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Now this is an oversimplification, but it's not too bad of an estimate:
The pack voltage is irrelevant.
Let's say you are running at 50% PWM duty, 500 amps. The diodes conduct half of the time. So, the power loss from them is...
1v*500amp*0.5 = 250 watts waste heat.
Now let's use mosfets instead of diodes. Say 10 in parallel. My 200v mosfets have a typical resistance of 0.0085 Ohms each. So, at 500 amps, 50% duty, the loss is...
0.0085*500*500*0.5*0.1 = 106 watts. Not too shabby! The mosfets I'm using are $5.50 each, and the diodes are $4 each (unless you get them from this one place that is out of them for the next couple months. Theirs are $2.50 each I think).
144 watts of heat is quite a bit. Has anyone ever grabbed a 100 watt light bulb? Those things are hot!
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