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I just got off the phone with a salesman from Vista Metals. He is sending me enough annealed Manganin sheet to make 3 or 4 1000 A shunts. What size bolts are you using on the main current connections on the controller? I will drill the outer holes to match that, and the cable will bolt up with the same hardware, to either the battery or the motor side.
I didn't get a price on more of the sheet, and it is an unusual alloy to find in this big a pieces. The temperature coefficient is specified at 15 ppm/deg C, either way.
I'll try to locate the voltage taps for 110 mV at 1000 A, so that a small divider can readily bring the output to 100 mV, once someone turns up a standard to calibrate it against.
BTW, at one point there was an issue with noisy current signal from the Hall sensor. A gain of 50 differential amplifier looking at this shunt should be much quieter.
I'll try for 110, but will accept 50 to 200 mv for 1000 A. This will be large current in a thin sheet, monitored at two points. An analytical solution is certainly possible, but would involve resurrecting too much mathematics I thought I understood in 1962.
If necessary, I can silver solder the taps, but I think that 1/4 - 20 brass bolts with crimp lugs should do fine. We'll see when the mail comes.
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