I'me creating a robot. I have a Tamiya Dual Motor GearBox (Dual Motor GearBox - ROB-00319 - SparkFun Electronics). I have a H-Bridge http://www.sparkfun.com/products/315 and a Arduino Uno.
I think this topic is not the first time but i want to power them with a battery. I have a 9 volt 170mAh Recharge accu and 4 x 1.2v 2300mAh AA battery.
I connect the 9 volt battery to the Arduino and the 4 x 1.2v 2300mAh to the pin on the H-Bridge to power the Motors. After 30 sec the motor slow down and the arduino uno will going off.
I have no experience with power consumption what so ever. So i think i made a hugh mistake by the choise of my battery.
Can anybody help me with this problem.
Please post your schematic and code; also - what happens if you try to run the Arduino off USB or an external power supply? The 9V battery may be the issue (though why the motors would slow down, without seeing your schematic, has me puzzled).
The motors in the Tamiya Dual Motor GearBox are an odd bunch. They are low voltage (3V) and relatively high current (over 2A stall current). So you have a couple problems here.
These motors won’t live long running over 3V, and you are driving them at 4.8V.
The SN754410 is only rated for 1A current, and your motors are drawing over twice that. (They also only operate down to a minimum of 4.5V, so just aren’t suited to work with the Tamiya motors at all)
You have a couple options to remedy these problems.
There is a pololu motor driver that was designed to work with the Tamiya motors, able to operate at 3V and handle the high currents.
There are replacement motors that will work with the Tamiya gearbox that operate at higher voltages and lower currents.
This motor will work fine with the SN754410 H-Bridge
9 volt 170mAh
That is a very small capacity and is the root of your run time problem. You could wire the positive 4.8vdc from your 4 series connected AA cells (I assume that's how you are using the cells, in series) to the Arduino +5vdc shield pin and get a lot longer running time.