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.
Archive for May, 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.
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.
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.
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.
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. 🙁
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.