Saturday, February 24, 2007

More Tools (i.e. toys...)

I've been mulling over some ideas for the past few days. The 914 doesn't run well at all when its cold and after going to the DEQ, I realized that I'm going to need a lot of work to get the car to pass emissions (it's a rather gross polluter right now). So, given that it's cold and rainy for a few months and I have the suspension, I decided to start the conversion, despite not having all the parts from ElectroAuto yet.

You know what that means: Time to buy toys! (er... tools) Most of my battery management research has been done at work using the equipment there, so I decided to bring the experiments home and analyze them with a cheap analog oscilloscope ($390 from Frys). I also ran out to Harbor Freight and got a 2.25 ton floor jack. Since I'm working out of a one-car garage (tight!), I need to use only half the handle to jack up the car. In fact, I jacked up the back end of the car this afternoon to poke around under there. I regret not taking more photos, but things look pretty clean.

The next step is to go back to Alan at A & P to replace the suspension and steam clean the engine compartment. Maybe I'll take a day off to go to A & P as well as Farwest Golf Carts to pick up some old 8V golf cart batteries for desulfation testing.

Tuesday, February 20, 2007

The Suspension is Here!

I received the suspension parts from ElectroAuto today. If you hadn't read before, the 18 8-volt golf cart batteries add 800 pounds to the weight of the car, so the suspension needs upgrading. It looks like I got new springs(blue), torsion bars (red) and two sets of matching shock absorbers (white/silver). If I go to the shop and have these replaced, I won't really be able to drive the car around. The real gamble is how fast the rest of the kit shows up. Unfortunately, I'm betting that ElectroAuto is going to take awhile before delivering the remainder of the kit, so I'll probably hold onto these for a bit.

On a slightly downer note, I ordered a $250 special desulfator for 6-24V batteries. It was supposedly shipped eleven days ago via priority mail but still hasn't shown up yet. I'd be kinda bummed if that got lost in the mail.

The 914 is still lurching violently until the car warms up. It idles fine at cold temperatures, and I messed with the cylinder head temperature sensor, so I'm thinking the trigger points in the bottom of the distributor are at fault. Time to go back to Alan at A & P...

UPDATE: Don Denhardt who makes the desulfators just called on the phone and let me know that the $250 desulfator arrived on February 12th, but is probably being held at the post office because it's insured and they need a signature. Perhaps the little note that they leave in my mailbox got lost with all the junk mail I throw out. I'll check tomorrow.

Sunday, February 18, 2007

Battery Equalizer Schematics Rev 1.0

I'm currently working on a battery equalizer for the 914 EV based on the whitepaper at the following link:

The above two schematics show the circuit that I'm experimenting with using 12V batteries. It seems to work fine on my bench. The circuit above costs less than $10 per battery in parts and I hope to make this available to everyone to help people make their batteries last longer.

By clicking on the images, you can get a much larger version of the pictures. Any feedback on how to improve the circuit would be welcome. I'll have to modify the circuit with a voltage doubler in the final stage to work with 8-volt golf-cart batteries for the 914 EV kit. Big thanks to Max at and all the other supportive engineers at HP for designing this circuit.

ADDENDUM: recently, many people have been asking me about this circuit and how well it's working. After some experiments awhile ago, I found that the capacitors simply do not transfer enough current to make this circuit viable, especially for the large amp-hour batteries needed for an electric vehicle. I currently drive an electric Civic and use resistive shunt balancers on it that seem to work well. The large 3-ohm shunt resistors are mounted away from the batteries on an aluminum base as a heatsink since they dissipate quite a bit of heat. The shunt balancers were purchased from Belktronix, but you could probably make them yourself with a low-current comparator that drives a FET to switch in the power resistor at a specified voltage (like 14.4V).

Friday, February 16, 2007

Whew! It runs again. Zivan mods are back too.

I took the 914 in to Alan at A & P Specialties this morning and his techs fixed the timing so the car runs smoothly again. The points were burned and had to be re-timed. The real acid test is if the car fires up tomorrow while getting cold all night. Alan said that if it ran poorly when cold, the block temperature sensor or the pressure sensor is probably having issues. I'll have to do more research on those items.

The other cool piece of news is that the Zivan NG3 charger came back today. I sent it to Electric Conversions to add a "low-power" switch so that it pulls 20 amps or 12 amps from a 115V outlet. The lower power setting will be great for charging at work or at friends' houses where there' s only a 15 amp circuit and there may be a light or two running off the same circuit.

Wednesday, February 14, 2007

If it aint broke, don't fix it...

Well, I tried to learn more about the distributor two evenings ago and really screwed up the engine timing. The 914 runs but really sputters and jerks around when cold and doesn't seem to improve much after warming up. I have an appointment at the shop on Friday to fix my "optimizations."

On a more interesting note, I prototyped a battery equalizer with two 12V UPS batteries earlier this week. The circuit seems to work just fine and I was able to get the voltage difference between two adjacent batteries from 1.0 volts down to 0.2 volts overnight. The process is asymptotic, so there are diminishing returns as the voltage difference converges towards zero.

This morning disaster struck the equalizer in that I swapped a 47uF flying tantalum capacitor for a 1000uF low-ESR electrolytic but forgot to change the switching frequency. The high-current FETs overheated and the plastic protoboard melted to my desk. Murphy's Law says that experience varies proportionately with equipment ruined. Ugh. I'll post a schematic in the next few weeks so other people can leverage it.

On a brighter note, ElectroAuto replied to my second e-mail and said that the new suspension for the 914 to handle the extra battery weight should go out this week. Once I have the suspension, I can have the shop install it and I can get to work. Let's cross our fingers...

Sunday, February 11, 2007

Major problems with Idling

One of the diseases that plagues the fuel-injected 914 is the difficulty in getting the car to idle under all conditions. My 914 starts up just fine but then stalls most of the time at stoplights after cruising on the freeway for 30 minutes or more (heating up the engine). It's also started jerking around when first accelerating from a cold start, sometimes rather violently that the whole car shakes back and forth. That can't be good for the transmission.

Many thanks to the folks at Pelican Parts who have several technical articles on how to fix your own 914. :


I spent the weekend researching the fuel injection system and found the idle adjustment screw. After a half-hour cruise on the freeway back home, I pulled off at a rest area and let the stall. The idle adjustment screw was easy enough to turn by hand, so I raised the idle speed while the engine was hot until it ran without dying. As far as the violent jerking when the car first starts, I'm going to look into the electronic throttle switch to see if there's problems there. I find it funny that the car doesn't jerk around anymore once the engine is up to temperature. There must be some expansion going on. We'll keep you posted.

Sunday, February 4, 2007

Phase One Complete

After fixing the headlamp switch and re-gluing the rear-view mirror back on, the 914 is fully operational and a total blast to drive! My friend Rick and I drove out to the Columbia Gorge for a hike. It was a beautiful day and having the Targa-top down allowed us to see all the mountains and cliffs on each side as we drove down I-84. I'm going to start commuting to work with the 914 to get used to the vehicle's capability and have some fun while it's still has the range of a gasoline car.

The only minor things left to fix are the accessory lights for the clock and oil-pressure guage and getting the clock working again. I hear fixing the clock is difficult, but I'll give it a shot. Many thanks to all my friends who have been so supportive of this project.

Saturday, February 3, 2007

Fixing the Headlamp Switch

After much fussing around to get the dashboard apart, I finally got the headlamp switch removed. It looks like the headlamp contact is completely burned off. That would explain why the headlights only worked intermittently. Luckily, the prior owner left another headlamp switch in the glove box. The switches are different, but I could cannibalize an electrical contact plate from the older "skinny" switch and replace the burnt one in my newer "fat" switch. I'll get some dielectric grease and a tie-wrap to close everything up tomorrow and try it out.

Since I took all the time to take this somewhat detailed picture, I submitted my findings to Pelican Parts so that they could post this as a technical addendum to their current article which only covers the older "skinny" headlamp switch.

The clock in the center console doesn't seem to work either. According to the technical articles at Pelican Parts, this is a common problem in the 914s and I'll have to perform some major surgery to get it working or blow $200 (ouch!) on a replacement. I think I'll try the surgery first and see what happens. Heck, I've always got the clock on the installed CD player, but it's just not the same...

Fixing all the Nitpicky Stuff

I stayed up last night until midnight repairing a whole bunch of little things that didn't work on the car. I'm actually quite psyched that I was able to do it all in about six hours.

Things that I fixed were:

- Add stainles steel seat adjuster handles
- Re-adjust the steering wheel so it was centered
- Fix the hi-beam headlight switch
- Fix the auto turn-signal cancellation worked again
- Fix the connection to the horn (the custom WoooGaa horn is great!)
- Re-attach the stripped handle for the seat lifter
- Fix the corroded connection to the cabin light
- Libricate the left door lock mechanism internally (was sticky)
- Fix the "stop" bolt for the left window so it would close all the way

The things I still need to do:

- Fix the headlight switch - Apparently a replacement is extremely rare. A new one online is over $400! By luck, there was a spare switch in the glove box, but I don't know how well it works. I'll probably end up taking the switch apart and cleaning off the contacts.

- Re-attach the inside rear-view mirror. On the drive home, I was adjusting the rear-view mirror and it pulled off the windshield. This was actually a blessing in disguise because it was mounted so high on the glass that I could only see about forty feet behind the car with the targa-top installed. By re-attaching it lower on the glass, I'll be able to look directly backwards and see the road and traffic behind me.

- Fix the windshield washer - This one is going to be tricky since the washer is powered by the air pressure in the spare tire. I've never seen this before and all the old pressure hose fittings are leaky. This problem is not as critical as the rear-view mirror or headlights so I might just let it go for awhile.

- Fix the clock in the center console

- Add bulbs to light the center console

- Fix the voltmeter in the center console, it always reads below 12V when idling. This might be an issue with the charging system, or the battery or the alternator. This problem will go away with the electric conversion, so I may just let it slide for now.

This is a really fun car to work on. It's much like the VW Dasher I worked on while in high-school, so I have a little experience.

Friday, February 2, 2007

Taking the 914 home

My friend Pete drove me out to Camp914 today to pick up the vehicle. Craig did a wonderful job on detailing it and showed me all the required controls. I drove it home without a hitch and spent a bunch of time reading the instruction manual (you're not supposed to do that!). There are a few minor things to fix, but overall, the car is fantastic. I even met the prior owner (Vince) at camp914 and heard his story. He even had all the paperwork for the car and traced its origin into the country many years ago. This is going to be a totally fun project!

Thursday, February 1, 2007

Going to Camp (Camp914, that is)

Well, today was the big day to dump some cash on a platform for the EV. After thinking about it and talking with some friends, I decided to splurge and spend a few thousand more on a much nicer looking car so I wouldn't have to worry about fixing up the cosmetics.

I really like the interior and the car drives well. There were minor things that didn't work like the horn and a notch in the trunk for the TargaTop, but Craig is going to work on those before I pick it up tomorrow. I still have to wait for more EV parts before I can start the conversion, so there will be much joyriding to be had in the meantime. YeeHaw!