Saturday, February 9, 2008

Reflections on Converting a 914 to an EV

Many things have passed through my mind over the past year and a half while converting this vehicle. I'd like to capture some of the good and bad things to help keep other people from falling into the same holes as I did. Here goes (in no particular order):

Things That Went Well During the Conversion
  • The 914 AC kit from Electro Automotive is a good one. The parts are high quality and the instructions take the user through the process step by step.
  • I received much support and encouragement from everyone around me. This included the folks at the Oregon Electric Vehicles Association, the motor control engineers at my work (HP), the communities at, the other 914 EV conversion folks (Thanks to Randy, Ross, Roger, Matt, Paul, and many more...) If you do your own conversion, tap into all these resources whenever you have an issue. Most people are very happy to help.
  • I had all the suspension, alignment and brake work done at a local shop called A & P Specialties run by Alan, who was also very supportive.
  • The conversion car came from and had very little rust and good structural integrity. Craig at Camp914 was also very supportive and let me swap parts when I needed something small to get the non-EV portions of the 914 working.
  • I modified the wiring in the original 914 AC kit (as suggested by Paul Jorg) to turn on the regen when the brake lights came on instead of controlling regen by releasing the accelerator pedal. This made the car much easier to drive (similar to an ICE vehicle). Azure Dynamics is going to add this rewiring to their future DMOC controller wiring diagram to help other EV conversions.
  • Given the huge support from the OEVA community, I was able to borrow a "real" crimper to attach all the lugs to the 2/0 gauge welding cable. This made the job much easier and I feel the crimps are much better connections.
  • I had a switch added to the Zivan NG3 charger which turns it down to 60% power, allowing me to plug into any 15 amp 115VAC socket at work and at friends' houses. I highly recommend sending your Zivan charger to the US support folks for this modification. It only cost me $60.
  • Adding a "real" battery monitoring system like the PakTrakr was key in monitoring the state of all the batteries. Support for the PakTrakr was excellent despite some of the noise in the system which caused spurious readings. One might consider using the EVision system from MetricMind too.
  • Writing a blog using was great for many reasons. First, I was able to keep track of my progress. Second, other folks could learn from what I had gone through. I often refer people back to specific pages when they have questions about their own conversions. Third, it greatly increased visibility to the online community and I'm hoping it raised awareness of EV conversion issues. The feedback I received from people was excellent. I even received a few posts from Mike Brown at Electro Automotive, the designer of the kit.
  • I really enjoyed working with Beth Silverman at Azure Dynamics. The AC24 motor and DMOC445 controller system are highly configurable. The AC motor also provides regenerative braking for free, which also aids in stopping the car with the heavier battery weight. It was easy to capture logs of system behavior, e-mail them to Azure Dynamics and get a good technical response back in a day or two. Beth and the Azure engineers saved me countless hours of debugging time by analyzing these logs and pinpointing problems with my setup.
Things That Didn't Go Well During the Conversion
  • I was rather disheartened by the uncertain delivery times of kit parts from Electro Automotive. The critical parts needed to complete the car took eight months for delivery. It's not the eight months that bothered me, but the claim by ElectroAuto that it would only take two months and then not communicating the delay to me. I still haven't received several of the non-critical parts such as gauges, hydrometer and some other things. If you order a kit from Electro Auto, make sure you have patience in waiting.
  • Most of my support for this kit came from other members of the EV community. This was rather disconcerting considering that my kit was the first 914 AC kit to ever be completed. I received minimal support from ElectroAuto and received most of my documentation from other 914 AC kit members who passed it to me "on the sly." I've heard of at least two other people who received their kit parts but no 914 AC instructions. They ended up asking me for the directions after receiving no response from ElectroAuto.
  • I'm not entirely sure why, but ElectroAuto shipped #2 gauge cable with the AC kit instead of the standard 2/0 gauge cable that came with the earlier 914 DC kit. The AC kit still pulls 300 amps and benefits greatly from the much thicker cable. If you get #2 gauge cable, go to your local welding shop and replace it with 2/0 gauge. The small expense of $150 will extend your range and power greatly. You can even cut a few strands off the edges of the stripped cable and jam on the #2 gauge lugs to save cost.
  • The transmission on the original 914 was bad and rattled the car violently. In my enthusiasm (read hubris), I tried to rebuild it myself. This is a job requiring special tools and expertise. If I had to do it again, I would definitely send it out for rebuilding by someone else or just purchase a newly refurbished 914 transmission. The old one sold nicely. The folks at have a member named "Dr. Evil" who does rebuilds for a very reasonable price. I bought a refurbished one for $850 shipped and sold the old one for $250.
  • I should have joined an online community of 914 owners at the beginning. There were several issues with the original car that I could have saved loads of time on (especially the transmission) by asking other (non-EV) 914 experts. It also provides an excellent place to buy and sell needed parts far more cheaply than other online sources. The online support for the 914 is very good, especially the technical articles at Pelican Parts.
  • The AC24 motor from Azure Dynamics is significantly underpowered for the 914 AC kit. It's acceleration at zero RPM was less than half the original ICE engine and half of that (at zero RPM) of the Advanced DC 9" motor in the 914 DC kit. If I had to do things over, I might seriously use the DC kit. The first question everyone asks me about the 914 EV is "how fast is it?" Most people seem to want want greater range, but are not willing to give up starting torque for it, especially for a Porsche. Azure Dynamics is trying to address this with the newer AC24LS motor which has 15% more power, but I don't know if that'll be enough. In short, paying $4000 more for the AC kit and getting half the power was frustrating.
  • The CCPower C400 DC/DC converter kept dying on me. There was virtually no support from the supplier and I ended up reverse engineering the whole unit (since a new one was $400) and worked with the power-supply engineers at my job to fix it. The unit still failed to work properly and I ended up replacing it with an Iota DLS-45 unit which sells for $135 and is commonly sold at the site for electric conversions. It also fits in the same space as the CCPower unit and puts out 50% more amps with no noise (the CCPower unit squealed and buzzed). The customer service at Iota Engineering was very prompt and answered all my questions quickly. Having said that, another 914 AC customer has reported zero problems with his CCPower unit, so I might have just had a bad unit.
General Themes During the Conversion Process
  • Converting a 914 to electric is a group effort. As mentioned above, I received support from the 914 community, the EV community, my co-workers, and many friends. People feel connected when they can contribute to another person's success and I found no end to help for this project. Get connected with the online 914 community at 914world or as well as with your local EV community.
  • Converting a 914 to electric is a process. There will be many unexpected problems, especially with a 30+ year old car. The AC kit had never been completed before and the instructions were a bit sketchy. I had to remind myself several times that I'm doing this for enjoyment and to take many breaks to keep from getting frustrated.
  • Converting a 914 to electric is a hobby. The phrase "There's a fine line between a hobby and insanity" comes to mind. This hobby will cost you far more than any amount of money you will save in gasoline when driving it around. The cost of the kit is roughly equivalent to eight years of gasoline. If you want a fuel efficient or no-gasoline vehicle, it'll probably be cheaper to buy one already made. There are also many avenues (Porsche clubs and EV clubs) that let you enjoy things vicariously without having to blow $20,000 on your own kit.
  • Understand your motivations and your motors. I purchased the kit as a no-gasoline commuter car solution. Most people want their Porsches to go fast, not long distance. The DC kit is better for a fast car, the AC kit better for smoother driving and (possibly) longer range, although that has yet to be proven.
As stated from day 1 in the title of this blog, all this information is meant to help others in considering their own conversions and getting through the process. Despite having made several "less than shining" comments about Electro Automotive, they are still a great company and nobody else makes a quality product like they do. I perceive them to be simply overloaded given the enthusiasm surrounding electric vehicles these days.

I wish everyone well in their path towards EV-dom.


Roger Daisley said...

Back to the DC/DC problem: You mentioned the noise. My CC Power DC/DC is absolutely quite. I'm wondering if there might have been some kind of grounding or ground loop problem? (Or, as you mentioned, just a defective unit.)

I've often wondered if I'd been better to have sprung for the AC power pack. Your description convinces me that the DC motor is best for my situation. It's very smooth and controllable. True, I give up regen, but in the long run, will it make any material difference?

I'd love to see your vehicle. Maybe the next time I'm in PDX we can arrange a cup of coffee at Starbucks. Same for you, if you get to Pullman.

Regards, Roger

TimK said...

Hi Roger,

I guess I must have had a bad DC/DC unit. The regen is nice for additional braking in the heavier car, but it doesn't really extend the range, especially for freeway driving. Please definitely contact me the next time your in PDX and we'll go for a spin.


Ross Cunniff said...

For me, the regen braking is key, since I drive it in town exclusively. But, your mileage might vary (literally!). FWIW, I am going AC on my next conversion, too (but using the much bigger AC55 motor).

TimK said...

Hi Ross,

Based on the
you have at your new ElectroJeep blog, it looks like you have the best of both worlds. High torque at low RPM for fast starts at stoplights as well as regenerative braking. It looks like the AC55 has just under four times the torque at zero RPM as the AC24!

Regards, Tim

Ross Cunniff said...

Yep, that's why I chose it. It's a monster, though - 233 pounds, 312 volts, it'll rip your lungs out, Jim. With 4x performance comes 3x the weight and 3x-4x the energy use...

onei57 said...

The greatest help to me was the blogs that you and the others have done. Electro Auto is one of the few places that offer a kit type conversion and it is well thought out. But the lack of cusomer service and slow delivery make this a poor choice but this is the only choice. That makes the blogs very valuable as well as EV community. Tim has been a great help, the support I should have gotten from Electro.

I believe the situation makes it a great time for someone to come up with a kit that will use a newer vehicle that will have a strong enough power to get out of the way of its self. A PT Cruiser maybe? Cheap enough, lots of room for batteries.

I've just started to "tune" mine so I'm not sure how well it will run but it does not keep up with traffic now. A long way from the 100 MPH car I was promised by Electro.

Now that the venting is over, do you think 12 volt batteries would have helped (maybe 16 = 192 volts)? I think the controller can be updated. Just an wondering....

Dave M said...


You and the others who have been working on these 914 kits and sharing their experiences have been inspirational as well as informative. Through it all, I most appreciate your comment that you intended this project to be something of a hobby. I'm sure there will be moments I'll have to remind myself of that when I really get into it.

Your post has also made me pause to reconsider my current plans. I personally like the idea of the AC kit and was all set to go that route, but your latest comments have me rethinking that approach.

I didn't select a mid-engine Porsche as my platform only to be envying the performance of Hyudais. Now, I'm thinking I need to revisit the DC motor potential for my project.

Say, does the 914 AC kit use reverse gear to back up or is it designed to reverse the motor? One of the things that attracted me to the AC motor was its ability to run in reverse. I'd be interested to hear anyone's experiences on that score.

TimK said...

Hi Matt and Dave,

Thanks for your comments. I do think a higher voltage (i.e. 12V batteries) would give slightly more power at the expense of range. The controller can be tuned for the higher voltage, but will limit the current going into the AC24 motor to prevent it from warping or burning out.
Dave, the AC kit has an input on the controller to go in reverse; however, the ElectroAuto kit uses the manual reverse gear on the transmission to go in reverse. DC motors can also go in reverse if you have a special "reversing" contactor that flips the terminals. It's a bit more cost, but works if you don't have a transmission.
Matt, how is your car running?


onei57 said...

I have about 12 miles on it. Needs to get better accleration and speed to be able to keep up with traffic. I was working with Beth at Azure performance tuning the motor in late January when we got a lot of snow and I went to Vegas for the Super Bowl. Waiting for the snow to melt off now. The throttle is only going .5 according to the controller so there is room for improvement. I'm just after a normal keep up with traffic situation.

TimK said...

Hi Matt,

Both Ross and I ran into the same issue and solved it with DMOC parameter tweaks. Check out Ross's entry here:


onei57 said...

I've done this. The next thing I'm going to do is to move the cable to the next hole up on the potbox and adjust the peddle stop down.

EVIE said...

For the record, Electro Automotive has improved their customer service exponetially as they have hired more experts to field calls and assist with problems. I have always been answered within one to two days. I am Mark and I am building an electric vehicle using a modified Bradley GT II. I am using the AC24LS and DMOC445. She is almost finished, her name is EVIE.

onei57 said...

The service has improved! But it still took 3 years to complete the order. Bill Lentfer has been very helpful in finishing the last few thing and refunding money for the rest that I got elsewhere.Hope it continues.