Ok, I tried to use 4x AA batteries to drive three servos at the same time and it worked! The problem was low signal voltage I guess. The servo specs said they were for 4.8-6V, and the regulator gave steady 4.97V that I used to power all the servos. The funny thing is that I could run three Futaba S3003 servos @5V without problems.
QuoteOk, I tried to use 4x AA batteries to drive three servos at the same time and it worked! The problem was low signal voltage I guess. The servo specs said they were for 4.8-6V, and the regulator gave steady 4.97V that I used to power all the servos. The funny thing is that I could run three Futaba S3003 servos @5V without problems.It's not about the voltage directly, but rather the current demand that the servos are drawing. Servo companies do a poor job of listing the maximum current they require and each brand and model of servo will consume a different amount and of course the mechanical load placed on the servos will drastically increase their current consumption. If you try and draw too much current from a voltage regulator it's output voltage will sag or even shutoff. So yes most hobby servos will work just fine with a steady 4.8 to 6vdc DC voltage, however the source of that voltage must be able to handle the peak current requirements of all the servos it is trying to power. I usually recommend that the DC power source be able to handle at least 1 amp per servo attached if you want to avoid voltage dips, board resets and other annoying problems that servos can bring to the party. Lefty
If you go with a R/C hobby BEC add a small 5 volt fan on that heatsink, they are designed to to have fairly constant airflow over the heatsink, think heli's and airplanes fast moving cars.Lastly if you plan on using a dedicated servo controller later make sure the output wires will handle your maximum amperage. If not you will have to change them out. I use a Castle Creations 20 amp for my bot, and it is nice and easy to switch wires, I am not sure why they don't come with 20 amp capable to start with.
You can get inexpensive UBEC voltage converters on ebay. You can add a small diode on the ground leg of the 7805 chip like below to increase the output voltage to 5.7v for better servo performance.