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Unread 29-12-2007, 15:31
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Re: Serial PWM motor controller

Quote:
Originally Posted by smartkid View Post
Also, what is a 4MHz Ceramic Resonator? I've looked one up, a little $1 part that I've seen before but what does it do?
A ceramic resonator is a low cost ocillator, usually used as a clock in a curcuit where the frequency of that clock does not have to be super accurate.


Quote:
Originally Posted by smartkid View Post
On the subject of the battery. I've done my homework on car batteries. I knew that the batteries weren't designed to be completely discharged and I will take care to ensure that the battery we use won't get that low. But I didn't know how long it would last, please trust me 8 hours is PLENTY

Car batteries usually have 40 Amp hours.
20% of that is 8 Amp hours.
The battery would only last 8 hours if only 1 Amp is being drawn. The CIM motors will draw far more than that (upwards of 132 Amps at stall for each motor ). At that current (not advised) you would get under 4 minutes before you would surpass the 20% draw on the battery. Now you shouldn't be drawing that much current, but calculating and budgeting the amount of current you draw and calculating how long your battery will last will tell you what type of battery (car/marine) you'll need.
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