Using 16v 5000 mAh battery with L293D motorshield

[ahsan_sami]

Hello.

I am using a 18650 Li-ion 3.7v/5000mAH 4 cell (total = 15.2V/5000mAH) battery pack to power up motors on my L293D motor shield. While this pack is connected to the shield, I remove the jumper and try to power up arduino separately with a 9V battery through DC power jack, but this battery doesn't provide enough current for the servo motor to work properly (I have tried to plug the servo into motor shield's servo terminals as well as to the analog pins but it doesn't work in either case). When I power up the arduino board using 5V/1A power bank (USB), the servo works fine. Please note that the jumper remains removed in all cases.

Now I was wondering if I place the jumper back in and use the same 15.2v/5000mAh battery pack to power Arduino as well. Will arduino's 5V regulator be able to handle this voltage and current? The max load on Arduino's 5V output will be one SG90 mini servo, which I think doesn't draw more than 1 amp?

I'll be grateful if someone could guide me on this. Thanks.

[groundFungus]

@ahsan_sami

Will arduino's 5V regulator be able to handle this voltage and current?

No. The on board 5V regulator is not heat sinked so will supply limited current before it overheats and shuts down. The amount of current depends on the voltage input to Vin or the power jack. The higher the voltage the less current can by supplied. I would use a buck converter to drop the 15V to 5V and connect that to the 5V on the Arduino, bypassing the, weak, 5V regulator. Then the rated current of the DC DC converter is available on the 5V line for the servo and other 5V peripherals.

The ancient technology L298 motor driver is a poor choice of driver for a battery powered device. That driver drops 2V to over 4V of the motor supply voltage and wastes that power as heat. Pololu (for one) has a good line of efficient modern motor drivers.