Archive for June 2010

Lessons Learned

June 13, 2010

Even though I am not completely finished with my conversion, I promised to share the lessons I have learned from it.  There may be more later as I get used to the car, have maintenance and warranty issues, etc.   But for now, my dos and don’ts of EV conversion:

  1. DO Use a high-voltage power pack. You get better range and performance, and it’s safer to work with (less amperage).  The only downside is the cost of having lots of batteries.
  2. DO Use lithium batteries. Better in every way, and they aren’t even more expensive if you plan to drive the car for more than 3-4 years.
  3. DO Use AC drive. Simpler installation, fewer parts, braking regeneration (which works very nicely by the way), better performance.
  4. DO Hire professionals for the work you can’t competently do yourself.  For me this was gasoline engine removal, welding, transmission repair and BMS troubleshooting.
  5. DO Get involved in the EV community, and the one for your make of car.  There are forums everywhere online, full of people in the EV world who are very helpful.  Same goes for the VW Type 3 folks.  But almost any make of car has enthusiasts who can help you.  And they want to help, so ask.
  6. DO Deal locally wherever possible.  I have had the best results working with people in town – the welding folks, mechanics, etc.  And the worst results dealing with anonymous websites far away.  For example, if I’d not been able to drive to my supplier to get the proper batteries (after two mis-shipments), the project would have been delayed at least another month.
  7. DO Buy tools if you need them.  Or rent. Or borrow.   Using the wrong tools is dangerous and yields bad results.  I hurt myself several times because I had the wrong jack, a lousy soldering iron, etc.  If you can’t bring yourself to buy tools, see #4 above.
  8. DO Be prepared for delays and frustrations. When you are making something one-of-a-kind, there will always be problems.  Things take longer than it seems they should, everything costs more than you hope, parts are hard to find or make.  In my case, my five month project has turned out to be most of a year.
  9. DO Get a garage. Working in the driveway has really slowed me down.  I’ve had long delays for bad weather.  I have to put my tools away in the house after every work session.  I was storing large components in the laundry room.  My neighbors’ patience was tested.  The good thing about working outdoors is chatting with all the folks who walk by and wonder what’s going on.
  10. DO Buy reference guides. My Bentley VW manual and the “Convert It” book by Mike Brown have been indispensable.
  1. DON’T Buy a kit. There are no complete kits on the market.  There are really only six main elements in the conversion and you can buy them separately for less (and get the best of each for your job).  The components are: motor and controller; batteries and BMS; charger; DC/DC converter; accelerator POT unit; and transmission adapter.  The minor components such as wire, connectors and relays are easily bought from an electronic supply house like Digikey or Mouser.  Gauges and the switchbox can be bought from an EV or general automotive supplier.
  2. DON’T Pay up front. For major components, use an escrow service like PayPal which pays the vendor when your stuff ships.  Two of my suppliers went out of business on me, one still owing me stuff.  If they won’t accept escrow, break up your bill of materials into small orders and pay each separately with a credit card – at least you can get your money back if they don’t deliver.  I’d suggest no single order of more than $2,000.  If your supplier folds, quickly contact the original manufacturer so they know what happened and can help you with warranty claims.
  3. DON’T Buy things you don’t understand. In my case, the BMS has been the most trouble.  It is far more complicated and sensitive than I expected.  I should have asked other people who had one before I bought it – I might have picked a different system if I had.
  4. DON’T Deal with Electro Automotive. This company is (was) the oldest in the business and has sold thousands of kits for conversions.   But their customer service is atrocious and they may now be out of business.  They don’t sell anything you can’t find elsewhere.
  5. DON’T Use welding cable. With lower voltage DC systems, welding cable is recommended to carry the high amperage.  With a high-voltage system, you don’t need it.  Welding cable is hard to work with, the lugs are difficult to connect to the other components, the wire is bulky and hard to thread through the car, and it’s expensive.  Use 8 gauge insulated wire instead – you can buy it anywhere.  If for some reason I had to rewire my car, I would toss all the welding cable.
  6. DON’T Cut corners on safety. This is a motor vehicle that carries human beings at high speeds.  You don’t want your battery boxes falling out, your flywheel disintegrating, your 12 volt power suddenly failing, you (or your passengers, or your neighbor’s cat) getting shocked, etc.  Insulate all your connections, cover your batteries, tape your tools, use heavy automotive-grade nuts and bolts, get your flywheel balanced, make sure your brakes and suspension are strong enough for the heavier car.  If in doubt, use a bigger bolt, or thicker metal, or fatter wire.  Use lock washers on every bolt.
  7. DON’T Sell your other car too soon. You will be running lots of little errands for this and that.  It’s nice to have your other car for this – sell it once your EV is a daily driver.  I rang up a pretty hefty bill with Zipcar.  But you can’t easily haul your motor or transmission to a shop on a bicycle or the bus.
  8. DON’T Buy a junker car to convert. I’ve been very happy that the car I started with was so nice.  Everything basically worked, the body is in good shape, etc.  Worst would be a donor car with electrical problems.  Converting to electric is hard enough without fighting problems with the basic running gear at the same time.

That’s it for now.  But who knows what the future holds?  Painful and expensive lessons are always lurking in most things in life…

Power play

June 13, 2010

I gave up on Electro Automotive and purchased a DC/DC converter from another company.  It arrived in just a few days.  On my first attempt to install it, I received a big shock, literally.  After connecting the unit, when I attempted to reconnect the main power a huge arc jumped from the wire to the battery.  I jumped almost as far.  No damage done; just a scare.  When I called the supplier they said, “oh yeah – we forgo0t to tell you about that.  You need thermistors.”  So a couple of thermistors are on the way and I can complete the installation when they get here.

As I understand it, the DC/DC converter wants to draw a huge charge right away to power up its capacitors.  The unit doesn’t have an on/off switch, so the draw happens as soon as power is applied.  Adding thermistors is supposed to help.  These little devices (they cost only $1.38) will absorb the initial draw, converting it to heat.  Instead of a big spark, the thermistors get really hot.  Once the unit is fully powered, the thermistors cool off and everything is normal.

I did all the wiring and installation of the DC/DC converter, leaving two open connections for the thermistors. The box is under the back seat next to the battery.   This is what it looks like:

DC/DC Converter

The battery is to the right.  The connections for this unit are pretty straightforward.  It took me about an hour to get it all done once the sparking issue was figured out.  This is the last major component in my conversion.  All that’s left is buttoning everything up and making it pretty (and getting the darned BMS to work properly).

I have gotten tired of getting little shocks every time I disconnect the main power to work on something.  So I added a service disconnect.  This is two large plastic blocks, called Anderson connectors, that snap together like giant Legos.  I cut the main positive and negative wires in the engine compartment and inserted this connector in between.  Now it’s a tool-less and shock-less process to disconnect everything.

Service Disconnect, Disconnected

Service Disconnect, Ready to Drive

This is a good safety measure also – if the car gets wrecked there is a fairly obvious way to shut off the power.