power regulated or not?

I have an arduino running at 3.3v -- the battery is 4.7; so it is being run thru as regulated power to the board via on board regulator. (This is a low power board, so not the regular low-quality voltage regulators)

I am controlling a few things (radio (data & voice) and some LED's) that pull (in total) more than I should over an arduino pin.

Everything (other than arduino) can run off battery direct power (3.3 -> 12v).

The question is: Will I get better battery life if I regulate the power to the other devices or should I let them have the battery connected directly? (My concern is in regulating the power, will I use up more power than if I just let the device use the battery directly)

Is the regulator linear or switch-mode?

I can use either. (the regulator on the board can't be used as I would be drawing too much power)

Draw a schematic. A pencil sketch photographed with a phone is sufficient. Show us what you have. Datasheets or product pages for each of the components will also be helpful to identify the main users of power.

well that is just it... I haven't wired anything up yet.

It'd be:

battery -----> Arduino

Then I'm asking if: battery ------> Arduino | +---> RadioModule

or if battery ------> Arduino | +---> voltage regulator to 3.3v ---> RadioModule

would be better. Will the regulator use up about the same energy making the net effect of lowering the voltage negligible, so close to running direct off the battery that it doesn't matter?

The radio module can work at 3.3 and 5v w/o issue; and always draws a max of 500ma during transmission (at least thru my ammeter it draws about the same)

Radio Modules: Data module http://nicerf.com/product_view.aspx?id=10 voice module http://nicerf.com/product_view.aspx?id=98

Which Arduino? If it's a 5V one, then it won't like running on 4.7V but a 3.3V one won't like taking inputs from 4.7V devices.

There's two kinds of voltage regulators: linear and switchmode. Linear regulators will always waste power. They are not efficient under any conditions. But they are cheap and reliable. It seems like the radio module may use one of these, since it draws the same current when powered on two different voltages. The extra power that 5V/500mA provides is simply wasted in the regulator.

Switchmode regulators on the other hand are usually around 90%-98% efficient. The power output is almost the same as the power input. Very little is wasted. You can even have boost regulators which will make 5V out of a 1.2V battery, allowing you to use more of the power stored in the battery by running it down to a lower voltage.

You would probably gain some battery life by running the radio with a 3.3V switchmode regulator but is that extra battery life worth the extra cost and complexity? The simple answer is to run everything (which has an appropriate input voltage range) direct from the battery with no voltage conversion.

Thank you. Yes, the arduino is 3.3v. I appreciate your answer.