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Author Topic: battery pack cannot power two continuous turn servos?  (Read 419 times)
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Hi,

I am trying to power two continuous turn servos with a 9 volt battery pack. When plugged in the servos 'click' every second or so and do not rotate. When plugged into a computer or outlet, they work just fine. I have asked a friend of mine and he had the same issue with his setup, but did not have an answer. The setup is an arduino uno that runs wires to a bread board, that holds the two servos and two IR sensors. Any ideas?
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Hi,

I am trying to power two continuous turn servos with a 9 volt battery pack. When plugged in the servos 'click' every second or so and do not rotate. When plugged into a computer or outlet, they work just fine. I have asked a friend of mine and he had the same issue with his setup, but did not have an answer. The setup is an arduino uno that runs wires to a bread board, that holds the two servos and two IR sensors. Any ideas?

What kind of 9v battery? I you mean those small rectangle one then I would be suprized if it could handle even one servo as such batteries have very low current capacity. You say you are powering the servos with a 9volt pack, is that directly? Almost all R/C servos have a operating voltage rating of 4.5 to 6.0 volts DC, above that could damage the servo.

Lefty
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I am trying to power two continuous turn servos with a 9 volt battery pack.

I can see two possible problems:

1) Most hobby servos want 6V. You may be hitting some overvoltage protection.

2) If that's a typical 9V battery, you'll only get 100-200 mA out of it. Each servo will want to draw up to an Ampere if it's stalled/blocked. Thus, you'll lack the power needed.

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I can tell you that R/C servos will NOT work at all on 9 volts.  As the others said, a single rectangular 9v battery wouldn't have the current capacity to run them if they WOULD work, but they will NEVER work on 9v.  If you actually have a battery pack adding up to 9v, remove 2 cells and you'll be fine.  The servos would probably work ok on 7.2 volts (6 NiCads, e.g.), but might be twitchy.  There are also digital servos available that work fine on 7.4 (2s LiPo), but they cost a LOT more.
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