Tuesday, March 21, 2017

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"

Friday, March 17, 2017

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. 

Tuesday, January 31, 2017

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.