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4AA=6vexcept rechargable AA are 1.2v each=4.8v (will still work)
Quote from: ed1380 on January 09, 2008, 06:52:34 AM4AA=6vexcept rechargable AA are 1.2v each=4.8v (will still work)4.8V is not enough to power both motors and servos. Both will work if they are powered separatelly win 4.8V. But if they are powered by a single pack of 4.8V there will be problems. When the motors switch directions, a power drop will occur and the microcontroller will reset. To avoid that, big capacitors (over 1000uF) have to be installed in parallel with the battery pack. But the voltage will drop quickly and will not be enough for the electronics to work properly. So this setup has to be avoided.Use at least one five cell NiMH battery (6V) pack to power your robots!
7.2V will kill most servos too
Regulating Voltage to a ServoAs you should already know, servos have a voltage rating. Go above that voltage and your servo overheats and possibly fries. So suppose you have a 7.2V battery and you want to use a 5V regulator to power your servos, is that a good idea?Short answer: No!Longer answer . . . it will work, but its a huge waste of battery power.So lets say you have your 7.2V regulated to 5V and the servos draw a total of 1.5A of current.Wasted power is:(7.2V-5V)*1.5A = 3.3WPercentage wise, its(7.2V-5V)/7.2V = 30.6%Thats the battery energy percentage wasted to thermal heat - almost 1/3rd!!!Speaking of heat, your voltage regulator probably has thermal shutdown, meaning that if it overheats it will throttle down current to your servos - meaning your servos will have lower torque and lower speed. If your voltage regulator doesn't have thermal shutdown, it will just fry instead (not a good thing).But if you still really really need to regulate for servos, get a switching regulator (like ~83% efficiency on average).
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