Ben Nelson's Electro-Metro Build thread

[Hondo]

Hey Ben, did the camera fall off when you shut the door? Been there done that. How is the acceleration with your new chip? I haven't downloaded the latest version, so mine is still pretty slow at start up. I get a squeel and a cut out if I push the pedal down too far at low motor rpms even though I'm only pulling 225 amps. Once the motor gets up to arounf 2k rpm I can floor it and the amps will climb up to around 500.

[MetroMPG]

Neat camera angles, Ben.

Hey - at around 0:30, is it your wheel wobbling slightly, or is it only the tire?

[MPaulHolmes]

Originally Posted by Hondo

Hey Ben, did the camera fall off when you shut the door? Been there done that. How is the acceleration with your new chip? I haven't downloaded the latest version, so mine is still pretty slow at start up. I get a squeel and a cut out if I push the pedal down too far at low motor rpms even though I'm only pulling 225 amps. Once the motor gets up to arounf 2k rpm I can floor it and the amps will climb up to around 500.

Hey Hondo! Also, you and Ben will have to slightly increase the values of Kp and Ki. That will have a greater impact on snappier acceleration than the throttle ramp rate I think. It's set to something that really only someone running at 144v would want. Maybe double both Kp and Ki. It's able to be set through the serial port.

[Clev]

Originally Posted by Joe_Bloe

now here's the tricky part -- maybe someone with better Unix-Fu than I can answer this. The filename has spaces in it. (Firefox Setup 3.5.4.exe). The only way I know how to do this is to use mget instead of get (there's only one file, it will work fine)
mget *.exe
that will download the install file to your directory on your hard drive. Good luck!

You can enclose the entire filename in quotes in most FTP clients.

[bennelson]

Hey Darin,

You're right, my tire does look crazy at 30 seconds into the video. It must just be the rubber, or even possibly some wild optical illusion. It drives fine, and I don't feel any wobble at all.

No, my camera never fell off while driving or closing the door. I am planning on doing some extra cool moving car camera shots in the future, so this was just a little test for that.

I'm really busy with work again, and probably won't have a chance to work on the car for at least a week. Oh well, maybe I can poke at the controller some evening sometime soon!

[anthonye81]

Originally Posted by bennelson

I am planning on doing some extra cool moving car camera shots in the future...

An assistant is invaluable. I've tried pointing the camera at myself so many times and it always turns out awful!

I've finally made it through the 130 page thread It is very inspiring Ben. For the first time I think I might now understand basic electrics! You seem to have become quite the EV spokesman in your part of the world too, good on ya.

I know your Metro is an ongoing project, but do you have a summary of the equipment you've put in the car, maybe a particular setup you've used for a decent period? Perhaps a basic schematic of the setup -- earlier you mentioned a shunt and resistor wired for precharge, however I can't picture how it fits into the system overall.

It's a great thread and I like how you have a go at anything and everything. Keep it up!

[bennelson]

Hey Anthony,

Thanks for the kind words.

My car really has been a continuing project, and I am always experimenting with it.

The single setup that I have used the longest was a 72V system. That's only 6 12V batteries in series. 72 volts is one of the natural cut-off points for the cost of many parts. 72V chargers and controllers are not terribly expensive. I was driving the motor with a Curtis 72V 300 amp controller during that time.

The car had fairly good performance for around town and roads up to 45 mph speed limits.

Also, at 72V, upgrading the suspension really wasn't an issue, and I had plenty of trunk space. 5 batteries went under the back seat, and one was under the hood.

The 72V system wasn't great on hills, and range was limited to about 20 miles total (running on used batteries).

Overall, a 72V system is great for anyone getting into electric cars, without costing an arm and a leg. It does have its limitations, but is still great personal transport.

[Daox]

Finally caught the video! That suction cup worked out really nice, I loved it!

[MetroMPG]

Originally Posted by bennelson

Overall, a 72V system is great for anyone getting into electric cars, without costing an arm and a leg. It does have its limitations, but is still great personal transport.

What are you talking about?!! 72 volts is an extravagant specification that leaves a car with gobs of surplus power! Sheesh!

[TheSGC]

How are the new batteries working out?