'87 Porsche 924s Electric Conversion

Hey guys, So over the summer my friend and I converted an '87 924s Porsche to fully electric. We are both now freshmen at Purdue University. The car uses a DC fork lift motor along with 750amp logisystems controller combined with 12-12v marine deep cycles batteries (hoping to replace these very soon). We are either looking at lithium or prius batteries (we are very limited on funds though being college students) The whole conversion cost 6000 but we got a 3800 dollar illinois government rebate so it only cost 2200. We have retained everything about the car except AC and power steering.

pictures: picasaweb.google.com/sean.kleinschmidt

In some of the pictures you will notice covers, we plan on covering the bottom of the car with thing alluminium along with covering the engine bay with plexiglass the covers are just to protect views from all the exposed high current and will eventually be made neater

My friend and I are currently working on developing a buisness dealing with electric vehicles and are looking to convert another car for a customer so if you looking for an electric vehicle, let us know :)

Anyways, let us know what you think!

Very cool project! Looks like you guys did a good job! Whats the range on that thing?

In reply to CLNSC3:

Currently our range is about 20-25miles we are now looking to replace the lead acid batteries(issues with being on a tight budget ) with NiMH batteries to hopefully double that range.

The user Nashco became a professional cheap Prius battery purchaser, so contact him (although I'm sure he will reply soon anyway).

Sounds like a fun project. Having done my own EV conversion, I will say that your high voltage wiring is kind of scary; you guys would be wise to give some more attention to where you route and locate the high voltage stuff. I know you mentioned adding covers, but there's a bit more to it than that, in my opinion. For example, your contactor is right by the front of the hood and up high. Not only is this area very exposed to admirers who might accidentally lean on the contactors while looking at the rest of your install and water coming in the front end, but in the case of a front end collision it's very likely that the hood would short out against the contactors. Another thing that looks a little iffy is your battery hold downs...I see fabric straps, that's an awfully heavy battery to expect those straps to hold in an accident. I know it's a hassle to redo stuff, but just keep in mind that nothing is perfect the first time and you'll learn as you go with this stuff. Been there, done that, I'm still learning a lot myself.

On my car, the contactors are housed inside of a plastic, waterproof enclosure with waterproof pass-throughs, all available from Home Depot for pretty cheap. Also, all of the high voltage cables are wrapped in orange (high visibility) conduit. This is a standard for all high voltage cables on cars so emergency response teams don't run the risk of electricution when they're trying to do their part to save lives. A poor man's way of making orange conduit is getting orange electrical tape (I like the 3M stuff from Lowe's/Home Depot) and wrapping your conduit with orange tape...only costs a few bucks. You can see some pictures of my contactor setup in this thread:

http://grassrootsmotorsports.com/forum/grm/west-coast-2009-challenger-awd-fiero-hybrid/10519/page7/

So, enough about safety....give us some performance numbers! What's the range, acceleration, weight, etc.? I'm pretty jealous of your conversion rebate, Oregon only covers 25%, but I'll still gladly accept the rebate. Also, I highly suggest you avoid Prius packs for a pure EV conversion. My setup uses Prius packs, but I'm only needing high bursts of power for short periods of time...which is what the Prius batteries were made for. For a pure EV, the Prius packs will really disappoint in terms of capacity (range)...great for short bursts of power, but not for long, extended drains. That's also a heck of a lot of used batteries to keep balanced...another thing I've learned the hard way. Lithiums are getting pretty good, but still very expensive when you include the cost of battery management and chargers that will work with them...I think they're getting very close to prime-time, better stuff is coming out all the time.

What are you guys using for instrumentation. Get any cool displays worked into the dash yet?

Bryce

MitchellC wrote: The user Nashco became a professional cheap Prius battery purchaser, so contact him (although I'm sure he will reply soon anyway).

Yup, I was typing my reply up and staring at the TV while you typed this! I don't know about "professional" but you're probably right that I'm one of the most Prius-pack-purchasin' fools around.

Bryce

Nashco wrote: Sounds like a fun project. Having done my own EV conversion, I will say that your high voltage wiring is kind of scary; you guys would be wise to give some more attention to where you route and locate the high voltage stuff. I know you mentioned adding covers, but there's a bit more to it than that, in my opinion. For example, your contactor is right by the front of the hood and up high. Not only is this area very exposed to admirers who might accidentally lean on the contactors while looking at the rest of your install and water coming in the front end, but in the case of a front end collision it's very likely that the hood would short out against the contactors. Another thing that looks a little iffy is your battery hold downs...I see fabric straps, that's an awfully heavy battery to expect those straps to hold in an accident. I know it's a hassle to redo stuff, but just keep in mind that nothing is perfect the first time and you'll learn as you go with this stuff. Been there, done that, I'm still learning a lot myself. On my car, the contactors are housed inside of a plastic, waterproof enclosure with waterproof pass-throughs, all available from Home Depot for pretty cheap. Also, all of the high voltage cables are wrapped in orange (high visibility) conduit. This is a standard for all high voltage cables on cars so emergency response teams don't run the risk of electricution when they're trying to do their part to save lives. A poor man's way of making orange conduit is getting orange electrical tape (I like the 3M stuff from Lowe's/Home Depot) and wrapping your conduit with orange tape...only costs a few bucks. You can see some pictures of my contactor setup in this thread: http://grassrootsmotorsports.com/forum/grm/west-coast-2009-challenger-awd-fiero-hybrid/10519/page7/ So, enough about safety....give us some performance numbers! What's the range, acceleration, weight, etc.? I'm pretty jealous of your conversion rebate, Oregon only covers 25%, but I'll still gladly accept the rebate. Also, I highly suggest you avoid Prius packs for a pure EV conversion. My setup uses Prius packs, but I'm only needing high bursts of power for short periods of time...which is what the Prius batteries were made for. For a pure EV, the Prius packs will really disappoint in terms of capacity (range)...great for short bursts of power, but not for long, extended drains. That's also a heck of a lot of used batteries to keep balanced...another thing I've learned the hard way. Lithiums are getting pretty good, but still very expensive when you include the cost of battery management and chargers that will work with them...I think they're getting very close to prime-time, better stuff is coming out all the time. What are you guys using for instrumentation. Get any cool displays worked into the dash yet? Bryce

Thanks for the ideas! Our high voltage is now sort of covered up as you can see in http://picasaweb.google.com/sean.kleinschmidt/PorscheHighVoltageSafety# Still no where near ideal but helps when we have the hood open showing people.

We have been and will continue to be upgrading the car in many ways in the coming months. In terms of gauges we have an ammeter and voltmeter http://picasaweb.google.com/sean.kleinschmidt/PorscheFinal#5369834204893340610

Our performance is lacking, our marine deep cycles have very bad sag to them. So our 0-40 is about 9sec while 0-60 takes 30secs (60 appears to be our top speed as of now) also our range is only about 10miles when driving hard or we can get about 25miles when keeping up with traffic.

We currently are talking to a guy who deals in Prius/Insight packs about getting some used cells and making our own packs but we arn't certain if this is the way to go, it mostly comes down to a budget issue (being freshmen in college we are quite broke)

Very cool! Glad to see others going for EV conversions.

If you don't mind me asking, where are you located. (You said Illinois, but where abouts.) I do have an agenda...

My codriver and I are President and VP (respectively) of our school's EV group. Our advisor has one of the last remaining S10 US Electricars. We also have and still autocross and drag race our Formula Lightning car. (Series sort of faded away in the early 2000s, most of the other schools got rid or mothballed their cars. We still very much have ours and continue to improve it.)

We are currently one of only two student chapters of the Electric Auto Association. Since you mentioned you were in college, I highly recommend becoming a student chapter of the EAA. Get more people excited and interested about EVs. Our group had been in hibernation for many years, but this year we kicked things into overdrive. We've already been in the local news, had reporters asking to interview us and see our cars.

If you wanna learn more about us or get in touch offline, the Doc really has immense knowlege on EVs our website is http://eva.studentorgs.wvu.edu. We could seriously talk for hours about EVs, same goes with you Bryce. We drooled over your EV conversion for hours going damn that is just wicked cool.

P.S. I am sending your pictures link to our advisor, just cuz its so awesome.

autoxrs wrote: Very cool! Glad to see others going for EV conversions. If you don't mind me asking, where are you located. (You said Illinois, but where abouts.) I do have an agenda... My codriver and I are President and VP (respectively) of our school's EV group. Our advisor has one of the last remaining S10 US Electricars. We also have and still autocross and drag race our Formula Lightning car. (Series sort of faded away in the early 2000s, most of the other schools got rid or mothballed their cars. We still very much have ours and continue to improve it.) We are currently one of only two student chapters of the Electric Auto Association. Since you mentioned you were in college, I highly recommend becoming a student chapter of the EAA. Get more people excited and interested about EVs. Our group had been in hibernation for many years, but this year we kicked things into overdrive. We've already been in the local news, had reporters asking to interview us and see our cars. If you wanna learn more about us or get in touch offline, the Doc really has immense knowlege on EVs our website is http://eva.studentorgs.wvu.edu. We could seriously talk for hours about EVs, same goes with you Bryce. We drooled over your EV conversion for hours going damn that is just wicked cool. P.S. I am sending your pictures link to our advisor, just cuz its so awesome.

I am located in Arlington Heights, IL (its the NW suburbs of chicago). Currently the car is here with us at Purdue we are bringing it home monday 11/23 for a while. We are planning on having a showing at 10am sunday 11/29 email me at sean.kleinschmidt@gmail.com for more information Anyone is welcome, just email if interested.

This is excellent, and makes me sad that I am so far away from attempting an EV conversion.

Do any of the off the shelf power management systems allow you to mix the short burst power of the Prius packs with the longevity of the deep cycles?

IIRC Prius packs dont supply that great of a burst. I think its about 125 Amps max (heavy abuse). You would need about 7 packs paralleled to match the amp output and capacity of a string of yellowtop optimas.

ah, so its more of a power/weight thing

Very cool.

When will you have it back in west laffayte I am only 30 min south of there

stan

MrJoshua wrote: IIRC Prius packs dont supply that great of a burst. I think its about 125 Amps max (heavy abuse). You would need about 7 packs paralleled to match the amp output and capacity of a string of yellowtop optimas.

That's arguable as you're comparing very different sized batteries. If you sized lead acid batteries the same as the Prius modules, you sure as heck wouldn't need 7 Prius modules to match the current of the lead acid. They're actually quite comparable current outputs when sized the same, but the nice thing about lead acid is that you CAN get bigger batteries if you need more current instead of running multiple batteries in parallel.

Using my car as an example, my motor wants about 85 kW (350V x 250A, or more realistically with voltage sag 300V x 300A or 250V x 350 A). In order to get that kind of power with Prius packs, I can heavily abuse 3 Prius packs (split into two parallel strings) or be gentle on 4.5 Prius packs (three parallel strings). To get the same with lead acid 12V batteries you can use a single string, as there is a wide variety of Ah ratings available compared to basically one cheap option with NiMH.

My application:

NiMH (heavily abused vs lightly abused)
3 Prius packs / 4.5 Prius packs
210 lbs / 315 lbs
$600-800 / $900-1100 (used prices)

Lead Acid (heavily abused vs lightly abused, ballpark numbers as lead acid max current varies between manufacturers)
26 12Ah batteries / 26 19Ah batteries
240 lbs / 320 lbs
$1000-1300 / $1500-2000

This is only looking at power delivery with little concern of range. As you can see, NiMH comes out a little ahead in weight and cost. A big part of this is that when you get Prius packs you get a whole slew of used batteries from a few wrecked cars, but they're very similarly matched. Good luck getting 26+ used, specialized, lead acid batteries with matched performance!!! Fortunately, lead acid is cheap if you have to buy new. With my $2009 car, I had to keep the budget as low as possible, so the used Prius packs were a no-brainer and I saved a few pounds going that route as well. I also got to use the Prius fuses, contactors, battery connectors, etc. that added up to a bunch more money saved. Another real advantage to the Prius modules is that they package VERY tightly and don't need any maintenance (water), which was also a big help for my car as I was really tight on space.

Now, when you start getting into much bigger packs with pure EV that needs some range on a budget, the lead acid starts to trump. You can upsize them (big deep cycle batteries) and still only have to deal with one string. You can abuse them with deep discharges and overcharging without as much concern, although it's still bad practice. Having to maintain 20-40 lead acid batteries is a hell of a lot easier to do than maintaining 200-1000 Prius modules. If I needed a lot more battery to get some range (and didn't have the gas engine to fall back on), I'd be using lead acid. If I fell into $20k, I'd go lithium, but that's a whole 'nother ball of wax.

Bryce

The current outputs are VERY similar when you size them Amp hour per Amp hour. Im using DC so I need BIG amps. I used 55 Amp hour yellow tops in my quick calcs in the above post which are capable of about 900amps peak. Believe me-I have seriously considered using prius packs. Charging is my issue. With my 20 yellowtops I can get 20 chargers off of ebay for around 200 bucks and go to town. The best I could figure for a prius pack is a quick and dirty circuit that basically plugs them into a 240v socket while I watch like a hawk.

MrJoshua wrote: The current outputs are VERY similar when you size them Amp hour per Amp hour. Im using DC so I need BIG amps. I used 55 Amp hour yellow tops in my quick calcs in the above post which are capable of about 900amps peak. Believe me-I have seriously considered using prius packs. Charging is my issue. With my 20 yellowtops I can get 20 chargers off of ebay for around 200 bucks and go to town. The best I could figure for a prius pack is a quick and dirty circuit that basically plugs them into a 240v socket while I watch like a hawk.

Yup, upscaling is the big issue when you need range (or in the case of a low voltage setup, LOTS of current). Charging is a completely seperate issue...IMO, using 20 individual chargers every time you want to recharge will wear out pretty fast. I'm shocked at how pricy high voltage chargers are, I think that's an area where prices are likely to drop a lot in the future...or at least get MUCH better chargers for the same money.

Bryce

Hey, I saw your car at Purdue when they had the alt-power vehicle show in front of Stewart. Great reading about your project!

petegossett wrote: Hey, I saw your car at Purdue when they had the alt-power vehicle show in front of Stewart. Great reading about your project!

Yep it was there! Are you local to purdue? The car will be back next semster so if you wanted to see it let me know.

My wife works in Armstrong & I'm frequently on campus for work, but we live in IL.

petegossett wrote: My wife works in Armstrong & I'm frequently on campus for work, but we live in IL.

Really? I'm in armstrong almost all the time working on EPICS (we are making an electric test go kart to make up the rules for the EV grand prix that will be held this year)

She's the receptionist for the Dean of Enginnering on the 2nd floor.

so i thought i'd update a little bit.

I am currently making a new electrics box that will be directly over the motor. Its going to be made out of extruded aluminium and clear polycarbonate. Hopefully I will have this whole box done with in the week. Just ordered some fans for it along with looking to purchase some temperature gauges.

-Sean

Finished up all the wiring rework today. Here are some pictures Before:

After:

Building of:

The rest of the pictures are on my Picasa account at: http://picasaweb.google.com/sean.kle...eWiringRework#

Looks good! Did you know there's a pic of the car on the Purdue.edu homepage? I saw it in the slideshow at the top of the page a couple days ago.