J1772 Charging Upgrade

What do you do with a working electric car?  Tear it apart and add more parts!

I bought the 120V charger with the goal of being able to charge up wherever I can find a 120V wall outlet.  That's great for home and any houses I visit or my work building, but electric vehicle charging stations with the J1772 plug are popping up everywhere.  I don't want to miss charging from one of these stations just because I don't have the right socket in the car.

I initially thought that I could install the J1772 socket and then run the power wires in parallel with the existing 120V socket and charging circuit.  Imagine my frustration when I found that you cannot derive the needed 120V neutral conductor from a 240V J1772 plug.  J1772 does specify a 120V option, called Level 1, but it's not supported by my Schneider unit and most other public charging stations.

So I had two tasks: step down from 240V to 120V and derive Hot, Neutral and Ground wires for the 120V circuit.  The solution comes in the form of a toroidal autotransformer.  I was given a pointer for this type of device to Toroid Corporation of Maryland.  They build a standard list of autotransformers, but I needed 240V in, 120V out and 15 amps of capacity.  As you can see from the table, they don't offer that as an off-the-shelf unit.  I contacted them and told them what I was looking for, and they replied back with a custom design, spec sheet and price quote.  I confirmed with my power engineer friend at work that this was, in fact, the part that I needed.  After confirmation, I sent my order in along with $228.41 and was told to expect it in a little over a week.

In the meantime, I worked on some prototypes to see where I would be able to fit it, in the tight confines of the front trunk.  I measured the available space with the battery box in place in the front trunk.  Then I built a cardboard mockup about the size of the real transformer.

I first tried a case with a clear removable cover from Polycase like I've used in other locations in the car.

It is definitely a tight fit!  Let's see how the plugs fit along the top edge... again very tight but not bad.

But my decision was made - the power sockets stick down too far to get the wires mounted and routed within the box.

I found this Cantex box at Lowes that just barely fits.  I held it in place with my endless supply of woodworking clamps, and drilled holes for the top and bottom bolts.  The top is a through-bolt but the bottom is a rivnut so the bolt head doesn't stick into the side of the battery on the other side of the battery box wall.

And here's the mockup with the transformer and both power sockets drilled and set into place.

Here's what the sockets look like from the top - just right.

Now we move on to positioning the real transformer.  You can also see the passive air vents I installed in the bottom and side of the box to help dissipate the ~94F heat the transformer will generate when I'm charging from a J1772.

You can see that it was custom built for me because it has my name on the label inside the wrapping!

Here's the test fit inside the box.

Here's the battery box back in place to show how it will look once installed.  What you can't see is I had to cut away some metal to allow the box to fit.  It was a curved piece of thin metal that was used to hold the spare tire in place.  No more spare tire, no more need for that bit of metal.

And here's how we access the charging sockets.  Both are waterproof in case some water gets in while I have the hood up during a charge.

I added some additional venting to the cover to make sure the heat isn't building up inside the box.

Here's the box, fully wired up inside.  Note the 3/8" hole drilled in the center of the transformer's potting material to allow me to run a big bolt through the box to hold it in place.  I also cut some steel spacers to size to center the transformer from side to side in the box to increase airflow.

You can't see it from here, but I installed the AVC1 board from Modular EV Power inside the box.  This board implements the car side of the J1772 safety charging protocol.  You could jury rig something up to fake it out, but for $37 on eBay you can't go wrong.  I hooked up 12VDC and ground, AC ground and a wire to the Proximity and Pilot pins of the J1772 socket.  I didn't take advantage of it yet, but it has normally-open and normally-closed relay outputs.  You could use this to light up an indicator that the car is charging or put an interlock so you can't drive the car while you're charging.  Not that anyone would every do that, of course!



If I had to do it again, I would use the newer AVC2 board, as it's enclosed in a nice box with better mounting tabs to protect the electronics.



I could have used twist-on wire nuts for the AC cabling, but I don't trust them enough to stay in place with all of the vibration this will be subject to.  I used Polaris connectors, which we use for high-current, thick-conductor bonding at my solar power company.  They're also dipped in plastic so they won't short out against anything else in the box.

Now that it was all wired up, it was time to test it.  I connected my Schneider station to a 240V breaker in my workshop.

This is the guts of the Schneider unit.  Technically it's not a "charger", it only delivers AC power to the charger mounted inside your car.  This is known in the industry as EVSE, Electric Vehicle Supply Equipment.  It consists of a couple of fuses, a contactor and a small circuit board that implements the EVSE side of the J1772 safety protocol.

I flipped on the breaker and the top green light lit up, signaling that it was receiving power and was anxiously awaiting an electric car to appear nearby.

The first test of my charging system was plugging in a 120V extension cord.  This tests whether the 120V hot, neutral and ground are wired correctly to the output cable, without involving the transformer.  Good news, it worked!  You can see the light in the extension cord and the voltmeter reading 119.8V at the output of the box.

The big test was now plugging the Schneider into my box.  For this to work, everything had to be wired right - the 240V from the socket to the transformer, the transformer to the 120V circuit, and the AVC1 board connected and properly talking to the Schneider safety circuit.  Happily, when I plugged in the J1772 and the thumb toggle clicked into place, the small LED lit up on the AVC1 board indicating it was ready for charging, then the contactor clunked in the Schneider, then the voltmeter showed 119.5V!  As soon as I pressed the thumb switch, the Schneider and AVC disconnected and power stopped flowing, just like it should, even with the plug firmly seated in the socket.

Declaring success, I will wait for Saturday to tidy the wiring inside the box, mount the box to the side of the battery box and install it back in the car.  Then I'll do the final wiring back up to the relay box and the rest of the conversion wiring harness.

Rear Trunk Hinges Complete

Well the saga of the rear trunk hinges has come to a conclusion!  After finding a replacement set and delivering them to the body shop, they blasted, primed and painted them to match the body color.

I buffed off the bracket and the pivot bolts.  I decided not to paint the brackets as they'll be sliding each time the trunk is opened and closed, scraping off the paint around the slot.

Here is the final parts assembly before installation.

And here is one of the brackets installed.  It's pretty tight in there with the battery box, so you can only see the pivot bolt in the upper-right.

With the trunk lid aligned and hinges tightened, I installed the long-waiting Camp914 TrunkShox to match the set in the front trunk.  It was a very easy procedure.  First you drill two holes in the fresh trunk hinge and bolt in the pivot bracket.

Then you snap on the gas struts and mark where the rear pivot bracket needs to go.  You then drill and mount the bracket.

One minor complication is the strut is blocked by the ridge for the gasket between the trunk and engine area.

I gently lowered the trunk, marked the area to cut out, cut it out, sanded and primed, giving what you see below.  I mixed up some paint and painted this area to match the body color the next day after the primer dried.

Here is the trunk, held up in place by the gas struts.

And here is the trunk shut for the first time in two years, and looking great!

Rear Trunk Hinges Found!

After many weeks of trying to find replacements for the body-shop-lost rear trunk hinges, I was given a pointer to a pointer to dc Automotive, a massive Porsche salvage operation that had them in stock, along with the small bracket and associated hardware.  There is apparently only one new one left on the planet, at Porsche in Germany, so I had to go into the used parts market.  $133 later, these golden magic parts showed up at my house.

I dropped them off at the body shop today.  They will blast, prime and paint them and get them back to me next week.  I have the car entered into the Warbirds, Wings and Wheels car show at the Paso Robles airport on May 14, so I have a pretty tight timeline to get the hood mounted and the J1772 connector and step-down autotransformer integrated into the charging system - more on this later!

New Rear View Mirror

I haven't attached my rear view mirror to the new windshield yet so I was thinking about buying a special unit where the mirror mount is integrated into the center sun visor bracket.  After a recommendation by a commenter on the blog, I decided to go ahead and order it.  You can only buy them on eBay from mack914-6 for $49.95.

Here it is:

I'll take another picture once I get it installed in the car.  I'm hoping it will help with the problem of the visors drooping down too.

Update: No, the visors still droop down.  Damn.

Earth Day 2012

I was invited to bring my Biodiesel VW Beetle down to the Earth Day event at El Chorro park in San Luis Obispo.  Next year I'll take the 914 down...

I was part of the Central Coast Clean Cities Coalition (C5) alternative fuel vehicle area.  We had a Nissan Leaf, but by way of FunRide, a green by-the-hour car rental service.

The local Honda dealer brought an Civic Hybrid.  He had planned to bring the Compressed Natural Gas version that they had in stock, but someone bought it a couple of days before the event.

The owner of this car brings it around to every event.  He's chopped it and removed a lot of weight and gets between 60 and 100 mpg.

This Arro Autogas van runs on Propane.

Aaron and his father brought these two factory-built electric Ford pickup trucks.  Ford only made 1500 of them, so they're very rare.  They were reconditioned by a specialty company, bringing the Nickel Metal Hydride battery pack back up to spec.

This is the main C5 booth, handing out literature about alternative fuel vehicles.

And here's the Beetle.  I also had pictures of the 914 so I talked about both of my non-gasoline cars with folks.

It was cloudy in the morning but cleared up and was beautiful and warm.  Of course I was facing the sun and got a little burn on my face, but it was worth it.

Porsche Club Autocross

When Porsche introduced the new 2012 911 (Codename 991) to the world's press, they did it on an unused runway at the Santa Maria, California airport.  Porsche spent a lot of money repaving the track, then "donated" it to the airport, but asked that it be made available for use by motorsports clubs.

The inaugural event was our local Porsche Club's autocross.  Since my 914 was still under construction I volunteered to be a track worker.  I was assigned to security, checking cars and people in and out of the track, and because it's an airport under TSA security regulations, I had to do a TSA background check and get a badge issued.  Unfortunately by the time the event came around, all TSA badges came back except for mine!  I didn't want to be sent to Guantanamo Bay for violating TSA regulations, so I switched over to timing which was a blast.  We borrowed timing equipment to give everyone accurate information on their runs, and we were able to run two cars on the track at once to keep the cars flowing through.

While there were a lot of Porsches, including a couple of screaming GT3s, the event was open to anyone with a vehicle.

 Even this sleeper of a pickup truck with a tremendous launch off the line.

Corvettes were well represented.  I found it interesting with all of that power that they were the slowest cars off the line.

Professional racer and local boy Townsend Bell showed up.  He told us that this was where he started his racing career, racing go-karts as a kid.  He drove a stock BMW M5 and came in with some of the fastest times of the day, of course.

The rain managed to hold off for us, but began pouring as we were picking up the cones and packing up.  Next time I'm definitely bringing the 914 to see how it compares!

K1 Speed Electric Go Karts!

I was up in the San Francisco Bay area with a day on my hands, so of course I went to Fry's and then I discovered the K1 Speed electric Go Kart location in San Jose.

The building is cavernous, with a pit area and a great track with some nice chicanes and hairpin turns.

The karts are remotely manageable - they can halt them, put them into slow mode, a little faster mode and balls-to-the-wall mode.  The acceleration and handling of these cars is nothing short of spectacular.

It's a very popular place on a Saturday afternoon, with groups of people coming in to race each other and a series of birthday parties.

Of course I was interested in the electric nature of the cars and the charging systems.  The karts have 20 HP DC motors and can go up to 60 mph.  Here's the charger, it can handle one kart on each side.

The charger has 3 charging phases, and it keeps track of current, voltage, battery capacity, battery energy absorption and charging time.  I was in trickle charge mode at this point.

It's a DC charger, using an Anderson connector with a large handle, dumping power right into the batteries.  The pit crew was very skilled at guiding drivers into the pits, flipping the power switch, and plugging in the charger.  When a new group of drivers is belted in, they pull the plug, flip the switch and guide them out onto the track.

I did the 3-session deal for I think $50, including helmet rental.  Each session is 7 laps and I was pretty wiped from the G-forces.  I placed 2nd and 3rd in my sessions, would have had 1st in the final session except for some douchebag that ran me up into the guardrail!