Hi
I´m building a voltage regulator for a hexapod 3dof, because I want to use a 12V 2500mAh pack which I already have.
The question is the dimensioning of the 6V Servo output, in my opinion 3A should be enough!?!?!?
I think you all have more experience with power consumption than me.
thanks a lot for your informations
You need to be able to supply 7 amps for an 18 servo hexapod. You will need to build or buy a high current, high effeciency regulator. The regulator will need to dissipate 6vdc at 7 amps, or 42 watts… I don’t think it’s worth it just to reuse a battery you already have. Not to mention the robot needs to work harder to carry the much larger battery. My advise to you is to ditch the 12vdc battery.
7 Amps? Uff …
thats much more as I thought…
what do you think, can I use the battery pack when I rewire it to 6V 5000 mAh ? Or is 6V to low?
A 6V battery isn’t exactly 6V, and it certainly doesn’t stay that way. The battery will have varying voltage across the discharge cycle. Google for the battery chemistry and “discharge curve”.
I too had been very concerned about power regulation with my bot and succeeded with a large and expensive solution. In the end, I think it was all in vain and have become an unregulated convert.
If you we’re trying to build an assembly robot, then yes, you’d need very good power regulation to get timely, repeatability. The complications of dealing with battery discharge are good and interesting problems to try to deal with in software. The servos won’t just stop working when your battery hits 5.9V, they just move a little slower and have a little less torque.
Another argument for using the 7.2V NiMH packs is ease of charging. There are tons of readily available circuits for charging these things and no danger relative to some of the newer batteries like LiPo.
Almost everyone here runs straight off these 7.2V packs. Be aware though that when they come off the charger they are even higher than 7.2V. The servos (except for the high end digital ones) are rated only for 6V and are officially out of spec even at the nominal voltage of a 7.2V pack. Anecdotal evidence from this forum suggests it’s not a problem, but if you’re a stickler about such things, it’s out of spec.
Maybe true, but I only use 7.2 direct for 422 and rarely 475. I usually use 6.0vdc for 475 and always for 645, micro and digital servos. 
Yes I know this fact already
The question was more in the way if you may prefer a 7,2V one…
And now i know you do 
I already have a lot of charger because my other hobby are model aircrafts, and for those I always use 4,8v packs for the Servos.
by the way, I will use Graupner C577 Servos, because I still have some of them from a few spar aircrafts …
To come to an end,
you say I should use a 7,2 V pack. So I will do … I don´t use my RC car that often anymore 
Robot-Explorer: Trust Jim’s advice over mine on which packs to use and drop the regulation plan.
Yes that´s what I will do…
Thanks for your help …
