August 23rd, 2010
On the drive home, the BMS decided it was a) too hot, b) over voltage, c) under voltage and d) really confused as to the state of charge. Sparky is hereby grounded until further notice. 
So, what I need to do is figure out the following:
a) why are banks of communication failing during acceleration?
b) why are banks of communication failing during charging (different banks mind you)?
c) why is the BMS not remembering the state of charge?
d) why is the BMS not presenting the correct state of charge via the 0-5v output?
Lots of work ahead for me.
Posted in Testing | No Comments »
July 24th, 2010
I’ve gotten the computer installed and working. It does some very simple processing, that (to be honest) should have been handled by the motor controller.
The embedded computer measures the outside temperature of the motor, and then turns the motor fan on or off, and changes the power level of the motor controller.
Simple stuff, really. I’m sure *someone* could have done it entirely in hardware, but being a computer programmer from years back, this was a better way for me to go.
Posted in Installation, Parts, Testing | No Comments »
July 16th, 2010
I’ve been playing with the Parallax Stamp computer and have come to this conclusion: it is fun. 
My main process is going to have these steps:
main:
read motor temp
if (temp < 130C) use high power, fan is off
else if (temp < 145C) use medium power, fan is off
else if (temp > 150C) use medium power, fan is on
goto main
This loop will only use 2 relays (one for fan, one for power control). If I were to use low power setting, I’d need another relay.
I’m hoping to install the computer this weekend, but the weather may delay that (getting REALLY hot here in San Diego). At the very least, I hope to replace the power supply for the BMS with something much smaller.
Posted in Research | No Comments »
June 21st, 2010
I’ve gone and purchased a small embedded computer to read the motor temperature and enable/disable the fan for the motor (www.parallax.com). Nice stuff, very easy to work with.
However, since I now have this computing capability, why not use it to set the power settings for the controller as well? The idea is that when the motor is cold, allow more power to flow into the motor, and when it is warm, turn down the power. Azure Dynamics has 3 power settings available (max, norm, economy), and that is selectable by resistance into a line into the controller.
Hmmm. This is gonna be fun.
Posted in Research | No Comments »
June 15th, 2010
After getting email from Azure and some really nice folks on the 914 conversion list, I have set the power limit for the motor to 30kw. I’ve also installed some custom-made airscoops.
Net result: no overtemp on the drive home. Yay! We’ll see how this works out for the summertime, but this means I can drive home now without a long stop somewhere. (FTW == For The Win, if you aren’t into the geek slang).
Here’s a picture of the custom airscoop:
Posted in Parts, Testing | No Comments »
May 31st, 2010
Well, I added a 10 inch fan to cool the motor, and while it did to *some* good, it didn’t do enough. I’ve sent data to Azure Dynamics to see if they have a clue what’s up. If I can’t find a way to stop the motor from overheating, I’ll have to find a new motor and controller combo.
Posted in Testing | No Comments »
May 27th, 2010
On the drive home it went into overheat mode at the 7 mile mark (out of 17 mile drive). Obviously, the removal of the rear air dam and the addition of the engine compartment air dam did not help.
Next stop – air scoops and fans.
Posted in Testing | No Comments »
May 26th, 2010
After some struggle, I got the new air dam in place, and took a video of the airflow. Attached are the three videos (in time order): before_mods, after_rear_valence, and after_air_dam. The videos show the yarn on the motor while driving. The yarn seems much more lively in the last video.
before_mods
after_rear_valence
after_air_dam
Posted in Research, Testing | No Comments »
May 26th, 2010
In order to figure out where the airflow is and is not, my mechanic suggested we use a really old technique – tape yarn to the car and see where the wind blows it. Well, we did that. We taped a whole bunch of yarn, courtesy of my charming wife, to the motor, transmission and engine compartment. Then we video taped the yarn whilst driving. We discovered that with the big battery box above the motor, there wasn’t very good airflow from the top to the bottom. Then we removed the rear valence (an air dam just below the rear bumper – used for the now non-existent bumper) and video’d again. Much better airflow. So now, I get to replace the air dam in front of the engine compartment with something bigger, and video again. If this doesn’t improve the airflow, then it will be time for air scoops.
Posted in Research, Testing | No Comments »
May 16th, 2010
Well, it is the motor that is being overheated. Not surprising, considering there is a huge battery pack just above the motor, blocking airflow upward. I’m now looking into how to install a fan or installing some ducting or both.
Posted in Testing | 2 Comments »
May 11th, 2010
Argh. Now that I’m driving the car more, the bugs are starting to come out. On the drive home today and yesterday, the controller has gone into over-temp protection. I need to figure out what is going on.
Posted in Research, Testing | No Comments »
May 8th, 2010
I’ve replaced all but the headlights with LEDs and seen a dramatic decrease in current during their usage. What was interesting is that I did not have to replace the blinker relay (apparently you need to on newer cars). I got the LEDs from www.superbrightleds.com.
I’ve also made regen a normal part of driving, so I’ll need to put back the circuit that lights up the brake lights when regen is active. The reason for this is to make shifting easier – when regen is active the motor quickly drops from high RPMs to almost zero within a second or two.
So I’ve done another set of calculations, and I’m getting 350wh/mile driving to and from work. Most of this is freeway driving with some stop-n-go.
Posted in Installation, Parts, Testing | No Comments »
April 22nd, 2010
Interesting drive. Naturally I was unable to gather stats on the drive in, as the RS232 connector came loose. *shrug* Time for duct tape. The drive home was successful, in that I was able to gather data. It also showed that I have some transaxle noise that needs looking at before I drive much more (Calling Dr. 914!)
So for those who are statistics fiends:
Current: min=-48a, max=123a
Voltage: min=330v, max=368.5v
Torque: min=68.6nm, max=120nm
I’ve attached the spreadsheet with all the data, so you can analyze it to your hearts content: InitialDriveHome
Oh – the current at freeway cruise was between 75 and 80 amps at 350v.
Posted in Testing | No Comments »
April 20th, 2010
I returned from my business trip to Bangkok (long story in itself) to find two boxes waiting for me – the replacement DC-DC converter and new cables for the BMS. It took me about 4 hours to replace the DC-DC converter and the 4 cables, but well worth the effort. The DC-DC converter works as advertised, providing 13.5 volts. The new cables eliminated the intermittent communications problems during charging.
Proof is that the batteries are now fully charged. I can see the car quivering with excitement in the driveway, begging to be driven. I think I’ll do that today.
BTW, EV Components has been great during all of this – providing excellent customer support and fast shipping of new parts.
Posted in Parts, Testing | No Comments »
April 6th, 2010
Ok, so some tweaks on the pedal parameters make a HUGE difference. I was able to get the accelerator to behave “normally”, and was able to get the regen to work with the brakes. Acceleration is good – better than the 1.8 liter engine. Braking is GREAT! Dang, I sure don’t need those high-priced brake upgrades now.
So now I get to do some fine tuning on the pedal, and it will be driving like a REAL car. 
I was able to pull only 90 amps, so I know there is more to push through.
Seriously, though, I was able to get up to 30 mph in first gear with no trouble, although there is a lot of vibration at 5k rpm, so I will have to pull the motor and balance the flywheel. *sigh*
So now I am waiting for the replacement DC-DC converter (previous one sadly fried due to operator error) and some cable components so I can rewire the BMS circuits.
The BMS works fine except for banks 5, 6 and 8. Oddly bank 7 is fine, but I will rewire it also, as it uses the Cheap Cabling. Hopefully this will take care of the communications errors with the BMS.
Posted in Testing | 4 Comments »
April 3rd, 2010
Ok, so in the process of trying to “optimize” the driving experience, I made a few mistakes. Fortunately, I’ve been able to fix almost all of them. The regen circuit now is activated by the brake lights, so the car now drives just like a car. Very cool.
While I was fussing around in the controller compartment, I tried to get the DC-DC converter to work. However, this resulted in me frying my DC-DC converter (fortunately, this is an relatively inexpensive mistake). The good thing is that EV Components has more of them.
I’m hoping to get the tachometer working tomorrow. I spent about 3 hours getting a neat circuit put together that will drive some indicator lights. One is the “ready” signal and the other is the “fault” signal – both from the motor controller. Since I know I’ll want to see these lights while driving and while testing, I set it up so there are two of each lights – one set in the dash and one set near the motor controller.
Radio Shack was my friend, as was Tim Kutscha for his diagram. Naturally, I didn’t do it exactly his way, but that is the fun of all of this. This version uses 2 resisters – one for each input and 4 transisters – one for each light. The box has 12v ready LEDs, the other lights are the more usual incandescent lights.
The circuit is inside this box:
Circuit for showing "Ready" and "Fault"
Posted in Rebuild, Testing | No Comments »
March 31st, 2010
Well, ok, I just took it for a drive around the block on the weekend. The regen action on the accelerator was kinda odd, so I’ll change that. Also the acceleration was a bit weak, but we’ll see how that changes with the updates. No clue about power usage, nor current usage, but again, that will change.
Planned updates: regen enabled during braking only, update the lights in the dash to show READY and FAULT status of the controller (and to show the status in the rear trunk too), add serial cables to the passenger area (so I can run a computer while driving).
Posted in Testing | No Comments »
March 23rd, 2010
Ok, I tested the safeties on the BMS and the motor controller – all seems to be ok. I do have some cutouts on the BMS during charging, but I suspect that is because the shielding on the cables are not all they are supposed to be. I don’t have cutouts on the cable supplied with the BMS, but I do on the stuff I bought from Fry’s (go figure, cheap stuff from Fry’s??? gosh, the mind boggles 
). For now, I will suffer with occasional communications errors, but I will have to replace the cables sometime (Thanks Davide!).
So tonight, the Moment of Truth. Will Sparky move? Stand by.
Posted in Testing | No Comments »
March 14th, 2010
Wow, what a lot of work. I have 108 batteries (the 109th doesn’t fit due to slight miscalculation…shrug), which means I have 216 bolts to fit in, 108 sensors to attach, etc. Next step is to test out the BMS to make sure it can handle the job properly. Fortunately, Elithion does a stellar job on their website, so I know what to do next.
Here is the front battery packs all wired up.
And here is the rear battery pack all wired up (my figures hurt now).
Posted in Installation | 4 Comments »
March 8th, 2010
In order for the Battery Monitoring System (BMS) to monitor all the batteries, there has to be some sort of device that attaches between each post on each battery. For the Elithion BMS, there are banks of these monitors and they all report to the BMS itself. It’s a bit complicated. Fortunately, the Elithion website has some very good hints on how to go about this. In the picture below, I have one bank connected up, with two more to go in that bay.
Posted in Installation | No Comments »
