[quote=“guntherv”][quote=“ncbob”]Just some info that I’ve gathered tonight after pulling the servotor board out of the hexy and installing 18 of my own personal servos to the board and doing some testing.
- Activating the more complex movements like walking forward/backward, rotating, belly flop, get up, dancing all never got higher than 1.9 amps peak, and generally was around 1.4 amps.
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I haven’t looked at the software yet on how the servo’s are started, but servo’s like that easily pull like 600 or 700 mA when stalled, which also means they will pull something like that if they start to move when there is “load” (=mounted in the robot).
so if you would for example make a move that starts 10 servo’s at once you will pull a (very short) spike of 7amp
You might not see this spike on a multimeter, most are rather slow.
this of course does not mean you need a 7amp power supply, but the power supply you use will need some beefy capacitors to handle this gracefully or the voltage will drop during a very short time. Cheap power supply’s often lack beefy capacitors .
If you use a 5V power supply for both the servo’s and the logic and on complex moves you have erratic behavior it might be an idea to simply add a beefy capacitor ( 10000uF 10v or so) to the servo power rail directly.
They cost almost nothing.[/quote]
This was tested the same way as when the servos were jerking and most of them didn’t move. The firmware was the only difference.
While a stalled servo would pull that much, to have all of them stall at the same time is very unlikely.
I’m not using something as crude as a multimeter to monitor/record the current and spikes.
The supply I use with the Lipo pack is more than capable of handling the current, it. Has a constant rating of 5A and a surge of 7a for 15 seconds. It works quite well powering my blade sr helicopter. Also once I switched the new firmware and my own servos I was able to use just about any power and all the servos worked. When I went back to the older firmware it started displaying the non-functioning behavior even if I just tried the ‘wave’ motion. In all the tests I did the only time I saw a difference was with the old firmware and the Lipo pack. It would shake and vibrate and more of the servos would work but it still wasn’t functional. When I used any other power source they just wouldn’t work, and it would just twitch when powered up.