Mark 3

Lately I havent been driving the car much and I realize it's for a few reasons - 

1. I have a bad cell (#23) that limits the range. Everything will seem fine and then this one cell will drop to below 3 volts, shutting the car down. It's back to 20 mile range, which isn't horrible, but it's a nuisance. 

2. Sometime after the last clutch replacement, the throwout bearing failed. It makes a horrible noise when engaged and I'm thinking it could catastrophically fail, which would be a problem... 

3. The controller is running too hot. My passive cooling systemm using a transmission cooler without fans isn't cutting it. 

4. Public charging takes way too long. At home I can charge it overnight and all is well, but if I need to charge it out in the wild, the charger just can't produce enough current to charge the pack in an adequate time. 

5. Manual steering is getting to be a real hassle. It was workable when it was a commuter car - I parked in a parking lot, but now as a city car I have to deal with parallel parking - sometimes backwards uphill. Power steering would make the car much more useful. 

So while searching for replacement CALB cells I noticed the price of new cells has dropped significantly. I had thought about using a Tesla or other wrecked EV pack, but I was worried about doing something stupid with an unforgiving battery chemistry. I wanted to stick with LFP (or LiFePO) cells, since they seem more resilient to user error. Furthermore, I didn't want to rebuild the battery racks if I could help it and I am limited to 156v Nominal by the Zilla 1k I'm using. If I go above that I would need to change controller and likely the motor. 

And so...

Pulling the motor exposed what was left of the throwout bearing. It was a twisted mess and surprisingly worked at all. Didn't get a picture though...

I found I had room to fit EVE 280ah cells, but only 46. I had to modify the nose rack to accommodate 14 of these since they are quite a bit bigger. I had a little extra space in the racks with the CALB cells, that's all gone now.

 

With the added amperage of the new pack, the charging problem would be much worse. I rewired the J172 to use 10 gauge wiring and was able to get a new air cooled 6.6kw charger just before the new Chinese tariffs kicked in.

It was a tight fit but all good.
 

I found a PC cooling kit that would fit my front grill area nicely. It came with 3 fans with LEDs that glowed different colors. Not really my style, so they got painted black. 

Another thing that's been bugging me is the temperature gauge on the dash. It's way out of scale for the temperature of the controller. You can't tell if something is wrong when the needle barely moves. I figured i better do it now or it would never get done. I was able to get it re- calibrated by the manufacturer. Now it's actually useful. Glad I did it.

What's left to do?

Power Steering.  I bought an electric power steering unit and tried to fit it in under the hood below the brake booster, but there just wasn't enough room.  And fiddling with it was holding up the rest of the project. There is an under dash kit for the Miata that uses a Prius p/s unit.  It's around $1000, so I will probably make my own. We'll see how that goes.  

Late Updates

Mark 3 

Been awhile since I've posted so wanted to give an update on recent changes. There have been lots of changes since this project started, some minor and some major. I think it would help to lay them out like this: 

Mark 1 - Lead Acid (AGM) battery pack, Zilla 1K controller, Warp 9 motor, Zivan charger, 20 mile range

Mark 1.1 - revised motor mounts 

Mark 1.2 - electric heater added 

Mark 1.3 - changed to J1772 charging port 

Mark 1.4 - added LED Daytime Running Lights (DRL) 

Mark 2 - upgrade to Lithium battery pack (48 100ah CALB cells). Mini-BMS, 40-50 mile range. 

Mark 2.1 - replace Zivan with Thunderstruck 2500 charger with EVCC Charge Controller 

Mark 2.2 - replace Mini-BMS with Orion and remove EVCC 

Mark 2.3 - add OBD2 port to Orion's CAN with Bluetooth and Android tablet for display 

 

Mark 3 - update battery pack to 46 EVE 280ah cells, upgrade charger to 6.6kw, 100-120 mile range.

Refuel 2017 at Laguna Seca (Weather Tech) raceway.

 Since Monterey is a couple hours from where I live, I needed to tow EV Miata to the track. Dropped it off on Saturday for the event on Sunday. I saw they had installed a few 220 outlets around and thought I might need a converter cable. Made a trip to the local home Depot and wired up a converter in the hotel room. 

Race day came and I was surprised to see the track parking lot full of Teslas. Mostly model Ses but a few roadsters as well. Turns out a few were racing and the rest was just there for a meet up and parade lap.

The racers meeting was basic but they did point out where the power outlets were laid out and explained that if we were racing you have priority over any non-racer charging. 

We got 2 races in, but the rules were to not pass anyone unless they signaled you, so not much of a competition but still fun. It was great to drive the car flat out and it is a great course. There were some prototypes and a couple of conversions so I was able to pass a couple cars, but those Teslas were just too damn fast. 

After the first race I was below 40% SOC and the only free outlet wasn't working. I thought it was my converter so opened it up and rewired it, but no charge was happening. There were a group (maybe 10) Teslas charging and I wedged my car next to one of 'em and took his power. He was livid. I explained to him that I was racing but since they hadn't told the Tesla folks the same message. 

2nd race comes and I've only got about 50% charge.  Now I couldn't pass anyone. Oh well, still fun. 

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.

 

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.

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!

DIY LED Daytime Running Lights for the Miata NA

If you are like me, you've been noticing that a lot of new cars have really cool LED running lights - or DRLs (Daytime Running Lights). Well, they seemed like something that would look slick on a NA Miata. But could I do this myself? After some research, I realized it wasn't as easy as I first thought - 

• the parking lights/blinker assembly is a sealed unit - you can't just unscrew the lens and install a row of LEDs. 
• how to handle the blinker (directional indicator function)? Two rows of LEDs? Install another bulb for the blinker? Make the whole thing blink somehow?
• What about the emergency function? The lights need to blink without the key on.

Well, I noodled on it for a while and came up with this idea.

• Use single row of LEDs - as many as I could fit - that would span the entire parking lights/blinker assembly
• find the brightest LEDs possible, but not surface mount - go old school to simplify assembly
• for turn indicators, just blink the entire row using a relay hooked to the blinker circuit.
• Tie another relay into the emergency flasher to activate the LEDs.

The plan was to run a new wire to the LEDs that was switched 12v - on when ever the key is on. This will allow the LEDs to light whenever the car is running, rather than just when the parking lights are on. Because we want the LEDs to blink when the indicator is on, we connect it to the Normally Closed (NC) position of a relay (so the LEDs are lit when the relay isn't) and to 12v ground to the other side. The wire that would normally go to the blinker goes to one side of the relay coil and the other side goes to ground. This allows the relay to activate when the blinker turns on, opening the circuit to the LEDs causing them to blink. The parking light lead isn't connected since the LEDs will be lit whenever the key is on anyway. So there are a total of 3 connections on each side.  This all works fine when the key is on, but your emergency flashers need to work with the key off. I added another relay in from of the other two that switches the input to the flasher when it's activated. 

Just to summarize, In driving mode, the LEDs are lit. When the blinker is activated, the relay closes and opens repeatedly causing the LED strip to blink. Since both LED strips are independent, while one is blinking, the other side stays lit. When you hit the emergency flasher, another relay kicks in to power the LEDs.

I ordered a kit of 100 super-bright LEDs and resistors from Parts Express. They also carried automotive grade 12v relays, so I ordered 3 of those. I bought a Perf Board (a perforated sheet of plastic for building electronics) at Radio Shack to assemble the LED strips.

With all of the parts in hand, and a wiring plan in my head, I began the work.

Step One- assemble the LED strips

Find the perf board and the LEDs and resistors. Insert the LEDs into the perf board making sure you get the polarity the same for all -doesn't matter which way at this point, but make sure the long lead or flat edge of the housing is all pointing the same way. You want the LEDs as close to each other as possible to get the most LEDs in the housing - more LEDs = more light. I ended up laying the LEDs in the pref board at an angle and got 39 in the row.

Next install the resistors beside the LEDs. Don't share the hole with the LED so that you can twist the leads together on the back side. This makes for a solid connection and holds both parts in the board. You can angle the resistors so that they are tight to the LEDs, or lay them out vertically (this just makes the resulting  board bigger. If you angle the resistors you will run out of room at the end of the strip. I put half the resistors above the LEDs and half below to make the board as compact as possible. It doesn't matter which side of the LED the resistor is on.

Now flip the board over an twist the LED leads to the resistor leads making sure the the LEDs are polarized right (long lead on the same side). You can add another wire for the outside edge of the LEDs and resistors or simply flatten them into a long strip that will be soldered together later.

Trim the excess leads from the twisted connections and solder.

Apply solder to the bundle of leads or your new lead that runs along the outside edges.

This picture is actually from a couple of steps later,
but I wanted to show the twisted leads down the center
and the leads at the top and bottom soldered together.

Step Two - test the LED strips and fix any loose wires

Solder a couple one lead to the top leads of the strip and one to the lower. Make them longer than you need so you can test it. Find a 12v source to test with  - I used a electric tire pump that has a 12v cigarette lighter output. Take note of which are the positive and negative wires  and make sure every LED lights. If one is out, check the connections and resolder until they all light reliably. Do this for both strips/

Step Five - cut the strip to size
Your perfboard is probably too big to mount.  We want to cut it down to something we can fit into the flicker housing.  Mark the perfboard outside of the soldered area and give your self some extra room for mounting it to the wire retainers.  Cut the excess.

Step Six - dissect the parking lights/blinker assembly

We only need the lens for our LED blinkers/DRLs. Pull the two parking/blinker lights from the car by removing the two screws on each and them pulling out the bulb/socket assembly from the back of each. 

As you can see the lens is attached to the reflector with tabs on the plastic lenses and a gray adhesive filler.To deal with the tabs, we are going to cut the reflector side so that the tabs don't have anything to hold on to.I used a dremel to do this, but I'm sure there are other ways.

Next I removed the gray putty that glued the lens to the reflector.  For this I used a spray solvent. It turned the hardened putty into a soft gooey mess...

And after some prying with a large standard screwdriver...






The lens came loose.

After some scraping with the screw driver and a razor blade, it came pretty clean.

Step Seven - trim the ends of the lenses


The lens interlock with the reflector where they mount to the car. I needed to be able to reach the mounting holes on either side, so this interlocking bit needed to go...

First I cut either end of the section that needed to be removed...

Then "nibbled" the section off with a pair of pliers.

Step Eight -