I am kinda newbie in electronics, so I searched a lot about which batteries should suit for this kind of setup. I came up to the conclusion that NiMPH or LIPO batteries were great for this.
One servo support until 6v, so I know that I shouldn't use batteries that has more than 6v as output (exept if using voltage regulator).
Some guys posted projects with 6v 2800mah NiMPH batteries, so I know that this should be correct for this project, however I can't find it here in Japan and take so much money to import them so I am searching for other suitable batteries (In contrary, I can get cheap 7.2V 4000mAh Ni-MH, but I would need a voltage regulator, right ?)
So here are my questions :
VOLTAGE: As one servo support from 4.2v to 6v, can I use any battery that outputs voltage in this range ?
CURRENT: How could I know how much current I need for 16 servo ?
For example : why a 6v 1600mAH will not be enough ? Will a battery of 5v 4000mah enough ?
The weird one: I was wondering if it was possible to use smartphone portable batteries, which are usually 4000mah DC5V/1.5A (MAX) Li-ion batteries. They are cheap, light, compact and are delivered with a charger. I am dreaming when I think I could use them as servo power supply ?
Sorry about my poor english, I hope this is understandable
clemaister:
Some guys posted projects with 6v 2800mah NiMPH batteries, so I know that this should be correct for this project, however I can't find it here in Japan and take so much money to import them so I am searching for other suitable batteries (In contrary, I can get cheap 7.2V 4000mAh Ni-MH, but I would need a voltage regulator, right ?)
Yes, a buck voltage regulator would work best. I use this one to power servos for my large scale RC Arduino airplane.
clemaister:
VOLTAGE: As one servo support from 4.2v to 6v, can I use any battery that outputs voltage in this range ?
Yes, but be aware that more voltage means more torque and more speed - so 4.2V is probably too low.
clemaister:
CURRENT: How could I know how much current I need for 16 servo ?
About 16-24A to be safe.
clemaister:
For example : why a 6v 1600mAH will not be enough ? Will a battery of 5v 4000mah enough ?
Either will work, but the 4000mAh will last you longer.
clemaister:
The weird one: I was wondering if it was possible to use smartphone portable batteries, which are usually 4000mah DC5V/1.5A (MAX) Li-ion batteries. They are cheap, light, compact and are delivered with a charger. I am dreaming when I think I could use them as servo power supply ?
Yes, you're dreaming. Servos draw anywhere between 1A to 1.5A when under full load, so multiply that by 16 and that is your total current draw. Worst case scenario, your cell phone battery will explode.
If you don't overload your servos and only move a few at a time, the max current drawn could be a fair bit
lower. If they are all active at once with significant load you'll need all that current. And you'll have to
worry about cooking the servos (they are not designed to operate at their max torque continuously and
simply overheat if you try). Metal-bodied servos are recommended for that sort of duty as they can
dissipate a lot more heat.
I was thinking of using a power supply harvested from an old HP desktop computer .it has multiple outputs like 12 V/5 amp, also 3.3V/2 amp, but another output I may use which reads 5 volt/12 amp...would it work when I have too many servos ??it is a switching mode as we all know..?did anyone try it ?
The original post talked about SG90s which have a rated stall current of 650mA so 1A per servo is a bit over the top for those particular servos. A 5V 12A PSU should work for quite a few SG90s but maybe not for bigger, more powerful servos.
And of course if you really have "too many servos" then it obviously won't work. That's what "too many" means.
Gee thanks , so I will go full speed as my experiment involves 6 servos, 3X SG90 and 3X MG995 ...optimistic that the desktop computer power supply 5V/12 amp will suffice.
