How to Feed a hexapod

I’m starting to mount a hexapod with a Arduino Mega and with 18 servos (Futaba S3003) and I need to feed. The arduino it will connect to a 9V battery and doubt is to connect the servos.

Some kits hexapods that I found on the Internet use 6v batteries and between 2300 and 2700 mah.

According to Futaba, the servo current drain depends on the load but under normal servo operation a servo will draw between 1 and 2 amps when activated. At idle it will draw about 15 milliamps.

The question is how to feed the servos:

  • A 6V NiMH battery 2300 mah
  • Two batteries of 6v 2300 mah NiMH in parallel
  • A 7.2v lipo battery but not which could choose

I have recommended the best option was the lipo battery (although I have not specified which) but I would like to know your opinion, especially someone who has some hexapod.

Sorry for my English.

carynx: I'm starting to mount a hexapod with a Arduino Mega and with 18 servos (Futaba S3003) and I need to feed. The arduino it will connect to a 9V battery and doubt is to connect the servos.

Some kits hexapods that I found on the Internet use 6v batteries and between 2300 and 2700 mah.

According to Futaba, the servo current drain depends on the load but under normal servo operation a servo will draw between 1 and 2 amps when activated. At idle it will draw about 15 milliamps.

The question is how to feed the servos:

  • A 6V NiMH battery 2300 mah
  • Two batteries of 6v 2300 mah NiMH in parallel
  • A 7.2v lipo battery but not which could choose

I have recommended the best option was the lipo battery (although I have not specified which) but I would like to know your opinion, especially someone who has some hexapod.

Sorry for my English.

I don't own a hexapod, but I think that if your chassis and the servos can handle the strain (if your servos are these, though - http://www.servocity.com/html/s3003_servo_standard.html - it has plastic bearings, which is -not- ideal for a walking robot, IMHO), then the dual-6V 2300 mAh NiMH batteries would probably be best; you'll probably get sufficient run time from them (4.6 Ah), even under load. With the lipo, you'd have to worry about the regulation of the battery voltage down to what is "safe" for the servos (6 volts), plus the charging system; on the plus side, such a battery would likely be of a lighter weight (but whether you could get one with a large amp-hour rating, I don't know offhand - probably, though).

As far as what I mean about plastic bearings not being ideal - you have to realize that these servos are going to be under a heavy side-force strain on the output shaft. That is going to put a heavy load on the bearing, as well as the output gear. This servo is not designed for this, having plastic gears and plastic bearings. It will likely be OK for initial building and testing, but I would seriously look into getting servos with metal output gearing and dual-ended metal ball-bearings on the output shaft for the long haul - something like this one:

http://www.servocity.com/html/s3305_std__metal_gear_bb.html

:)

At first I thought of servos with metal gears but they are rather more expensive than servos with nylon gears and had to use 18 servos, the total cost was too high.

You hope that the hexapod has no more than 2 kg and as yet I have not bought all the servos, opt to change 6 of them TowerPro SG5010 with much more force.

From there I turned out much better for lighter weight lipo but I hope someone else can advise me.

cr0sh, I could recommend some lipo battery?