NiMH Battery Pack C Rating

Lynxmotion Legged Robots
1

Hi,

I am working on a Robotics Project which will be using 17 Servos. The Lynxmotion Site suggests for several of its Hexapod Kits to use the 6V NiMH 2800mAh Battery Pack found at the following Link:

lynxmotion.com/p-426-60-volt-ni-mh-2800mah-battery-pack.aspx

Towards the bottom of this Page, the Specifications mention that the Maximum Discharge Current for this Battery Pack is 28A (corresponding to the “C” Rating). Meanwhile, in the information Section at the very bottom of the page, it is mentioned that the Battery is provided with an 18 Gauge Wire. According to the theory, this size of wire should have the ability to deliver only 5 Amps (even though the Battery has the ability to discharge at a faster rate).

My question is the following. Is this Battery Pack sufficient (considering the gauge size of the wire) to deliver enough Amps (C Rating, or discharge Rate) to power 17 Standard Size Servos, considering that a single Servo could pull up to 2.5 Amps upon starting (most likely not all the servos will be active at the same time, but a certain amount could – perhaps 8 to 10)? It appears that it could since Lynxmotion is selling them with their Hexapod (which have 18 Servos), but the theory doesn’t appear to hold.

Thank you.

Joseph

2

There was a typo in the description - the maximum continuous discharge current is ~1C = 2.8A (not 28A).
The discharge current can spike to ~10C (28A) for a few milliseconds when needed (for example upon startup).
We have used the 6V 2800mAh battery extensively in 18DoF walking robots without issue (based on standard sized Hitec servos such as the 645MG).

3

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[font=Verdana, sans-serif][size=1]Thank you for your reply. I had one last question if I may. Do you include a Capacitor between each Servo and the Battery Pack in order to handle these spikes? In the affirmative, what type and of how many [/size]microfarads[size=1]?[/size][/font]
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[size=1][font=Verdana, sans-serif]Thank you again for your time.[/font][/size]
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[size=1][font=Verdana, sans-serif]Joseph[/font][/size]

4

Not a bad idea, but in the spirit of simplifying the setup, we do not include capacitors.

5

Thank you for your time!