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I just made a 7.2V 6-cell NiMH battery back with a 2300mAh rating. Will it be enough to power this motor of an RC car? (I will link the datasheet). At maximum efficency it draws 13A at a nominal 7.2V. How will the battery pack be able to deliver this current when it's current rating is well below that? I have tried reading various articles and reading through motor datasheets, but I cannot understand how it works. Here is the link

I would greatly appreciate it if anyone could help me understand this

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    \$\begingroup\$ If you are using AA cells, I'm sure you won't get anything near 13 Amps, and wil probably have a hard time reaching the no-load currrent of 2.4 Amps. \$\endgroup\$ – Peter Bennett Sep 17 '15 at 22:53
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    \$\begingroup\$ the current draw of the motor totally depends on the torque required, which would be related to various things like the weight of the RC car, gearbox used, speed etc, so 13A may or may not not be the peak current draw, Also for RC cars i would suggest you use high discharge LiPo batteries specifically designed to be used for RC cars. they should be able to handle the higher peak current demand pretty easily. \$\endgroup\$ – user7994 Sep 17 '15 at 23:51
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2300mAh is not a current limit - it tells you how long the battery will last a a particular current flow. 2300mAH mans that it could supply 2300mA for one hour, 1 Amp for 2.3 hours etc. At high rates of discharge this proportionality falls down.

Typically RC model cars that use the type of motor you describe will use subC cells that can provide many 10's of Amps.

As Peter says if your batteries are just AA cell they will be more limited.

This is a data sheet for 2300mA AA cells (datasheet).

Each cell has 40 mohm internal resistance when 50% discharged so at 13A current the voltage will drop by about 0.5V down to about 0.7V, or only 2.8V for the entire battery.

I think that although the car will move but the performance will be very limited - you need a bigger battery such as 7.2V RC battery pack.

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Here is a data sheet for an Energizer 2300 mAhr NiMH battery.

At 13 amps it will not work. A 1C rating is the capacity divided by 1 hour, in this case 2.3 amps. 13 amps is 13/2.3, or 5.6 C, which is way beyond what the battery is intended for. Purely as a SWAG (Scientific Wild-Ass Guess), your battery pack will put out about 4 to 5 volts for about 5 minutes at 13 amps. It will also get extremely hot, and there's a decent chance you'll damage one of the cells if you run it to full discharge.

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If you are using AA type cells, I doubt you'll be able to get 2.4A from your series-connected battery pack.

If you want to use that type/size battery, I suggest you build an 8p6s battery pack as follows:

1. Make 6 battery banks (i.e. connect 8 cells in parallel (i.e. all + on one bus metal wire/strip & all - on another bus metal wire/strip). <-- make 6 of those banks (48 cells required).

2. Connect each battery bank in series (i.e. connect the + of bank 1 to the - of bank 2, connect the + of bank 2 to the - of bank 3... etc until you have all of the banks wired in series. The first - (bank 1) and the last + (bank 6) are the metal wires/strips that you will connect to your motor (i.e. in the simplest connectivity arrangement for testing purposes).

When fully charged, that battery pack should power your motor for ~1 hour at the motor's maximum efficiency and deplete the battery to ~50% of full charge.

If you want the motor to operate less time, then remove an equal number of cells from each bank (e.g. 1 cell from 6 banks or 4 cells from each bank). If you want your motor to run longer, add an equal number of cells to each bank.

Have Fun!

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