Hot voltage regulator Arduino mega 2560

Other Hardware General Electronics
1

Hello guys, Iam using arduino mega 2560 to make a robot that consists of :

  • 4x 6v gear dc motor
  • 2x L293D
  • 1x Bluetooth module (HC-06)
  • 1x LDR
  • 3x leds
  • 1x temperature sensor (LM35)
  • 2x small speakers
  • 1x micro sd card module
  • 1x 16*2 LCD + 1x potentiometer
  • (and in the future I will connect 3 micro servos)
    So, the problem is :
    When I power arduino with a USB cable it works fine. but when I connect it with 11v battery (3 ultrafire)
    the voltage regulator gets hot.
    Is it safe ?
    if not. any suggestions ?

Thanks.

2

Where's the 6V for the motors coming from?

3

Near the bottom of this page's content about powering the Arduino is a paragraph about the limits of the voltage regulator. You will see that, as the supply (battery) voltage goes up, the current available without heating the regulator goes down (see the table). The regulator can dissipate a limited amount of power (watts). The regulator is not used when on USB power so it won't heat.

4

Hardizzer:
So, the problem is :
When I power arduino with a USB cable it works fine. but when I connect it with 11v battery (3 ultrafire)
the voltage regulator gets hot.
Is it safe ?
if not. any suggestions ?

So what is the current coming out of the 11v battery, you forgot to say ?

5

kenwood120s:
Where's the 6V for the motors coming from?

I have a power supply for the motors (3 ultrafire batteries 11v) so I have 6 ultrafire batteries, 3 for the arduino and other stuff and 3 for the motors

srnet:
So what is the current coming out of the 11v battery, you forgot to say ?

Each ultrafire battery is 4800mAH, I have 3 for powering arduino so 3x4800=14,400mAh

groundFungus:
Near the bottom of this page's content about powering the Arduino is a paragraph about the limits of the voltage regulator. You will see that, as the supply (battery) voltage goes up, the current available without heating the regulator goes down (see the table). The regulator can dissipate a limited amount of power (watts). The regulator is not used when on USB power so it won't heat.

Thanks for the information, but what do I exactly do to prevent heating of the voltage regulator ?

6

what do I exactly do to prevent heating of the voltage regulator ?

2 choices. Draw less current from the regulator or lower the supply voltage. The lower the supply voltage the less power (V*I) that the regulator must dissipate. Your batteries are 3.7 volts apiece. If you use 2 in series (instead of 3) the supply voltage is lowered to 7.5V which is still above the low voltage of the regulator and the regulator can supply more current without overheating.

From the link in reply #1:

– 12 V Power Supply: I = 2 / (12-5) = 2 / 7 = 285mA
– 9V Power Supply: I = 2 / (9-5) = 2/4 = 500mA
– 7 V Power Supply: I = 2 / (7-5) = 2/2 = 1A

7

Thanks I will try using 2 batteries, but will 2 only enough to power all of these stuff ?

8

mAh isn't current, it's capacity.

And I still don't understand how the motors are wired and where they get 6V.

9

Hardizzer:
Each ultrafire battery is 4800mAH, I have 3 for powering arduino so 3x4800=14,400mAh

That is just wrong.

You do not have 14,400mAh available, you have only 4800mAH as the batteries are in series.

And 4800mAH only tells you how much current the batteries are able to supply over time.

What you need to know is what is the current actually flowing in the circuit and you do have to measure it. If your building a robot then using a multimeter to check how much current is flowing should be part of the basic testing.

10

kenwood120s:
mAh isn't current, it's capacity.

And I still don't understand how the motors are wired and where they get 6V.

Me neither.

If the OP wants help they need to provide us with the diagram they produced when desigining the circuit.

11

Sorry, i'am still a newbie in electronics, But I learned that current is measured by Amps.
Also isn't capacity is measured by uF ? :o

Idk. Anyways, I will make a diagram. 1 min.

12

Capacity = electric charge and is measured in coulombs, mAh and Ah. Battery capacity is simply
the charge it stores chemically.

Capacitance = charge per unit voltage in a capacitor and is measured in farads. Nothing to do with batteries.