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Chamilun - very nice - thanks for sharing! It's fun to see other P-car owners have dabbled with the same thing. Although there are many good reasons for going AC now, I went with DC because we thought we'd end up with better performance... we shall see!
I will read through the read, but I'd bet our setups were/are quite similar. i bought the top of the line motor at the time. Main limitiations were battery, battery, and more battery
So, after another test drive this morning, two remaining cells were found that reported lower than average voltage when loaded heavily. Turns out both include approximately 4 to 5 ft of cables length in-between sensors. Cells voltages measured with a cable of this length included, will report a more significant voltage sag (more than if measured right at the cell). This doesn’t cause any problems, but does explain why the BMS is reporting the lower voltages on these cells during heavy loads (like momentary 800A pack amps). There is a section in the BMS software that allows us to enter an appropriate compensation value for the resistance of buss bars and cables such as this situation.
Kirk also spent a good bit of yesterday pulling the battery box & fuse assembly that’s mounted on the driver’s side of the motor, checking it’s connection (which was one of the two mentioned above). It, and all other connections in the box were fine. This supports the long-cable resistance theory. Now that the compensation values are in the BMS, the next test drive should prove it. Hope to have more to report soon!
Testing of the heater system went very well. The 3 water heater units produce noticeably warm heat in about 1 minute. Not bad of a wait at all, for a water system in an EV. And quicker than most gas car heaters. Together, the 3 units can produce just a little bit more heat (on full blast fan) than what the stock heater system is capable of dissipating. This is exactly what we want - no wasted “unusable” water heating capability, and not under-powered.
A "defrost" switch has been added to the left of the stereo, replacing one of the place-holders... although the switch doesn't actually do anything, the yellow light here indicates when the new water heating system is on. A relatively elegant solution, if I do say so myself. Everything is still controlled by the stock temperature unit, and things ran smoothly, going on and off appropriately, during the 20 minute test.... so it looks like one more item can be checked off the list! A photo of the heaters below:
dont want to toot my own horn, but I was one of the progenitors of the heated water system. At that time, everyone using ceramic heaters. I used one heater quite similar to your setup. Worked very well. Not sure why you used 3 (???), as the current drain wasnt the best with one (12 amps +-).
I got flack for not including a blow-off valve at the time.
IrocMan - Thanks for the kind words... what Tesla are you driving, a Model S or Roadster? Either way, I'm a little envious, but I wanted a roadster with 4 seats that cost less than 50 grand... so this is my attempt at a poor man's Tesla!
Chamilun - Crazy, you were well into this before I was. There certainly has been a wealth of knowledge online that we rely upon for this build. I'm not quite the pioneer you were, but still enjoying the process and trying to push the "hobby" further. Truth is, we wanted to go ceramic heat, but it was too noisy - electrical noise that is. Part of this build was putting in a high-end stereo and we were fairly certain the ceramic heater would have had some serious side effects on the audio system when both were running. Went with 3 heaters to help the system heat up fast and get as hot as a stock system would have allowed. We really were trying for an electric car that performed as well or better in all regards to the stock vehicle. TBH, I didn't realize how much extra time some of the extras were going to take when I made the list of everything we were going to put into the build!
Cheekybird - thanks for following... hope to get to the point where I can finally drink the beer after this long adventure. Hard to believe it has been 21 months! I am amazed at the total amount of views this thread has received thus far. I sorted posts by views and this is on the front page, having just passed two about IMS issues and a third about 996 reliability! Can't wait to get some real footage to you guys when we start driving and fine-tuning things... 0-60 times, 1/4 mile etc!
Edit: I'm probably getting a *little* ahead of myself with that last comment - I am extremely excited to see how close the build is getting, but there is definately more to be done. ALSO, to Chamilun or anyone else in or visiting the Oregon / Eugene area, happy to show you the car when finished... still waiting to show it off to myself...
I currently have a Model S P85 with all the goodies except the wider rear tires of the P+ (long story). A fantastic car, 7 seater, LOT of torque and good handling thanks to an awesomely low gravity center with the battery pack under the car. The car drifts like a go-kart!
I like the Roadster too but find it too unbalanced not really in the way I like. An electric 911 with the ability to have two kids in the back and that would keep the handling characteristics of a 911 would be a awesome car.
I'm sure Porsche will get there relatively soon...
If you come by the Bay Area in CA let me know, I'll be happy to let you drive the Model S
There is no good way to fit the motor cooling fan unit planned for, because of size. Tried scenario’s in the plastic bumper space, in the trunk space, and no luck. It’s pretty enormous. So I’ll pick-up a new one (or two) smaller units this weekend... more to come on this, hopefully.
Kirk has been monitoring and adjusting the finish charge process(s). I thought you’d be interested in that, so see the annotated a screen shot below!
Still following here too.
would love to have a four seater electric sports car convertible... i'll just keep living vicariously through this thread...
fyi, in my Tesla S85, the winter temps plus our heater absolutely kills our range. as much as 40% depending on conditions. When doing long trips in the winter, we very sparingly use our heater and instead use the seat warmers as much as possible.
yes, for our Volt, our Summer range is about 40 depending on terrain, but winter can go as low as 32 miles. Best feature ever is the remote start for heat or a/c. So you can heat up the vehicle while its on the charger before leaving
OK, so after lots of hemming and hawing... we had to come to the conclusion that there was no way to get a fan well placed in the engine bay. The decision was made to move the fan under the rear fender... there was just no-where else this monster blower assembly would fit (even without a filter on it)! Gotta admit, I'm kinda glad this isn't a part of the car that will be shown... so consider these photos "for your eyes only":
Hi Rutsy,
Just wondering how loud the fan will be?
That's one of the few complains I'd have about the Tesla and was wondering if some static or dynamic insulation could be used to attenuate the noise.
Fan noise is really annoying on an EV at low speed!
07-31-2014, 02:26 PM
