Wednesday, May 22, 2013

Otmar at the Maker Faire

The Maker Faire is always a good time but while checking in I spotted a double VW Westfalia - two campers welded together to make one long bus.
I only heard of one of these creations and it belonged to Otmar - creator of the Zilla controller. Finding it had Oregon plates and a Biodiesel sticker confirmed my suspicion. 
No sign of him on Saturday, but on Sunday, my dad flagged me down to talk with a guy wearing a goofy purple hat - it was Otmar. He asked how I liked my Zilla (which I love) and we talked for 15 or 20 minutes about the state of the conversion market and the different projects he's working on. I asked him to sign my Zilla 
And I got a picture with him. It was an ethereal experience, which my smudged camera lens can attest to.

Monday, March 11, 2013

New Contactor

So the car has been in the road for 4+ years and running relatively trouble free. In late November, though, it suddenly shut down on my way to work. I was able to pull over and restart it, but it was troubling. The Zilla error codes pointed to motor over speed, contactor stuck and low 12v supply - the usual hodgepodge of errors I see when the SLI battery is low.

I recharged the SLI battery over night but on the way to work the motor shut down again. It did restart and once I was home again I checked my wiring to the controller, thinking a loose 12v, ground or tach lead could be causing the problem. Everything looked Kosher. 

The next day on the way to work it shut down. I coasted off the freeway and parked. I tried restarting it, but this time instead of the familiar contactor "thump" I heard a sizzling sound. I pulled the pack emergency disconnect, pulled my meter from the glove box and made some quick tests. I quickly found that the contactor points had welded closed - which was probably the sizzling sound I heard.

I was using a Kilovac  EV200 contactor and though rated for up to 2,000 amps and can handle 500 amps at 320volts continuous. EV Source points out that these ratings are based on a very large cable size -300 MCM, which translates to about 4.5/0 where I am using 2/0. I was told the connector bolts would get warm from the resistance and ultimately weld shut (which they apparently did), but they never got warm to the touch in my typical drive ad never discolored to indicate overheating. Evidently the bolt temperature doesn't relate well to the contact temperature inside...

This is how the original EV200 contactor looked in the High Voltage Enclosure:

So naturally I wanted to upgrade to a contactor that wouldn't die on me again.  I looked at Nanfeng and Albright but ultimately decided on a Gigavac. The Tech Support at Gigavac said my 350 amp continuous at 170 volts was within spec for the GX14 as long as I used copper buss bars to dissipate any heat.  

The GX14 is larger than the EV200 has a lower cable connection point than the EV200. After going through numerous mounting plans, I came up with one that  used buss bars to connect the cable from above to the input bolt below and to the Ferraz/Shawmut fuse

This is how the Gigavac GX14 looks in the redesigned high Voltage Enclosure:

You can see the copper bus bar on the right middle under the 2/0 cable. The contactor is the black circular unit in the middle. The output of the contactor goes to a short bus bar into the Ferraz/Shawmut fuse positioned vertically. It's bolted to the output cable to the Controller.

Wednesday, May 30, 2012

How to Retrofit an EV conversion to J1772 in 7 easy steps

Over the last 6 months or so, more and more  public charging stations have been installed around town so I finally decided it was time to join the J1772 club. For those of you not familiar with the term, J1772 is the designation for the plugs and inlets that are the official standard for EV charging in the US. With the standard connection on my car, I could take advantage of these charging spots - and many of them are free. 

My old charger port was a L6-20 which was cheap and fine for charging at home, but few public places had this style connector waiting for me... It had served me well over the last 4 years, but change is good.

Most of the local stations I ran across were from Coulumb, so I set up an account at ChargePoint and got a $5 card for using their chargers. How's that for thinking ahead?

Original L6-20 charging port

The whole process of installing the J1772 was easier than you'd think. Here are the steps I took:

Step 1 - buy a J1772 Inlet. The Inlet is the part that goes on the vehicle. I also needed to buy the plug end so that I could convert my home charging gear (a.k.a EVSE or Electric Vehicle Charging Equipment)  to J1772 also. There are a few places that sell these parts - and they aren't cheap, btw. I bought mine from TucsonEV . I had a few questions which they promptly answered and they were quick to replace a pin which wasn't correct from the factory - no complaints.

Step 2 buy resistor(s) and diode. The J1772 standard expects to see signalling between the charger and the outlet in order to power up the connection. Here's a link to a description of the electronics for the signalling involved.  Your charger is probably like mine in that it doesn't have a way to provide these signals. One could wire up a switch to manually provide the signalling, or buy a circuit board to to fake it out, or you could do like me and hard wire it so the EVSE thinks the charger is always ready and turns on the juice. This is a low voltage, low current application, so the parts are cheap and should be readily available. You need a diode that will handle 20ma and 856 to 908 ohms worth of resistors. I couldn't find a 900 ohm resistor so I used a 560 and 330 in series. These parts came to about $6.00 at 'the shack."
Parts needed -J1772  Inlet, diode and resistor(s)
Step3 remove old inlet and test fit the new I pulled out the old inlet and disconnected the wiring from it. Then I dropped in the new J1772 unit in it's place. The screw holes for the old inlet didn't match the J1772, but to my surprise, the holes for the original Miata gas filler neck did! This made the swap real easy. If you aren't this lucky, you'll need to drill the mounting holes for your new inlet.

Step 4 Soldering the power pins Disassemble your inlet and figure out where the wiring needs to be placed for proper assembly. Mine had a pin retainer that needed to be over the wires before the pins were soldered on. I added a short wire to the ground so that I could easily connect the resistors and diode later. The power pins took a lot of heat to get up to temperature - more than my soldering gun would put out. I ended up using a butane plumbers torch at a low setting to warm up the pins. I tinned both the wire and the pin and then mated them together one at a time. 

Step 5 solder the pilot pin connection The pilot pin is the small one on the lower left. The one on the right is the proximity pin, which I understand isn't used. Connect your resistor(s) in series (end to end) with the diode. The stripe on the diode should go toward the ground wire. Solder one end of the component is soldered to the pin and the other end to the ground wire we put in earlier. It doesn't matter which order the parts go in as long as the diode is properly oriented.  Once you solder it, shrink tube it or tape it up and insert the pin in place. 

Step 6 Install the inlet assembly  Time to put the whole thing back together. Make sure the wires don't bind and a properly held in place by strain relief nut on the back.

Inlet installed - I later rotated it 90 degrees to allow the cord in my garage to connect easier
Inlet with cover and strain relief installed from inside the turnk

Step 7 test it out Drive out to your local charging station and plug in. Mine was at a Walgreens Drug store. Though the lot was full, the EV spot was empty, so I pulled in, plugged in and waved my little ChargePoint card in front of the charger. I heard a click and then the sound of the  charger in my car starting up - sweet.

Free parking and a free charge - Life Is Good!

Tuesday, February 7, 2012

dead battery

Well, haven't had much to post about in quite a while. Generally I come home, plug the car in and in the morning I unplug it and drive it to work. Simple as that.

Tonight it wasn't so simple...
It was a misty morning so I drove to work with my driving lights on - not the headlights, just the driving lights - it wasn't dark, or rainy just a little misty. So I park in the lot in plenty of time for my 9:00 meeting and at when I return to my car at 6:00 - nothin'. No dash lights, no familiar thump of the contactor, just nothin'. At first I wasn't sure what had happened, then I noticed that the light control was still on - the battery was dead. Without the 12v battery, the contactor won't close, the controller won't get operating voltage, nothing will work.

Now I sat for a minute and remembered something... When I first built the car I had the DC/DC converter connected directly to the pack, but it was constantly charging the battery and draining the pack, so I put in a relay so that the DC/DC converter was only active when the key was on. Now there was a small mechanical switch on the side of the relay that allowed you to activate it manually, I knew if I could get the relay to close, the DC/DC converter would provide the 12v needed to get the car to work.

I popped the hood and unscrewed the cover of the High Voltage Enclosure to access the relay, With a flash light I checked either side for the switch - there it was on the driver side - just below 2 high voltage leads. I   turned the ignition key on then dug a pen out of my laptop bag thinking it would safely flip the switch, but it wouldn't reach it. I thought about it for a minute, but I knew I had to use my finger to do this. I put my left hand behind my back (an old trick I learned from a TV repairman - you don't want to touch ground with your left hand when you get a jolt on your right and have the shock pass through your heart...) and with my right index finger reached between the wires and pushed the little plastic tab in.  It made a satisfying clack as the relay closed and the 12v from the DC/DC converter kept it that way.

I closed the hood and got behind the wheel. Everything looked normal now., As I turned the key into the start position I heard that familiar thump of the contactor and we were mobile.

It was dark and with the headlights on I knew eventually the 12v would drop pretty low and the controller wouldn't like it - maybe enough to stall out - so I took the streets home. Sure enough, about a mile from my door the "Check Engine" light came on solid but she continued to drive fine. I got her home and safely into the garage.

I can't think of another car that will start with a completely dead battery. I've compression started a lot of cars, but never with the battery completely dead. Even the old crank-start cars needed a battery for ignition, right? These electric cars are somethin' aint they?

Monday, September 5, 2011

Cool electric car decals

Been looking for some good EV stickers for my electric Miata, but all the stickers I found were from the 90's and quite dull.

One winter I came across some cool lightning bolt graphics at a ski shop. Comes out they were from Electric Sunglasses. A little research and I found some stickers that clearly said "electric", were cool and didn't break the bank.


If you want to get some for yourself, just send me a comment and I'll pass along the URL.

Saturday, September 3, 2011

Miata "hood" alignment

I see a lot of Miata's with hood problems - or at least that's how they look. You know the ones, where the hood sticks up higher than the pop up headlights. I always wondered how the hood got that far out of alignment, but that's not what's rong at all.
After doing a lot of under hood work I found my car exhibited the same hood issue. But I wuickly found out that it wasn't the hood at all, just the headlight covers...

 There isn't any bracing in the back of the Miata headlight covers. Any pressure will cause them to bend down creating what looks like a hood alignment problem. Luckily, the fix is really simple...

Prop open the hood, grab a rag and "love up" the underside of the headlight covers. Apply a little upward pressure as you rub across the width of the cover. Don't pull hard, just  gently pressure is all it needs.
 In no time your headlight covers will be back where they belong and your hood will fit like new.

Wednesday, August 31, 2011

$8 Fix for a faded Miata bumper

If you have an early Miata with original paint, chances are the front bumper has faded. You have probably read about different polishes or treatments that should work, but none worked on my car. Here's how the nose used to look - tired and faded...

Then I got the idea that what was really wrong was that the clear coat was gone. I tried a little cear touch up paint to test the ides, and it worked! I went to the local auto parts store and bought a can of Duplicolor clear for $8. I masked off the metal work, so that only the rubber bumper was exposed and laid down 3 coats of clear before the can gave out.
Here is the result:
After a couple of days, I rubbed it in with some polishing compound to bring out the shine and there you have it. No need for an expensive paint job and no more embarrassing faded nose - and for only $8!