COOL!

Last summer I was complaining about the undersized cooling system in the PorschEV and how it would send the inverter into thermal limiting, usually at the most inopportune times. How does sudden loss of power at highway speeds sound? The good news is the inverter protects itself from heat damage, but it's pretty disconcerting when it happens.

The cooler was a dual core Derale with one coolant loop for the motor and charger and the second for the inverter. With two Pierburg pumps and a 10" electric fan, it was adequate for the cooler months, but this is TEXAS and in the Summer (that's 2/3 of the year) it just didn't cut it.

A bit of Googling turned up a higher capacity aluminum replacement for the stock Porsche 924S radiator that was bundled with two 10" electric fans. Unfortunately, those fans  didn't fit so I wound up ordering a pair of 9" fans that did the job. I also found silicone 90 degree Elbow Reducer hoses that connect the 1.5" radiator outlets to the rest of the 5/8" system.


Here's a comparison of the two coolers. We're clearly adding capacity with the new system.

Mounting the new radiator had its own set of challenges. Long story short, the lower 3" of the radiator support was cut off at some point in its lifetime, so the original radiator was sort of dangling, held in place by some creative application of zip-ties. I devised a more secure if equally creative support involving angle iron and eye bolts. It feels secure and at least it's all metal.

The plumbing went together fairly easily using what was already there and rerouting the hoses so the pump output goes first through the inverter, then through the charger and finally through the motor before it passes through the radiator and then back to the catch tank for the pump.

One pump and catch tank was removed (set aside for the next project) and I think I'll use the space for a windshield washer fluid reservoir. Only one change was needed to attach the inverter output to the charger input. With everything on one cooling loop, I hope there is enough capacity to keep it all cool calm and collected.

The first short test is encouraging. With ambient temperature in the low 100's F (up to 104 in the sun on the road), a short 5 mile run around the neighborhood had the inverter steady at about 46C while the motor showed anywhere from 50 to 90C. At stop lights, the temps dropped to about 43 for the inverter and 48 for the motor, well below the 55C max recommended input temperature.

We're checking off the list of annoyances little by little. Next item is to get the air conditioning charged and working. How did we ever get along without it?

It's Always Something

You may be old enough to remember the late great Gilda Radner and one of her stable of characters, Rosanne Rosannadanna. If not, maybe you've seen it on old SNL reruns. Anyway, her trademark line,"It just goes to show you, it's always something — if it ain't one thing, it's another" seems to apply to my EV projects.

Saturday I took a little jaunt down to Barnes & Noble to kill an hour browsing. I can generally speed skim a book in about five minutes and get the gist of it, so I rarely buy any. It's an enjoyable diversion, especially on days like last Saturday when the wife has flute students stacked up at the house all day.

So I'm driving the PorschEV and thinking: "Wow, this thing is running especially smooth this morning." Uh-oh! That usually means something's not right. Sure enough when I stepped on the brakes it was clear that the power boost was missing in action. The good news is the brakes still worked but with much higher effort, so I drove home without incident.

You may recall from my Road Test video that I was complaining about how noisy the power brake vacuum pump was. It seemed like a good idea at the time since it was a Ford product from the same eTransit Connect that supplied the Siemens motor and Azure Dynamics inverter. It was a diaphragm type pump, and when it was in service it made a huge clickety-clack racket. Mounted directly over the passenger footwell, I think the noise was magnified by the sheet metal of the battery tray and no amount of Dynamat was going to dampen the sound to my wife's satisfaction.

I pulled the offending part and tested it with my bench battery. Click - nothing. DOA. Casters up. Pinin' for the fjords. Pushin' up Daisies. Good riddance. 

I'd been looking at options for a quieter vacuum pump and settled on a HELLA 009428081 High Performance Electric Vacuum Pump. Ordered it Saturday afternoon and it was on my front porch Monday afternoon, free shipping with my Amazon Prime membership. Based on reviews and such, it seems to be OEM for current Subaru and Volvo as well as some GM models. It's smaller and lighter than the Ford unit and as a centrifugal pump, it promises to be quieter as well.

I reused the mounting bracket including the rubber buffers, so the new pump is double damped but still made a pretty noticeable whirring sound on the bench. The good news is that the sound gets mixed with the cooling fan and power steering pump and all of that is just background noise. The clattering vibration is gone and the brakes are back to normal so we'll declare a small victory on this one.

"It just goes to show you, it's always something — if it ain't one thing, it's another"

Ancient History and Interior Updates

Absent mindedly scrolling through Porsche 924 videos on YouTube (actually looking for customization ideas), I stumbled across a video that looked hauntingly familiar.

Yes, it's the PorschEV with a video walk around by a previous owner. He comments on the bra hiding some body damage. All the details right down to the wear on the driver's seat and the aftermarket radio leave no doubt that this is my car. Nice bit of archival information, what Antiques Roadshow might call "provenance".

Did I mention the radio? My wonderful kids pitched in to get me a new sound system and voltmeter for my upcoming birthday. The radio portion of the old one worked ok, but the CD player was non-operational and it lacked the Bluetooth connectivity I've come to appreciate so much with my Leafs. The new unit is a JVC KD-X330BTS with the Bluetooth hands free phone and music streaming features I was looking for. I figured that as long as the center console was opened up for the radio, I might as well replace the useless oil pressure gauge with something that actually registered some worthwhile information. The Bosch Voltmeter filled that niche very nicely. Both were available at our local Pep Boys store.

The clock on the right still keeps perfect time, so it stays. In the center are the air conditioning controls and I ran a set of wires from the temperature rheostat for future use as an input to the PWM A/C compessor when I get that charged this summer.

These projects are always an educational opportunity and I learned that the Kenwood brand is manufactured by JVC. That meant the wiring connector was a direct plug-in for the new radio and I didn't need to rewire anything. It did seem like a good time to replace the shop-worn old radio antenna with a modern rubber mast style.





The microphone for the hands-free bluetooth phone link is mounted to the stationary steering wheel housing and seems unobtrusive enough. I called each of the kids on the hands-free to thank them for their gifts. OK, it might have been a bit of a victory lap as well.






I'm very pleased with the results and feel like it really dresses up the center console. 

PorschEV Charge Monitor

It's been a while since there has been news to report on the PorschEV. We had another mechanical challenge just before Christmas. Motoring merrily down a street in my neighborhood, there was a clattering noise, then the motor spun up to redline and the car slowed to a crawl. After a flatbed ride over to Pro Automotive, Robert Juarez opened the access panel for the motor coupler and found the driveshaft spline had separated from the coupler flange. The good news is they were able to extract it from the rear by dropping the transaxle so I wouldn't need to disassemble the entire motor bay. The weld held just fine, but the metal just outside the weld let go. Robert fabricated a new flange from thicker higher strength steel so I'm hopeful that we'll get more than a year out of it. Unfortunately there are no photos of the new piece, but here's what the old one looked like. That jagged hole used to be the drive shaft spline fitting. Once again the electric stuff is no problem, it's the mechanical bits that bite you.

While the PorschEV was out of commission, I spent some of my holiday planning for the charging monitor I mentioned in the last post. Not surprisingly, just the right electronic bit turned up on eBay. This Dual LED Digital DC600V 100A Voltmeter Ammeter Voltage Amps Meter+SHUNT ships from Hong Kong and arrived shortly after New Year's about the same time the PorschEV came home. No free shipping this time, but $5.99 from the other side of the world is remarkable! 


As usual, the documentation is in pretty sketchy Chinglish, but I found this wiring diagram that helped (not sure where). I learned later that I needed to reverse the leads on the shunt to get it to display the Amps.

The shunt is rated for 100A and 75mV, so I couldn't just wire it into the existing traction pack wiring. I had a spare contactor and I used that to control a parallel
negative charging line so the shunt is out of play when the car is running.


With so much more going on in the rear compartment, I added another charge control relay in the same housing as the meter. It looks a bit messy since I used spade taps to attach multiple lines to the relay connections, but the function is pretty simple.

It is switched on by the relay in the AVC2 module when the charge cable is plugged in. It then passes 12 volts to close the negative line contactor and power the meter. It also energises the charge control relay in the front that closes the mid-pack contactor and powers the charger, DC/DC converter, and forward coolant pump.

It sounds complicated, and I should put together a wiring schematic so I'll remember all of it if something goes astray in several years. But for now, I'm delighted to have a means of checking the progress of a charge.

With the wiring and shunt tidied up, this area may look crowded,

but since most of it is black, it will disappear in use. The normal view of the charge monitor will be through the rear hatch glass.

I watched one charge cycle last night and it works perfectly. The voltage display increased through the constant current phase until it reached the 400 volt target, then held as the amp display moved down during the constant voltage phase until it reached zero. Checking the controller output with the laptop at that point indicated the charge was complete. Unplugging the charge cable removes power from the entire charging circuit including the charge controller, so it is reset and ready to start the next time the charge cable is plugged in.

Revamped Charging for the PorschEV

I have been so pleased with the new charging arrangement on the evTD that it finally got me motivated to rethink and rework the charging for the PorschEV. To recap, although I had plans to consolidate both the charge controller and the DC/DC controller in a single box, space constraints forced the DC/DC converter to the hatch area near the batteries, so the controller went along with it. Probably as a result of too much handling and user error, the DC/DC controller failed early on and Jack Rickard kindly replaced it with a newer version which has worked perfectly. The older version Charger controller has done its job just fine, but loses its configuration from memory between charges. That means that for every charge, I have to open the hood, drag out my trusty MacBook, plug in the USB cable, and reset the target voltage and termination amps before plugging in the J1772. It's a nuisance and pretty much negates the possibility of convenience charging while I'm out and about. Ideally, I should be able to simply plug in the J1772 like I do with the Nissan Leaf and now evTD.

Jack Rickard of EVTV told me that the controllers are all programmed to support the Volt Lear Charger, the Volt APM (DC/DC Converter), and the UQM Lear Charger and have enough processing capacity to run all three concurrently. Here's how he described it on the EVTV Forum:

Well, he did say "you could PROBABLY run all three at the same time", so once again I think I'm on the bleeding edge of what has actually been put into service. If not me, then who? I say go for it! Disassembling the Charger controller, it was clear that there were two sets of Can Hi and Can Lo connections, so that wiring harness will need to be thought out. 

There are also three separate 12v+ connections going to the connector, so it's clear that a junction box will be needed to organize the connections up front.  It turns out that the original black plastic housing for the controller will do just fine. The terminal post on the left is provision for a traction pack negative connection for a volt/amp meter for monitoring charge progress. More on that in a future post. The white and brown wires on the top are the CAN connections to the control box in the rear. The main reason I put this project off is once again twisting this old body into unnatural positions while snaking the CAN wiring through the firewall, behind the dashboard, through the console, under the arm rest, and through the rear seat upholstery and trim panels to keep everything tidy and mostly out of sight.

Once the wiring gets to the rear, it's threaded through the gland fitting into the rear controller and simply added to the screw connectors for Can Hi and Can Lo. The terminals are well marked on both versions of the controller, so it's pretty easy to make the right connections. Once everything is hooked up, it's time to test. 

I'm pleased to report that it all works as Jack described, "certainly" more than "probably"!

Here's a screen grab showing both the DC/DC (APM) and Charger active at the same time. I do want some visual feedback on the charge process without hooking up the laptop. The Leaf has three blue lights and the evTD has the JLD404, so I'll be adding a volt/amp meter for the traction pack that is only active during charging and visible through the rear glass near the charge port. More on that in a future post. Stay tuned ...

evTD Refinements

WARNING! ACHTUNG! Long and involved post ahead. You have been warned!

Truth to tell, the final days of construction on the evTD were pretty frantic. I had a deadline to leave for EVCCON 2012, and I might have taken a few shortcuts. I've also learned a thing or two in the four years since she became roadworthy. This became most apparent several months ago when I had a gentleman from Germany who was very interested in purchasing the car. The deal fell through as we learned that the German Dept of Motor Vehicles was intent on making it impossible to register any imported one-off vehicle. As part of the process I wrote a user's manual to support the sale. Documenting the steps for each simple action it became clear that things weren't so simple:

Charging

1. Pull out the Emergency Stop Switch to close the main contactor
2. Connect laptop computer to Charger Controller with USB cable
3. Using an ASCII terminal program as outlined in the TC Charger User Guide, check and reset the charging values if necessary. I generally charge to a Target Voltage of 256 volts (approximately 3.55 volts per cell), a Target Current of 20 Amps, and a Terminating Current of 5 Amps.
4. If charging from the Alternate NEMA L6-20 Inlet Port, connect both ends of the charge cable before turning the white auxiliary charging switch to “ON”. This prevents arcing at the plugs when applying power.
5. If charging from the J1772 Inlet Port, open the cap on the inlet and insert the J1772 plug until the catch snaps into place. Ensure that the NEMA L6-20 plug from the J1772 inlet is plugged into the alternate inlet port, then turn on the white auxiliary switch. Finally, turn on the toggle switch on the J1772 Inlet box to begin charging.
6. When charging is complete, turn off both switches on the inlet boxes and push in the Emergency Stop Switch to open the main contractor before removing the charge cord.

That's a far cry from my ideal scenario - just plug it in.

The Law of Unintended Consequences now comes into play. The AeroVironment TurboCord  made the NEMA connection redundant, so out it came. In its place, I installed a nice sealed 12 volt battery for a Mazda Miata that fit really nicely in that space. I'd been running on the DC/DC Converter only since I had installed the NEMA box, and it seemed that it would reduce wear and tear if the battery supplied the power for those things that run even when the car is off. Those things are called parasitic loads for a good reason - they'll suck the life out of your 12 volt battery in no time at all.  One startup failure showed me it's not good to let your auxiliary battery run down to 3 volts keeping the radio, GPS speedometer,  JLD404 volt/amp meter, and AutoBloc AMP fuel gauge driver powered up. 

Then there's the emergency switch. You may recall an earlier mishap with this thing. At the time I rewired it so it wasn't carrying the full 12 volt load, but it was still an extra step to pull it before turning the ignition switch or charging and push it back in when you're done.

Finally, what's with the charging controller losing its memory settings so the laptop is necessary for each charge? I had wired the positive lead to an unswitched 12 volt and the little computer chip set was apparently subject to some surge issues while the car was running that erased its settings.

So here's the plan: build a little circuit box that takes over the control of the 12 volt battery, the emergency switch, and the charge controller. All of that is predicated on rewiring the emergency switch to a switched circuit so it will automatically energize the main pack contactor when the key is switched on. That eliminates the Soliton1 controller error that causes an annoying error light when I forget.

This all took a great deal of head-scratching time and one important little electronic component.

Found this on Amazon and figured for $15.00 how could I go wrong? It's an XINY Voltage Control Relay. It's one of those amazing Chinese gadgets that does all kinds of magical things with free shipping and absolutely no documentation. A bit of Googling around turned up a few documents in Madarin and this one in English. You're welcome.

The function I use is the voltage triggered relay that engages when the voltage reaches a preset lower value and then disengages at an upper value. I have it set to kick in the main pack contactor when the voltage drops below 12 volts which runs the DC/DC Converter until the voltage reaches 13.4 volts, then removes power from the contactor.

While I was at it, the same thing can be done with the charger, so I added some circuitry to manage that as well. I have a Tucson EV J1772 Adapter Box that I bought back in 2011 for the eBugeye. It has a simple toggle switch controlling the J1772 pilot signals, so I moved that function to a relay so the switch could also control power to the Charge Controller. Since the hood must be raised to charge anyway, one switch didn't seem so bad. I may move to an AVC2 controller in the future, but for now this is fine.

The circuit winds up looking like this:

I know it's not SAE spec, but it works for me figuring out logically what goes where. In real life, the box wound up looking like this:

The black box at the top is the J1772 Pilot Signal relay and the smaller black box below the terminal block is the diode to prevent the charge controller from getting power during other operations.

The XINY voltage control relay is mounted to the lid and wired to the terminal strip inside. I'll build a housing for the XINY that shows only the voltage LED, but for now it's still a pretty tidy installation.

evTD Gets LED Headlights

I'm still trying to get the 12 volt system under control on the evTD. Whenever the cooling fans and pump are running (most of the time here in Texas) and I turn on the headlights, the voltage sags below 12 volts. There's a momentary shudder and error light from the Soleton1 controller due to current inrush to the sealed beam headlights. Even after it recovers, the lighting still seems dim and yellowish and the high beams pull down the voltage further and cause the controller error light to flash. I replaced all of the secondary lights with LEDs a couple of years ago with limited success, so it's time to have a go at the headlights.

I ordered a set of Truck-Lite LED 7 inch round headlights. The prices have come down significantly over the last couple of years, but they are still a bit pricy compared to sealed beams. These are advertised for Jeeps mostly, although they do reference "other classic cars". They have a standard plug connection that is compatible with the old sealed beams and they are an easy and direct replacement.

Here are some before and after photos:

Sealed Beam Headlights

Sealed Beam Pattern

LED Headlights

LED Pattern

I am very pleased with the optics of the new lamps: the light is whiter and more intense than the old sealed beams. It makes night vision much better and I think I'll put a set on the PorschEV just because of the improvement for driving after dark. The voltage sag results are a mixed bag: no more controller shudder when turning on the lights and the voltage holds just above 12 volts with the cooling system running, but with high beams voltage drops below 12 volts and turns on the error light. These lamps are rated for 1.8 amps draw on low beams and 3.6 amps for high beams so at this point I think I need to look at the cooling fans and pump to see if I can cut back on the current draw and subsequent sag they are causing, Stay tuned ...