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Old 12-05-2014, 09:10 PM   #6959 (permalink)
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Originally Posted by Astro View Post
At low speeds 4 strings of 130v and high current then at some speed flick a switch and have contactors in the pack that change it to 2 strings of 230v. Sort of like a 2 speed gearbox. It would give you the high current at low speeds and high voltage at high speeds.
My warp 9 and warp 11 are rated for 160V, maybe 170V. I read somewhere .. perhaps over at EVTV? .. that you start to damage the brushes above 170V. I don't remember if it's just the brushes that wear or if the commutator starts to pit as well. I can't locate it right now but I remember that I don't want to experience it.

As for changing battery pack configurations while moving, it sounds risky to me. Contactors take a certain time to open and a different time to close. All things fail eventually. If one set of contacts fails to move at the correct time, the failure will be catastrophic, in my opinion.

In my experience, a battery pack at 50V and 100A will deliver about the same V*A at whatever voltage you select. So at 50V you get 100A, at 25V you get 200A, at 15V my Curtis controller will limit to 300A, so I get max current and max torque up to maybe 17V.

I think that 3 strings of the max voltage the motor can safely handle may give the most current without damaging the motor.
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