Maximizing battery life with a motor

Hello Everyone,

I have up till now been tied into the unlimited power that comes out of a power supply, and am ready to make the jump to the untethered world of battery power. I was wondering if there are any tips or tricks to getting the most out of a battery while using it to drive a small motor.

The driver I am considering is Motor Driver 1A Dual TB6612FNG http://www.sparkfun.com/products/9457

The motor I am considering is Micro Metal Gearmotor 100:1 Micro Metal Gearmotor 100:1 (Sale) - ROB-08910 - SparkFun Electronics

I will be using a Arduino Pro Mini 328 - 5V/16MHz http://www.sparkfun.com/products/11113 to control everything.

Basically the motor and on/off button is the only thing using electronics. I know the driver has a pin that can put the driver into stand-by mode, I am looking for any other suggestions or tricks to making this motor spin for two years off of a 9-volt battery/sarcasm

Not many tricks you can use because current is current.
You could use a DC to DC converter to match the voltage to your motor to exactly what it needs, that would maximize the efficiency of your power supply chain.

Thanks Mike,

So what you're saying is that the "sleep" pin on the motor driver is basically the one and only thing that will eliminate unwanted current loss??

From a general point of view, controlled acceleration or "soft start" will save a bit of energy when you first apply power to the motor. You might also want to consider regenerative braking to feed energy back into the battery during braking or stopping. Plenty thick cables and good connections will also minimise resistive power losses in the power cables.

So what you're saying is that the "sleep" pin on the motor driver is basically the one and only thing that will eliminate unwanted current loss?

No, just don't make the motor move, that saves current.

You might also want to consider regenerative braking to feed energy back into the battery during braking or stopping.

Only if the battery is a rechargeable secondary cell.

Plenty thick cables and good connections will also minimise resistive power losses in the power cables.

You will be hard put to it to measure or see any effect.

The best way to save power would to be minimize the load on the motor. Low friction, appropriate gear ratios, minimal load, ect.

Thanks for all the replys, guys.

Here is the datasheet for the motor http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Robotics/KM-12FN20-100-06120.pdf

Under Electrical characteristics, it identifies the "On Load" characteristics (point 3.3) as having a current draw of 135 mA (point 3.3.1) and a speed of 95 RPM (3.3.2). Are these the ideal operating conditions of the motor where efficiency will be highest (except for, of course, no load)?

Are these the ideal operating conditions of the motor where efficiency will be highest

No.
Define what you mean by efficiency in this context.

Lets say that I have a set size of battery. I want to make something spin at ~90 RPM.

Should I get the motor that is geared with an "on load" speed of ~100 RPM and run it near full power/speed, or shoudl I get a motor that is geared for an "on load" speed of much higher (maybe 450 RPM), and run it with less voltage? I am assuming that it is not as easy as running the motor very slow and saving a proportional amount of battery power.

I am trying to maximize the amount of time that the battery will spin the motor at ~ 90 RPM (These RPMs are not necessarily what I am working with, I am interested in learning how this stuff is related)

In general a DC motor operates best at high speed, so gearing down a high speed motor is the best approach.
Running a motor at a lower voltage is not such a good idea, in this context.