Why Does Deep Hc Cause So Much Battery Drain?

[CPT_GhostLight]

This may be a dumb question, but I used Deep HC for the first time a few days ago and it drained the coil battery in about 3 hours and that wasn't even using Deep HC the whole time. I was mainly switching back and forth between Fast, Deep HC and Single Frequency to test the responses on different targets and it was the first time ever my coil battery went dead.

Is Deep HC increasing the voltage or current output of the coil causing the quicker battery drain? I ran the detector yesterday for 7 hours, not using Deep HC, and there was still charge left in the coil when I was done. Just curious why one program uses so much more battery power. 🤔

[Jeff McClendon]

Similar thing happens using the Beach Diving program. Those lower (larger) frequencies require more power to maintain is all I can guess. There are hints about this in the manual too. Power management must be tricky to design.....

[PimentoUK]

Best guess, based on Deus 1 coils:
The same transmit coil is used for all modes, regardless of frequency choices. So the Inductance is fixed.
Inductive reactance, XL = 2 * pi * f * L
notice it increases with frequency ... halve the freq, the reactance halves. etc.
Current through the TX coil is: I = V / XL
where V is the amplitude of the ( assumed sinewave ) transmit voltage signal.

So, if you lower the frequency of the transmit waveform, the current through the coil increases. This increases the battery drain.

XP have taken steps that mitigate some of this, by using a more complex transmit signal ( DeepHC & Dive ), that has less low-frequency component , but it's still a power-draining choice.
See this thread:
https://www.detectorprospector.com/forums/topic/18707-not-much-chat-about-multi-frequencies/?do=findComment&comment=198887

It also affects other selectable freq machines; NokMak mention it in the Impact manual, for example. No doubt the Deus1, and the Equinox run at 4 or 5kHz will be affected by it.

[Gary XP]

Slightly off topic but just as a follow up, please make sure you have the unused volumes turned off.

I found it made a difference to my battery life.

[SwiftSword]

2 hours ago, Gary XP said:

I found it made a difference to my battery life.

That should just affect the battery life of the remote, though, no? The remote lasts forever for me, it's the coil and headphones that run out for me. 

[F350Platinum]

33 minutes ago, SwiftSword said:

That should just affect the battery life of the remote, though, no? The remote lasts forever for me, it's the coil and headphones that run out for me. 

Yep. The coil is on its own using it's power up with the lower frequencies. Deep HC is the biggest drain I've seen. Don't use it much.

[Jeff McClendon]

2 hours ago, SwiftSword said:

That should just affect the battery life of the remote, though, no? The remote lasts forever for me, it's the coil and headphones that run out for me. 

I am under the impression that the processor for all functions/battery management, etc is in the coil, not the remote. So, what Gary is saying……you might want to listen to and try.

[phrunt]

This is from the Deus 1 manual, I found it interesting, for me at least running higher frequencies using it for gold nuggets I get significantly better battery life

I pity the fool that runs 4kHz with TX Boost looking for deep silvers or something, 6 hours, when looking for nuggets at 80kHz it's 25 hours, even without TX boost the 4kHz is 12 hours, under half the 80kHz.

[CPT_GhostLight]

Yep, that all makes sense. I do have all unused accessory audios at zero output as Gary suggested. The D2 Manual does say that Deep HC and Diving modes should last 8 hours, so perhaps my coil was not charged all the way. I will have to do some more testing because Deep HC was great for confirming deep coin targets. If I can get it to run 8 hours, that will do just fine.

[SwiftSword]

On a side note, I recently started favoring the Sensitive FT program. At least in my soil/find conditions, I don't appear to be losing any depth over Deep HC, and it seems to discriminate better than Deep HC (at least I feel I dig less trash). I can go out for a max of ~2hrs at a time, so battery life isn't that critical to me. 

That's purely anecdotal and non-scientific, of course.