Arduino Uno and SLA battery connection

Other Hardware General Electronics
1

Hi,

I need to power an Arduino Uno from a 12v 22ah SLA battery. The arduino will be connected to an IBT-2 43A H bridge which will drive a 12V DC motor.

Having done some research, I understand there are multiple ways to power the Arduino Uno. Would the following link be a safe way to do it?:

https://playground.arduino.cc/Learning/LeadAcidBatteryAdapter

Thanks

Michael

2

Hi, Yes that will work.. Be careful with how much current you draw from arduino 5V for other things. See:

https://arduino-info.wikispaces.com/QuickRef#pwr

3

Thanks Terry.

The only things connected to the Arduino Uno will be the IBT-2 43A (BTS7960) motor driver and possibly an IR optical sensor. Do you think this would be a problem?

The IBT-2 driver will be connected to the same battery, so I'm guessing that would not draw much from the Arduino Uno?

Thanks again,

Michael

4

The reason caution is recommended is that when the power source is 12V... the regulator runs hotter. Since it runs hotter... and there is no heatsink... you need to de-rate the documented values for current capacity on the regulator.

The 1.5A capacity of the regulator is only valid if it stays cool. When using 12V, that 1.5A capacity might be closer to 600mA before it overheats and shutsdown.

5

pwillard:
The 1.5A capacity of the regulator is only valid if it stays cool. When using 12V, that 1.5A capacity might be closer to 600mA before it overheats and shutsdown.

Current limit of the 5volt regulator of an Uno is ~800mA, with <=7volt on the DC socket.
The Uno itself uses ~50mA of that.
That drops to ~150mA (~100mA available) at 12volt.

OP's motor driver doesn't use that much.
Read the datasheet of the optical sensor, or post a link.
Leo..

6

Thanks for the replies. I can see the potential issues with this now.

Leo, the optical sensor is the slotted LM393 module, here

I've read that the other way to do this is to use a DC-DC buck converter. Is there an off the shelf module that I could use with the uno - if that's a better route to go down?

Thanks again,

Michael

7

That module use about 25mA.
Most of it is the IR LED (180ohm resistor = 20mA), and 3mA (1K) for the small LED.
Leo..