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What is a suitable portable power supply for 5 servos? Answered

For a project 5 servos are needed. Currently I am thinking of using a 9V battery to power them, but several articles say that the 9V would not be sufficient or it would destroy the servo.
Some articles claim that using a voltage regulator would work, others say to use a higher power battery preferably a LiPo battery.
The servos used are 5 Micro Servo SG90 servos.

So if a 9V could be used what is the appropriate method?
If instead of using a 9V battery a LiPo should be used what should the power of the battery be?

12 Replies

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ephtermulo (author)2016-07-28

It will depend upon the power rating of your servo motors? as well as the load that it will drive. Better design a relay driver that will operate your servo motors to have equal distribution of power supply. Consider also the amperes, the lower the ampere, the weaker it drives the rotation.

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iceng (author)ephtermulo2016-07-28

Thanks for the detailed explanation and schematic using a ULN2003 to drive individual relays for each servo.

Both my question and your answer seem to have disappeared from this topic.

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ephtermulo (author)iceng2016-07-28

I don't know why it disappeared. I'm glad I could help :)

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ephtermulo (author)2016-07-28

In terms of building circuits and controlling motors like servo motors, the key is to provide equal distribution of power supply (according to its voltage and ampere requirement, you must not exceed or lesser) and that is the use of relay drivers. (I hope you consider also the load before you buy servo motors.) ULN2003 is one example of relay driver, and you could also operate it using microcontroller.

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iceng (author)2016-07-24

A Furby uses fewer motors...

What are you making that needs so many ?

BTW a 9 Volt battery is extremely low energy

( hardly warms a pocket with change ) ... yes, unthinkingly I dropped one in my pocket and surprise it shorted touching some coins.

Definitely not meant to power a gaggle of servos as Quadrifogilo has pointed out.

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Itec (author)iceng2016-07-24

A Robotic Hand for a project.

I am considering buying a Lipo battery but would a 7.4V battery be sufficient?

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iceng (author)Itec2016-07-24

You do understand the servos are made to use 5V ...

Running on 7.4V will shorten the life of the servos.

I would use a switching down regulator to power the servos and never use the hand as Wolowitz did in the Big Bang Theory :-)

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Itec (author)iceng2016-07-24

For that will have to use a 5V regulator so that prob is fixed. Or else boom....

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Quadrifoglio (author)2016-07-23

If you aren’t using a 6V battery, you are going to have to use a voltage regulator to get 5 to 6 volts. The spec for Operating Voltage for the Tower Pro Micro servo 9g SG90 is 3.0-7.2 volts with a nominal of 4.8 volts. Higher voltage (9V) will likely cause the servo to fail.

Google tower pro sg90 battery power supply and pick what best suits your needs https://www.google.com/search?q=servo+sg90+micro+servo+9g&oq=Micro+Servo+SG90+servo&aqs=chrome.1.69i57j0.1307j0j4&sourceid=chrome&ie=UTF-8#q=tower+pro+sg90+battery+power+supply. Solutions range from 4 AA to Venom 3000mah 6 volt battery to stepping down 12V..

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Itec (author)Quadrifoglio2016-07-24

Thank you. Currently considering buying a LiPo battery

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Quadrifoglio (author)Itec2016-07-24

Consider using a 5V / 3-5A transformer (aka wall wart) during breadboarding and move to the battery when you have the rest of it figured out.

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