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  #41  
Old 06-06-2011, 08:42 AM
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Default Re: Porsche 944 conversion DC/LiFePO4

I havenít completed any major milestones lately, however Iíve been working on a lot of little projects.
I temporarily mounted the main battery voltage and current gauges in the center console below the very stylish Sony CASSETTE deck. Just to see how visible they were at different angles for both the driver and passenger. They are pretty bright, so I will have to do something about that on the actual install. Right now I simply have them powered off a 24v wall wart, so itís shows the voltage and current draw at the meters. The meters obviously match, but they are also configurable and have two built in alarms that could be used for just about anything. Since I will be relying on the Soliton1 for low pack warning and limp mode I donít need that, but it might be useful to have a high/low current LED as a reminder when Iím at or below 1C on the pack (some sort of GREEN LED) or above 500A (some sort of RED warning LED).

The gauges below the stereo are the only ďout of placeĒ gauges that I was willing to add to the car, and they will be individually switched so that when I donít need specifics I can run without them and they will be turned off. Since Iím behind schedule and hope to get the car on the road this summer/fall I had to skip some of the custom projects to have a hope of finishing. The Arduino based battery monitor/SOC meter will be on hold for awhile. So I need some sort of off the shelf SOC/AH meter so that I have a way of monitoring the pack. (I also want it to drive the stock fuel gauge as a SOC meter) To do that there are basically two choices, one is the Ziva Plus from Australia, or the EV display from Florida. Total cost of the two meters is similar so it comes down to features, the EV display wins there so itís probably going to be the meter of choice. The one problem is the lack of extra gauge locations in the 944 and as mentioned before, Iím not willing to just mount it anywhere. The new stereo (whatever that might be) should have a clock, so the stock 944 clock should become redundant, it also happens to be a similar shape and size to the EV display without the housing.

I still have to confirm the dimensions, however it looks like it might be workable with minor modifications.
Since Iím keeping the A/C in the car I need a way to power the stock compressor. For simplicity I decided to run it off of the tail shaft of the motor (at least to get me started). This requires a 7/8″ keyed serpentine pulley, I couldnít find one anywhere, so the best choice was to adapt the stock Porsche crank pulley to the 7/8″ keyed shaft. The easiest way was to use some off the shelf parts and weld an adapter to bolt on the stock pulley.

Iíll get a better photo of the pulley soon, but the whole adapter including key stock was less than $10. Also visible in the above photo is the tach sensor made by Recharge Car. I had planned on making my own tach sensor, however itís hard to resist the simple bolt on version, especially when itís not a bad price either. This feeds into the Soliton1 and the Soliton1 outputs a modified signal to drive the stock tach in the car.

I also started crimping some of the main cables, along with the very short A2-S2 cable on the motor. I am using 4/0 awg wire in the motor loop, and 2/0 for the batteries. I was able to get the cables printed at no extra charge, so of course they say electricporsche.ca



Iíve been trying to decide how to mount the commutator end of the motor for awhile now, and after laying under the car for awhile scoping out the options I came up with a plan. There is a plate on the end of the motor that attaches on the bottom to a Bosch Rexroth extrusion that will be mounted to the stock strut brace as well as two larger tapped holes in the frame. Above the motor the same plate will hold the bracket for the Soliton1 and throttle. This is also the first time Iíve fired up the CNC router to make a part for this project. Everything worked very well and the plate turned out as expected. There are quite a few extra holes, but that is simply because it was recycled from a larger plate meant for an LCD tv mount.

And of course I canít make something on the CNC machine without a little engraving.

Due to the thickness of the plate and the proximity to the tach sensor I had to make a small pocket for the body of the sensor to sit in. This allows the sensor to mount in the stock location on the tail shaft. I will need to get some allen head cap screws to re-install the sensor since the stock bolts interfere with the plate.

The DC/DC converter charging board never seems to be finished. Once I got the previous design finished I did some more testing with the A123 20AH cell and the due to the low impedance of the battery, the current output went through the roof. This is fine for charging one cell, but when I have a string of 96 in series I simply wouldnít be able to supply enough power to the dc/dc converters.
The solution?
A feedback loop on the trim adjustment of the dc/dc converter that lowers the voltage output to maintain the preset current, and as the cells charge the voltage goes up to maintain current until it hits the CV portion of the charge and then it tops out at the preset voltage. Like one of the previous versions of the charger it will have two stages or settings so that when I plug into 240V the dc/dc converter portion will automatically increase the current output to make use of the extra power. The other change in design was removal of the voltage monitoring system due to the large amount of programing work. This project will be put off until the car is on the road and essentially finished and I have some time to work on it again. Since I still need some sort of LVC monitoring and Iíd like to see how the cells are doing Iíve decided to incorporate 2 cell log 8′s onto each charging board. This is made easier by the fact my design is already based on 16 dc/dc converters per PCB which means I just need two cell log 8′s per board to monitor the cells.

The cell log 8′s can easily be removed from their plastic casings leaving a fairly small light weight PCB that just begs to be plug into something other than a wiring harness. (ya I know my picture shows it plugged into a wiring harness, the PCBís arenít done yet!)
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  #42  
Old 06-07-2011, 06:58 AM
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Default Re: Porsche 944 conversion DC/LiFePO4

I really like your few little updates. Nice work!

It was amazing how there's advertising on your car .... I appreciate especially Electricporche.ca on orange cable 2 / 0 ....

One question: Why you don't use straight copper bar on the motor instead use two lugs and a wire?
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  #43  
Old 06-07-2011, 07:57 AM
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Default Re: Porsche 944 conversion DC/LiFePO4

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Originally Posted by Yabert View Post
I really like your few little updates. Nice work!

It was amazing how there's advertising on your car .... I appreciate especially Electricporche.ca on orange cable 2 / 0 ....

One question: Why you don't use straight copper bar on the motor instead use two lugs and a wire?
I had the wire

Honestly the terminals on the 11HV are WIMPY, there's a reason even the new Warp9 has 1/2" terminals. I had planned for the solid bar, but after installing a temporary 4awg wire to spin up the motor I decided to use a 4/0 wire instead. I'm sure I could get the correct rotation on the bar to sit flat on both terminals but for now it's a wire. The Panduit lugs and crimper work really well though (even if I did a couple extra crimpers per lug vs the instructions.. oops)

The orange wire came from an ebay seller, I wasn't able to track down any orange wire locally without special ordering at insane prices. The printing was included for free which is a cool touch.

I have some time off starting tomorrow so I hope to get all the little things out of the way, including finishing the motor mounting, installing the heater, vacuum pump, gauges, reinforce the transmission mount, clean up some old wiring and remove all the unused fuses and relays, interface with the stock gauges for coolant temp etc. Then prep the car for batteries even though it will be awhile before I have them.
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  #44  
Old 09-06-2011, 06:34 PM
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Default Re: Porsche 944 conversion DC/LiFePO4

I made the local paper, front page of the business section, perhaps it's time for an update
She got a couple details out of context but it's a good write-up. She also did some of her own research to give a better background to the article.

The first page scanned twice because I couldn't fit the whole length on the scanner.

It's led to inquiries by CBC Radio and interest in having my car featured in the Alberta Pavilion at the Global Clean Energy Congress to be held here in Calgary in early November.

I'm not a tree hugger, but this is the type of interest I was hoping the car would draw and expose people to existing alternative energy sources.

Now to get the damn car finished!!
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  #45  
Old 09-06-2011, 09:34 PM
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Default Re: Porsche 944 conversion DC/LiFePO4

The car has been progressing slowly, work has been busy so I haven't had the time or energy to do all the things I had hoped to have complete by now. There is no drop dead completion date, so I will just keep plugging away and make sure things are done right. Just like everything else in this build decisions are made, then changed, then changed again! I finally have the batteries on hand. It's not the Thundersky that I chose early on, it's not the Headways that I switched to later. The winner is A123 and the 20ah pouch cells. They aren't easy to get, and for a product that's made in AMERICA (or Korea) the easiest way to get your hands on them is from China. The cells test incredibly well though, so I think it's just the right cell for my car and my goals. From the cells I have on hand I will be building a 15.8kwh pack to get me started this should give me 60-100km of range if I drive nicely, or a lot of fun on my 17km commute to work. I'm still working on the details of the connection method but I will be using aluminum blocks/spacers to create the series/parallel connections that I need.



I have been putting off removing the transmission for months since I knew it would be a lot of cramped under the car work to get it out. Finally I bit the bullet and went ahead with the removal, and it turned out to be exactly as expected, not horribly difficult just time consuming and uncomfortable under the car with limited working space. I took this opportunity to strengthen the transmission mount at the same time, a seemingly common fix is to use a two part urethane to encase the stock rubber transmission mount to remove unwanted movement but unlike a steel or aluminum mount it won't transmit all the gear noise to the cabin.



With the transmission out the gas tank removal was very simple and straight forward. With the gas tank out the hatch floor removal was also simple and straight forward. And finally with no hatch floor the transmission installation could not have been easier. I will get the remaining bolts torqued down and the new Stage 8 locking CV bolts installed then the drive train is virtually complete and should hold up to the extra torque from the electric motor.



I did a quick test fit of the locking 3 prong socket that I may use for my charging port, it fits well in the stock filler opening.






Battery boxes to come!! I also have the coupler back from Charlie of evcouplerconnection.com so I will have to slide the motor forward and reinstall the coupler. This time I will photograph the process a bit better along with the mounting of the A/C, controller, vacuum pump and throttle.

This update was in Draft form so long that many things had changed. As it turns out there is a completion date (or dates)!!! I have agreed to do a small informal presentation at work about the electric car project so it would be really nice if I could BRING THE CAR. Completion date #1 Oct. 12th, the car really only needs to drive there and back.
With the exposure the car has received there is interest in showing it at the Global Clean Energy Congress, completion date #2 Nov. 1st.

If the scan of the newspaper article is difficult to read just click on the link below for an online version.
The Calgary Herald.
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  #46  
Old 09-08-2011, 02:35 AM
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Smile Re: Porsche 944 conversion DC/LiFePO4

Hi Rwaudio,
Really intersted in your build as i am currently buying a Porshe 944 S2 to convert, Few questions if you got time, why did you go for the Warp 11hv against the Warp 9 ? I have been looking around and listening to people and it seems a Warp 9 should be ok, Is it because you intend to have a High voltage pack?
Also Can you tell me How many cells will you put in the Engine compartment, and how will the overall weight balance out?
Im Thinking of using a Warp 9 with Warp-drive controller running to start with 50 200AH Sinolopy Batteries but im not sure how many i will get in engine compartment.
I really like the idea of losing the clutch and think i will go this way as well. Also would be very interested in your overall weight when finished do you think lighter or heavier than stock...
Cheers hope everything is going to plan.
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Old 09-08-2011, 01:48 PM
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Default Re: Porsche 944 conversion DC/LiFePO4

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Originally Posted by Spyder.ev View Post
Hi Rwaudio,
Really intersted in your build as i am currently buying a Porshe 944 S2 to convert, Few questions if you got time, why did you go for the Warp 11hv against the Warp 9 ? I have been looking around and listening to people and it seems a Warp 9 should be ok, Is it because you intend to have a High voltage pack?
Also Can you tell me How many cells will you put in the Engine compartment, and how will the overall weight balance out?
Im Thinking of using a Warp 9 with Warp-drive controller running to start with 50 200AH Sinolopy Batteries but im not sure how many i will get in engine compartment.
I really like the idea of losing the clutch and think i will go this way as well. Also would be very interested in your overall weight when finished do you think lighter or heavier than stock...
Cheers hope everything is going to plan.
Hello Spyder.ev I chose the 11HV over the warp 9 purely for performance (300 peak hp). I am using the Soliton1 and will have a 300+ volt pack, this should give me plenty of torque AND horsepower. I will be using a 96S pack of 60ah (3x 20ah) A123 cells. These are small and lightweight and will all fit in the hatch area nicely. This simplifies wiring and will allow me to keep a single pack temperature (I hope) With the 225lb motor, adapter plate/coupler/controller/power supplies for the charger all going in the front I should be very close to stock weight distribution (as it was with a full tank of gas). I might be a bit heavier in the rear but I would prefer the bias to be slightly to the rear than slightly to the front. I'll move things forward if I'm more than 53-55% rear though.

With a Warp9 and careful planning you could probably get 15-20 cells up front. There is a lot of room in front of the motor where the radiator was removed, there is also a bunch of space beside the motor on the passenger side, the drivers side is fairly full with the steering/brake booster etc. Depending on the controller size, there is also a bunch of room on top of the motor. 200ah cells might not give you a lot of flexibility to use the available space efficiently though. Based on my very light A123 pack I should come in at stock wet curb weight or maybe even slightly under.

Just consider that 50x 200ah cells is well over 600lbs, my pack will be under 300lbs before connecting bars. So unless you lighten the car in other places you will end up over stock weight. So many pieces on the 944 are aluminum or lightweight so not as much weight comes out as you might think.

The other thing to be careful of is the transmission, lots of torque can actually rotate the transmission and put the CV joints out of alignment causing them to break. The urathane fix as mentioned on rennlist.com works well and is cheap, that's what I did to my transmission mount. I don't know anything about the S2's but you would probably want the higher ratio transmission that the turbo's come with to take advantage of the increased torque.

Good luck with your conversion!
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Old 09-09-2011, 11:28 AM
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Default Re: Porsche 944 conversion DC/LiFePO4

Thank you for sharing all the details of your build. I have started my own Porsche 944 (83) conversion. You can check out the thread under Technical discussions called "It begins..."

Pulled the transmission out last night. I had not heard of the improvements available for the mounts, thank you for sharing that. Hopefully starting on pulling engine tomorrow.

You are doing a great job with your posts. I am terrible at that, as well as pictures - I know... I know... get better at it, lol. But thank you for all you have done here so far, it will help me quite a bit.

As I get further into the build and make up my mind on motor/controller/batteries I will start a thread that might be useful to others. Right now I'm just stripping out all the unnecessary components. Unlike others, I have no affection for the Porsche interior or the outdated exterior, and I will be re-creating into my version of modern, comfortable and stylish. Flat panel displays, LED lighting, etc.

I am really looking forward to seeing how your car performs when you are done!

Cheers!

Shock
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Old 09-10-2011, 07:38 AM
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Default Re: Porsche 944 conversion DC/LiFePO4

Quote:
Originally Posted by shock View Post
Thank you for sharing all the details of your build. I have started my own Porsche 944 (83) conversion. You can check out the thread under Technical discussions called "It begins..."

Pulled the transmission out last night. I had not heard of the improvements available for the mounts, thank you for sharing that. Hopefully starting on pulling engine tomorrow.

You are doing a great job with your posts. I am terrible at that, as well as pictures - I know... I know... get better at it, lol. But thank you for all you have done here so far, it will help me quite a bit.

As I get further into the build and make up my mind on motor/controller/batteries I will start a thread that might be useful to others. Right now I'm just stripping out all the unnecessary components. Unlike others, I have no affection for the Porsche interior or the outdated exterior, and I will be re-creating into my version of modern, comfortable and stylish. Flat panel displays, LED lighting, etc.

I am really looking forward to seeing how your car performs when you are done!

Cheers!

Shock
I don't blame you for wanting to change the interior on the '83! My wifes car is an '83 944 and well I have to say it's hideous compared to the '86. I like the exterior though and with some fresh paint I'm sure I'll be happy with mine.

(one of my main goals is that the car is identical to the gas version in appearance and the missing exhaust pipe and a small emblem is the only tell, the interior won't give away it's secret either)

Good luck with your conversion I look forward to seeing what you come up with, especially for the interior!
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Old 10-23-2011, 09:29 AM
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Default Re: Porsche 944 conversion DC/LiFePO4

Well a small update, I had a presentation at work where I agreed to bring/display the car, so I worked night and day for a week just to get it to a drivable state (not finished but drivable) I only had a 32S3P pack (54Ah 105v) so I didn't get a ton of performance out of the 11HV, but it was still an amazing drive!!!! My first real EV grin, so it provided extra enthusiasm for my presentation. The car was as smooth and quiet as I could have hoped for, everything worked perfectly, I was a bit worried about my 12v system since I don't have the dc/dc converter in yet (needs minimum 137v) so I supplemented the yet to be removed crappy lead acid with a 20ah pack of headways and all was well, headlights and everything worked perfectly. On 100v the 11hv peaks out around 3000rpm and power drops off before 2000rpm. Acceleration was still pretty good though because I could still draw upto 1000 battery amps if necessary, (the lack of voltage did limit the conditions where I could coax it into drawing any kind of big current though) it reminded me of driving a diesel.... tons of torque and limited rpm range, but QUIET. I had no problem keeping up with traffic, and had a brief period at around 70mph. I needed 4th gear to have the rpm range to get there though, and I did notice that battery current seems lower in lower gears for a given speed IE. 3rd vs 4th for 55mph. All in all the car was a blast to drive, it's a bit under powered with such a low pack voltage. The presentation went very well there was interest and questions from a large portion of the crowd (made up of many titles from professional engineers, software developers, accountants all the way to admin and shop technicians. (I work for a company that develops control and automation systems for the oil field, service rigs, frac etc).

Clutchless shifting is a breeze, no issues there. Upshifting is smooth and fairly seamless if you just let it drop into gear (not good for drag racing) down shifting if/when necessary does require an extra second or two but you can see the motor rpm increase as the syncro's match the speed even without touching the throttle. The coupler is good now, Charlie at evcouplerconnection.com did a great job the 2nd time around on the coupler. It was a nice tight fit requiring a rubber mallet to install on the shaft, it's the perfect length and now spins true. Obviously I haven't tested it past 3000rpm but the drive train is smooth and quiet up to that point. I used 2nd and 3rd gear for the trip, with the brief use of 4th above 55mph due to limited rpm.

I do have a hand full of cells that I believe to have high IR as their "defect" instead of low capacity, two groups had some swelling and got much hotter than the rest of the pack, terminals were fine, but the cells themselves got quite hot. I will pull those groups from the pack and test them, but I can live with 6 or 9 of 96 having high IR for the price I paid as long as the same type of ratio carries forward for the rest of the cells. I didn't expect them all to be as good as real cells and I was prepared for a few issues like this. I probably won't test the car again till I have at least 200v but at that point I think it would make a great daily driver giving enough capacity to get to/from work without needing to recharge and better performance at a lower current draw.

It's been a long time coming and I would like to thank all of those that have provided input, suggestions and answered questions along the way. I still have a lot of work to do, but the Soliton1 worked great, I configured and wired everything with the assumption that it would work and when it came to testing (9:30pm the night before I had to drive it to work) everything worked flawlessly except I still had idle setup, oops! I'm using the start input, tach input, "Valet" input, and LVC input.
I did have to "learn" how the controller wants to use the start input though since I'm not using the status output light. Turn the car to run, wait for the contactors to engage within the Soliton THEN turn the key to start and release. The Porsche has a safety where you can't go to start twice, IE if you turn the key to start before the contactors click you have to turn it off completely and try again. Good for keeping uninstructed people from driving the car, but not some weird complicated ritual that I would need to do just for me to drive the car. Outputs are Battery current to the oil pressure gauge, Tach to the tach obviously and controller temp to the coolant temperature gauge. I may go with battery voltage instead of controller temp to one of the gauges so that all the basic info is available in the stock instrument cluster without the need for turning on the external digital (don't match the look of an '86 Porsche) type gauges. I also need to order an EV Display to run the fuel gauge and the main unit should fit where the stock clock was. There is a main wiring harness from the Porsche that ran right by the terminal strips on the Soliton1 so I was able to get switched 12v, start signal, and interface with the gauges (except the tach) all with the stock wiring. The ground wire in that group was bad so I had to run a separate ground wire for the Soliton, but once I zip tie/techflex the wiring it should look clean and minimal.

The Mes Dea vacuum pump works perfectly, and it's pretty quiet. When I'm stopped at a light with no other noise I can hear the pump and feel a slight vibration in the steering wheel. It's very minimal though and with the radio on I wouldn't hear the sound, I may have to work on the vibration though, it's very subtle, but it's there. Power brakes work great, the pedal feel is good, I may add a vacuum reservoir to let the pump run longer but less often though. The Evnetics throttle works as expected and pedal feel is good. I'm using the Warp speed sensor from rechargecar.com (bought from Mike at evpropulsion.com who provided great service). It seems to work well with the Soliton1, I haven't been able to hit the rev limiter however the tach is smooth and responsive.

I'm very happy with the choice of donor car, the 944 drives very nicely as an EV, it's been nice to work on and it should last many many years. I finally have an EV grin! I can't wait to drive it every day.
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