Sleuthing the Soneils

Against my better judgment, I took apart one of the failed Soneil chargers yesterday afternoon to see if I could find out anything about the failures. There weren't any burned components or obvious damage. After powering up the unit with the cover off, I could verify that the isolation transformer between the AC side and battery side wasn't getting pulsed, and thus passing no power to the battery (or the LED). It seems that the UC3842A chip DC-DC converter chip used to drive the FET which pulses the transformer was dead. It's power supply had a resistance of about 3 ohms to ground (bad).





After mulling over the circuit in my head last night. I tried to compile a list of facts I know about the failure:

Facts:

• The batteries were all fully charged in the morning, despite the charger failures
• The batteries with working chargers had ~13.7 volts on them, the failing ones, ~13.4
• There were far more failures in the batteries in the front of the car
• The front batteries are closest to the negative pack voltage
• I plugged in the rear batteries first when testing the chargers
• The rear batteries typically have slightly more charge on them because they get warmer
• I started all rear battery chargers simultaneously on a power outlet strip
• I started all front battery chargers one-by-one by plugging them into power cords with three outlets on the end
• The components crossing the isolation barrier in each charger are: a transformer, an opto-isolator, and three ceramic capacitors (.01 uF at 250V)
  

Hypotheses:

• Since all batteries were at nearly full charge, the failure must have happened at the end of the charge cycle, perhaps when the charger transitioned from acceptance charge (14.7V at 3.5A) to float voltage (13.7V)
• Since the front batteries typically finish charging last and I also plugged them in last, perhaps a surge from the rear battery chargers (when shutting off) caused failures in the front battery chargers
• Is suspect that the capacitors at the isolation barrier in the chargers failed because they have a breakdown voltage of 250V. When charging one battery, this is fine. When charging a long series string of batteries (oh, say, 144V), the charger output stage can float +/- 144V relative to the AC voltage on the input stage. 120V AC really becomes 170V DC when rectified. Add this to 144V and you get 314V, which is clearly above the 250V rating in the isolation capacitors.

Based on this, I don't think sending the chargers back for replacements would really help the situation. If all the chargers have the same 250V isolation caps, then they would all fail eventually. I suppose I could take all the chargers and replace the isolation caps with similar values but give them a 1KV voltage rating.

I'm trying to figure out the best option for now. To drive the car, I'll probably need to re-install all the Belktronix resistive shunt balancer modules. The car would be driveable but it would still take a long time to charge. I don't like the idea of hand-modifying twelve Soneil chargers, but that would probably be what it takes to get them working.

I could send all the Soneil's back and get the Joule chargers again. That is, after checking with the designer that they support 1KV of isolation. The Joule chargers draw 35mA of current when sitting there unplugged. This hypothetically translates to 2857 hours of discharge from 100Ahr batteries or about 4 months until the batteries are completely dead. If I went on a long vacation, I guess I would leave the chargers plugged in on float charge anyway. The Joule chargers also only charge with 6A, which means (despite a bad PFC rating), I might be able to plug in all chargers to a 15 amp AC circuit (The Soneils pull about 18 amps for all 12 chargers).

This is a really bad time because we have so many electric vehicle events happening now. Having a dead EV is not too appealing. I'll ponder this for a bit.

Happy Sunday morning.

A dark day with the Soneils

This morning was a dark morning.

I received the Soneil chargers yesterday around noon and stayed up until 11:30 last night to install them. After installation, I powered them up and all chargers lit up with an orange LED. Yay. This morning, I got up and half of the chargers had a green lit LED and the other half were dark. I used a Kill-a-Watt meter to determine that the dark units were pulling no current at all.

I've heard rumors that Soneils don't like to be attached to a series pack.

It looks like my EV is dead for the near term. Putting the Belktronix system back in with all of its shunt resistors and battery boards does not sound appealing right now.

Ugh.

Fixing the Potbox, Soneil's Arrive

Over the past few days, the car has still been lurching around despite the potbox parameter adjustments that I've made inside the controller. I contact Bob Bath, the original CivicWithACord builder who sold me my PB5 potbox. It was brand new from KTA Services and not used/worn-out. Yesterday in stop-n-go traffic, the car was lurching again and the controller faulted when I haphazardly floored the accelerator with the car out of gear. After expressing my frustration, Ives at Synkromotive highly recommended that I install the factory throttle position sensor (TPS) from the original Civic instead of using the PB5 potbox.


Here's the factory Civic TPS installed. I mounted in the same place as the PB5 potbox, but used a piece of 1.5" angle iron 4" long to mount it. Unlike the PB5 which only has two wires, this TPS has three which allows for higher reliability and more accurate signalling to the controller.


Here is the rear side of the installation. You can see the top of the grey-painted angle iron that I bolted to the engine mount side. I had to chamfer one corner to prevent interfering with the engine mount rubber. The actual electrical potentiometer is black at the far left of the picture, while the cable attachment is on the far side of the large butterfly intake valve. There were some extra bolt holes in the throttle housing, so I just used a piece of all-thread and bolts to suspend a small piece of 3/4" angle iron to support the fixed point on the throttle cable.

After a test drive, the system was sooooooo much better. I can creep forward with the car now and the lurching is gone except when I really stomp on the accelerator. I'm now completely convinced that the PB5/PB6 potboxes are complete crap compared to the factory throttle position sensor. It's too bad the TPS doesn't go down to zero ohms, so it can't be used for many other controllers like a Curtis.



After I arrived back home from the test drive, the FedEx truck showed up and dropped off 13 brand new Soneil 7amp chargers. I've been waiting for these for over a month now and am happy they are here. This will replace the Belktronix charging system and allow me to remove all the spaghetti associated with the shunt resistors and battery monitoring boards.

This is a good day. The car is running smoothly again, and I'm psyched to get these new chargers put in. Have a great weekend everyone.

Cheers, Tim

Moving the Instrumentaiton

Since the Synkromotive controller has its own motor speed limiter based on input directly from the Zolox sensor, I decided to clean up the instrumentation by removing the RPM gauge and moving the Link-10 E-meter onto the dashboard. While this removes some of the "coolness" factor without a tach, I like the more simplistic look as I tend to be a minimalist.


Here's the empty pillar pod with the gauges and wiring removed. I'll probably run the local Civic used-parts store and simply get a piece of replacement trim.


Here's where I moved the E-meter to. I can actually see it quite well when driving. It's sitting in the same hole where the defroster button used to sit. I simply carved a rectagular hole in the dash and moved the defrost switch down a few inches. It protrudes a bit, but still works fine.

In addition to moving the gauges, I wired up the "oil" light to the warning light on the Synkromotive controller. The oil light requires it's input wire to pull down to ground. Since the motor controller puts out a +12V signal when there's a fault, I used a simple transistor circuit (see the schematic at the end of this post) and drove the transistor gate through a 3.3K ohm resistor.

Synkromotive Potbox Issues and Temperature Faults

Over the past week, I've been able to give the Synkromotive controller some good real-world experience during my commute. The controller is very smooth and has several parameters to keep the battery pack healthy. I also like that the Synkro controller doesn't tap off the main pack for part of its power supply which has led to pack imbalances in the past. You can see several voltage-current graphs on the Synkromotive website here. Click on SynkView at the bottom. You'll have to install MS Silverlight to see the graphs. Click on Logfiles/Civic and then an .XML file on the right to see various drives.

One major issue I had was that the car tended to lurch when first starting up. This isn't too bad on the freeway, but can be a real pain when in stop-and-go traffic. Last Thursday I was driving home in hot weather in stop-and-go traffic on the freeway in the middle lane. The car seemed to get progressively worse during the drive home with its "lurch-starting."

About 2/3 of the way home, the controller faulted and just stopped the car dead in the middle of the freeway. I attempted to clear the fault and get the car started again by turning the ignition key off and on. I must have been impatient (sometimes it takes a full six seconds for the controller to precharge and be ready), but I wasn't able to clear the fault. Traffic was slow, and two kind men helped me push the car off the left side of the road. This was a somewhat unnerving experience, but I guess it's part of the game when trying out a Beta-test motor controller. After propping open the hood, removing the primary 12V power from the controller and hard-booting it, it seemed to start up again and I drove the rest of the way home.

The beta controller units have been having a few issues with noisy temperature sensors. During initial acceleration, the electrical noise tends to cause a spike in the temperature sensors, causing the controller to shut down. After I got home from this incident, I observed some of the potbox inputs (Ainput in the Smi window) and realized that I have a really crummy PB5 potbox. The resistance goes from zero ohms and jumps up erratically to 400 ohms or so and then goes smoothly up to 5K. With this new information, I was able to set the "zero throttle" point above the 400 ohm point which makes acceleration much smoother and bypasses the glitches in the potbox.

Yesterday, I was driving someone home in the Civic. Again, it was a hot day and we were in stop-and-go traffic. The controller faulted again and shut the car down. Fortunately my friend, who was in a hurry, could walk the remaining eight blocks home while I rebooted the system. Ives at Synkromotive gave me some updated firmware with some extra noise filtering on the temperature sensors. After running the car through the same route with the new firmware and doing some extra stop-and-go testing, I couldn't get the controller to fault again. We'll see what happens the rest of the week.

Despite the faulting condition, I've been extremely happy with the power, smoothness, logging and programmability of the Synkromotive controller. This is going to be a really good product when it hits the shelves in July.

Going to the Electrathon/HPV Event at PIR

Last weekend, I took the Civic-EV to Portland International Raceway to show it off at the Electrathon/Human-Powered Vehicles event there. Memorial Day weekend is the one weekend that PIR can't make any loud noises, so they actively recruit electric vehicles and bicycles of all types to race.


Here's Gary's Honda Insight EV with lithium ion batteries and an Siemens AC motor.


This shows some of the velomobiles (encased recliner cycles) present at the event. They really fly.


Here's my humble Civic next to Paul B's Corbin Sparrow.

It was really hot that weekend, but the new controller held up well on the freeway.

Installing the Synkromotive Controller

I stopped by the Synkromotive shop this morning and picked up my beta-test controller that I've been wanting to try out. After running out and buying some more magna lugs and welding cable, I came home and removed the Belktronix controller and all the associated wiring.


With the old controller gone, I had to figure out how to place the new contactor and controller. Here's my mock placement. I placed the contactor slightly behind the controller to limit the cable lengths I would have to use and keep the high-voltage connections away from eager fingers. After the placement, I removed the piece of thick plastic below, drilled some mounting holes and bolted the controller and contactor in place.


This picture shows all the high-voltage 2/0 gauge cable hooked up. I was very fortunate that I could reuse all the old cables and simply crimp on new lugs. My purchase of 12 extra feet of 2/0 gauge cable was for naught, but I'm glad I got it anyway since the welding shop is only open on Friday.

The high-voltage connections on the Synkromotive controller are well thought out, especially if the controller is near the motor and parallel to it. The funny downside is that the connector bars are vertical instead of horizontal, forcing me to use less-common "L" lugs on the 2/0 cable to attach things. I'll have to give this feedback to Synkromotive.


Here's the preliminary installation. I don't have the motor RPM sensor hooked up yet, but I wanted to get the system going because there's an electric car show this weekend at PIR (we're demonstrating EVs along side the Electrathon and Human-Powered-Vehicle folks).

The Synkromotive controller is fully digital and has a USB port on the side. After firing up the user interface program, I was able to verify that everything was mostly operating. Given that this is a beta program, documentation is slim at best and full of bugs. I've already given much feedback regarding specific points in the document that cause confusion.

After checking all the voltages, I rotated the potbox by hand with the transmission in neutral and (Voila!) the motor spun. As of 11:30pm, I took it for a quick test drive around the block. The acceleration was very smooth; however, it wasn't as peppy as I had hoped. The amps never got above 150, so I'm guessing there's some calibration I need to do with the potbox. Anyhow, after 7.5 hours, I successfully swapped out the old controller for the new.


I'm a big fan of an uncluttered engine compartment. While the Synkromotive controller definitely has some wiring, the Belktronix system was a bit more out of control. Here's a bunch of the "spaghetti" that I removed with the older controller. I like seeing the removed chaos in a box.

Once I get the individual Soneil chargers, I can remove additional wiring and clutter without all the shunt balancer boards on top of each battery.

Whoosh, I'm liking this new controller! Tomorrow I'll tweak settings a bit more and see if I can take it on the freeway to PIR for the show.

Cheers,
Tim