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Old 11-06-2020, 12:44 AM   #379 (permalink)
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spyder2 - '00 Toyota MR2 Spyder
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I just got my hall effect ammeter in the mail today, so I went to the old Honda Pilot (3.5L V6) and tried it out. Temperature was probably around 60F, so a fairly easy start. Obviously, cranking is pretty quick and I only have a crappy multimeter so I may have missed the peak of the voltage spike, but the highest number I saw was 233A, the next number that flashed was something like 178, and then maybe like 90?. Maybe we can call it...300 peak?

The little 100F capacitors have a series resistance of 12mohm, so at 300A we're looking at a 3.6V drop (yikes!). Actually, if you're starting at 11V, that lands you at 7.4V, which is still above the "cold cranking" procedure minimum. We have around 5-6 coloumbs of charge before we're down to 9V, which isn't much.

Multiply the capacity by 5 however, and we're in business. The 500F caps would be able to push out 300A without breaking a sweat, and we would have several hundred usable joules for cranking.
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