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Unread 25-09-2012, 14:18
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Jon Stratis Jon Stratis is offline
Mentor, LRI, MN RPC
FRC #2177 (The Robettes)
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Re: Lithion-Ion Batteries

Lets take a look at that S3674-1660 motor a bit more...

Quote:
For an apples to apples comparison, Hobby King has a 36mm diameter brushless inrunner (S3674-1660) for $39.20 each. This motor has a Kv of 1660 rpm/V, a max current draw of 60A, and max power of 1600 Watts.
power = current x voltage. Running at 12V and 60A, the maximum power input into the motor is 720W. Where's the other 880W coming from? It's a perpetual motion machine!

Realistically, that 1600W comes from running it at higher current/voltages. That motor is supposedly rated to 22.2V, according to the website. But even at that voltage, 60A only provides 1332W of input power!

So, all of these numbers need to be taken with a huge grain of salt. Without actually testing the motor with our system (in other words, take your proposed set up and hook it up to an FRC robot) and measuring the output, the comparison can't really be Apples to Apples.

Your numbers significantly overestimate the power this motor/controller combination would provide you.
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