Thread: Discussion Comp ARF "Spark"
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Old Jul 26, 2009, 01:11 PM
JimDrew is online now
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Xtreme Power Systems
Lake Havasu, AZ
Joined Jun 2005
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Typically, you only use a few hundred milliamps during a flight. Capacity and current capability are two different things and this is where people get confused. There are those that figure if they are using a really big pack that there will be sufficient power - that is not always correct. There are also those that believe sine they are only using a few hundred milliamps of current per flight that the current draw can't be very high - that is usually incorrect.

Even though you may only use a few hundred milliamps during a flight, you could still be seeing 10A surges, but for just milliseconds. With non-computer based receivers, this was not a big deal as this resulted only in a worst case of a "glitch", but usually went un-noticed. With computer based systems, a current draw exceeding what the cells can delivery results in a voltage drop. When this drop is tool much, the receiver will reboot. During this time, there is no control. When the receiver comes back online it may be told to continue to do the last thing that caused the reboot and it happens again.

We use A123 cells in all of our aircraft. My Spark is getting two 1100mAh, one to each end of the receiver's servo "bus". No switches too, as they are the number 2 source of power system failures (with batteries being number 1).
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