to add more info to my situation. I am trying to use a 20kg servo. When I plug in a 9kg servo everything works as it should. The 20kg servo have a working voltage range of 4.8v-6.8v. Again, everything works with a micro servo.
I ran a sweep and the servo works
I looks like I can't just use the servo.write() function. that only works with small servos. I had to use a math function and use the PWM and step the servo down.
then maybe definitely I should try using a RC car battery to power the servo.
I am currently using 4 AA batteries to provide 6v. I have a 7.2v RC battery that I cant try with a servo I have that can take up to 7.4v.
this is the specs of the servo I got:Item: DS3218 20KG Large Torque Digital ServoStall Torque (5V): 19 kg/cm (263.8oz/in) Stall Torque (6.8V): 21.5 kg/cm (298.5 oz/in) Speed : 0.16 sec/60°(5V) / 0.14 sec/60°(6.8V) Operating Voltage: 4.8 ~ 6.8 DC Volts Dead brand: 3μs Weight: 60 g (2.12 oz) Motor Type: DC MotorGear Type: Copper & Aluminum Working frequence: 1520μs / 333hz Size: 40 x 20 x 40.5 mm ( 1.58 x 0.79 x 1.60 in) Features: - High performance digital standard servo High-precision metal gears with hard anodizing CNC aluminium middle Shell Dual ball bearings Package Included: 1 x DS3218 20KG Large Torque Digital Servo1 x 25T Adjustable metal servo armIf you think its still a power problem then maybe I should try using a RC car battery to power the servo. I mean that is what the servo is really meant to be used for.
The standard arduino servo library produces a 50Hz signal with a pulse width varying between 1 and 2ms.