Battery life?

I've read in many different places that using headphones saves batteries.

Can anyone tell me if this is true? Is battery drain substantially less with headphones?

I think most speakers are 8 ohms and most headphones are 32 or more ohms - does this make a difference in battery life? Does the difference in resistance affect the drain on the battery?

The setting of my volume pot seems to be about the same whether I use headphones or the onboard speaker - does this mean battery drain is the same?

And if there is a difference in battery life, how much difference? A little or a lot?

Has anyone done an actual field test and compared battery life using speaker vs. headphone?

Thanks!

---Dan Hughes, [danhughesbooks.com]

Every major manufacturer will tell you expect better battery life if you use headphones...Certainly would depend on your unit, type of batteries and headphones along with your setting as I know for sure pinpointing is a big draw along with volume and threshold settings shortening the lifespan...perhaps a call to the manufacturer can answer your multi questions..

Unless you are lowering the volume on the unit when you use headphones, your most likely not saving any battery juice.

Impedance values for piezo transducers in head phones versus external piezo or paper speaker drivers really take about the about amount of juice from the amplifier or any amplifier for that matter. I've never seen any detectors with
buffered input jacks where plugging in phones automatically attenuates volume from the amplifier. They just let impedance do the buffering. Even if they do buffer an output jack, the amp is still working just as hard to produce the required output, buffering is achieved by increasing the output impedance.

Its the higher impedance that causes the head phones to tangibly have lower perceived volume. Now keep in mind, you're putting these tiny drivers over your ears so it should seem just as loud as your external speaker. This is one of the reasons the headphones are higher impedance otherwise we'd blast our heads off with the same exact volume level of the phones vs the ext speaker.

If you want to compare an 8 ohm load v.s. the 32 ohm load on the same speaker / driver. It takes 4 times the power to produce the same decibel output (SPL) measured in db on the same amp, with 32 ohms vs 8 ohms.

If anyone leaves the volume level at the same setting on a detector and goes from
headphones to the external speaker, the current draw on the amp should be the exact same.

The reason why most manufactures state you will save battery power is that they believe most of us turn the volume down when we use phones. Even if you do turn the volume down, it would be a negligible difference in battery power savings.

Hope I didn't disappoint any of you with such a simple explanation :-)

Grant

Hmmmmmmmm............My battery life is nearly double whilst using headphones. I believe the tiny headphone speakers require less mA current draw vs. the large external speaker. I use external speaker exclusively whilst digging pits..........and headphones all other times. In any case, I have the volume at max.

Hmmm, I wonder.... nearly double you say.
Its been quite sometime since I've hunted without headphones and I never seemed to notice much of a difference when hunting without. Not to dispute your comment Tom but I'm tying to learn something here.

Maybe they are are attenuating the power on the amp and not simply buffering the signal via increased impedance of the headphones?

>>believe the tiny headphone speakers require less mA current draw vs. the large >>external speaker

Would they have built this in by design or coincidentally as you say minus the draw on the amp. Hmmmmmm This would be the only logical reasoning.
This would be 100% absolute if the speaker were paper with lower efficiency.
It would take more power to pump its volume as opposed to a more efficient pieso electric. I just don't remember if the ext speaker was paper or piezo. Either way it has to be exactly what you mentioned Tom.

Man, I'm ready to pop the hood on my 3D :-)
Tom, I sure you've had one of them open recently, is the speaker paper?

Grant

The older CZ-5's were paper. Now.....I have witnessed a FEW of the newer CZ-3D's with polyP..........and most with paper. I think this is determined by 'batch' purchase.

Paper or Polypropylene can have the same efficiency but Piezo will always be at the higher end of even the best paper / poly drivers efficiency ratings. Piezo also usually do not have an impedance load or much of one.
Its all clear now.
Anyways, guys use your head phones if you want to save battery power.
Tom schooled me on it.

Now for more interesting stuff,,,,,,,,

Anyone working on anything ?
Any good hunts ?

Grant

I use Rayovac in my F75. On a typical set of new batteries, I get from 35 to 40 hours when using headphones (Killer Bees), but without head phones it's more like 18 hours.

Hi All,, I thought I would make an educated guess on this question and make this comment even though I'm not usually very loquacious .. Metal detectors,stereos etc, are usually resistored down internally in the circuitry before the audio portion that you hear in your headphones ever reaches the headphone jack. So because of this, there is less current draw vs the internal speaker....I hope this answers your question logically.... JJ