Ben Nelson's Electro-Metro Build thread

[ndavid79]

Originally Posted by bennelson

The other trouble that I have is that my analog volt meter only goes to 100 - so even a fully charged 96V system is too much for it. Right now, the volt-meter is disconnected. I may temporarily replace it with with a cheap-o multimeter for now. I would much prefer an analog meter to a digital one though.

Don't forget about the concept of a voltage divider... Two equal value (something high for low watt dissipation) resistors in series across the pack, with your analog volt meter's + connected to the middle... Your volt meter will display 1 for every 2 pack volts (40 for 80v, 60 for 120v, 80 for 160v, etc).

My electrics knowledge is limited in this voltage range, but a quick gander at Ohm's Law & a calculator, gives me two 30kohm'ers for 1/4 watt resistors @ 144v nominal / 170v max.

[bennelson]

Yeah, doing something with resistors had been mentioned to me to change the range the volt-meter is good for. I guess my voltage is still a bit in the air right now, so I don't want to mess with something I need to physically change out.

Today, I picked up some cheap hub caps at the auto parts store. They are just plastic, nothing special, but I think the car looks a little nicer with them.

Car with just painted rims (which are rusting....)


Car with new hub caps.


Not sure I ever directly mentioned it before, but I added an ELECTRIC sign to the back of the car.



I have noticed that I do drive a little more aggressively now, just so that the car seems to have speed and power, rather than people thinking that all EVs are slow and have poor acceleration. That's not the EV's, that's just the way I usually drive!

[mrbigh]

Whoa.... installing the hubcaps just changed the appearance of the vehicle, before it just looked "nude".
Now you would have to shave everyday to keep with the flow
Nice looking conversion, congrats

[bennelson]

http://www.youtube.com/watch?v=Lm5IATVw3WI

While I built a battery warmer for the Electro-Metro a while back, I never got it installed.

There was some sort of a problem that was setting off the GFI on my charging power outlet AND the GFI in the car.

I took the cover off the warmer, fixed the problem, and installed the warmer in the car.

Running the warmer for an hour or so seemed to bring the batteries up to "Not Cold" temperatures, which is all I am trying to do - just get the batteries somewhere between 50 and 70 degrees F.

I will still need to experiment to find out what the ideal run-times for the battery warmer are at various temperatures.

Since the battery box is INSIDE the car, any heat escaping from the battery box should help to heat the cabin (at least a tiny bit!)

[bennelson]

Been real busy with work lately, so not much time for improvements.

The car is much cozier with the pre-heaters running before going for a ride. The last time I went for a drive, without pre-heating, the car did feel rather sluggish.

I finally got a chance today to play around with the car a little more - this time, working with the interface software to the Cougar controller.

Adam walked me through the software over the phone, helping me get connected up, and tweak a few settings. I should get a chance over the next couple days to tweak the controller to match it's settings to my particular motor. I should be able to get more power and better acceleration, just by changing some software settings. I am looking forward to it!

[MPaulHolmes]

What software version are you using? Did he show you how to upload new software? I think you'll like the sensorless over-rev protection (very nice to have on ice). Also, did he show you how to tune the PI loop? There are a couple constants that can make the response snappier. Version 1.7 and 1.8 have the over-rev protection. I can send you one if you want to try them.

[bennelson]

I'm still on Cougar OS 0.9!

Adam said I should probably hold off on updating the software for at least a few more days as he has another version up his sleeve. I am interested in the over-rev protection, but I also want to re-rig the hardware for Cougar-Controlled pre-charge/main contactor on/off.

I have had a weird issue with how the controller reacts to the tires on ice and snow. Since I actually know a little about tweaking the controller now, I should be able to data log what actually happens, and use that to figure out how to improve winter handling.

[MPaulHolmes]

Your controller is set to throttle proportional to current. It should probably be changed to a more curtis like behavior. That's super easy to do in software. See, it tries to see a certain amount of current if your throttle requests it. Like 50% throttle will mean the controller will try to get 50% of max current. You can change that behavior over the serial port really easily.

[bennelson]

Today's exciting news is that I (finally) got the most current version of the ReVolt Open Source (Cougar) Controller firmware loaded into the controller.

Along with that I now also have the RTD Explorer latest version installed, to be able to view data from the controller AND tweak its parameters in real-time!

Special thanks to Adam for helping walk me through all the steps to get it going.

The really weird thing is that BEFORE working on upgrading the controller, I ran into a problem where it wouldn't output ANY current to the motor. I ended up removing the controller for bench-testing. Eventually, we tracked the problem down to one of the setting in the controller (throttle_ramp_rate?) to being set to ZERO. How it got set to that, I have NO idea - some crazy bug? Who knows!?!?

I also didn't like that fact that it was rather difficult to see either of the LEDs on the controller with the metal cover in place. I solved the problem by drilling two holes through the case, just above the LEDs. (packaging tape will keep rain out for now) I would eventually like to have a clear plastic cover for the controller to show off its cool circuit-board guts!

With the new software and firmware installed, I only had time for one quick ride around the block before having to call it a day. I am pretty excited about all the new settings I can tweak, and how the controller runs the main contactor now.

-Ben

[MPaulHolmes]

Another way to see the leds is have wire go to the control board, and then have the LEDs actually poking out of holes in the case. You know those black snap things that the LEDs can get plugged into? A friend of mine did that, and it looks really really nice.