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Old 04-21-2010, 06:48 PM   #3351 (permalink)
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Originally Posted by bones007 View Post
I have a question about pre-charging the controller. Is there any reason why we shouldn't just put a resistor in parallel with the main contactor and just leave it there. If we do so then the controller caps will always be charged up and there is no need to wait some time before closing the contactor.
Aside from the other reasons mentioned above, I think an important reason is to protect the controller during charging. My 144V pack will reach 183V during equalization. While everything in the controller is rated for 200V, there's no need to expose it to high voltage. A capacitor's voltage rating can decrease with age. A malfunctioning charger can push the voltage past your set point. If your charger isn't isolated, voltage spikes from the AC line can fry your controller components too.

so, overall it's a cheap way to avoid some failure modes while making things a little safer.

ReVolt AZ testing thread:
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