you might want to try your hand at assembling a motor controller from a kit...."


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## mora (Nov 11, 2009)

Yes, Tess is correct. Though OpenRevolt can be bought as ready-to-use unit for a bit higher pricetag. 144V battery voltage is dangerous so good care must be taken anyway. And if OP decided to go 192V or higher OpenRevolt is out of question.

Are you sure you need 11" motor? The link you posted said original 5-cylinder produces 126 ft/lbs at 3000 rpm and 115hp at 5500 rpm. You could get those figures out of 9" motor (even higher torque to that same rpm) and save dollars towards better controller for example, hehe. And you'd save some weight at the same time too.


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## quattrogreg (Oct 5, 2012)

I do have experience soldering and working with electronics, however I am not sure if I am comfortable enough to build a controller from their kit. How much is the premade version? or what are some other options? I know of the Solution 1 but that seems to be the pricey Crown "Joule" (see what I did there), is there a middle ground?
Also I am fairly determined to stay with the Kostov 11" i think that the price difference is negligible for the performance difference and potential, the weight isn't much of a factor since the final EV will result in less weight (I believe) than the OEM car. (The Kostov still can run on 144V correct?)

I really appreciate all of the help all of you are giving  I would be very lost without your insights.


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## CrazyAl (May 9, 2011)

Ace_bridger said:


> Have you monitored your 'normal' daily drives to see how many miles you do each day?


That is a good idea. You can download a free trip monitor sheet in pdf or excel format.
If anyone has any comments about those documents, let me know and I can add things to it.


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## CrazyAl (May 9, 2011)

quattrogreg said:


> Hello,
> 
> My goals are to retain the stock transmission (and AWD), have brisk acceleration and decent top speed with about a 30 mile range (at first). (I may rally or icerace this car)


Are you going to keep the rear seats (ie. will it still be a 5 seater?)
Will you be required to have a roll cage if you rally or ice race it?
Have you looked at the rules that the car must comply to if you rally or ice race it?
If you are going to race it, just keep in mind that motor cooling will become an issue.

It sounds like a fun ev project.

Look forward to seeing the progress of your conversion.


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## quattrogreg (Oct 5, 2012)

CrazyAl said:


> Are you going to keep the rear seats (ie. will it still be a 5 seater?)
> Will you be required to have a roll cage if you rally or ice race it?
> Have you looked at the rules that the car must comply to if you rally or ice race it?
> If you are going to race it, just keep in mind that motor cooling will become an issue.
> ...


To start with this will be my daily driver so i can work out kinks and such, To do rallycross or iceracing (as in frozen water) you don't need a roll cage however it is recommended so I will try doing some racing to see how it handles and if I like this car for those purposes it will become fully caged and stripped down, otherwise I will be building another gas engined car for racing.
As far as rules go they are fairly lenient and I can always compete in the super modified class (maybe they will even make an EV/hybrid class). For saftey I feel as long as I install everything correctly it will be much safer than an gas powered car (no flammable fluids etc.)
However I will be keeping airflow and room for a radiator in mind for this project.
I am also looking forward to this project  However it probably wont start till late november due to fund raising and school work load


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## drgrieve (Apr 14, 2011)

quattrogreg said:


> (The Kostov still can run on 144V correct?)


The HV voltage versions of motors should be run at a higher voltage - otherwise you will not reach a high RPM.

For example the Kostov 11 Alpha is nominal 250v. So try to aim for you pack under full load to still be able reach 250v. With 20% sag for example you pack nominal would need to be 300v. (which is over 90 cells).

At 144v a 11 inch motor will give you nothing over the 9" except extra weight. A 11 inch motor in this scenario will make your car slower.

For a light weight car, wanting performance on a budget look at a Solition jr and a Kostov 9" 220v. This makes for a nice light weight responsive car.

For batteries assume for now you do 250 watts per mile. For 30 mile range at 80 DOD you need a 9 kwh pack. A pack this small using prismatic cells will not give you much performance so you'd need to look at pouch cells like A123. However these cells are harder to package (there are some good recent threads on solutions for this recently). So for the smallest pack to make 150 kw peak using the latest Calb grey cells you'll need ~18kwh pack. To go with the junior use 60ah cells. You'll need around 90. At $75 each that's close to $7k.


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## evmetro (Apr 9, 2012)

Another way to have an ev on a shoestring budget is to buy a used conversion that somebody is tired of. Get it running, or strip the ev parts and transfer them to your audi. I would look at a lighter vehicle personally, but of course I am not you! You seem pretty smart for your age, so I bet you can get yourself rolling around in an ev... best of luck to you.


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