View Single Post
Old 08-04-2009, 11:26 AM   #2145 (permalink)
Join Date: Feb 2009
Location: phx
Posts: 260
Thanks: 0
Thanked 48 Times in 38 Posts
Originally Posted by MPaulHolmes View Post
The EVTech people told me that too fast of a change in voltage or too large a voltage into an A/D channel can cause latchup.

Joe, one experiment you could do, (although I don't recommend it) is to turn up the hardware overcurrent shutdown point some (also change the software to allow for higher current) then slam on the gas. I predict at 16 MHz that you would get latchup with the LEM 300. It's actually a very noisy signal. I looked at it on the oscilloscope. It seems to me to be the most obvious cause of the latchup

Eek! sounds dangerous! Everything seems rosy at 16 Mhz, so I may not risk it at this point.

Originally Posted by MPaulHolmes View Post
Anyway! Temperature is what we're talking about! Sounds like good savings for the mosfets. Cutting the resistance from 20 Ohms to 10 Ohms could only be done safely if we used 2 mosfet drivers. Voltage spikes would increase. Any idea what they are like right now? 144v isn't too close to 200v, but it isn't really far away either.
wait - are the gate resistors 20 ohm or 30 ohm? They're 30 ohm on the wiki schematic...

Originally Posted by MPaulHolmes View Post
One thing to consider: The capacitors are rated for 3000 hours at 105 degC. Right now they are only getting into the 60's so that doesn't sound that bad. Even if they did get to 100 degC, if you drove for 1 hour per day at 100 degC, you could drive for around 10 years.
Nice! I vaguely remember some talk about 85C, but if it's 105C that's even better! I agree then - temps in the 60s is probably better than fine. In fact, we may not even need active cooling - just seal up the case and let it heat up.
ReVolt AZ testing thread:
  Reply With Quote