12 volt 20 amp power supply for Arduino

[mikadoz325]

Greetings, hope all is well. I have a question, I want to power my 6 mg90s servos with a 12 volt 20 amp battery charger power supply, will my board and servos blow up when connected externally with DC barrel jack and breadboard?

I used a 12 volt 500mA power supply but it could only power ONE servo. When connected to two servos, nothing happens.

What should one do?

Thank you

[slipstick]

Those servos will not take 12V directly. And if you try to power them from the Arduino 5V pin that will not work...it can't deliver enough current and you will probably kill the regulator if you try it.

Also 12V battery chargers are not usually regulated supplies so that could easily kill the Arduino.

Steve

[mikadoz325]

Thank you very much for the information. At least I will not try my board. I decided to get a 5v 2A power supply and it is powering 3 servos. The others blew from the 12 volt experiment.  Any idea on how to fix a servo? Is the speed of the servo dependent on the Arduino code?

Thanks

[slipstick]

12V will have destroyed the internal electronics and possibly the motor. Probably not worth trying to fix. I don't think you can buy spares.

Arduino code can slow servo speed using the Sweep example technique or VarSpeedServo.h instead of the normal Servo.h. But if you just do a plain write(angle) it will go as fast as it can.

Steve

[gilshultz]

Just a quick note, most battery chargers for home use run off the mains. Typically they have a transformer rectifiers and some basic control stuff. They need to put out at least 14V to charge a 12V battery, most put out a lot more. There is no filter cap so you get a pulsating DC, probably 2X your line frequency. Spend a few bucks and buy or build a lab power supply.  Get the Arduino cookbook and read it. Also on line there are many videos etc showing the Arduino and how to do what you want. This additional information will go a long way in getting your problem solved. Once you get past this you then need to select your sensors and actuators.  At that point you start on the hardware design and write your software.

[MarkT]

If you need a 6V 6A supply, a 12V 20A supply is not ideal is it?

You can use the rediculously cheap LM2596 buck-converter boards to bring 12V down to lower voltages
efficiently, they are rated at 2 to 3A IIRC.  As they are adjustable output voltage they are good to have
a few of for future projects

[gilshultz]

If you elect to use the buck converter with the battery charger you will need to add a capacitor maybe a few thousand uf so the buck converter can get a reasonable DC supply. Another option is to connect it to a battery, they make great filters.