Battery Drain With Different Coil Sizes?

[MartinL]

It seems logical to me that larger coils would impact battery runtime hours, versus a very small coil would. Anybody measured this? Am I totally wrong in my assumptions? I know some detectors have boost power, but what does coil size have to do with standard operations while using the smallest coil, and then the largest available coil for that machine(no added boost and also with added boost on each coil size?) martin

[Fire Fighter 43]

I've never noticed a difference in battery life with different sized coils. It would be interesting to see if there is a measurable differance. My guess would be that it does not make a differance.

[Jason in Enid]

You coil is an antenna, not a light bulb. Larger spreads the signal over a wider area. That's all it does.

No change in the amount of power used.

[MartinL]

I decided to test this out. I have a rechargeable pack now in the White's V3i, and it is isolated in open air with only the low threshold tone running. The first coil is the 6x10DD. I will monitor the battery drop every hour on the hour for at least 3 hours, all set to a timer. Next, I'll install a fresh charged set of batts(same exact batteries) and pop on the 10&quot:grin:2 for the same cycle of hourly tests,,,not changing any settings, just the physical swap of the coil and the fresh battery pack.

Something just pokes at me about all that extra wiring in a large coil compared to a small coil. I know that the coil is not totally active and is an antenna, but what makes the depth field into the ground if there's not some electrical activity exerted by the coils? My momma was from Missouri so I'm one of those Show me kinda people.

Back atcha later. martin

[Bell-Two]

Let us consider the size of coils a small 6 and a larger 12 since the flow of electricity must cover more ground or the electrons in this case it seems logical that it would take more energy but the speed of electricity is 186,000 miles per second and drain cause by the larger coil would be so minute it would make no practical difference. The following is something I found that has some interesting thought.

We are told, by physicists, that electricity travels the same exact speed, through a wire, that light travels through a vacuum (the famous speed c). There are two problems with that, aren't there?

Electricity is the flow of electrons. Electrons have mass. Relativity says that things with mass cannot travel at the speed c. Only things with no mass (zero rest mass) can (and must) travel at c.

Even light cannot travel at c, when it is travelling through other substances. Light slows down, to travel through glass, water, or air. So, how can electrons travel at c, through copper?

Well, it turns out that physicists are right; electricity does travel at c. Also, electrons do not travel anywhere near c, within a wire. Electricity travels at c, while electrons do not.

When an electron enters one end of the wire, an electron leaves the other end of the wire. This effect takes place at the speed of light (c). But, they were not the same electron. A different electron exited the wire. And that clears up my two objections, above.

[MartinL]

Hysterisis and power saturation, skin effect of the added wirng length, twist patterns within those larger coils could greatly throttle down electron flow through, so the literal speed of light travel can't be held constant. With multiple frequency speeds such as the 7.5 and 22.5kHz, especially with the 3-tone detecting units, there is a lot of mode mixing in combination with the simple power saturation I mentioned before. This could be minimized if extreme quality control was maintained on the coil manufacturing, but that would probably cause the price to an average consumer to be outrageous over time.

I'm still conducting the hourly tests here, so we'll have something to reference off of by tomorrow. I decided to restart with a fresh set of hot charged batteries so all would be fair between the 6x10 and the 10 concentric coil. Besides, the V3i had a timer function set to 30 minutes for inactivity and a restart would have been more fair. I've max'd that setting to an hour now. It may take until midnight, but we'll see if there is any marginal, real-life effects due to coil sizes of the 6x10 and the 10 as the only variable.

Hey, it's a fun way to burn a cold day in December anyway ;-) martin

UPDATE: The test results backed up the insignificance of coil size. If anything, the larger coil was easier on the batteries while sitting with the quiet hum of the threshold. Either coil size will basically get 4 hours of runtime with the internal speaker. No sense in reporting the hourly voltages here.

[Zip Zip]

If i remember correctly,,,Carl at Whites said that the box part of the detector doesn't know or recognise the size of the coil that is plugged into it. It just responds to the signals from the coil. hth ,,Zip