Thursday, February 14, 2008

Bent Latch?

Friday, January 11, 2008

Adaptor Plate has Arrived

I received my Canadian Electric Vehicles adaptor kit from EV Parts a week ago and test fit it to my motor and transaxle.

It fits great, and the build quality is excellent. The only missing piece is a block-off plate for the starter. Now I just need to figure out which of the four orientations is best for the electrical connections on the motor.

Wednesday, December 19, 2007

Easy-Peasy Electric Heat for your VW Type 3

Editor’s Note: For those of you who just stumbled onto this post, I’m referring to a Type 3 that’s been converted to run on a big pack of batteries rather than the standard engine. Your average alternator isn’t going to be able to supply enough power (particularly voltage) to run the system described below, and you’d be wasting the perfectly good heat that comes off the exhaust system of your engine.

Most of the commercial heater replacements that are out there for conversion EVs are designed for use with formerly water-cooled vehicles. As such they’re designed to fit in the place of the original heater core (which looks like a small automotive radiator about the size of a stack of half a dozen CD cases), or to heat a liquid that’s circulated through the stock heater core. In either case, they’re not cheap.

Because our Type 3s were air-cooled, they used a different way to capture the engine’s waste heat, namely by circulating the heating air and hot engine exhaust through a heat exchanger. From inside the passenger compartment you were basically looking at a 2.5” diameter pipe under each side of the rear seat blowing hot air in. To combat the noise problem, VW installed a muffler on each tube that was basically a plastic bellows with a mesh tube inside, with batting between the tube and the plastic. These mufflers also split the flow of hot air between the rear- and front seat vents.

To replicate this situation, we need both a steady stream of air and a way of heating it. To provide the former, I’ll be using a second-hand heater blower from a ‘75-‘79 VW Bus. It has two outlets that will be connected under the trunk to where the original heat exchangers were connected. (If you’re having trouble finding one of these, you could also consider this kit, designed as a booster for the stock heating system in a VW Beetle or Ghia).

I’ll heat that air with a couple of ceramic heating elements much like the one I linked to above. Except that we’re going to get our heaters at Target for less than $20 a pop. These heaters have a nice simple thermostat in them as well, which we’ll use to automagically turn the heater on and off at a comfortable interior temperature.

The guts of these heaters will go inside the plastic muffler thingies under the rear seat, once we remove their original guts.

Here’s the step-by-step:

  1. Go down to Target (or over to their website at the link above) and pick up a couple of “Warm Fusion” (get it?) ceramic space heaters. The reason we want ceramic heaters is that they have an inherent positive temperature coefficient, which is a fancy way of saying that once they reach a certain temperature (around 180 degrees) they choke off the current flowing through them until the temperature drops back down. So they never get red hot the way some electric heaters do. They also have a size and shape that lend them to mounting inside the bellows.

  2. Open the heaters by removing the five short screws that hold the front to the back. Then remove the four long screws that hold the black guts in place. The five wires connected to the metal core are standard quick-connects surrounded by little fiberglass braids, so just slide back the braids and pull them off. Pry off both knobs, and unscrew the thermostat from the plastic case. Finally snip off the wires going to the little thermal switch attached to the guts, leaving as much wire as possible attached to the switch.

  3. Pick up a set of eight #8 by 1.5” machine screws with nuts and lock washers. Use them to affix the little mounting ears that fell off in the middle of step 2 back onto the guts so as to hold the metal core firmly in its plastic carrier.

  4. Now go to your car and remove the heater mufflers from under the rear seat. This is done simply by compressing them enough to slip them off of the tubes they’re connected to.

  5. Eviscerate these mufflers. They snap apart, and then it’s dead simple to pull out the original guts. While you’re doing this, note that they are worth something like $375 each at a certain online retailer. Tell yourself that those must be N.O.S. parts.

  6. Take the new guts and place them round-end-first into the forward half of each muffler housing. This will require a bit of force, since you want to get the little “ears” surrounding the screw holes into the second groove of the housing. In fact, you will probably need to shave some material off of these ears to get the thing to fit. You should end up with the front of the heater housing roughly flush with the front of the muffler housing. Orient the connections so that they point towards the branch tube that goes to the rear seat vents.

  7. Wire up the heater cores as shown in the diagram, and route the cables through a hole in one of the muffler halves.

  8. Now just snap the back of each muffler housing back on, and put it back under the rear seat.

  9. To mount the thermostat, drill the appropriate holes at the location shown here (from the Ebersp├Ącher Auxilliary Heater installation instructions). Your type 3 may look slightly different depending on it’s vintage, but you get the idea. You’ll need to drill three holes in total (one for the knob and two for the mounting screws).

  10. Now wire one terminal of the thermostat to a wire that’s hot when the ignition is on. Connect a wire to the other terminal and run it back to power the fan as well as the relay that powers the heater cores.

Now whenever the ignition is on and the temperature is below the thermostat’s set-point, the heater will come on. For further control, you can hook the old “heater on” lever to a microswitch and put it in series with the thermostat. But to my mind that sounds like that will just confuse people.

Please note that I have yet to test this out, and it’s entirely possible that stuff will melt. I will post an update once I’ve stress tested this setup a bit.

Monday, October 02, 2006

VW Type 3 Stop-, Tail- and Turn Signal Lights

One of the modifications I'm making to the car is to replace all of the red and amber lamps with LEDs. Here is a list of the bulbs and their power consumption:

Location Bulb Qty. Incandescent Power LED Power
Peak Typical Peak Typical
Headlights H4* 2 60W 55W N/A
Front Parking/Turn Signals 1157 2 21W 5W 3W 0.4W
Brake Lights 1156 2 21W 0W 3W 0W
Rear Turn SIgnals 1156 2 21W 0W 3W 0W
Tail Lights 67 2 5W 5W 1W 1W
Total Wattage: 256W 130W 140W 114W
Total Current @12V: 21A 11A 12A 10A

While all of these wattages are miniscule compared to the traction pack capacity, my DC to DC converter is only 30A. If you add in the current draw of the heater blower motor, rear defrost, seat heaters, and other lighting, you pretty quickly approach or exceed its capacity, particularly at night with the high beams and flashers going. That said, with a full complement of LED bulbs running $150 (that's with the fancy 3W Luxeon bulbs for all the 1156es and 1157s), you could also upgrade the DC to DC at that price. But with a pair of conventional bulbs approaching $5, you only need to replace them 4 or 5 times to break even on bulb cost. Plus the lag between, say, applying the brakes and having the brake lights illuminated is all but eliminated.

*I replaced the stock sealed-beam lights with a pair of 7" round Hella H4 housings.

Wednesday, July 26, 2006

Overall Philosophy

I've often seen advice to the tune of:

Come up with an overall vision or philosophy for the project before you begin. This will help with the countless small decisions you will have to make as you plan and complete the project.

This is something I seem to struggle with on a lot of projects, not just EV-related, and not even just car-related.

There are two areas in which I'm struggling with this, and being something of a perfectionist*, I want to be consistent with whatever route I choose.

So the first question is how true to original the restoration should be: For instance, do I need to locate window seals with a molding groove, or go for the cheaper and more available "Cal look" versions? The second question is more subtle, but basically it boils down to whether I want a more plug-and-play or a more integrated conversion. For instance, do I adjust or replace the torsion bars to correct the ride height, or do I add air shocks? Another instance of this question is how much sheet metal surgery should I do to get the batteries in an optimal location.

Some might advise to take the easy approach to each question, but I've seen some awfully homely restorations and conversions that take this approach. Or one can take the "perfection at all costs" approach, much like my EV conversion role-model, John Wayland. But given real-world constraints on things like time and money, where do I draw the line?

Suggestions are appreciated, and failing that I'll probably follow up with a post of what I've decided. In the mean time, I'm going to take care of the few obvious no-brainer tasks, like fender beading.

*This is coming from a guy who having received a Lego model of a Ferrari Enzo, decided to assemble it so that all the pieces, where possible, had the little "LEGO" text on each button aligned.

Air Shocks

I just found some Monroe Air Shocks for a '69 Type 3 (I'm assuming it will work for all IRS models). These might be a good way to bring the car back up to level ride height with the extra battery weight in the rear. The other option could be to adjust the torsion bars up a couple of notches. I'm not sure how this affects the handling and the life of the torsion bars, however. I'm going to fire off a post to the VW-EV mailing list and see if they have some insight.

Tuesday, January 10, 2006

Rant: The EV Magic Box

As I look at all the stuff necessary to convert this car to electric power, I'm coming to realize that a lot of the existing parts available are sub-optimal. Like most things in a market economy, they are more of a result of who can make money making what than parts that coherently fit together as a whole. What would be ideal would be some kind of magic box that would integrate AC motor control, battery charging, a 12VDC power supply, and an optional fluid heater into one enclosure. AC Propulsion's AC-150 system comes close. It integrates a first-rate AC motor controller with a high-power charger (with excellent power factor) by recycling the magnetics and electronics of the drive system, and it integrates the DC/DC converter. It is also designed to integrate cleanly with a vehicle that wasn't originally designed to be electrically powered. But the system also has its shortcomings: it is far too expensive (at US$25,000) for an EV hobbyist, the enclosure is too bulky to integrate cleanly in many donor cars, and the minimum nominal battery voltage is too high for a lightly-modified vehicle. It seems to me, however, that these shortcomings can be addressed, primarily by reducing the power level. A hundred and fifty kilowatts may make for good publicity, but most people don't expect that kind of power from their vehicle, particularly given the phenomenal torque characteristics of an AC system. An "AC-75" would be a much more practical system for everyday use[1]. The second change I would make would be to water cooling (in fact, nearly everyone without Alan Cocconi's rumored chip on his shoulder would probably make the same change :). While you can argue that an air-cooled system is simpler, smaller, lighter and cheaper, a suitable heat-rejection system is already installed in nearly every conversion donor car, and water cooling makes the packaging of the motor and electronics much simpler. So I'd replace the two large heat sinks and fans with cold plates, some hose, and a small pump. Finally, the minimum 336 volts are simply too many. Depending on battery chemistry, it's either too much weight, too much cost, or both [2], although this may change as lithium battery chemistries mature (at 3.6 volts per cell and with their excellent weight characteristics, both the cell count and weight could be reasonable). If the minimum nominal voltage were roughly half that, it would be much more accessible for people using mid-priced batteries like Optimas. I don't know enough about their Reductive™ charging topology, but lowering the voltage to 180 or so should still allow charging from a 120V source. Alternatively one could go the route Toyota has gone with their newer hybrid systems and create a bi-directional DC/DC converter to raise the voltage that's practical for batteries to one that's practical for motor control. But the cost would probably be hard to justify at hobbyist EV volumes. Another place to save money would be on the RPM range, since most donor vehicles retain the original transmission. Shrinking the torque/speed range to something resembling that of an internal combustion engine could provide some opportunities for further cost savings. One side advantage of such a system is that there is exactly one termination point for the high-voltage wiring: the magic box. The only exception would be a resistance heater, but it may be possible to integrate that with the water cooling (with Peltier devices or a bigger cold plate enhancing the heat rejection of the electronics) so that a fluid heater could built into the unit. In the end, the cost for the combo would have to be about $5,000 at retail. Without a large market to recover the NRE costs, it's probably not economically feasible. But maybe some sort of open-source-style development process could bootstrap things, especially if it was a BSD-style license that allowed commercial interests to embrace and extend it. [1] I can understand why AC Propulsion is reluctant to produce such a beast: there's not a lot of money to be made in EV conversions, and at that power level they would be competing directly with DC systems that can advertise better performance. [2] If you're optimizing the cost and performance of the motor/drivetrain pair, this is probably pretty close to the optimum. But if you're optimizing for run-of-the-mill donor cars, this is at least twice as high as is practical.

What I've Got

One of the motivating factors for doing the electric conversion is that I already have a collection of EV parts that I can use for this project: a motor, controller, charger, DC/DC converter, and a bunch of battery interconnects and 2/0 welding cable to tie it all together. The motor is an 8-inch-diameter 100-pound beast. It is a series-wound DC motor made by Advanced DC and given model number XP-1263A. It is an experimental higher-voltage rewind of their workhorse 2003-06-4001A 8-inch motor, and to the best of my knowledge is no longer in production. The "A" indicates that it incorporates a tail shaft. The controller is the Curtis PMC 1231C-8601 "Whiner" (so called because it cuts back the switching frequency at low power to a very audible 1.5kHz). It will do 500 amps from a 96V to 144V (nominal) battery pack. The charger is a Zivan NG3 configured to charge a 144V pack of Optima Yellow-Top batteries from a 120V outlet. The DC/DC converter was designed for use in RVs to step down mains power to the 12V required by the battery-powered devices. It appears to be no longer available. If memory serves, it is a 30-amp unit that runs happily off a 144V battery pack. The interconnects are designed for creating series packs of batteries with standard SAE (automotive) posts. They work quite well and look very professional, although all that lead makes things a bit heavier than they need to be.

Quick Note

Blaine, Washington-based California Import Parts is selling OE seat rail bushings for the '62-'72 Type 3. Get 'em while you can!.

Monday, January 09, 2006

Next Steps

The project is going to go a little slow for a while. I have some other projects that need time, money, and attention that could otherwise be spent on the car, but currently are more important and/or urgent. My general course of action is going to be to complete the restoration first, and then launch into the electrification. Obviously in some cases this won't be practical, but it has a couple of advantages, not the least of which is that I can sell it as an ordinary VW project car should the need present itself. It will also give me a lot of time for the sort of head-scratching contemplation that goes into making a good electric conversion. In any case, the immediate next steps will be:
  • Unbolt the fenders and re-attach them with the beading in place
  • Reinstall the bumpers, headlights, taillights, turn signals, and the like
  • Clean up the dashboard and install the gauges
  • Reinstall the hood and trunk latches and the door handles
After that, it'll be time to start ordering parts. First on the list are:
  • A new windshield
  • New window, door and trunk seals
  • Interior parts
Once those are installed the basic restoration will be complete, and it'll be time to spec out and order the electric conversion parts.

A Few Pictures

Thanks to my new camera phone, I now have a few pictures of the "body-in-blue" to show off. The combination of the CCD in the camera and the fluorescent lighting don't really do the color justice, and it's not helped by the lack of chrome, rubber, or glass to set off the color, but you get the idea.