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Old July 5th, 2012, 12:49   #9
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Join Date: Feb 2007
Because a NiMH doesn't provide all the amperage your motor needs, there's a few factors that contribute to ROF

So another cool metaphor goes like this;
The battery is your gas tank. The Mah rating is the gallon size of the tank, the amperage is the energy potential of the fuel, and the voltage is how fast that fuel gets to the motor.

Now here's where it gets tricky, as you increase the physical size of an NiMH or NiCd cell, the surface area for chemical reaction increases, that by some magic formula that increases the amount of amperage the cell is able to produce.

more voltage = higher ROF
larger cell size = higher ROF

more voltage = higher ROF
larger cell size = doesn't matter
higher C rating = reduces internal resistance of the pack, gives you a bit higher ROF
If your motor only draws 8A, then supplying 200A won't make it go any faster than supplying 16A
But your constant draw from your motor has to be less than what your pack can provide, otherwise you can damage the LiPo.

For a benchmark, an 8.4v large (sub-C cell) battery will give you about the same ROF as a 9.6v mini (2/3A cell)
And due to it's ability to supply all the amperage you need, a 7.4v LiPo battery CAN provide the same ROF as a 9.6v mini.
The 9.6v will often provide higher ROF when directly compared, but the 7.4v provides more torque allowing you to run a higher ratio gear set.

I bet you thought batteries weren't so complicated eh? lol
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