01-03-2009, 03:29 AM
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#91 (permalink)
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PaulH
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,832
Thanks: 1,368
Thanked 1,202 Times in 765 Posts
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I'm an idiot...
Hello everyone! I'm an idiot! I killed the mosfets. oops. I should have only installed 1 or 2 for testing instead of 5. Oh well, I have 5 more that I can mess with. From now on, one at a time! There are a few things that could have caused them to fail in a short circuit state that I can think of:
1. I kept plugging and unplugging batteries and stuff in strange orders, and occasionally I think I maybe plugged the wrong thing to the wrong thing. I need to label the wires. hehe.
2. Maybe I should use an actual on/off switch instead of trying to put alligator clips onto battery terminals. That might make voltage spikes as it turns on and off, especially when I did the 60v test. There could have easily been a spike of 40v over I bet. And mosfets don't tolerate going over their rated voltage AT ALL!
3. I'm an idiot.
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01-03-2009, 10:16 AM
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#92 (permalink)
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Losing the MISinformation
Join Date: Oct 2008
Location: Southern Missouri
Posts: 393
Thanks: 15
Thanked 3 Times in 3 Posts
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Spiking the mosfets... sounds like a dance...
Ouch.
Well, you could be nicer to yourself, and say "too impatient" or something like that. I guess the only difference in you and most of the rest of us is that you had to go and tell the rest of us about it. 
Oh, and Sabrina, don't let him get too close to any forks... 
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The brake pedal is my enemy. The brake pedal is my enemy. The brake pedal...
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01-03-2009, 10:53 AM
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#94 (permalink)
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Losing the MISinformation
Join Date: Oct 2008
Location: Southern Missouri
Posts: 393
Thanks: 15
Thanked 3 Times in 3 Posts
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Contributions???
Hey, Ben: Make Paul up one of those donation goal charts. Maybe he can get a few donations to help replace those Mupp... I mean mosfets that he spiked! 
__________________
The brake pedal is my enemy. The brake pedal is my enemy. The brake pedal...
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01-03-2009, 10:59 AM
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#95 (permalink)
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EV test pilot
Join Date: Jan 2008
Location: Oconomowoc, WI, USA
Posts: 4,435
Thanks: 17
Thanked 663 Times in 388 Posts
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Quote:
Originally Posted by Intrigued
Hey, Ben: Make Paul up one of those donation goal charts. Maybe he can get a few donations to help replace those Mupp... I mean mosfets that he spiked! |
I'm working on it.
I finally convinced him to give me his PayPal info so I could get a donation point going!
I was thinking that maybe the graphic should be a stack of mosfets that gets taller as he gets closer to the goal. |
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01-03-2009, 11:06 AM
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#96 (permalink)
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Losing the MISinformation
Join Date: Oct 2008
Location: Southern Missouri
Posts: 393
Thanks: 15
Thanked 3 Times in 3 Posts
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Quote:
Originally Posted by bennelson
I was thinking that maybe the graphic should be a stack of mosfets that gets taller as he gets closer to the goal.
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LOL! Have "The Count" counting them as they go up...
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The brake pedal is my enemy. The brake pedal is my enemy. The brake pedal...
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01-03-2009, 12:54 PM
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#97 (permalink)
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PaulH
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,832
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Ben, you're right! I'm going to fix it and do it better. I have a running list in my mind about what I can do differently. I'm off to home depot right now to get a few switches, maybe a higher power soldering iron, I'll shorten the leads to the motor (because that can cause problems with voltage spikes too).
Intrigued: My wife told me I could only have a bowl of cereal this morning (it uses a spoon). I was impatient... There, I said it... I watched Dr. Phil, Oprah's protege, and he told me that I need to learn to forgive myself.
These practice mosfets are only $3 each, so I'm glad I'm learning how to break them, so I can learn how NOT to break the $15 dollar ones!
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01-03-2009, 05:02 PM
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#98 (permalink)
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PaulH
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,832
Thanks: 1,368
Thanked 1,202 Times in 765 Posts
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It works again!
I removed the 5 bad mosfets, and added a single mosfet. Now there are switches too! No more confusing unplugging and plugging. The wheel turns just fine with just one mosfet! The EVTech people feel that I need to add HARDWARE current limiting, and that could have contributed to the failure. I didn't mention that there was no current limiting at all. hehe. I'll definitely do that for the car's version, although I still think it can be done in software. Ian is still driving around with his 144v 600amp controller with software current limiting.
I'm going to look at the behavior of the mosfets with the oscilloscope later, but I have to get ready for class on monday! dang it!
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01-03-2009, 05:49 PM
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#99 (permalink)
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EV test pilot
Join Date: Jan 2008
Location: Oconomowoc, WI, USA
Posts: 4,435
Thanks: 17
Thanked 663 Times in 388 Posts
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Hey Everyone,
This is a great project that is worthy of our support.
If you have the means, please contribute. All contributions go straight to purchasing parts for the project.
To contribute, please visit my blog at:
Green Cars: Videos and More!
and "Adopt a Mosfet"
`
[EDIT]: I removed the link I had here, as it didn't seem to work. The CONTRIBUTE button on my blog seems to work fine. Wish I could figure how to embed it here though!
Last edited by bennelson; 01-03-2009 at 09:21 PM..
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01-03-2009, 06:03 PM
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#100 (permalink)
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Batman Junior
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,515
Thanks: 4,062
Thanked 6,959 Times in 3,603 Posts
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Adopt a Mupp... I mean mosfet! I'll adopt one.
Quote:
It's time to get things started!
On the most sensational inspirational celebrational Mosfetational
This is what we call the Mosfet Show!
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