I need to power 8x Analog-Servos R3630. I tried to power them with 4x AA 1.5V batteries to get a total voltage of 6V, but in the testrun with 3 servos attached one of them didn't work.
I figured that I have to supply a stable Voltage of 6V and up to 2000mA.
My plan is to connect a 12V Wattack switching adapter to a BEC to reduce the 12V to 6V. Now I plan to connect all 8 servos to the BEC.
Does that work?
Do I get the 2000mA for the best performance for the servos?
I hope you can help me out on this since I'm not very experienced in electronics and arduino.
You need to know the stall current for the servo, and that information is not listed on the page you linked.
However, the stall current is likely to be 1 Ampere or greater, and the power supply must be able to provide that for EACH servo that is moving at once.
If all eight servos will be moving, plan on a 5-6V power supply capable of 8 Amperes minimum.
Stall current 1.3A per servo. 8 servos 1.3A x 8 =10.4A. That power supply can on supply 2.5A. Neither a 5A BEC fed from a 2A supply or a 2.5A power supply will provide 10.4A.
This doesn't make sense. The stall current is measured with the shaft locked, so the load is effectively infinite. Please post a link to where you obtained that figure.
Something like a 6V SLA battery might be better.
Perhaps not, because the voltage of a freshly charged "6V" SLA battery (actually about 7V) can be higher than the absolute maximum servo voltage. Again, a specification is needed.
Thanks for posting the spec sheet. It does not state the stall current, but judging from the "no load" current of 1300 mA @ 6V, the stall current may be higher than 5 Amperes. No wonder it will not run on AA batteries.
If so you will need a 6V, 5A power supply to run just one servo, and possibly a 40A, 240 Watt power supply for all 8 running at once.
Do you really need such a powerful servo?
Consider using a different servo that matches your load requirements and has a complete specification sheet.
jremington:
Perhaps not, because the voltage of a freshly charged "6V" SLA battery (actually about 7V) can be higher than the absolute maximum servo voltage. Again, a specification is needed.
Then again in my experience a specification of 4.8V to 6V for hobby servos means a 4 or 5 cell NiCd/NiMH battery (4.8V/6V nominal). A 5-cell Nixx pack can also easily reach 7V+ when fully charged.
It's one of the differences between hobby level specs and "real" specs.
Can it be that the simpelest way to power them is with 4x AA each?
The simplest way to power the servos is to buy a well regulated power supply capable of providing the current required for all of them. Large numbers of such power supplies are available on line.
Do you seriously think it is practical to go around every day or two and replace 32 AA batteries?
DerSteiN:
The 5 cell Nixx pack might destroy the servos with 7 volt right? They are build to run at 6V max.
The servos are built to run on 6V nominal batteries...that includes 5-cell 6V NiMH packs and 6V SLAs. Many thousands of modellers run that type of servo on 5-cell NiXX packs with no problems. The manufacturers know very well that 6V nominal batteries will sometimes be over 6V.
Having said that, for your purposes a regulated mains power supply will probably work out best.
jremington:
Thanks for posting the spec sheet. It does not state the stall current, but judging from the "no load" current of 1300 mA @ 6V, the stall current may be higher than 5 Amperes. No wonder it will not run on AA batteries.
From the torque and speed ratings its a 2W mechanical output device, so 1.3A stall current is entirely
believable. Just poor datasheet (all too common for hobby stuff)
) this should do the job for all of the servos or am I missing something?
