so i been working with some servos on an RC project i'm working on. and here is the thing most servos have 2 modes
Speed @ 4.8v: 0.21 sec @ 60 deg.
Speed @ 6v: 0.16 sec @ 60 deg.
Torque @ 4.8v: 3.3 kg.cm
Torque @ 6v: 4.1 kg.cm
(also seem some high speed servos that only work at 6V)
i would like to get them working on 6V using an separate battery for the servos, so i'm thinking in building a power distribution board for the servos, so i have a 2 cell 7.4v battery my first thought was to use a 7806 Voltage regulator but what will happen when the battery drops bellow 6v? i been thinking that maybe using a charging pump but most of them seem to be for 5/5.5V like the LTC1751, MCP1253, TPS61200.
so maybe i'm approaching this the wrong way, can anyone give me pointers to get in the right direction?
i may have to add i'm relatively new to electronics (learning my way trough it now)
Just keep in mind that each servo should have at least one amp of current available for it, so design your regulator(s) to support the max number of servos you wish to power at any given time.
Most RC hobbiest use a UBEC like below to act as a power regulator. They are more efficient than linear regulators and have a 6v setting for supplying servos.
I'm using a 3S Lipo for mine instead of 2S. I had an extra one from my Parkzone P-51...
Like you, I didn't just want to plug in a BEC- I wanted to make one to learn. I found a simple design that seems to be working well. I have two 7806CT voltage regulators running in parallel. On each side of the regulator I have a 10uf cap to ground. Then the outputs go through a diode and then join before going to the servos. I'm sure my lingo is incorrect.
I found the schematic online and copied it. The schematic ads two leds so you can tell if one isn't working becaues of overheating, but I didn't bother with that. You don't get exactly 6V, but pretty close.
c131frdave:
Oh, and I only used two regulators instead of 3 because each are rated at 1 amp, and I am only driving 2 servos.
Yes, it looks to be an effective circuit. But keep in mind that when a project is portable and battery based, duration of the batteries is an important and perhaps expensive goal and the use of older linear voltage regulators is costing extra money in either less duration or requiring a larger mAH rated battery pack then one might otherwise require. Switching regulators should certainly be the first preferred method considered in this day and age.
Yes, it looks to be an effective circuit. But keep in mind that when a project is portable and battery based, duration of the batteries is an important and perhaps expensive goal and the use of older linear voltage regulators is costing extra money in either less duration or requiring a larger mAH rated battery pack then one might otherwise require. Switching regulators should certainly be the first preferred method considered in this day and age.